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Introduction: Persian walnut (Juglans regia) is an economically important nut fruit species cultivated worldwide for its nutritious kernel and timber quality wood. Walnut trees are mostly hetero-dichogamous and, depending on the genotype, some cultivars are protogynous, while others are protandrous. Although selfing is possible when male and female blooms overlap, the dichogamy of the species promotes outcrossing. In addition to sexual reproduction, some reports indicate that elements of apomixis may occur in commercial orchards of walnut varieties and in the last two decades, nut production by apomixis has been reported in walnut. However, there are no reliable studies on the occurrence of apomictic reproduction based on cytoembryological observations and/or molecular marker-progeny tests. This study addresses the combined use of molecular and cytological analyses to gain new insights into the population genetics and reproduction systems of J. regia. Methods: We systematically analyzed the reproductive origin of individual progeny plants from 8 different cultivated walnut genotypes using microsatellite genotyping and carried out cytohistological investigations of 5 cultivated walnut genotypes arising seed sets from isolated flowers, to shed light on the mode of reproduction. Results and discussion: These cytometric and genotyping analyses did not support any asexual mode of reproduction or asexual propagation by seed and all individuals studied were identified as zygotic plants produced by crossing. Likewise, the cytological findings did not confirm completely the first component of apomixis, namely apomeiosis. On the other hand, according to histological evidence, adventitious embryony seems to take place at low frequency. Overall, our findings suggest that the occurrence of gametophytic apomixis is unlikely in J. regia, but sporophytic apomixis cannot be completely ruled out. [ABSTRACT FROM AUTHOR]

The increment in global temperature reduces crop productivity, which in turn threatens food security. Currently, most of our food supply is produced by plants and the human population is estimated to reach 9 billion by 2050. Gaining insights into how plants navigate heat stress in their reproductive phase is essential for effectively overseeing the future of agricultural productivity. The reproductive success of numerous plant species can be jeopardized by just one exceptionally hot day. While the effects of heat stress on seedlings germination and root development have been extensively investigated, studies on reproduction are limited. The intricate processes of gamete development and fertilization unfold within a brief timeframe, largely concealed within the flower. Nonetheless, heat stress is known to have important effects on reproduction. Considering that heat stress typically affects both male and female reproductive structures concurrently, it remains crucial to identify cultivars with thermotolerance. In such cultivars, ovules and pollen can successfully undergo development despite the challenges posed by heat stress, enabling the completion of the fertilization process and resulting in a robust seed yield. Hereby, we review the current understanding of the molecular mechanisms underlying plant resistance to abiotic heat stress, focusing on the reproductive process in the model systems of Arabidopsis and Oryza sativa. [ABSTRACT FROM AUTHOR]

Urbanization is changing the conditions in which many species live, forcing them to adjust to these novel environments. Floral size and shape are critical traits for the reproduction of plants pollinated by animals as they are involved in the attraction of pollinators and in efficient pollination. Variation in size and shape could be affected by urbanization via its modification of the abiotic environment (habitat fragmentation, water availability, temperature, soil properties), or via its impact on the biotic environment of plants (pollination, herbivory). Although numerous studies have assessed the impact of urbanization on pollinator communities and many plant traits, few have investigated its impact on floral size and shape while quantifying the proportion of the total urbanization effect that is due to biotic interactions. In this study, we tested if urbanization and pollinator visitation rates affect the flower shape of the spotted jewelweed, Impatiens capensis. We quantified the size and shape of flowers in frontal and profile views using geometric morphometrics for 228 individuals from six populations from the region of Montreal, Canada. Pollinator visitation rates were estimated at each site and the main pollinators were found to be bumblebees, honeybees and hummingbirds. We found that floral size and shape are significantly correlated with urbanization as measured by the amount of vegetation in the surrounding environment of the plants (mean normalized vegetation index, NDVI) and by the visitation rates of bumblebees and honey bees. Partitioning of the total flower shape variation suggests that urbanization affects flower shape through abiotic factors and via its impact on pollinator visitation rates. While further studies from other cities are necessary to confirm the role of urbanization in shaping the floral shape of I. capensis, these results support the idea that urbanization could affect flower shapes. [ABSTRACT FROM AUTHOR]

The ability of temperate forest herbaceous species to recover from anthropogenic disturbance and to colonize new secondary woods is limited by both seed shortage (lack of dispersal) and suitable safe sites (sites where seedling establishment is possible). In this study, which originated in 1998–99, I added seeds of 14 species, including six phylogenetically related pairs classified as common or restricted in distribution, to both occupied and unoccupied upland forest sites. I recorded emergence the first year and followed yearly survival for an additional five years. Adding seeds resulted in flowering individuals for 12 of the 14 species and an additional species established by vegetative spread. I concluded that dispersal, rather than safe sites, was most limiting. Species with restricted distributions, which also have larger seeds than related common species, had higher survivorship over five years. Minimum longevity ranged from 8–18 years, suggesting that once on site, long-term persistence is possible. A practical implication of these results is that limited funding and other resources can be focused on seed addition techniques, particularly for larger-seeded species. Because the mean age to first flowering was six years, a second practical implication is that the traditional monitoring protocol of following plants through to reproduction as a measure of restoration success may be difficult for many long-lived species. Using "citizen scientists" to monitor may help make long-term monitoring more feasible beyond the limited time frame of grant funding. [ABSTRACT FROM AUTHOR]

Pollen, as the male gametophyte of plants, plays a critical role in plant sexual reproduction. Investigating pollen-specific promoters not only helps to understand the regulatory mechanisms of pollen development but also provides tissue-specific promoters for plant genetic engineering. Previously, wheat promoter PSG076 was found to confer pollen-specific activity in tobacco. To determine the tissue-specific activity of PSG076 in wheat, a 1.4-kb promoter fragment was fused with the β-glucuronidase (GUS) reporter gene and stably introduced into wheat via particle bombardment. Histochemical analysis in T1 progeny plants showed that the activity of PSG076 promoter was detected specifically in mature pollen and pollen tube. No GUS activity was found in other floral and vegetable tissues. Weak GUS staining was also visible in pollen at 45 days post anthesis (DPA). Further analysis showed that GUS activity was found weakly in middle tricellular pollen grains and increased rapidly as pollen matured. These results indicated that PSG076 promoter has strong activity specifically at late pollen development stage and can be utilized in genetic engineering investigations for creating male sterility in wheat and other plant species for hybrid seed production. [ABSTRACT FROM AUTHOR]

The salt marsh bird’s beak (Chloropyron maritimum subsp. maritimum) is an endangered plant thought to be dependent on large-bodied pollinators for effective pollination and reproduction. Thirty-three years after an initial survey (Lincoln 1985), we returned to the Naval Base Ventura County, California, to repeat surveys and quantify changes in the C. maritimum subsp. maritimum pollinator community. We found similar pollinator abundance, richness, and nesting preference in both years. However, in terms of pollinator composition, we found significantly different communities—those found in 2017 being composed of pollinators with significantly smaller bodies (i.e., shorter intertegula distances [mm]) than those found in 1984. We hypothesize that changes in pollinator size are the result of differential persistence of the pollinator community and may have significant effects on the rare plant’s reproduction. While ramifications could be substantial, anecdotal evidence suggests that smaller-bodied bees may also serve as adequate pollinators of C. maritimum subsp. maritimum. Future work will quantify changes in reproductive output. [ABSTRACT FROM AUTHOR]

