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LED light technology has been used in recent years in plant breeding due to its proven energy efficiency, low cost, and high quality for the enhancement of crops, including some aromatic medicinal plants (AMPs). Nonetheless, although several studies have shown that specific wavelengths can increase the content of bioactive compounds used by pharmaceutical, medical, and perfumery industries, there is limited information on this topic and the possible implications for plant stress in AMPs. The current systematic review focused on the effects of LED light on the physiological response, metabolite synthesis, and flowering induction in three important AMP genera: Lavandula, Salvia, and Thymus, belonging to the Lamiaceae family. A literature search was performed in the Web of Science and Scopus databases. This review is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The bibliographic analysis highlights the significant variation in physiological responses to different light spectra between species, even within the same genera, implying a need to optimize light conditions in each species to achieve the best results. Finally, this review provides essential information for laying the groundwork for future research focused on enhancing AMPs using LED light to overcome various types of stress.

Raspberry is a berry whose fruit is not tolerant to storage; breeding varieties with extended storage time and high comprehensive quality are significant for raspberries in cold regions. 1-Aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) is a limiting enzyme in the ethylene synthesis process, which plays essential roles in fruit ripening and softening in plants. In this study, the RiACS1 gene in raspberry (Rubus idaeus L.) variety ‘Polka’ was cloned. The RiACS1 gene overexpression vector was constructed and transformed into tomato plants using the Agrobacterium tumefaciens infection method to verify its function in their reproductive development. The RiACS1 gene, with a total length of 1476 bp, encoded a protein with 491 amino acids. The subcellular localization analysis of the RiACS1 protein in the tobacco transient expression system revealed that the RiACS1-GFP fusion protein was mainly located in the nucleus. Compared with the control, the flowering time and fruit color turning time of transgenic strains were advanced, and the fruit hardness was reduced. Overexpression of RiACS1 increased the activity of ACC synthase, ethylene release rate, and respiration rate during the transchromic phase. It changed the substance content, increased the content of vitamin C and anthocyanin in the fruit ripening process, and decreased the content of chlorophyll and titrable acid at the maturity stage. In addition, RiACS1 increased the relative expression levels of ethylene synthesis-related genes such as SlACS4, SlACO3, and SlACO1 in the fruit ripening process, while it decreased the expression levels of SlACS2 at the maturity stage. These results suggested that the RiACS1 gene could promote early flowering and fruit ripening in tomato plants. This study provided a basis for further modifying raspberry varieties using molecular biology techniques.

Robinia pseudoacacia L., commonly known as black locust, is a nitrogen-fixing species characterized by multiple uses. Among these uses, black locust is of special interest to beekeepers due to its abundant flowering and delicious honey. Given the great importance of honey production in Italy, beekeepers are looking for genotypes that have a delayed flowering time. As a consequence, the aim of the present study was to develop a complete protocol of micropropagation for genotypes, which have been selected in the Veneto region due to their delayed flowering, i.e., about 3 months, in comparison with the normal flowering time (from late April to early June). The subsequent steps of the micropropagation protocol (explant decontamination, shoot induction, proliferation, and rooting) were investigated and optimized. The most effective decontamination treatment of explants (axillary buds from shoots developed in a greenhouse) was obtained using 50 mg/L AgNO3 for 20 min. This method resulted in the highest survival and regeneration rates for the explants (90%), although contamination was slightly higher than when using HgCl2 and NaOCl. The best medium for shoot establishment was MS with 1 mg/L of mT, which achieved 100% regeneration of the explants. In comparison with BA, mT at 1 mg/L was shown to be the best stimulator of shoot proliferation, especially in combination with 0.7 mg/L GA3 (Proliferation Rate, 4.7). An intermediate 2 h treatment with AgNO3, in combination with mT, was shown to be beneficial in improving the shoot proliferation and quality in the subsequent subculture in a gelled medium. As for shoot rooting, the shoots that were pre-treated in NH4NO3-free and mT-free MS medium gave the highest ex vitro rooting percentage in a cell tray (80%) and the highest number of roots per shoot (3.6). This optimized protocol opens the door to the massive micropropagation of valuable genotypes of black locust selected for delayed flowering. This is an outcome of extraordinary importance for beekeepers.

In recent years, pistachio (Pistacia vera L.) cultivation is undergoing a great expansion in Spain, which is promising for regions where water and winter chilling are not limiting. Many areas of Castilla y León (Spain) provide suitable conditions for pistachio production, but heat requirement could be a limiting factor. The aims of this study were (i) to investigate the status of pistachios in Castilla y León and the relationships between phenology and agroclimatic conditions and (ii) to assess the performance of three pistachio cultivars (‘Kerman’, ‘Lost Hills’, and ‘Golden Hills’) in a plantation within this region. This work describes the phenological and productive behavior of three pistachio varieties in seven orchards over three years. The chilling requirements were exceeded, and heat accumulation was sufficient to complete the cycle in all seasons. Bloom and harvest occurred later in ‘Kerman’ than in ‘Golden Hills’ and ‘Lost Hills’. In general, ‘Kerman’ had higher nut yield than the other two cultivars but also had more non-split and blank nuts, aspects that should be considered for future plantations. Despite the interannual variability in yield, a trend to increase the production with water received was observed, but this also affected the quality and modified the splitting percentage.

In a warm winter due to climate warming, it is necessary to suppress early flowering of autumn-sown wheat plants. Here, we propose the use of cytoplasmic genome effects for this purpose. Alloplasmic lines, or cytoplasmic substitution lines, of bread wheat (Triticum aestivum) have cytoplasm from a related wild Aegilops species through recurrent backcrossing and exhibit altered characteristics compared with the euplasmic lines from which they are derived. Thus, alloplasmic lines with Aegilops mutica cytoplasm show delayed flowering compared with lines carrying normal cytoplasm. In the wheat flowering pathway, VERNALIZATION 1 (VRN1) encodes an APETALA1/FRUITFULL-like MADS box transcription factor that plays a central role in the activation of florigen genes, which induce floral meristems in the shoot apex. Here, we compared expression of VRN1 alleles in alloplasmic and euplasmic lines after vernalization. We found that alloplasmic wheat showed a lower level of VRN1 expression after vernalization compared with euplasmic wheat. Thus, nuclear-cytoplasm interactions affect the expression levels of the nuclear VRN1 gene; these interactions might occur through the pathway termed retrograde signaling. In warm winters, autumn-sown wheat cultivars with spring habit can pass through the reproductive growth phase in very early spring, resulting in a decreased tiller/ear number and reduced yield performance. Here, we present data showing that an alloplasmic line of ‘Fukusayaka’ can avoid the decrease in tiller/ear numbers during warm winters, suggesting that this alloplasmic line may be useful for development of varieties adapted to global warming.

Grapevine (Vitis vinifera) is an important and popular perennial fruit tree cultivated worldwide. Grapevine ripening is affected by flowering time, and although members of the MADS-box protein family play vital roles in regulating flowering in plants, the functions of MADS-box proteins in grapevine remain largely unknown. AGAMOUS-LIKE 11 (VvAGL11), a MADS-box gene in grapevine, was reported to be a regulator of seed morphogenesis. In this study, heterologous overexpression of VvAGL11 was found to significantly promote flowering in Arabidopsis, suggesting that its active expression in grapevine may induce early flowering and ripening. Transcriptome analysis showed that VvAGL11 overexpression affected the expression of genes involved in stress responses, hormonal signaling responses, and flowering regulation. Notably, VvAGL11 significantly increased the expression of key flowering genes such as FLOWERING LOCUS T (FT), APETALA3 (AP3), and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 5 (SPL5), which might have contributed to the early flowering in Arabidopsis. In summary, we characterized a novel flowering regulator, VvAGL11, which could be a potential target for early ripening breeding in grapevine.

PROTEIN ARGININE METHYLTRANSFERASES (PRMTs) catalyze arginine (R) methylation that is critical for transcriptional and post-transcriptional gene regulation. In Arabidopsis, PRMT5 that catalyzes symmetric R dimethylation is best characterized. PRMT5 mutants are late-flowering and show altered responses to environmental stress. Among PRMT5 targets are Arabidopsis thaliana GLYCINE RICH RNA BINDING PROTEIN 7 (AtGRP7) and AtGRP8 that promote the transition to flowering. AtGRP7 R141 has been shown to be modified by PRMT5. Here, we tested whether this symmetric dimethylation of R141 is important for AtGRP7’s physiological role in flowering time control. We constructed AtGRP7 mutant variants with non-methylable R141 (R141A, R141K). Genomic clones containing these variants complemented the late-flowering phenotype of the grp7-1 mutant to the same extent as wild-type AtGRP7. Furthermore, overexpression of AtGRP7 R141A or R141K promoted flowering similar to overexpression of the wild-type protein. Thus, flowering time does not depend on R141 and its modification. However, germination experiments showed that R141 contributes to the activity of AtGRP7 in response to abiotic stress reactions mediated by abscisic acid during early development. Immunoprecipitation of AtGRP7-GFP in the prmt5 background revealed that antibodies against dimethylated arginine still recognized AtGRP7, suggesting that additional methyltransferases may be responsible for modification of AtGRP7.