SUMMARY: Success in plant reproduction is highly dependent on the correct timing of the floral transition, which is tightly regulated by the flowering pathways. In the model plant Arabidopsis thaliana, the central flowering repressor FLOWERING LOCUS C (FLC) is precisely regulated by multiple flowering time regulators in the vernalization pathway and autonomous pathway, including FPA. Here we report that Arabidopsis MEDIATOR SUBUNIT 8 (MED8) promotes floral transition in Arabidopsis by recruiting FPA to the FLC locus to repress FLC expression. Loss of MED8 function leads to a significant late‐flowering phenotype due to increased FLC expression. We further show that MED8 directly interacts with FPA in the nucleus and recruits FPA to the FLC locus. Moreover, MED8 is indispensable for FPA's function in controlling flowering time and regulating FLC expression. Our study thus reveals a flowering mechanism by which the Mediator subunit MED8 represses FLC expression by facilitating the binding of FPA to the FLC locus to ensure appropriate timing of flowering for reproductive success. Significance Statement: Initiation of flowering at the appropriate time is a fundamental trait in the life cycle of plants that have evolved to maximize plant reproductive success in various environmental conditions. We revealed that MED8 directly interacts with FPA in the nucleus and recruits FPA to the FLC locus to mediate FLC expression, thereby regulating flowering time. [ABSTRACT FROM AUTHOR]

The success of plant reproduction is highly dependent on effective seed dispersal. This study aimed to evaluate the potential seed dispersal effectiveness of cattle for Malus sieversii. The impact of cattle on the dispersal quantity and dispersal quality of M. sieversii seeds was explored based on camera trapping, GPS tracking, and germination trials. The results showed that, on average, cattle visited M. sieversii trees 477.33 times during a two-month observation period. Out of these visits, 315 were specifically for fruit removal. The fruit removal rate per cattle visit was as high as 96.67%. Additionally, cattle were able to disperse M. sieversii seeds up to a maximum distance of 533.67 m, with an average dispersal distance of 134.62 m. The average distance of cattle movement was recorded as 176.95 m/h, with peak activity observed during 11:00–13:00 and 19:00–21:00. The germination rate of M. sieversii seeds that passed through the digestive tract of cattle was significantly higher than that of control seeds. Finally, the emergence rate and survival rate of seeds dispersed by cattle to forest edges and gaps were significantly higher than those dispersed to understory. These findings suggest that cattle can serve as effective long-distance dispersers of M. sieversii seeds and may play a crucial role in the regeneration and expansion of M. sieversii populations in the Ili Botanical Garden. [ABSTRACT FROM AUTHOR]

Pollination and seed dispersal are crucial processes for plant reproduction, sharing ecological relevance and similarities, yet they have rarely been considered together. Flowers appear to express greater phenotypic diversity than fruits due to multiple confounding factors, which pose challenges for comparative analyses. The colours of flowers and fruits are important visual signal traits in pollination and seed dispersal, evolving under different selective pressures from their respective pollinators and seed dispersers. Birds constitute a unique plant‐interacting group that participates in both pollination and seed dispersal events. In this study, we focus on red flowers and red fruits associated with avian mutualists to gain insight into the intrinsic differences between flowers/pollination and fruits/seed dispersal.We conducted comparisons of colouration between 94 red flowers pollinated by birds and 99 red fruits dispersed by birds. The colour diversity was compared in both the spectral space and the avian colour vision spaces. Colour conspicuousness was analysed using avian colour vision models, as well as bee models. Pigeon colour preference was tested by controlled experiments utilizing red stimuli with and without secondary peaks at short wavelengths.Red fruits had lower colour diversity than red flowers, with redder hues and fewer secondary reflectance peaks. Avian colour vision models illustrated that fruits were more conspicuous than flowers achromatically, but not chromatically. Pigeons did not show preference for red with or without a secondary peak.Although both are red, there are significant differences between flowers and fruits in terms of colour diversity, spectral properties and colour perceptions. As we exclusively considered avian mutualists, these differences cannot be attributed to the differences in interacting animal groups or to their colour vision properties. This implies that the differences in evolutionary history between flowers and fruits may deserve further attention to understand the colour evolution. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Landscape disturbance frequently results in reduced pollination and reproduction of animal‐pollinated plants. However, few studies globally, and no studies in Australia, have focused on the impact(s) on plants with nocturnal moth pollinators. This study measured natural levels of reproduction of the common, nocturnally moth‐pollinated plant Stackhousia aspericocca Schuch. ssp. Cylindrical inflorescence (W.R.Barker 1418) (Celastraceae) across a range of reserves of varying sizes within a fragmented landscape of southern Australia. We hypothesized that plant reproduction would show a positive relationship with reserve area. Nocturnal pollinator surveys confirmed that night‐flying settling moths of the families Geometridae and Noctuidae visited flowers of S. aspericocca ssp. Cylindrical inflorescence in the study region, and 8 out of 16 captured, flower‐visiting moths carried more than 100 pollen grains of the study species (overall mean ± SD: 616.69 ± 1155.70). Two individuals of the common geometrid moth Oenochroma vinaria each carried over 3000 pollen grains. Thus, visiting moths may remove and carry large amounts of pollen. In contrast to our initial hypothesis, however, plant reproduction, measured as proportional fruit‐set and mean seed number per fruit, showed no relation to reserve area across two consecutive years, and mean levels of plant reproduction were spatially similar throughout the fragmented landscape of the study region. It is hypothesized that the reproductive resilience of S. aspericocca ssp. Cylindrical inflorescence in the study region is due to effective pollination by common, night‐flying moths, which may utilize both the reserves and their surrounding matrix to complete their life cycle(s). [ABSTRACT FROM AUTHOR]

Although flower temperature plays an important role in plant reproduction, how it varies spatially on the flower surface is unclear, especially in alpine plants. To characterize spatial variation in flower surface temperature, we examined thermal images of flowers of 18 species along an altitudinal transect from 3200 to 4000 m on Lenglong Mountain on the north-eastern Qinghai-Tibetan Plateau. The surface temperature varied considerably within a flower or floral unit in all plants under sunlight, and was about 1 °C with a maximum of 11 °C higher in the center than at the edges. Solar radiation and flower shape significantly affected the temperature range and standard deviation and the ratio of flower center to edge temperature. The spatial variability of temperature increased with flower size. Flowers in the Asteraceae had higher surface temperatures, greater spatial variability of temperature, and consistently higher and more stable temperatures in the center than at the edge. The ratio of flower center to edge temperature increased with altitude in most species. Heat buildup at the flower center is likely to be widespread in alpine plants; further studies are needed to explore its ecological and evolutional roles. [ABSTRACT FROM AUTHOR]

Alsophila spinulosa (Wall. ex Hook) Tryon is one of the few remaining tree ferns on Earth. As a living Mesozoic fern fossil, it has great significance for studies on paleo-climate and paleo-environmental changes. A. spinulosa also has considerable ornamental and medicinal value. This study assessed in vitro spore germination, gametophyte development and sporophyte regeneration in A. spinulosa and established efficient protocols for gametophyte proliferation, callus induction and regeneration from sporophytes. The effects of several plant growth regulators (PGRs) and their concentrations on gametophyte development and sporophyte formation were also investigated. No morphological variations were observed on PGR-free Murashige and Skoog (MS) medium although the presence of PGRs in MS medium induced some variations during the development stages of filaments and prothallia. When filaments formed on the surface of each prothallium, prothallia could be proliferated. Highest prothallium proliferation coefficient (PPC) was 6.6 within 30 days on MS medium with 1.0 mg L−1 6-benzyladenine. Sporophytes readily formed roots on PGR-free MS medium or in MS medium with 0.2–1.0 mg L−1 indole-3-butyric acid and/or α-naphthaleneacetic acid, with a minimal 93% rooting. After young rooted sporophytes were transferred to a vermiculite and peat substrate, survival percentage was 92.7% within one month (and 88.7% after two months). Callus was successfully induced and adventitious shoots formation from sporophyte base on MS medium with 0.2 mg L−1 2,4-dichlorophenoxyacetic acid and 0.5 mg L−1 thidiazuron. Each callus cluster could differentiate into mean 13.6 sporophytes. [ABSTRACT FROM AUTHOR]

The in vitro growth of the pollen tube (PT), an object of comprehensive and intensive research, is a model for studying the mechanisms of sexual reproduction in higher plants. We have studied the potential role of reactive oxygen species (ROS) in the in vitro germination and growth maintenance of the petunia (Petunia hybrida E. Vilm.) male gametophyte. The exogenous treatment with H2O2 influences the PT germination and polar growth in vitro. The addition of H2O2 to culture medium increases both the percentage of pollen grain germination and the PT length in the case of long cultivation, but inhibits both processes during the first hour of cultivation. This suggests that endogenous ROS play a decisive role in the early stages of pollen germination, with the sensitivity to endogenous ROS emerging later over the course of their growth. The addition of diphenylene iodonium chloride (DPI), a NADPH oxidase inhibitor, considerably decreases both the germination and the growth of the petunia male gametophyte at low concentrations (0.1 μM), and completely arrests the growth at high concentrations (1 μM). ROS are necessary for polar growth of the petunia male gametophyte; they are secreted in the early stages of pollen grain activation and are further localized to the initiation of the PT, mainly in the PT apical part, during polar growth, as confirmed with the help of intravital fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Lisianthus has long-lasting, white, blue-purple, velvet or pink flowers. Varieties that can be used in pots, outdoors, or cut flowers are widely used and it is essential to develop new varieties to increase their commercial value. Breeding studies with classical methods can take a long time in lisianthus. Techniques to create variation in these plants and facilitate their reproduction always contribute to shortening the breeding period and one of the best known of these methods is plant tissue culture. This study aimed to investigate the micropropagation possibilities in lisianthus and examine the effects of auxin and cytokinin applications and doses on shoot reproduction. Supplemented with 10 different plant growth regulators in Murashige and Skoog (MS) medium, leaf explants from lisianthus plants that were germinated under in vitro conditions (seedlings) were cultivated. 6-benzyl aminopurine (BAP) was utilized in 5 doses (0.5, 1.0, 2.0, 3.0, and 4.0 mg L-1 ) alone in the first 5 groups. Naphthalene acetic acid (NAA) was also added to the BAP mediums at a concentration of 0.5 mg L-1. Shoot formation, shoot lengths, the number of shoots longer and shorter than 1 cm, and regeneration of new shoots after subcultures were determined. According to the results, MS mediums containing 3.0 and 4.0 mg L-1 BAP could be good starting mediums for regenerating new lisianthus shoots from leaf explants. These treatments got the highest values both in shoot formation and the number of shoots longer than 1 cm. It has been determined that 3.0 mg L-1 BAP alone can be used for both organogenesis from leaf explants and shoot proliferation in single node culture. In vitro shoots of the lisianthus species were easily rooted and both PGR-free MS or ½ MS mediums. Lisianthus shoots propagated under in vitro conditions can be rooted under ex vitro conditions both in the float hydroculture and in the soil mixture. The acclimatization stage was optimized also successfully. [ABSTRACT FROM AUTHOR]

This study aims to determine the effect of a concentration of 2,4-D added to the Murhasige and Skoog (MS) basic media on porang callus induction and the effect on various explant sources. The study was conducted in the form of experiments in the Laboratory of Bioscience and Plant Reproduction Biotechnology, Department of Agriculture, Faculty of Agriculture, Hasanuddin University from August to December 2021. The experiments were based on a Completely Randomized Design (CRD) pattern arranged in a factorial way with two treatment factors. The first factor was the concentration of 2,4-D consisting of five levels of treatment: without 2,4-D (0.0 mg L-1), 0.5 mg L-1, 1.0 mg L-1, 1.5 mg L-1, and 2.0 mg L-1. The second factor was the source of explants consisting of three levels: the petiole, leaf midrib, and leaf blade. The results after five months showed that the interaction between the concentration of 2.0 mg L-1 2,4-D with the petiole explants had the best effect on callus induction time (12.25 days) and callus weight (2.97 g). The concentration of 2.0 mg L-1 2,4-D had the best influence on the callus induction percentage (83.33%), and petiole-derived explants had the best influence on the callus induction percentage (91.67%). Administration of 2,4-D at a concentration of 2.0 mg L-1 and the petiole-derived explant gave the best results in this study; therefore, it is expected to be applied to the development of porang plant seeds in vitro. [ABSTRACT FROM AUTHOR]

Transcription factor IIB (TFIIB) is a general transcription factor for RNA polymerase II, exerting its influence across various biological contexts. In the majority of eukaryotes, TFIIB typically has two homologs, serving as general transcription factors for RNA polymerase I and III. In plants, however, the TFIIB-related protein family has expanded greatly, with 14 and 9 members in Arabidopsis and rice, respectively. BRP5/pollen-expressed transcription factor 2 (PTF2) proteins belong to a subfamily of TFIIB-related proteins found only in plants and algae. The prior analysis of an Arabidopsis atbrp5 mutant, characterized by a T-DNA insertion at the 5′ untranslated region, demonstrated the essential role of BRP5/PTF2 during the process of pollen germination and embryogenesis in Arabidopsis. Using a rice transformation system based on CRISPR/Cas9 technology, we have generated transgenic rice plants containing loss-of-function frameshift mutations in the BRP5/PTF2 gene. Unlike in the Arabidopsis atbrp5 mutant, the brp5/ptf2 frameshift mutations were not transmitted to progeny in rice, indicating an essential role of BRP5/PTF2 in both male and female gamete development or viability. The silencing of rice BRP5/PTF2 expression through RNA interference (RNAi) had little effect on vegetative growth and panicle formation but strongly affected pollen development and grain formation. Genetic analysis revealed that strong RNAi silencing of rice BRP5/PTF2 was still transmissible to progeny almost exclusively through female gametes, as found in the Arabidopsis atbrp5 knockdown mutant. Thus, reduced rice BRP5/PTF2 expression impacted pollen preferentially by interfering with male gamete development or viability. Drawing upon these findings, we posit that BRP5/PTF2 assumes a distinct and imperative function in the realm of plant sexual reproduction. [ABSTRACT FROM AUTHOR]