The MADS-box gene family constitutes a vital group of transcription factors that play significant roles in regulating plant growth, development, and signal transduction processes. However, research on the MADS-box genes in cassava (Manihot esculenta) has been relatively limited. To gain deeper insights into the functions of the MADS-box genes in cassava development, in this study, we undertook a comprehensive genome-wide identification of the MADS-box gene family in cassava. We identified a total of 86 MADS-box genes with complete domains in the cassava genome, designated as MeMADS01 to MeMADS86. Through bioinformatic analyses, we investigated the basic physicochemical properties, conserved motifs, chromosomal locations, and phylogenetic relationships of the cassava MADS-box genes. The MADS-box gene family of cassava exhibited conservation, as well as species-specific characteristics, with intron loss being a predominant mode of evolution for the MADS-box genes. Expression pattern variations in the MeMADS genes across different tissues offer insights into their potential functions. Time-ordered gene co-expression network (TO-GCN), transcriptome data, and RT-qPCR analysis suggested the responsiveness of the MADS-box genes to drought stress. Meanwhile, MeMADS12 might be involved in regulating flowering under drought conditions via an ABA (abscisic acid)-dependent pathway. These findings provide valuable resources for a deeper understanding of the biological roles of the MADS-box genes in cassava.

Petunia stands as the top-selling bedding plant in the U.S., and improved lighting control in greenhouses holds the potential to reduce crop production time and optimize crop quality. This study investigated the impact of four distinct daily light integral (DLI) conditions with and without supplemental far-red (FR) radiation on the growth of petunia liners and subsequent development of finish plants. Two experiments were conducted in spring (9 April to 18 June 2021) and winter (28 October 2021 to 6 January 2022). Petunia cuttings were rooted in a common environment and then transferred to four greenhouse sections with different DLI treatments: 6, 9, 12, and 15 mol·m−2·d−1 for four weeks. Within each DLI condition, half of the plants were exposed to 28 μmol·m−2·s−1 supplemental FR radiation for 16 h daily (equivalent to 1.61 mol·m−2·d−1 light integral). The number of flower buds and open flowers were tracked daily. Representative liners were destructively harvested and evaluated after four weeks of lighting treatments. The remaining plants were transplanted and moved to a common DLI condition of 15 mol·m−2·d−1 for an additional three weeks before being destructively harvested and evaluated as finish plants. The primary finding reveals the promoting effect of DLI on flowering, branching, morphology, and biomass accumulation of petunia liners, with many effects persisting into the finish stage. A threshold DLI of 9 mol·m−2·d−1 was identified, as lower DLI (6 mol·m−2·d−1) resulted in extensive stem elongation, rendering the plants unmarketable. Higher DLI levels were found to be optimal in terms of flowering and morphology. Supplemental FR accelerated flowering by up to three days in the summer experiment and up to 12 days in the winter experiment. However, FR had limited impact on the number of flower buds and open flowers, branching, and shoot and root weight of the finish plants. Interactions between DLI and FR were observed on some parameters, whereby FR effects were more pronounced under lower DLI. Overall, both higher DLI and supplemental FR exhibited beneficial effects, but DLI had a more pronounced effect. Thus, DLI during petunia liner production appears more important than adding FR. This study well simulated the commercial propagation and production of petunia plants, providing practical insights for decision-making regarding lighting strategies.

Accurate prediction of flowering times is essential for efficient orchard management for kiwifruit, facilitating timely pest and disease control and pollination interventions. In this study, we developed a predictive model for flowering time using weather data and observations of budbreak dynamics for the ‘Hayward’ and ‘Zesy002’ kiwifruit. We used historic data of untreated plants collected from 32 previous studies conducted between 2007 and 2022 and analyzed budbreak and flowering timing alongside cumulative heat sum (growing degree days, GDDs), chilling unit (CU) accumulation, and other environmental variables using weather data from the weather stations nearest to the study orchards. We trained/parameterized the model with data from 2007 to 2019, and then evaluated the model’s efficacy using testing data from 2020 to 2022. Regression models identified a hierarchical structure with the accumulation of GDDs at the start of budbreak, one of the key predictors of flowering time. The findings suggest that integrating climatic data with phenological events such as budbreak can enhance the predictability of flowering in kiwifruit vines, offering a valuable tool for kiwifruit orchard management.

Photoperiod is a pivotal regulatory factor in the flowering of Camellia oleifera Abel. (C. oleifera). GIGANTEA (GI) serves as a pivotal regulator, not only orchestrating the intricate circadian rhythm but also governing photoperiod-dependent flowering. In order to explore the function of GI in C. oleifera (CoGI), we obtained a CoGI gene-coding sequence and analyzed a CoGI protein sequence using bioinformatics. Furthermore, we conducted a spatiotemporal expression analysis of CoGI. And a yeast two-hybridization assay was used to screen the interacting proteins of CoGI. Evolutionary analysis revealed high conservation of the CoGI protein, which clustered with the GI protein from Camellia sinensis (CsGI) on a common evolutionary branch. The expression of CoGI was different in each part, and a tissue expression analysis revealed that the relative expression level of the CoGI gene is highest in the leaves of C. oleifera, while it is at its lowest in the seed coats. Transgenic Arabidopsis thaliana (Arabidopsis) overexpressing CoGI exhibited early flowering under long-day conditions. In addition, the yeast two-hybrid library screening revealed interactions between seven C. oleifera proteins and CoGI: CoACR9, CoLAO, CoDExH12-like, CoIT1K-like, CoUPF0481, CoIDM3, and CoAt4g27190-like. The findings demonstrated that CoGI is crucial to C. oleifera’s flowering.

Heat stress represents a significant environmental challenge that adversely impacts the growth, physiology, and productivity of wheat. In order to determine the response to high temperatures of the wheat varieties developed mostly in the Pannonian environmental zone, as well as varietal differences, we subjected seven varieties from Serbia, one from Australia, and one from the UK to thermal stress during anthesis and mid-grain filling and combined stress during both of these periods. The changes in chlorophyll fluorescence and index, leaf temperature, and main agronomic traits of nine winter wheat varieties were investigated under high temperatures. Heat stress negatively affected leaf temperature, chlorophyll fluorescence, and the chlorophyll index during different growth stages. Compared to the control, stress at anthesis, mid-grain filling, and combined stress resulted in yield reductions of 32%, 46%, and 59%, respectively. Single treatment at anthesis had a more severe effect on the number of grains per plant, causing a 38% reduction compared to the control. Moreover, single treatment during mid-grain filling resulted in the greatest decline in grain weight, with a 29% reduction compared to the control. There was a significant varietal variation in heat tolerance, highlighting Avangarda and NS 40s as the most tolerant varieties that should be included in regular breeding programs as valuable sources of heat tolerance. Understanding the genetic and physiological mechanisms of heat tolerance in these promising varieties should be the primary focus of future research and help develop targeted breeding strategies and agronomic practices to mitigate the adverse effects of heat stress on wheat production.

Previous studies have shown a negative correlation between chilling accumulation (CA) and heat requirements (HRs) in peaches (Prunus persica (L.) Batsch), consistent with findings in other plants in spring events. However, there is a lack of comparative research on the CA–HR relationship in peach varieties with different chilling requirements (CRs), and the specific impact of CA on HR reduction remains poorly described. To address this, we investigated the effects of CA on the days and HR for flowering in 54 peach varieties of differing CRs. Scanning electron microscopy was used to observe the effects of CA on the phenology of floral organ development in a selected peach variety. Our results indicate that, in general, peaches exhibit a reduced HR and accelerated flowering as the CA increases, but that the strength and trend of the CA–HR relationship is influenced by the CR and the variety. Low-CR varieties showed less sensitivity to CA increments, requiring higher relative increases in CA to significantly lower the HR, whereas high-CR varieties appeared to be more sensitive, with even modest changes leading to substantial reductions in HR. However, variations from this generality exist, even within varieties displaying the same rCA (the ratio of CA to CR). Additionally, we provide a summary of the relationship between the rCA and drHR in peaches of differing CRs, and identify several varieties exhibiting a strong response in the CA–HR relationship. This study also highlights the impact of CA on flower bud development, revealing slower progression under lower CA levels and accelerated growth with an increased CA. In particular, we identified the critical period of the enlargement and initiation of green scales as indicative of successful pollen grain formation. Finally, we present a schematic of the CA–HR relationship for flowering in peaches.