Background and Aims It has been demonstrated that nitrogen (N) addition alters flower morphology, floral rewards and pollinator performance. However, little is known about the effects of N addition on plant reproduction, including fruit set and seed set during selfing and outcrossing, floral and vegetative traits, and pollinator performance. We hypothesized that N addition would influence fruit set, seed set in selfed and outcrossed flowers, the relationship between vegetative and flower traits, and pollinator performance. Methods A 2-year pot experiment was conducted in which Capsicum annuum was exposed to three levels of relatively short-term N supply, i.e. 0 g m–2 (no N addition, as a control), 4 g m–2 (4N) and 16 g m–2 (16N), which are equivalent to about 0-, 1- and 4-fold of the peak local N deposition. We measured flower rewards, flower morphology, flowering phenology, as well as pollinator visitation rate, fruit set and seed set by self- and outcross-fertilization of C. annuum. Results The four levels of N addition increased plant biomass, biomass allocation to flowers, flower size, stigma–anther separation, nectar production and pollen production, resulting in an increase in pollinator visitation and fruit set. Nevertheless, the control and 16 levels of N addition reduced plant biomass, biomass allocation to flowers, flower size and stigma–anther separation, and nectar and pollen production, and consequently decreased pollinator visitation and fruit set. Exclusion of pollinators and hand-pollination experiments revealed that low levels of N addition were associated with high seed set in outcrossed flowers; however, this trend was reversed in flowers grown in the control and 16N treatments. Conclusion Our results suggest that an optimal level of 4N can enhance the correlation between flower traits, pollinator performance and plant reproduction. Our findings cast new light on the underlying mechanisms of plant–pollinator interactions and plant adaptation to nitrogen deposition. [ABSTRACT FROM AUTHOR]

Kinetic tensiometric dependences and isotherms of wetting leaves of the Prime potato were obtained for aqueous solutions and submicron dispersions of nonmicelle-forming surfactants (Tween 85, Brij L4, and Silwet L-77). A technique has been developed for determining the rate of penetration of the studied liquids into potato leaves. The penetration rate increases with increasing surfactant concentration. The permeability and wetting efficiency increase in the following row: Tween 85 < Brij L4 < Silwet L-77. The data obtained make it possible to evaluate the prospects for using the studied aqueous surfactant dispersions as platforms for the delivery of biologically active components into the leaves of potato plants to inhibit the reproduction of pathogens. [ABSTRACT FROM AUTHOR]

Summary: Germline development is a key step in sexual reproduction. Sexual plant reproduction begins with the formation of haploid spores by meiosis of megaspore mother cells (MMCs). Although many evidences, directly or indirectly, show that epigenetics plays an important role in MMC specification, how it controls the commitment of the MMC to downstream stages of germline development is still unclear.Electrophoretic mobility shift assay (EMSA), western blot, immunofluorescence, and chromatin immunoprecipitation coupled with quantitative PCR analyses were performed. Genetic interactions between BZR1 transcription factor family and the SWR1‐SDG2‐ER pathway in the control of female germline development were further studied.The present findings showed in Arabidopsis that two epigenetic factors, the chromatin remodeling complex SWI2/SNF2‐RELATED 1 (SWR1) and a writer for H3K4me3 histone modification SET DOMAIN GROUP 2 (SDG2), genetically interact with the ERECTA (ER) receptor kinase signaling pathway and regulate female germline development by restricting the MMC cell fate to a single cell in the ovule primordium and ensure that only that single cell undergoes meiosis and subsequent megaspore degeneration. We also showed that SWR1‐SDG2‐ER signaling module regulates female germline development by promoting the protein accumulation of BZR1 transcription factor family on the promoters of primary miRNA processing factors, HYPONASTIC LEAVES 1 (HYL1), DICER‐LIKE 1 (DCL1), and SERRATE (SE) to activate their expression.Our study elucidated a Gene Regulation Network that provides new insights for understanding how epigenetic factors and receptor kinase signaling pathways function in concert to control female germline development in Arabidopsis. [ABSTRACT FROM AUTHOR]

Vinasse is not only effectively used in pest control but also creates a conducive environment for the growth of antagonistic microorganisms. Thus, this study aimed to evaluate the potential of vinasse applied via soil for the management of root-knot nematodes in soybean culture. The experimental design was entirely random, in a factorial scheme (2 × 6), consisting of two species of nematodes, Meloidogyne incognita and M. javanica, under vinasse application at five concentrations (20, 40, 60, 80, and 100%) and one control (water), with five repetitions. Soybean plants Intacta cv. M-Soy 8644 IPRO were inoculated with 4000 eggs/juveniles of each species separately. At 60 days after the first application of vinasse, evaluations of parasitism and agronomic characteristics in soybean were performed. Stillage resulted in the highest average values for root volume and root fresh mass in plants inoculated with M. incognita, showing respective increases of 24.33% and 14.92% compared to plants inoculated with M. javanica. However, concentrations exceeding 60% had a detrimental effect on all agronomic variables of soybean. For parasitism, an interaction among the factors was observed, with a significant effect (p < 0.01) for most of the evaluated variables, except for the number of eggs in the soil. The concentration equivalent to 60% vinasse promoted a sharp reduction in parasitism for the two nematode species, making reproduction on plant roots unfeasible. [ABSTRACT FROM AUTHOR]

The evolution and diversification of proteins capable of remodeling domains has been critical for transcriptional reprogramming during cell fate determination in multicellular eukaryotes. Chromatin remodeling proteins of the CHD3 family have been shown to have important and antagonistic impacts on seed development in the model plant, Arabidopsis thaliana , yet the basis of this functional divergence remains unknown. In this study, we demonstrate that genes encoding the CHD3 proteins PICKLE (PKL) and PICKLE-RELATED 2 (PKR2) originated from a duplication event during the diversification of crown Brassicaceae, and that these homologs have undergone distinct evolutionary trajectories since this duplication, with PKR2 fast evolving under positive selection, while PKL is subject to purifying selection. We find that the rapid evolution of PKR2 under positive selection reduces the encoded protein's intrinsic disorder, possibly suggesting a tertiary structure configuration which differs from that of PKL. Our whole genome transcriptome analysis in seeds of pkr2 and pkl mutants reveals that they act antagonistically on the expression of specific sets of genes, providing a basis for their differing roles in seed development. Our results provide insights into how gene duplication and neofunctionalization can lead to differing and antagonistic selective pressures on transcriptomes during plant reproduction, as well as on the evolutionary diversification of the CHD3 family within seed plants. [ABSTRACT FROM AUTHOR]

We encountered unexpected transgene silencing in Arabidopsis thaliana sperm cells; transgenes encoding proteins with no specific intracellular localization (cytoplasmic proteins) were silenced transcriptionally or posttranscriptionally. The mRNA of cytoplasmic protein transgenes tagged with a fluorescent protein gene was significantly reduced, resulting in undetectable fluorescent protein signals in the sperm cell. Silencing of the cytoplasmic protein transgenes in the sperm cell did not affect the expression of either its endogenous homologous genes or cotransformed transgenes encoding a protein with targeted intracellular localization. This transgene silencing in the sperm cell persisted in mutants of the major gene silencing machinery including DNA methylation. The incomprehensible, yet real, transgene silencing phenotypes occurring in the sperm cell could mislead the interpretation of experimental results in plant reproduction, and this Commentary calls attention to that risk and highlights details of this novel cytoplasmic protein transgene silencing. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: A diversity of values is needed to maximize the effectiveness of conservation planning, including policies and programs. The results of the United Nations Biodiversity Conference (COP 15) in Montreal, Canada, highlight the importance of a shift towards recognizing multiple ways of knowing in ecology and conservation. This review aims to provide a baseline of what is known about culturally significant plants in the Great Lakes Region of Eastern North America. The results of this research provide insight into the ways in which ecology has been conducted in the past and the importance of changing the way ecology is conducted in the future. Summary: Biocultural conservation theory allows for an examination of complex problems using systems thinking and conserving biological and cultural diversity together. In the Great Lakes Region of Eastern North America, wild medicine plants are an important part of what Anishinaabe people understand as Mini bimaadizi, or the good life, and of aki miijim, or traditional food systems. Given the various threats facing wild plant populations and continued global change, this review aims to investigate what is known about the pollination and breeding systems of culturally significant plants in the Great Lakes Region. The overall goal is to determine what proportion of these plants have had basic ecological studies done and the degree to which culturally significant plants in this region rely on insect pollination. A systematic review of the literature was conducted on breeding systems and pollination of culturally significant plants. Half of all the culturally significant plants included lacked specific information related to reproduction. Most plants that have been studied relied on outcrossing, and the most commonly reported pollinators were in the Apidae family. With the complex interactions between plants and pollinators and many insect pollinators experiencing population declines, it is important to determine the dependence of culturally significant plants on animal pollination. These findings will be relevant to conservation planning and policy in the future. [ABSTRACT FROM AUTHOR]

With the proposed EC reform, Value for Cultivation and Use (VCU) trials will include sustainability as a driver, broadening their scope from agricultural varieties to horticultural and fruit ones, and a plethora of derogations to variety registration and seed certification standards will be added or deepened; however, it is unlikely that the EU and Member States' plant variety protection schemes, farmers, or end consumers will truly benefit from it. [ABSTRACT FROM AUTHOR]

Nectar robbers and thieves are common antagonists in plant–pollinator communities, where they deplete nectar without pollinating flowers, substantially affecting plant reproduction. Nevertheless, little is known about the relative abundance of such nectar exploiters in communities, even though spatiotemporal changes in the frequencies of antagonists and mutualists can exert opposing selection pressures on the traits of the interacting species. Although these effects are highly dependent on the community context, interspecific interactions have almost exclusively been studied in interacting species pairs or single‐plant studies. We hypothesized that flowers might experience a trade‐off between filtering out robbers and thieves. We used an extensive dataset of video‐recorded flower–visitor interactions along a complete elevational gradient in wet and dry seasons on Mount Cameroon to assess spatiotemporal changes in robbing and thieving associated with several floral traits. Of the 14,391 recorded visits, ~4.3% were from robbers (mostly bees and birds) and ~2.1% were from thieves (mostly flies, bees, and moths). Only 29 and 39 of the 194 studied plants were robbed and thieved, respectively. We found that specialized floral traits that prevented thieving (such as long floral tubes or spurs) made flowers susceptible to robbing, and vice versa. Cheating behavior was most frequent at mid‐elevations, with more frequent robbing during the wet season and thieving during the dry season. These trends were linked to the local floral trait composition and the associations of cheating groups with specific floral traits. Our results suggest that the roles of antagonists and mutualists in shaping partner traits may vary across communities and that they deserve more attention in future studies of interspecific interactions. [ABSTRACT FROM AUTHOR]

Cupin&lowbar;1 domain-containing protein (CDP) family, which is a member of the cupin superfamily with the most diverse functions in plants, has been found to be involved in hormone pathways that are closely related to rhizome sprouting (RS), a vital form of asexual reproduction in plants. Ma bamboo is a typical clumping bamboo, which mainly reproduces by RS. In this study, we identified and characterized 53 Dendrocalamus latiflorus CDP genes and divided them into seven subfamilies. Comparing the genetic structures among subfamilies showed a relatively conserved gene structure within each subfamily, and the number of cupin&lowbar;1 domains affected the conservation among D. latiflorus CDP genes. Gene collinearity results showed that segmental duplication and tandem duplication both contributed to the expansion of D. latiflorus CDP genes, and lineage-specific gene duplication was an important factor influencing the evolution of CDP genes. Expression patterns showed that CDP genes generally had higher expression levels in germinating underground buds, indicating that they might play important roles in promoting shoot sprouting. Transcription factor binding site prediction and co-expression network analysis indicated that D. latiflorus CDPs were regulated by a large number of transcription factors, and collectively participated in rhizome buds and shoot development. This study significantly provided new insights into the evolutionary patterns and molecular functions of CDP genes, and laid a foundation for further studying the regulatory mechanisms of plant rhizome sprouting. [ABSTRACT FROM AUTHOR]

Keywords: data synthesis; database; germination; open science; plant reproduction; repository; seed; trait EN data synthesis database germination open science plant reproduction repository seed trait 466 470 5 09/25/23 20231015 NES 231015 Data availability The data and code used to produce this article are available at https://github.com/efernandezpascual/seedarcms. The need for a global archive of primary seed germination data The seed ecology community has recently recognized the need to synthesize knowledge, setting the research agenda for functional seed ecology (Saatkamp I et al i ., [34]). I SeedArc i compiles primary seed germination data to synthesize the seed germination spectrum at a global scale. The theory underlying the seed germination spectrum has been laid out by decades of work on seed ecology (Baskin & Baskin, [1]), but empirical studies testing major ecological hypotheses at both global and local scales remain elusive without a standardized seed germination database. [Extracted from the article]

Nuclear fusion is essential for the sexual reproduction of various organisms, including plants, animals, and fungi. During the life cycle of flowering plants, nuclear fusion occurs three times: once during female gametogenesis and twice during double fertilization, when two sperm cells fertilize the egg and the central cell. Haploid nuclei migrate in an actin filament-dependent manner to become in close contact and, then, two nuclei fuse. The nuclear fusion process in plant reproduction is achieved through sequential nuclear membrane fusion events. Recent molecular genetic analyses using Arabidopsis thaliana showed the conservation of nuclear membrane fusion machinery between plants and the budding yeast Saccharomyces cerevisiae. These include the heat-shock protein 70 in the endoplasmic reticulum and the conserved nuclear membrane proteins. Analyses of the A. thaliana mutants of these components show that the completion of the sperm nuclear fusion at fertilization is essential for proper embryo and endosperm development. [ABSTRACT FROM AUTHOR]