The reproduction of rare and endangered plant species is one of the most important factors determining the stability and survival of their populations, and knowledge of the barriers to successful reproduction is essential for species conservation. Habitat loss and slow reproduction due to low fruit set are usually considered the main threats to Cephalanthera longifolia and C. rubra (Orchidaceae). The aim of this study was to analyse the natural fruit set of these species during three consecutive years in Lithuania in the northern part of the temperate zone of Europe. Six populations of C. longifolia and three populations of C. rubra were studied each year from 2021 to 2023. During the study period, 49.3% to 54.4% of C. longifolia and 40.0% to 54.3% of C. rubra individuals produced no fruit. Over the three-year period, fruit set in individual populations of C. longifolia ranged from 5.2% to 19.5%, whereas fruit set in populations of C. rubra ranged from 4.1% to 18.8%. Significant weak or moderate correlations were found between plant height, inflorescence length and the number of flowers in the inflorescence and fruit set of both species. Flower position in the inflorescence had a significant effect on fruit set in both species, and the fruit set rate of lower flowers was higher than that of upper flowers. Significant but weak correlations were found between the fruit set and most of the environmental factors analysed. The results of this study suggest that the fruit set of C. longifolia and C. rubra is dependent on insect pollination of the flowers, which in turn is affected by habitat conditions.

The Lycoris radiata (L’ Herit.) Herb. is a perennial bulbous plant characterized by its high ornamental and medicinal value, exhibiting a unique growth rhythm where the flower and leaf do not coexist and a period of summer dormancy. However, its metabolic response to various developmental stages remains unclear. To address this gap, we conducted a non-targeted metabolomic analysis spanning six developmental stages of L. radiata. The results showed that most differentially accumulated metabolites (DAMs) demonstrated enrichment predominantly in carbohydrate and amino acid metabolism pathways, with the former being more active during vegetative growth and the latter during reproductive stages. The proportion of DAMs categorized under “quaternary ammonium salts”, “tricarboxylic acids and derivatives”, “fatty acids and conjugates”, and “pyrimidine nucleotide sugars” was notably higher in comparisons between the flowering and dormancy stages than in other comparative groups. Furthermore, DAMs involved in the KEGG pathways of C5-branched dibasic acid metabolism and lysine biosynthesis were uniquely identified during the transition from Dormancy to Flowering. The proportion of DAMs associated with “linoleic acids and derivatives” and “pyridines and pyridine derivatives” was notably higher in the leafing out versus flowering comparison than in other comparative groups. Furthermore, the glycolysis/gluconeogenesis pathway was uniquely enriched by DAMs during this phase. This study provided an in-depth view of metabolite changes in L. radiata over its annual growth cycle, enriching our understanding of the regulatory mechanisms governing its development, dormancy, and flowering.

There is evidence of the negative effects on canola seed yield caused by shading (SH) and high temperature stress (HT) separately, but the combined effect of both stresses has not been studied. This work aimed to (i) evaluate the effects of SH and HT stresses, alone and combined, on floral development, seed yield and quality, (ii) quantify the resulting effect (additive, synergistic, antagonistic) of combined stresses, and (iii) examine the utility of the photothermal quotient (PTQ, solar radiation/temperature ratio) to predict seed yield in stressed canola crops. Two field experiments were performed in Buenos Aires (Argentina) applying HT daytime temperature stress (25–30 °C from 1000 to 1500 h), SH (−80% irradiance), and SH + HT combined stresses, with C unstressed (20 °C and 100% irradiance) crops. Long and short duration SH and HT strongly affected floral development (fewer flowers and pods, with smaller ovules) and seed yield (reduction from −40 to −90% respect to C). Combined SH + HT exhibited detrimental synergistic effects on seed yield and oil concentration for long duration stresses, whereas antagonistic effects were mainly observed for short stresses. We conclude that the PTQ (cumulative from 100 to 500 °Cd after flowering) summarizes adequately the detrimental effects of combined post-flowering abiotic stresses on canola seed productivity.

Damask rose is an important essential oil crop. In the present study, plants were subjected to three different water deficit levels (70, 40, and 10% available water content) for two periods (June–October). Plant phenology, growth, essential oil yield, gas exchange features, membrane stability and major antioxidant defense elements were monitored across two years. Soil water deficit was related to quicker completion of the growth cycle (up to 7.4 d), and smaller plants (up to 49.7%). Under these conditions, biomass accumulation was jointly constrained by decreased leaf area, chlorophyll content, CO2 intake, and photosynthetic efficiency (up to 82.8, 56.9, 27.3 and 68.2%, respectively). The decrease in CO2 intake was driven by a reduction in stomatal conductance (up to 41.2%), while the decrease in leaf area was mediated by reductions in both number of leaves, and individual leaf area (up to 54.3, and 64.0%, respectively). Although the reactive oxygen species scavenging system was activated (i.e., proline accumulation, and enhanced activity of three antioxidant enzymes) by water deficit, oxidative stress symptoms were still apparent. These effects were amplified, as soil water deficit became more intense. Notably, the adverse effects of water deficit were generally less pronounced when plants had been exposed to water severity during the preceding year. Therefore, exposure to water deficit elicited plant tolerance to future exposure. This phenotypic response was further dependent on the water deficit level. At more intense soil water deficit across the preceding year, plants were less vulnerable to water deficit during the subsequent one. Therefore, our results reveal a direct link between water deficit severity and plant tolerance to future water stress challenges, providing for the first time evidence for stress memory in damask rose.

Catnip (Nepeta cataria L.) plants produce a wide array of specialized metabolites with multiple applications for human health. The productivity of such metabolites, including nepetalactones, and natural insect repellents is influenced by the conditions under which the plants are cultivated. In this study, we assessed how field-grown catnip plants, transplanted after being propagated via either single-node stem cuttings or seeds, varied regarding their phytochemical composition throughout a growing season in two distinct environmental conditions (Pittstown and Upper Deerfield) in the state of New Jersey, United States. Iridoid terpenes were quantified in plant tissues via ultra-high-performance liquid chromatography with triple quadrupole mass spectrometry (UHPLC-QqQ-MS), and phenolic compounds (phenolic acids and flavonoids) were analyzed via UHPLC with diode-array detection (UHPLC-DAD). The highest contents of total nepetalactones in Pittstown were found at 6 weeks after transplanting (WAT) for both seedlings and cuttings (1305.4 and 1223.3 mg/100 g, respectively), while in Upper Deerfield, the highest contents for both propagules were at 11 WAT (1247.7 and 997.1 mg/100 g, respectively) for seed-propagated and stem cuttings). The highest concentration of nepetalactones was associated with floral-bud to partial-flowering stages. Because plants in Pittstown accumulated considerably more biomass than plants grown in Upper Deerfield, the difference in nepetalactone production per plant was striking, with peak productivity reaching only 598.9 mg per plant in Upper Deerfield and 1833.1 mg per plant in Pittstown. Phenolic acids accumulated in higher contents towards the end of the season in both locations, after a period of low precipitation, and flavone glycosides had similar accumulation patterns to nepetalactones. In both locations, rooted stem cuttings reached their maximum nepetalactone productivity, on average, four weeks later than seed-propagated plants, suggesting that seedlings have, overall, better agronomic performance.