The demand among the population for protein products, which are essential for a healthy diet, is a pressing issue today, which constantly requires scientists and manufacturers to search for alternative protein analogues. That is why the aim of the research was to study the impact of a diet based on plant and animal raw materials on the reproductive capacity, growth, and development of the body. In the experiment, the duration of pregnancy in pregnant females was determined; the average number of rats born per female of the respective group; the weight of females before pregnancy; the weight of females on the 7th, 14th and 21st day of pregnancy. The postnatal development of rats of the control and experimental groups was compared. In newborn rats, the following were determined: age of ear drum detachment; craniocaudal size at birth; craniocaudal size on the 5th day; age of hair coat appearance; age of eye-opening; weight of rats at birth; weight of rats on the 7th, 14th and 30th day of life. The results obtained indicate that there is no negative effect of the vegetable semifinished product using soya-wheat texture and meat cutlet on the reproductive functions of rats and the development of offspring. During the experiment, female rats showed no signs of toxicosis, visible pregnancy disorders, or physiological disorders. During the dynamic observation of the weight of experimental females in all experimental groups, no decrease in weight gain was recorded compared to control animals. The weight and postnatal dimensions of newborn rats of the experimental groups did not differ from those of the control. For the first time in laboratory animals, based on an integrated approach using modern research methods, the effect of long-term consumption of food based on semifinished products from soy-wheat texture and meat cutlets on the reproductive functions of rats and the development of offspring was studied, which is of practical value in the context of the health of females and offspring of mammals under the influence of an alternative nutritional factor. [ABSTRACT FROM AUTHOR]

The timing of flowering and other components of phenology such as duration and synchrony can affect reproductive success and recruitment by influencing the environment a plant will experience throughout its flowering period. Pollination is a common explanation for why flowering phenology may affect reproduction, but it is not well understood how variation in pollination might interact with the abiotic environment to affect plant reproduction. Here we monitored a population of spring ephemerals, Claytonia virginica , for one flowering season and examined the effects of flowering phenology and the environment on plant reproduction in two treatments: plants supplemented with additional outcross pollen and unmanipulated control plants. Different aspects of reproduction were measured at both the population and within-plant levels: number of seeds produced by individual plants (seed production), per-fruit seed viability (the proportion of viable seeds out of the total number of seeds per fruit), percent germination, and number of days to germination. Soil surface temperature, light, and moisture data were also collected. The flowering phenology and environmental predictors most important for each measurement of reproduction differed between control and pollen-supplemented plants. For example, in both pollen treatment groups, more days in flower was consistently a positive predictor of seed production, but the environmental factors affecting seed production varied, with increasing pollinator visitation mostly affecting seed production in the nonsupplemented group and soil moisture positively affecting it in supplemented plants. Phenological and environmental predictors also differed for proportion of viable seeds and timing of germination. Our germination results support the hypothesis that the mechanisms that control early flowering time in the maternal plant may affect the timing of other life history events such as seed germination. Additionally, we show some evidence that changes in the maternal abiotic environment, particularly temperature, may alter progeny phenotype. No clear seasonal resource trade-offs were evident, as has been shown in other studies of spring ephemerals. Our results show that the abiotic environment interacts with the pollination environment to affect plant reproduction, with different environmental factors predicting reproduction in control versus pollen-supplemented plants. [ABSTRACT FROM AUTHOR]

Plants inhabiting environments with stressful conditions often exhibit a low number of flowers, which can be attributed to the energetic cost associated with reproduction. One of the most stressful environments for plants is the Antarctic continent, characterized by limited soil water availability and low temperatures. Induction of dehydrins like those from the COR gene family and auxin transcriptional response repressor genes (IAAs), which are involved in floral repression, has been described in response to water stress. Here, we investigated the relationship between the water deficit‐induced stress response and the number of flowers in Colobanthus quitensis plants collected from populations along a latitudinal gradient. The expression levels of COR47 and IAA12 genes in response to water deficit were found to be associated with the number of flowers. The relationship was observed both in the field and growth chambers. Watering the plants in the growth chambers alleviated the stress and stimualted flowering, thereby eliminating the trade‐off observed in the field. Our study provides a mechanistic understanding of the ecological constraints on plant reproduction along a water availability gradient. However, further experiments are needed to elucidate the primary role of water availability in regulating resource allocation to reproduction in plants inhibiting extreme environments. [ABSTRACT FROM AUTHOR]

Phytoremediation is an economical technique for the biological treatment of soil and water contamination. Improving the growth of plants used in this technique leads to greater efficiency of the process. Herein, Lemna minor plant used in phytoremediation was collected from Sarab-e Nilufar region of Kermanshah province, Iran, and maintained in a culture medium. This study focused on the preparation of Ormus solution based on crystalline salt extracted from the salt mountains of Karmowstaj region in Fars province, Iran, to increase the proliferation of Lemna minor. The optimal growth conditions, including the pH of the medium, the residence time in the Ormus preparation process, and the concentration of Ormus solution were analyzed using the response surface methodology (RSM) based on a Box-Behnken design (BBD) model. Numerical optimization based on the quadratic model was carried out to achieve the maximum growth percentage. The percentage of the proliferation of Lemna minor varied from 34.6% to 117.3%, while growth was highest at a medium pH value of 10.75, a residence time of 72 h in the Ormus preparation process, and an Ormus concentration of 17 g.L−1. The results revealed that Ormus, as a supplemental fertilizer, under optimal conditions can significantly increase the rate of plant reproduction. Herein, the Ormus solution was applied for the first time to increase plant growth. In addition, the operating factors, including the pH of the medium, the residence time in the Ormus preparation process, and the concentration of Ormus solution, were optimized using the RSM based on a BBD model. In this study, Ormus was introduced under optimal conditions as a suitable additive to increase the proliferation rate of plants. [ABSTRACT FROM AUTHOR]

Leucine-rich repeat receptor-like kinases (LRR-RLKs) are an important subfamily of receptor-like kinases (RLKs) in plants that play key roles in sensing different biotic and abiotic stress. However, the role of LRR-RLKs in herbivore-induced plant defense remains largely elusive. Here, we found that the expression of a rice gene, OsRLK7-1, was induced by mechanical wounding, but was slightly suppressed by the infestation of gravid females of brown planthopper (BPH, Nilaparvata lugens) or white-backed planthopper (WBPH, Sogatella furcifera). Through targeted disruption of OsRLK7-1 (resulting in the ko-rlk lines), we observed an augmentation in transcript levels of BPH-induced OsMPK3, OsWRKY30, OsWRKY33, and OsWRKY45, alongside heightened levels of planthopper-induced jasmonic acid, JA-isoleucine, and abscisic acid in plant tissues. These dynamic changes further facilitated the biosynthesis of multiple phenolamides within the rice plants, culminating in an enhanced resistance to planthopper infestations under both lab and field conditions. In addition, knocking out OsRLK7-1 impaired plant growth and reproduction. These results suggest that OsRLK7-1 plays an important role in regulating rice growth, development, and rice-planthopper interactions. [ABSTRACT FROM AUTHOR]