The oil sunflower is an important oil crop and ornamental plant. Flowering time affects the environmental adaptability and final yield of oil sunflowers. Floral induction is one of the important events that determines subsequent reproductive growth and seed setting, but there has been no systematic study on the regulation of gene expression during the transition from vegetative growth to reproductive growth in oil sunflowers. In this study, an oil sunflower mutant displaying early flowering (ef) was obtained by heavy ion beam irradiation. This mutant had a stable genetic trait, and its flowering time was 15 days earlier than the wild type (WT) in the field. The histology result showed that the ef mutant induced floral meristem at 6-leaf stage earlier than WT. The shoot apical meristems (SAMs) of the ef mutant and WT at 4-leaf, 6-leaf, 8-leaf, 10-leaf and budding periods were collected for RNA sequencing. The results showed that the transition from the leaf meristem to the floral meristem resulted in significant changes in the transcriptional landscape. Overall, 632, 1825, 4549, 5407 and 2164 differentially expressed genes (DEGs) were identified at 4-leaf, 6-leaf, 8-leaf, 10-leaf and budding periods, respectively. These DEGs were mainly enriched in biological pathways, including plant hormone signal transduction, carbon metabolism, protein processing in endoplasmic reticulum, secondary metabolism, and photosynthesis. We also found significant differences in the expression levels of starch and sucrose metabolism-related genes in the ef mutant and WT, indicating that sugar signaling plays an important role in the early flowering of oil sunflowers, especially SUC9 and sugar synthesis and degradation enzyme genes. In addition to hormone and sugar signals, flowering integration genes SOC1, AP1, FUL and LFY were upregulated in the ef mutant, and genes in photoperiod, aging, autonomous and temperature pathways were also involved in the regulation of floral transition. The results showed that plant hormones, sucrose metabolism, and flowering genes synergistically cause the early flowering of oil sunflowers. Our study provided important information for understanding flowering and is helpful for the genetic improvement of sunflowers.

In flowering Chinese cabbage, early booting is one of the most important characteristics that is linked with quality and production. Through fixed light intensity (280 μmol·m−2·s−1) and fixed intermittent lighting in flowering Chinese cabbage, there was early bolting, bud emergence, and flowering. Moreover, the aboveground fresh weight, blade area, dry weight of blade, and quantification of the leaves in flowering Chinese cabbage were significantly reduced, while the thickness of tillers, tillers height, dry weight of tillers, and tillers weight were significantly increased. The chlorophyll contents and soil–plant analysis and development (SPAD) value decreased in the early stage and increased in the later stage. The nitrate content decreased, while the photosynthetic rate, vitamin C content, soluble sugar content, soluble protein content, phenolic content, and flavonoid content increased, and mineral elements also accumulated. In order to explore the mechanism of intermittent light promoting the early bolting and flowering of ‘49d’ flowering Chinese cabbage, this study analyzed the transcriptional regulation from a global perspective using RNA sequencing. A total of 17,086 differentially expressed genes (DEGs) were obtained and 396 DEGs were selected that were closely related to early bolting. These DEGs were mainly involved in pollen wall assembly and plant circadian rhythm pathways, light action (34 DEGs), hormone biosynthesis and regulation (26 DEGs), development (21 DEGs), and carbohydrate synthesis and transport (6 DEGs). Three hub genes with the highest connectivity were identified through weighted gene co-expression network analysis (WGCNA): BrRVE, BrLHY, and BrRVE1. It is speculated that they may be involved in the intermittent light regulation of early bolting in flowering Chinese cabbage. In conclusion, intermittent light can be used as a useful tool to regulate plant growth structure, increase planting density, enhance photosynthesis, increase mineral accumulation, accelerate growth, and shorten the breeding cycle.

Phenological studies have a crucial role in the global change context. The Mediterranean basin constitutes a key study site since strong climate change impacts are expected, particularly in mountain areas such as Sierra Nevada, where we focus. Specifically, we delve into phenological changes in endemic vascular plants over time by analysing data at three scales: entire massif, altitudinal ranges, and particular species, seeking to contribute to stopping biodiversity loss. For this, we analysed 5262 samples of 2129 herbarium sheets from Sierra Nevada, dated from 1837 to 2019, including reproductive structure, complete collection date, and precise location. We found a generalized advancement in phenology at all scales, and particularly in flowering onset and flowering peak. Thus, plants flower on average 11 days earlier now than before the 1970s. Although similar trends have been confirmed for many territories and species, we address plants that have been studied little in the past regarding biotypes and distribution, and which are relevant for conservation. Thus, we analysed phenological changes in endemic plants, mostly threatened, from a crucial hotspot within the Mediterranean hotspot, which is particularly vulnerable to global warming. Our results highlight the urgency of phenological studies by species and of including ecological interactions and effects on their life cycles.

Field experiments were conducted in three successive seasons (2019–2021) to evaluate the effects of four commercial organo-mineral fertilizers with biostimulating action (Hendophyt®, Ergostim®, and Radicon®) on the vegetative and productive performance of young almond trees (Prunus dulcis, cv. Tuono) grown in a semiarid climate in Southern Italy. Foliar treatments were applied three times during each season (at the swollen bud, beginning of flowering, and fruit set-beginning of fruit growth stages). Both 2020 and 2021 were adversely affected by late frosts, resulting in damage to the flowers and small fruits without any positive effect of the biostimulant applications. In contrast, the results obtained during the normal climate year (2019) indicated that the growth of trunk diameter and shoot length of trees tended to increase in biostimulant treatments compared to those of the control. The number of buds and flowers per unit length of the branch revealed no significant differences among years and all compared treatments. However, in 2019, the fruit set percentage, number, and weight of kernels per tree were significantly higher in the biostimulant treatments compared to those of the control. To this regard, the use of biofertilizers is suitable for maintaining soil fertility and improving crop productivity This information holds significance for almond tree growers.

The prediction of floral bud progression in commercial peach cultivars promotes knowledge about the adaptability of cultivars to the climatic conditions in a specific location under a climatic variability context. Phenology is relevant to improving the scheduling of cultural practices in peach orchards. This research aimed to predict the floral bud progression of three peach cultivars: ‘Harvester’, ‘Red Globe’, and ‘Rubyprince’. Floral bud progression was assessed using one-year-old shoots collected from an orchard located at the Chilton Research and Extension Center, Alabama. Samples were evaluated under laboratory and growth chamber conditions. We recorded the flower developmental stages daily to identify the transition among stages. Daily temperature records were used to estimate the heat requirement in terms of Growing Degree Days (GDD). After dormancy release, samples needed between 23 to 39 and 37 to 42 days to reach the petal fall stage for season 1 and season 2, respectively. In terms of heat requirements, cultivars needed between 425.5 to 721.5 and 684.5 to 777 GDD to end flowering. A logistic curve was adjusted to describe the growth of the different floral stages over time. The results are key to supporting peach growers in crop management practices such as orchard establishment, irrigation, fertilization, freeze and frost protection, and pollination under climate variability scenarios.

Plant phenology reflects the reproductive responses of plants to seasonal cycles and climate change. Herbarium collections can be valuable tools for filling in gaps in phenological studies. We investigated the seasonality of the reproductive phenology of Xiquexique species using circular statistics, estimated their flowering and fruiting periods by interpolation via inverse distance weighting based on herbarium specimens (n = 290), and analyzed the relationships among phenophases, temperature, and precipitation using generalized linear models. Xiquexique species flowered and fruited throughout the year, with X. gounellei exhibiting peak flowering in February and peak fruiting in March, while X. tuberculatus exhibited those peaks in August–October and August, respectively, with decreased intensity during the austral winter. The maps produced through interpolation showed higher probabilities of flowering and fruiting between February and August at sites with mean annual rainfall rates between 500 and 800 mm. Temperature and precipitation were positively correlated with flowering. Xiquexique tuberculatus is important for providing continuous resources to pollinators and seed dispersers in the Caatinga. Herbarium collections and interpolation methods for filling in gaps concerning the reproductive ecology of Cactaceae can aid in better understanding altered phenological patterns resulting from environmental changes.

Plants experience a variety of adverse environments during their vegetative growth and reproductive development, and to ensure that they complete their life cycle successfully, they have evolved specific defense mechanisms to cope with unfavorable environments. Flowering is a vital developmental stage and an important determinant of productivity in the lifetime of plants, which can be vulnerable to multiple abiotic stresses. Exposure to stress during this period can have dramatic effects on flower physiological and morphological development, which may ultimately lead to a substantial loss of yield in seed-producing plants. However, there has been increasing research evidence that diverse abiotic stresses, ranging from drought, low temperature, and heat stress can promote or delay plant flowering. This review focuses on how plants alter developmental direction to balance between survival and productivity under drought and extreme temperature conditions. Starting from the perspective of the functional analysis of key flowering-regulated genes, it is of great help for researchers to quickly gain a deeper understanding of the regulatory effects of abiotic stress on the flowering process, to elucidate the molecular mechanisms, and to improve the regulatory network of abiotic-stress-induced flowering. Additionally, the important agronomic significance of the interaction between abiotic stress and the flowering regulation of perennial plants under climate change conditions is also discussed after summarizing studies on the mechanisms of stress-induced flowering in annual plants. This review aims to clarify the effects of abiotic stresses (mainly drought and temperature) on plant flowering, which are significant for future productivity increase under unfavorable environmental conditions.

C4 grasses coevolved with fires, employing specialized adaptive traits to recover from recurrent fires of varying regimes, thereby maintaining plant diversity and plant population stability. However, the knowledge of how C4 bunchgrasses recover from varying fire return intervals (FRIs) is limited. Biomass, tillering, flowering, and growth-related traits of Digitaria eriantha, Themeda triandra, Sporobolus fimbriatus, and Cymbopogon plurinodis were assessed in 0- (unburned), 1-, 2-, and 4-year FRIs, each applied in two 0.5 ± 0.01 ha plots from 1980–2022 at the University of Fort Hare research farm, South Africa. FRIs and grass species interacted significantly on biomass production, crown size, tiller production, and reproductive tillers, with responses varying interspecifically depending on the FRI. Cymbopogon plurinodis attained higher total biomass in 1-year FRI, whereas T. triandra produced relatively low biomass in all FRIs compared to 0-year FRI. Nonetheless, T. triandra attained nearly two to three-fold more tillers per plant and three to five-fold more reproductive tillers in 2- and 4-year FRIs compared to other FRIs. Similarly, S. fimbriatus had two-fold more reproductive tillers in 2-year FRIs compared to 0- and 1-year FRIs. We deduce that C4 bunchgrasses respond differentially under recurrent fires depending on the fire return interval, with 2- and 4-year FRIs promoting vegetative and sexual regeneration by enhancing tillering and flowering.

Non-heading Chinese cabbage (cabbage) is an essential green leafy vegetable, and bolting and flowering are necessary for reproduction. However, further research is needed to study the effect of photoperiod on the bolting and flowering of cabbage, particularly on the development of the stem. In this study, we performed phenotypic analysis and measured endogenous gibberellin levels in the cabbage. We carried out these experiments under four different photoperiodic treatments, 12 h (light)/12 h (dark), 14 h (light)/10 h (dark), 16 h (light)/8 h (dark), and 18 h (light)/6 h (dark). The results showed that the time of bolting and flowering gradually decreased with increasing light duration. The development of stems was optimal under the 16 h (light)/8 h (dark) photoperiod treatment, and the same result was obtained via cytological observation. In addition, the changes in the endogenous gibberellin3 (GA3) content under different photoperiodic treatments were consistent with the development of stems and peaked at 16 h (light)/8 h (dark). At the same time, qRT-PCR analysis showed that the relative expression of the key gibberellin synthase genes, BcGA3ox2 and BcGA20ox2, exhibited upregulation. When treated with exogenous GA3 and its synthesis inhibitor, paclobutrazol (PAC), exogenous gibberellins significantly promoted bolting; conversely, gibberellin inhibitors suppressed the bolting, flowering, and stem elongation of cabbage. Therefore, the photoperiod may regulate cabbage bolting by regulating endogenous GA3.

Trehalose, trehalose-6-phosphate synthase (TPS),and trehalose-6-phosphatase (TPP) have been reported to play important roles in plant abiotic stress and growth development. However, their functions in the flowering process of Rosa hybrida have not been characterized. In this study we found that, under a short photoperiod or weak light intensity, the content of trehalose in the shoot apical meristem of Rosa hybrida cv ‘Carola’ significantly decreased, leading to delayed flowering time. A total of nine RhTPSs and seven RhTPPs genes were identified in the genome. Cis-element analysis suggested that RhTPS and RhTPP genes were involved in plant hormones and environmental stress responses. Transcriptome data analysis reveals significant differences in the expression levels of RhTPSs and RhTPPs family genes in different tissues and indicates that RhTPPF and RhTPPJ are potential key genes involved in rose flower bud development under different light environments. The results of quantitative real-time reverse transcription (qRT-PCR) further indicate that under short photoperiod and weak light intensity all RhTPP members were significantly down-regulated. Additionally, RhTPS1a, RhTPS10, and RhTPS11 were up-regulated under a short photoperiod and showed a negative correlation with flowering time and trehalose content decrease. Under weak light intensity, RhTPS11 was up-regulated and negatively regulated flowering, while RhTPS5, RhTPS6, RhTPS7b, RhTPS9, and RhTPS10 were down-regulated and positively regulated flowering. This work lays the foundation for revealing the functions of RhTPS and RhTPP gene families in the regulation of rose trehalose.

Insect pollinators are in population decline due to environmental and chemical stressors. Including native forbs in pastures could benefit grazers and pollinators; however, their forage and flowering characteristics are not fully documented. The objectives of our research were to evaluate 12 native forbs for persistence, forage mass, nutrient composition, and flowering patterns under repeated defoliation. Twelve species were planted in a small-plot experiment in 2018. Response variables were measured from 2020 to 2022. Annual (partridge pea, PPEA, Chamaecrista fasciculata) and biennial (black-eyed Susan, BESU, Rudbeckia hirta) species established high (p < 0.05) plant populations during the first season; however, the PPEA declined (p < 0.05) in forage mass during 2021. Tall species (Maximilian sunflower, MSUN, Helianthus maximiliani; cup plant, CUPP, Silphium perfoliatum) increased in forage mass, produced high-quality forage, and flowered during early fall. Lanceleaf coreopsis (LCOR, Coreopsis lanceolata) produced consistent (p > 0.05) forage mass and flowered in spring. The purple coneflower (PURC, Echinacea purpurea), Illinois bundleflower (ILBF, Desmanthus illinoensis), and oxeye sunflower (OSUN, Helopsis helianthoides) produced high-quality, consistent (p > 0.05) forage mass and flowered mid-season. Interseeding the BESU, ILBF, PPEA, LCOR, PURC, OSUN, and MSUN or CUPP would produce high-quality forage and floral resources throughout summer.

Cut tulip flower production, typically cultivated using hydroponic systems, often faces the challenge of stem toppling due to calcium (Ca) deficiency in the nutrient solution. Growers generally grow various tulip cultivars to meet market demands. In hydroponic production, plants require precise nutrient concentrations to promote growth and development, as the food reserves in the mother bulb are insufficient and vary depending on the plant cultivar. This study aimed to assess the impact of different tulip cultivars and Ca deficiency on tulip growth, flowering, and physiological changes. Two cultivars of tulip, namely, ‘Strong Gold’ and ‘Orange Juice’, were subjected to three distinct nutrient solution treatments, namely (1) deionized water (DI) only (without any plant nutrition added), (2) complete solution (Hoagland’s complete nutrient solution), and (3) Ca deficiency solution. The results indicate that the ‘Orange Juice’ tulip was particularly susceptible to Ca deficiency, exhibiting stem toppling and flower abortion similar to those grown in DI. Ca deficiency led to a reduction in root length and leaf area but did not affect the plant height. Additionally, it had a negative impact on bulb qualities, resulting in a decreased bulb fresh weight and bulb circumference in both tulip cultivars. Furthermore, Ca deficiency and DI reduced the photosynthetic rates, and Ca deficiency increased the transpiration rate in the tulip. The leaf concentrations of nitrogen (N), phosphorus (P), and Ca were decreased under Ca deficiency and DI, while magnesium (Mg) levels increased under Ca deficiency treatment compared to the complete nutrient solution treatment.

Angelica sinensis is a “low-temperature and long-day” perennial plant that produces bioactive compounds such as phthalides, organic acids, and polysaccharides for various types of clinical agents, including those with cardio-cerebrovascular, hepatoprotective, and immunomodulatory effects. To date, the regulatory mechanism of flowering under the photoperiod has been revealed, while the regulatory network of flowering genes during vernalization, especially in the role of lncRNAs, has yet to be identified. Here, lncRNAs associated with flowering were identified based on the full-length transcriptomic analysis of A. sinensis at vernalization and freezing temperatures, and the coexpressed mRNAs of lncRNAs were validated by qRT-PCR. We obtained a total of 2327 lncRNAs after assessing the protein-coding potential of coexpressed mRNAs, with 607 lncRNAs aligned against the TAIR database of model plant Arabidopsis, 345 lncRNAs identified, and 272 lncRNAs characterized on the SwissProt database. Based on the biological functions of coexpressed mRNAs, the 272 lncRNAs were divided into six categories: (1) chromatin, DNA/RNA and protein modification; (2) flowering; (3) stress response; (4) metabolism; (5) bio-signaling; and (6) energy and transport. The differential expression levels of representatively coexpressed mRNAs were almost consistent with the flowering of A. sinensis. It can be concluded that the flowering of A. sinensis is positively or negatively regulated by lncRNAs, which provides new insights into the regulation mechanism of the flowering of A. sinensis.