Heat stress can severely inhibit plant growth and reproduction, resulting in heavy financial and crop yield losses. Heat shock transcription factors (HSFs) play an important role in regulating plant responses to abiotic stress. However, compared with the in-depth study of HSF gene function in herbaceous species, reports on the regulatory mechanism of the response of HSFs to heat stress in trees are scarce. Here, we demonstrated that PtHSFA4a is induced by high temperatures in Populus trichocarpa leaves. Intense GUS activity was detected in the leaves of PtHSFA4a promoter-GUS reporter transgenic line under heat stress. Ectopic expression of PtHSFA4a in Arabidopsis thaliana enhanced heat stress tolerance, which reduced malondialdehyde and reactive oxygen species levels. RT-qPCR revealed that the expression of key heat stress-related genes (that is, AtMBF1c, AtZAT12, AtAPX1, AtHSA32, and AtHSPs) was upregulated in PtHSFA4a transgenic plants. Additionally, PtHSFA4a directly bind to the promoters of AtAPX1 and AtHSPs under heat stress to enhance heat tolerance by upregulating the antioxidant defense system and maintaining protein folding homeostasis in A. thaliana leaves. These findings provide novel insights into the molecular mechanisms underlying PtHSFA4a-mediated regulation of plant responses to heat stress. [ABSTRACT FROM AUTHOR]

Among all the different organs of a plant, flowers might have one of the most dynamic microbial communities, since many microbes are transmitted during flowering by insects and pollen. However, little is known about how these microbes affect floral characteristics and plant reproduction. Among the microbes transmitted to flowers, pathogens may have highly negative effects on plants' fitness. In this study, we investigated whether a bacterial pathogen, Erwinia mallotivora, occurs on flowers of the host plant Mallotus japonicus, and whether the transmission of the pathogen to flowers can result in systemic infection and/or reduction of fruit production. The pathogen has been reported to infect through leaves, while its ecology on flowers is unknown. We first confirmed the presence of the pathogen on flowers, indicating possible transmission by visitors or pollen. Then, we showed that the bacteria can infect the plant through flowers by inoculating the pathogen to both male and female flowers. Interestingly, the symptoms on leaves appeared earlier on the female plants than on the males. Besides, the inoculation significantly decreased fruit set of the female plants. Our results suggest a higher cost of infection in a female than in a male once the pathogen infected flowers. Although the effects of pathogen infection to flowers have rarely investigated in wild plants, it would be an interesting topic for future study if such sexual differences in the infection cost can cause sexual conflict and intraspecific adaptation load. [ABSTRACT FROM AUTHOR]

Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) genes encode a subfamily of receptor-like kinases (RLK) that regulate diverse processes during plant growth, development, and stress responses. The first CrRLK1L was identified from the Catharanthus roseus, commonly known as Madagascar periwinkle. Subsequently, CrRLK1L gene families have been characterized in many plants. The genome of T. aestivum encodes 15 CrRLK1L genes with 43 paralogous copies, with three homeologs each, except for -2-D and -7-A, which are absent. Chromosomal localization analysis revealed a markedly uneven distribution of CrRLK1L genes across seven different chromosomes, with chromosome 4 housing the highest number of genes, while chromosome 6 lacked any CrRLK1L genes. Tissue-specific gene expression analysis revealed distinct expression patterns among the gene family members, with certain members exhibiting increased expression in reproductive tissues. Gene expression analysis in response to various abiotic and biotic stress conditions unveiled differential regulation of gene family members. Cold stress induces CrRLK1Ls -4-B and -15-A while downregulating -3-A and -7B. Drought stress upregulates -9D, contrasting with the downregulation of -7D. CrRLK1L-15-B and -15-D were highly induced in response to 1 hr of heat, and combined drought and heat stress, whereas -10-B is downregulated. Similarly, in response to NaCl stress, only CrRLK1L1 homeologs were induced. Fusarium graminearum and Claviceps purpurea inoculation induces homeologs of CrRLK1L-6 and -7. The analysis of cis-acting elements in the promoter regions identified elements crucial for plant growth and developmental processes. This comprehensive genome-wide analysis and expression study provides valuable insights into the essential functions of CrRLK1L members in wheat.

IntroductionInteractions between flowering plants and visiting wild bees are crucial for ensuring pollination and subsequent plant reproductive success. However, bee diversity in an area has rarely been recorded in relation to seed set in native plants. In this project, we investigated the effect of local wild bee communities on seed set in four common wild plant species.MethodsPotted plants of Centaurea jacea, Cichorium intybus, Sinapis arvensis, and Salvia pratensis were placed for pollination experiments, in two distinct habitat types that we expected to show distinct bee communities, namely near-natural grassland and perennial wild flower strips, in Germany.ResultsOur results showed that near-natural grassland had a higher bee species richness and an increased seed set compared with flower strips that displayed a higher bee abundance in most study locations. Although we found effects of bee diversity on seed set, we did not detect a significant effect of bee abundance. Furthermore, the seed set in response to wild bee diversity differed across the plant species.DiscussionWe conclude that bee-friendly habitats ensure a high seed set in wild plants, but that the impact varies between different plant species.

Diurnal and nocturnal pollinators are fundamental for the functioning of natural ecosystems and food security. However, differences between diurnal and nocturnal pollination networks and the contribution of these pollinators to plant fecundity have not been assessed comprehensively within a community context. In the Dajiuhu subalpine wetland of central China, we supplemented data from an intensive field survey with the analysis of pollen loads carried by diurnal and nocturnal pollinators to compare the structures of diurnal and nocturnal pollination networks using network parameters. Simultaneously, we compared the contribution of diurnal and nocturnal pollinators to plant reproduction of the nine dominant species based on stigma pollen placement. We found that although diurnal and nocturnal pollination networks exhibited a similar structural organisation, the diurnal network displayed greater stability and broader interaction with pollinators and plants compared to the nocturnal network. However, nocturnal pollinator species tended to establish less generalised interactions with the available floral resources. Both diurnal and nocturnal pollinators played a significant role in plant reproduction, and nocturnal pollination can result in greater pollen germination. In terms of stability, the lower redundancy of links within nocturnal networks suggests they may be more vulnerable to the temporary or permanent disappearance of plant resources in the study area. Our findings highlight the differences in the contributions of diurnal and nocturnal pollinators to plant reproduction at the community level, demonstrating that nocturnal pollinators are not redundant in maintaining species diversity in communities. This knowledge should play a pivotal role in preventing future pollination declines and improving pollinator conservation efforts.