Petunia (Petunia × hybrida Hort. Vilm.-Andr.) is a well-suited plant for sustainable landscape issues in borderline areas with irrigation with saline water. Salicylic acid (SA) as a modulator performs an imperative function in modulating plant salt tolerance. However, there are a few reports on the effect of SA on petunia plants irrigated with saline water. During the 2022/2023 season, a factorial pot experiment in a randomized complete block design was carried out in Riyadh, Saudi Arabia, to assess the effect of SA concentration (0, 500, 1000, 2000 mgL−1) on petunia plant growth, flowering, ion content, chlorophyll level, and proline concentration under irrigation with salty water (230, 1500, 3000 mgL−1). Saline water up to 3000 mgL−1 dramatically reduced plant growth, chlorophyll, ions, and flowering attributes, while the contrary was observed in proline and sodium concentrations as compared to the control treatments (irrigation with tap water). Foliar spraying with 1000 mgL−1 SA considerably boosted plant growth and flowering as well as chlorophyll, proline, and ion content compared to untreated plants under such salinity levels. Alternatively, the application of 1000 mgL−1 to normal or salinized water significantly decreased the Na content in non-treated plants under such a salinity level. Accordingly, using 1000 mgL−1 of SA under salt stress conditions could be a useful technique to lessen the mutilation induced by the use of salinized water in the era of climate change.

Flower bud formation in the apple tree life cycle is associated with multiple biological processes. To explore the physiological and molecular mechanisms underlying the protein and metabolite changes in buds with different flowering capabilities, axillary buds with no flowering (Ab), long-shoot buds with a low flowering rate (Lb), and spur buds with a higher flowering rate than the Lb (Sb) were analyzed using a Tandem Mass Tag™ proteomic technique in combination with nLC–MS/MS analyses. We identified 471 (88 up- and 383 down-regulated), 459 (176 up- and 283 down-regulated), and 548 (387 up- and 161 down-regulated) differentially expressed proteins in Sb vs. Lb, Sb vs. Ab, and Lb vs. Ab, respectively, that were involved in carbohydrate, amino acid and lipid transport, and metabolism. Additionally, 110 (91 increased and 19 decreased), 89 (71 increased and 18 decreased), and 99 (37 increased and 62 decreased) metabolites having significantly different levels were identified in Sb vs. Lb, Sb vs. Ab, and Lb vs. Ab, respectively. The identified metabolites were related to amino acids and their isoforms, sugars and polyols, and organic acids, and occurred at significantly greater levels in the Sbs than the other buds. Thus, flower bud formation is a complex process that involves various biochemical materials and signals, such as carbohydrates, amino acids and their isoforms, and organic acids.

Long noncoding RNAs (lncRNAs) are crucial components in regulating the flowering of plants. However, the regulatory mechanism of lncRNAs underlying salicylic acid (SA)-induced flowering remains unknown in duckweed (e.g., Lemna gibba L.), an aquatic model species with significant potential applications in agriculture and industry. In this work, L. gibba plants were collected at four crucial time points during SA-induced flowering and subjected to PacBio full-length sequencing and strand-specific RNA sequencing. A total of 474 lncRNAs were identified, of which 31 were differentially expressed and involved in SA-induced flowering. A trans-regulatory analysis found that these lncRNAs displayed temporal-specific expression trends and mainly participated in stress metabolism, photosynthesis, jasmonate metabolism, and transport under SA treatment. Five lncRNAs were determined to act as targets of miRNAs that played critical roles in regulating flowering. In addition, fifteen lncRNAs showed co-expression with flowering-related genes, and lncRNA03 and lncRNA25 were identified as key players involved in flowering via lncRNA-miRNA-mRNA interactions. Finally, twelve lncRNAs related to trans-regulation, miRNA targets, or co-expression with flowering-related genes were verified by qRT-PCR. These findings deepen our understanding of lncRNAs in SA-induced flowering in duckweed and provide valuable resources for in-depth functional analysis in the future.

This study extensively characterizes the morphological characteristics, including the leaf morphology, plant structure, flower development, and trichome features throughout the entire life cycle of Cannabis sativa L. cv. White Widow. The developmental responses to photoperiodic variations were investigated from germination to mature plant senescence. The leaf morphology showed a progression of complexity, beginning with serrations in the 1st true leaves, until the emergence of nine leaflets in the 6th true leaves, followed by a distinct shift to eight, then seven leaflets with the 14th and 15th true leaves, respectively. Thereafter, the leaf complexity decreased, culminating in the emergence of a single leaflet from the 25th node. The leaf area peaked with the 12th leaves, which coincided with a change from opposite to alternate phyllotaxy. The stipule development at nodes 5 and 6 signified the vegetative phase, followed by bract and solitary flower development emerging in nodes 7–12, signifying the reproductive phase. The subsequent induction of short-day photoperiod triggered the formation of apical inflorescence. Mature flowers displayed abundant glandular trichomes on perigonal bracts, with stigma color changing from whitish-yellow to reddish-brown. A pronounced increase in trichome density was evident, particularly on the abaxial bract surface, following the onset of flowering. The trichomes exhibited simultaneous growth in stalk length and glandular head diameter and pronounced shifts in color. Hermaphroditism occurred well after the general harvest date. This comprehensive study documents the intricate photoperiod-driven morphological changes throughout the complete lifecycle of Cannabis sativa L. cv. White Widow. The developmental responses characterized provide valuable insights for industrial and research applications.

Sugar beet is an important root crop with a biennial life cycle. In the first year of its life cycle, it produces huge amounts of leaf and root mass used for the production of sugar and bioethanol, livestock feed, confectionery and pharmaceuticals, fertilizers, and soil restoration. Normally, after exposure to cold temperatures during winter storage, in the second year of its life cycle, it enters its reproductive phase. However, during the first year of growth, sugar beet plants may be susceptible to producing flowering shoots, or “bolting”, due to vernalization and long-day conditions. Bolting reduces both the yield and the sugar content of roots. Here, we review the published research works that study the environmental factors influencing bolting, the genetic (including epigenetic) and physiological mechanisms that regulate the transition to the reproductive phase, and the agrotechnical and breeding practices used to prevent bolting. Models of gene networks that regulate the transition to flowering are presented. Methods for selecting non-bolting plants using conventional, marker-assisted, and genomic breeding are demonstrated. Attention is also paid to the speed breeding technology that stimulates bolting and flowering sugar beet plants in an artificial climate. Growing sugar beet plants “from seed to seed” can potentially accelerate the breeding and seed production of sugar beet. This review compares different conditions for inducing bolting in sugar beet in climatic chambers and greenhouses. It examines parameters such as temperature, duration of light exposure, and light intensity during the pre-vernalization, post-vernalization, and vernalization periods. The present review may be useful for specialists in sugar beet cultivation, breeders working on developing cultivars and hybrids that are resistant to bolting, and molecular biologists studying the genetic and physiological mechanisms underlying the transition of plants into the flowering stage.

Saline water is used in floriculture as an alternative to freshwater in arid regions such as Saudi Arabia (SA). However, salt stress considerably accelerates serious physio-biochemical changes associated with a decline in plant establishment. Recently, humic acid (HA) foliar spraying has induced plant stress tolerance in the era of climate change; however, its precise roles in the floriculture industry within saline conditions are not yet well documented. A factorial pot experiment throughout the 2022/2023 season was conducted in the Nursery of Sustainability and Environmental Developmental Department, King Saud University, Riyadh, SA, to evaluate the potential effects of HA (0, 500, 1000 and 2000 mg/L) on growth, flowering and some physiological characteristics of Ivy geranium (Pelargoniumpeltatum) plants irrigated with saline water (230 “control”, 2000 and 4000 mg/L NaCl). Irrigation with saline water markedly inhibited plant growth, flowering attributes, the chlorophyll index, as well as macro and micro-nutrient levels, but increased the content of iron, sodium and proline in plant shoots relative to plants irrigated with non-salinized water. However, HA mainly at 1000 mg/L significantly improved plant growth, flowering capacity, nutrient status, proline accumulation and chlorophyll index under salinized or non-salinized irrigation water. Additionally, spraying of HA concentrations (500, 1000 and 2000 mg/L) under normal or salinity conditions significantly increased shoot sodium content relative to non-treated plants under such salinity levels. Our findings highlight the significance of HA concentrations (500, 1000 and 2000 mg/L) in improving the salt tolerance of Ivy geranium. Within the scarcity of irrigation water, it is recommended to irrigate Ivy geranium with saline water up to 4000 mg/L NaCl associated with spraying HA concentrations in special 1000 mg/L.

Strawberries are a very important economic crop; thus, a lot of research has been conducted on several production areas. However, phenological performance is still lacking information, especially when it comes to modeling. Therefore, this study aims to develop a phenological model for flower–fruit development under hydroponic conditions to support growers’ decision-making. Two day-neutral cultivars, ‘Albion’ and ‘San Andreas’, were established in a drip hydroponic system in Auburn, Alabama for the 2022–2023 production season. Phenological data were collected daily on 30 flowers per cultivar for three periods (Oct 25–Dec 16, Dec 27–Feb 21, and Feb 28–Apr 16). Weather data were obtained from a weather station placed in the greenhouse. Growing degree days (GDD) accumulation was calculated for each stage and cycle using a base temperature (Tb) of 3 °C. The Gaussian model was adjusted for each stage and cycle using a non-linear procedure to obtain Gaussian curves. Simulations were made for the model assuming temperature would increase or decrease by 1 °C. Six stages were identified, and their cycle ranged from 43–56 days to be accomplished. ‘Albion’ needed more days to reach maturity, with 51, 56, and 47 days, and ‘San Andreas’ took 43, 54, and 46 days for cycles 1, 2, and 3 respectively. In addition, for cycles 1 and 2, not all the buds reached maturity, as expected. Stage 5 (fruit formation) needed more days than the rest of the stages to be completed. Because of the different starting dates for each cycle, the starting GDD was different as well. A sensitivity analysis simulation of the model showed that if temperature decreases by 1 °C, the GDD accumulated to complete the stages would be less (same dates), and it would be more if the temperature increased by 1 °C. The opposite happened with the days, if the temperature increased by 1 °C, the duration of the stage decreased, and it would increase if the temperature decreased by 1 °C, affecting stages 4, 5, and 6. Overall, ‘San Andreas’ performed better than ‘Albion’ under hydroponic conditions during three productive cycles.

One of the most important crops of the Mediterranean, watermelon (Citrullus lanatus), is almost exclusively established through seedlings. For many years, agronomists, nurseries, and farmers have aimed to produce and use high-quality seedlings for better growth in the field. However, seedling quality has not been examined as to what defines the subsequent plant, flower, and fruit development, and to what extent. Our aim was to test whether different seedling qualities labeled as “Optimum”, “Acceptable”, or “Not Acceptable” for cultivation actually perform variably in terms of vegetative, flowering, and fruit development, as well as fruit quality after a full growing cycle in the field. Vegetative growth (stem diameter, plant area, and leaf number) was evaluated until flowering and was enhanced for Optimum plants. The flowering of Not Acceptable plants started two days later, while Optimum plants retained a greater number of female flowers throughout the two-week blooming evaluation. Most importantly, Optimum plants developed mature fruits four and six days faster than the Acceptable and Not Acceptable ones, respectively, showing considerable yield earliness. The photosynthetic mechanism, as well as fruit morphology and phytochemical content, were not affected by quality categories. Overall, indeed it is important to use high-quality seedlings to achieve yield earliness of watermelon fruits.

The antioxidant defense system can be stimulated by growth regulators in plants when they are under stress, such as exposure to pathogens. There are a lot of natural growth regulators on the market, but no research has been carried out yet to determine how effective they are. This field and laboratory study examines the impact of two commonly used Russian growth regulators, Crezacin and Zircon, along with artificial infection with Fusarium culmorum on the antioxidant system of naked oat. The results show that, compared to the control, Crezacin-treated plants had higher contents of low molecular weight fructose and nonenzymatic antioxidants like proline, phenolic compounds, and flavonoids. Zircon-treated plants had a lower content of proline, carbohydrates, and lower total antioxidant activity than the control plants. The obtained data show that Crezacin treatment mainly affected nonenzymatic systems of the antioxidant defense. This treatment was more successful than the Zircon application, which did not show any appreciable effectiveness and was typically associated with an improvement in oat productivity. The treatment with growth regulators and a fungal suspension performed at the flowering phase provided the best effect on the biochemical parameters and productivity of naked oats. Moreover, oat treatment with the pathogen promoted the reproductive capabilities of the plants, while growth regulators helped in avoiding infectious stress.

Camellia oleifera Abel., which produces fruits of high comprehensive utilization value, is an important woody oil tree in China. ZEITLUPE (ZTL) is a blue light receptor and clock component protein that is involved in various physiological and biochemical processes. However, the expression pattern and function of C. oleifera ZTL (CoZTL) remain unclear. In this study, the coding sequence of the CoZTL gene was isolated and the protein function was explored using bioinformatics and expression analyses and heterologous expression techniques. The results showed that the CoZTL protein was highly conserved during evolution and was on the same branch of the evolutionary tree as the ZTL proteins from Ipomoea nil and Nicotiana attenuata. CoZTL was mainly expressed in the fruit shells and stems of C. oleifera, and its expression level fluctuated greatly during flower bud development. Transgenic CoZTL-overexpressing Arabidopsis plants showed delayed flowering under long-day conditions as well as light-dependent promotion of hypocotyl elongation. Furthermore, yeast two-hybrid library screening revealed that seven C. oleifera proteins (CoAAT, Coβ-GAL, CoLAT52-like, CoCAR4-like, CoAO, CoUQCC1, and CoADF 2) interacted with CoZTL. Our results indicate that CoZTL plays an important role in C. oleifera flowering and hypocotyl growth.

Transcriptomic and gene expression analysis have greatly facilitated the identification and characterization of transcriptional regulatory factors and effectors involved in dormancy progression and other physiological processes orchestrated during bud development in peach and other temperate fruit species. Gene expression measurements are most usually based on average values from several or many individual buds. We have performed single-bud gene analysis in flower buds of peach across dormancy release using amplicons from the master regulatory DORMANCY-ASSOCIATED MADS-BOX (DAM) factors, several jasmonic acid biosynthetic genes, other genes related to flowering development, cell growth resumption, and abiotic stress tolerance. This analysis provides a close view on gene-specific, single-bud variability throughout the developmental shift from dormant to dormancy-released stages, contributing to the characterization of putative co-expression modules and other regulatory aspects in this particular tissue.

Climate change has had a significant impact on apple phenology and fruit quality worldwide. Similarly, a decline in fruit quality has been observed in major apple-producing areas of Korea. It is predicted that the ideal cultivation areas for apples would need to shift toward higher latitudes due to these changes. Hence, the objective of this study was to assess the influence of climate change on apple cultivated in a higher-latitude region. To achieve this goal, we investigated the flowering and harvest times of apples. Additionally, we measured fruit weight, soluble solid content, and titratable acidity over a period of 20 years in a higher-latitude region in Korea. Subsequently, we examined the relationship between temperature, phenology, and fruit quality through the use of linear regression and correlation analysis methods. The 20-year meteorological data revealed a consistent rise in temperatures. Consistent with this trend, we found a significant advancement in budbreak and flowering dates for the two major apple cultivars grown in a higher latitude in Korea. Furthermore, the increase in temperatures has positively influenced fruit quality, indicating that climate change has an impact not only on phenology, but also on the quality of apples in Korea. Considering the projected gradual increase in temperature, our findings strongly support that higher-latitude regions in Korea have the potential to become optimal locations for apple cultivation.

Optimizing profitability is a challenge that strawberry farmers must face in order to remain competitive. Within this framework, plant density can play a central role. The aim of this two-year study was to investigate how planting density can induce variations in plant growth and yield performances in an alpine mountain strawberry cultivation (Martell Valley, South Tyrol, Italy), and consequently quantify the farm profit. Frigo strawberry plants cv. Elsanta were planted in soil on raised beds and subjected to five different planting density levels (30,000 and 45,000 as large spacing; 60,000 as middle spacing; 90,000 and 100,000 plants ha−1 as narrow spacing, corresponding to a plant spacing of 28, 19, 14, 9, and 8.5 cm, respectively). Our findings indicate that the aboveground biomass in plants subjected to low planting density was significantly increased by +50% (end of first year) and even doubled in the second year in comparison with plants in high planting density. Those results were related to higher leaf photosynthetic rate (+12%), and the number of crowns and flower trusses per plant (+40% both) (p < 0.05). The low yield (about 300 g plant−1) observed in the high planting density regime was attributable to smaller fruit size during the first cropping year and to both a reduced number of flowers per plant and fruit size during the second year (p < 0.05). Although the highest yield (more than 400 g plant−1) was obtained with wide plant spacing, the greatest yield per hectare was achieved with high planting densities (28 t ha−1 in comparison with 17 t ha−1 with low plant density level). However, the farm profit must take into account the costs (especially related to the plant material and harvesting costs) that are higher under the high planting density compared with the other density regimes. Indeed, the maximum farm profit was reached with a density of 45,000 plants ha−1 which corresponded to EUR 22,579 ha−1 (over 2 years). Regarding fruit quality, fruits coming from the low plant density level showed a significantly higher color index (+15% more red color) than fruits from high plant density (p < 0.05). In conclusion, our results suggest that a middle planting density can be a fair compromise in terms of plant growth, yield, and farm profit.

As spring frost proves to be an increasing risk throughout Slovenia and Europe, a better assessment of frost risk is needed. The statistical approach presented in this article consists of the conditional probability that the last spring frost occurs before budburst or flowering. The analysis was conducted using two separate phenological models and phenological data of various grapevine (Vitis vinifera L.), apple (Malus domestica), and sweet cherry (Prunus avium L.) varieties in locations across Slovenia. The increase in risk of spring frost for grapevine ranged from 1 to 1980, from 0.06 to 12 for apple, and from 1 to 180 for sweet cherry. Overall, the varieties most prone to frost proved to be Refošk (Teran) and Merlot grapevine varieties as well as the Germersdorf sweet cherry variety. We have identified the location in the hilly region with moderate climate where the Bobovec apple variety is grown as the least exposed to frost. Although counterintuitive, the GDD generally proved somewhat more efficient than the two-phase phenological model BRIN, although not in all cases. For the purpose of the study, the phenological models were calibrated, and the model parameters can serve as invaluable information for further research of this topic.

The flexibility of LED technology, in terms of energy efficiency, robustness, compactness, long lifetime, and low heat emission, as well as its applications as a sole source or supplemental lighting system, offers interesting potential, giving the ornamental industry an edge over traditional production practices. Light is a fundamental environmental factor that provides energy for plants through photosynthesis, but it also acts as a signal and coordinates multifaceted plant-growth and development processes. With manipulations of light quality affecting specific plant traits such as flowering, plant architecture, and pigmentation, the focus has been placed on the ability to precisely manage the light growing environment, proving to be an effective tool to produce tailored plants according to market request. Applying lighting technology grants growers several productive advantages, such as planned production (early flowering, continuous production, and predictable yield), improved plant habitus (rooting and height), regulated leaf and flower color, and overall improved quality attributes of commodities. Potential LED benefits to the floriculture industry are not limited to the aesthetic and economic value of the product obtained; LED technology also represents a solid, sustainable option for reducing agrochemical (plant-growth regulators and pesticides) and energy inputs (power energy).

With global warming, mean winter temperatures are predicted to increase. Therefore, understanding how warmer winters will affect the levels of olive flower induction is essential for predicting the future sustainability of olive oil production under different climactic scenarios. Here, we studied the effect of fruit load, forced drought in winter, and different winter temperature regimes on olive flower induction using several cultivars. We show the necessity of studying trees with no previous fruit load as well as provide evidence that soil water content during winter does not significantly affect the expression of an FT-encoding gene in leaves and the subsequent rate of flower induction. We collected yearly flowering data for 5 cultivars for 9 to 11 winters, altogether 48 data sets. Analyzing hourly temperatures from these winters, we made initial attempts to provide an efficient method to calculate accumulated chill units that are then correlated with the level of flower induction in olives. While the new models tested here appear to predict the positive contribution of cold temperatures, they lack in accurately predicting the reduction in cold units caused by warm temperatures occurring during winter.

Safflower (Carthamus tinctorius L.) is a highly adaptable but underutilized oilseed crop capable of growing in marginal environments, with crucial agronomical, commercial, and industrial uses. Considerable research is still needed to develop commercially relevant varieties, requiring effective, high-throughput digital phenotyping to identify key selection traits. In this study, field trials comprising a globally diverse collection of 350 safflower genotypes were conducted during 2017–2019. Crop traits assessed included phenology, grain yield, and oil quality, as well as unmanned aerial vehicle (UAV) multispectral data for estimating vegetation indices. Phenotypic traits and crop performance were highly dependent on environmental conditions, especially rainfall. High-performing genotypes had intermediate growth and phenology, with spineless genotypes performing similarly to spiked genotypes. Phenology parameters were significantly correlated to height, with significantly weak interaction with yield traits. The genotypes produced total oil content values ranging from 20.6–41.07%, oleic acid values ranging 7.57–74.5%, and linoleic acid values ranging from 17.0–83.1%. Multispectral data were used to model crop height, NDVI and EVI changes, and crop yield. NDVI data identified the start of flowering and dissected genotypes according to flowering class, growth pattern, and yield estimation. Overall, UAV-multispectral derived data are applicable to phenotyping key agronomical traits in large collections suitable for safflower breeding programs.

Hazelnuts have recently gathered tremendous attention due to the expansion of the confectionary industry. However, the sourced cultivars fail to perform in initial phase of cultivation as they enter bare survival mode due to changes in climatic zones, for example, Southern Ontario, where the climate is continental, as opposed to the milder climate in Europe and Turkey. Indoleamines have been shown to counter abiotic stress and modulate vegetative and reproductive development of plants. Here, we examined the effect of indoleamines on the flowering response of the dormant stem cuttings of sourced hazelnut cultivars in controlled environment chambers. The stem cuttings were exposed to sudden summer-like conditions (abiotic stress) and the female flower development was assessed in relation to endogenous indoleamine titers. The sourced cultivars responded well to serotonin treatment by producing more flowers compared to the controls or other treatments. The probability of buds resulting in female flowers was highest in the middle region of the stem cuttings. It is interesting to note that the tryptamine titers of the locally adapted, and N-acetyl serotonin titers of native hazelnut cultivars, provided the best explanation for adaptation to the stress environment. Titers of both compounds were compromised in the sourced cultivars which resorted mostly to serotonin concentrations to counter the stress. The indoleamines tool kit identified in this study could be deployed in assessing cultivars for stress adaptation attributes.

Timely flowering is a determinative trait for many economically valuable species in the Dendrobium genus of the Orchidaceae family, some of which are used for ornamental and medicinal purposes. D. nobile, a representative species of nobile-type Dendrobium, normally flowers in spring after exposure to sufficient low temperatures in winter. However, flowering can be stopped or disrupted by the untimely application of high temperatures. Little is known about the regulation and the mechanisms behind this switch. In this study, we report two isoforms from the KFK09_017173 locus of the D. nobile genome, named DnFCAγ and DnFCAβ, respectively, that cooperatively regulate flowering in D. nobile. These two isoforms are generated by alternative 3′ polyadenylation of DnFCA (FLOWERING CONTROL LOCUS C in D. nobile) pre-mRNA and contain a distinct 3′-terminus. Both can partially rescue late flowering in the Arabidopsis fca-1 mutant, while in wild-type Arabidopsis, they tend to delay the flowering time. When introduced into the detached axillary buds or young seedlings of D. nobile, both were able to induce the transcription of DnAGL19 (AGAMOUS LIKE 19 in D. nobile) in seedlings, whereas only DnFCAγ was able to suppress the transcription of DnAPL1 (AP1-LIKE 1 in D. nobile) in axillary buds. Furthermore, the time-course change of DnFCAγ accumulation was opposite to that of DnAPL1 in axillary buds, which was remarkable under low temperatures and within a short time after the application of high temperatures, supporting the suggestion that the expression of DnAPL1 can be inhibited by a high accumulation of DnFCAγ in floral buds. In leaves, the accumulation of DnFCAβ was in accordance with that of DnAGL19 and DnFT (FLOWERING LOCUS T in D. nobile) to a large extent, suggesting the activation of the DnAGL19–DnFT pathway by DnFCAβ. Taken together, these results suggest that the DnFCAγ–DnAPL1 pathway in axillary buds and the DnFCAβ–DnAGL19 pathway in the leaves cooperatively promote flowering under low temperatures. The long-term and constant, or untimely, application of high temperatures leads to the constitutive suppression of DnAPL1 by a high level of DnFCAγ in axillary buds, which consequently delays floral development.