This document explores the impact of environmental stress, specifically heat stress and low light conditions, on plant reproduction. It discusses studies conducted on different plant species to understand the effects of these stresses on reproductive organs and processes. The studies reveal that heat stress can lead to abnormalities in anther development, reduced pollen viability, and altered gene expression related to carbohydrate metabolism. Low light conditions delay flowering, reduce pollen viability and stigma receptivity, and affect seed quality. The findings provide insights into the physiological and molecular mechanisms underlying plant reproductive responses to environmental stresses. [Extracted from the article]

IntroductionPersian walnut (Juglans regia) is an economically important nut fruit species cultivated worldwide for its nutritious kernel and timber quality wood. Walnut trees are mostly hetero-dichogamous and, depending on the genotype, some cultivars are protogynous, while others are protandrous. Although selfing is possible when male and female blooms overlap, the dichogamy of the species promotes outcrossing. In addition to sexual reproduction, some reports indicate that elements of apomixis may occur in commercial orchards of walnut varieties and in the last two decades, nut production by apomixis has been reported in walnut. However, there are no reliable studies on the occurrence of apomictic reproduction based on cytoembryological observations and/or molecular marker-progeny tests. This study addresses the combined use of molecular and cytological analyses to gain new insights into the population genetics and reproduction systems of J. regia.MethodsWe systematically analyzed the reproductive origin of individual progeny plants from 8 different cultivated walnut genotypes using microsatellite genotyping and carried out cytohistological investigations of 5 cultivated walnut genotypes arising seed sets from isolated flowers, to shed light on the mode of reproduction.Results and discussionThese cytometric and genotyping analyses did not support any asexual mode of reproduction or asexual propagation by seed and all individuals studied were identified as zygotic plants produced by crossing. Likewise, the cytological findings did not confirm completely the first component of apomixis, namely apomeiosis. On the other hand, according to histological evidence, adventitious embryony seems to take place at low frequency. Overall, our findings suggest that the occurrence of gametophytic apomixis is unlikely in J. regia, but sporophytic apomixis cannot be completely ruled out.

The increment in global temperature reduces crop productivity, which in turn threatens food security. Currently, most of our food supply is produced by plants and the human population is estimated to reach 9 billion by 2050. Gaining insights into how plants navigate heat stress in their reproductive phase is essential for effectively overseeing the future of agricultural productivity. The reproductive success of numerous plant species can be jeopardized by just one exceptionally hot day. While the effects of heat stress on seedlings germination and root development have been extensively investigated, studies on reproduction are limited. The intricate processes of gamete development and fertilization unfold within a brief timeframe, largely concealed within the flower. Nonetheless, heat stress is known to have important effects on reproduction. Considering that heat stress typically affects both male and female reproductive structures concurrently, it remains crucial to identify cultivars with thermotolerance. In such cultivars, ovules and pollen can successfully undergo development despite the challenges posed by heat stress, enabling the completion of the fertilization process and resulting in a robust seed yield. Hereby, we review the current understanding of the molecular mechanisms underlying plant resistance to abiotic heat stress, focusing on the reproductive process in the model systems of Arabidopsis and Oryza sativa.

Molecular clocks are the basis for dating the divergence between lineages over macroevolutionary timescales (~105 to 108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes display a clocklike behavior. This “epimutation clock” is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation clocks recapitulate known topologies and branching times of intraspecies phylogenetic trees in the self-fertilizing plant Arabidopsis thaliana and the clonal seagrass Zostera marina, which represent two major modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity. [ABSTRACT FROM AUTHOR]

Summary: Urbanization can affect the timing of plant reproduction (i.e. flowering and fruiting) and associated ecosystem processes. However, our knowledge of how plant phenology responds to urbanization and its associated environmental changes is limited.Herbaria represent an important, but underutilized source of data for investigating this question. We harnessed phenological data from herbarium specimens representing 200 plant species collected across 120 yr from the eastern US to investigate the spatiotemporal effects of urbanization on flowering and fruiting phenology and frost risk (i.e. time between the last frost date and flowering).Effects of urbanization on plant reproductive phenology varied significantly in direction and magnitude across species ranges. Increased urbanization led to earlier flowering in colder and wetter regions and delayed fruiting in regions with wetter spring conditions. Frost risk was elevated with increased urbanization in regions with colder and wetter spring conditions.Our study demonstrates that predictions of phenological change and its associated impacts must account for both climatic and human effects, which are context dependent and do not necessarily coincide. We must move beyond phenological models that only incorporate temperature variables and consider multiple environmental factors and their interactions when estimating plant phenology, especially at larger spatial and taxonomic scales. See also the Commentary on this article by Zhu & Song, 239: 2057–2059. [ABSTRACT FROM AUTHOR]

Ecosystem engineering consists of a ubiquitous and fundamental class of interactions where some organisms promote state changes in biotic and abiotic materials which indirectly affect others. Since the concept was created as a counterpoint to traditional flux‐based models, pollinators have never been considered to promote ecosystem engineering because they modulate the supply of resources used by seed/fruit consumers. However, dry fruits may persist in the environment for long periods after seed dispersion as empty structures that are an additional alternative for occupancy. These increase the realized niche of some organisms, being a clear example of biogenic habitats. Here, we demonstrate how pollination may boost ecosystem engineering using an illustrative case study based on a specialized interaction between a bee and an orchid with characteristic capsular fruits. We demonstrate that the orchid is fully dependent on the pollinator to set fruits. Post‐dispersal fruits are voluminous and remain attached to the plant for several years. By investigating the occupation patterns of arthropods, we show that post‐dispersal fruits are highly suitable for occupants when compared to pre‐dispersal and dispersing fruits. Only 13.3% of post‐dispersal fruits were never occupied, 33.3% had organisms inside and 53.3% showed signs of previous occupation. We propose that pollinators are allogenic engineers and plants autogenic, since they promote state changes through their actions and their own physical structure, respectively. Thus, pollination is a case of cooperative ecosystem engineering whereby the effects of the interaction between two or more species expand habitat suitability. Since most plants rely on pollination to set fruits, we suggest that pollination‐mediated engineering constitutes a widespread phenomenon. This offers a new perspective about the effects of pollination in nature, highlighting the importance of pollinators and opening new avenues of investigation of ecosystem dynamics and biodiversity maintenance. [ABSTRACT FROM AUTHOR]

Pollen germination in vivo on wet stigmas is assisted by the receptive fluid—stigma exudate. Its exact composition is still unknown because only some components have been studied. For the first time, hormonal screening was carried out, and the fatty acid (FA) composition of lipid-rich (Nicotiana tabacum) and sugar-rich (Lilium longiflorum) exudates was studied. Screening of exudate for the presence of plant hormones using HPLC-MS revealed abscisic acid (ABA) in tobacco stigma exudate at the two stages of development, at pre-maturity and in mature stigmas awaiting pollination, increasing at the fertile stage. To assess physiological significance of ABA on stigma, we tested the effect of this hormone in vitro. ABA concentration found in the exudate strongly stimulated the germination of tobacco pollen, a lower concentration had a weaker effect, increasing the concentration did not increase the effect. GC-MS analysis showed that both types of exudate are characterized by a predominance of saturated FAs. The lipids of tobacco stigma exudate contain significantly more myristic, oleic, and linoleic acids, resulting in a higher unsaturation index relative to lily stigma exudate lipids. The latter, in turn, contain more 14-hexadecenoic and arachidic acids. Both exudates were found to contain significant amounts of squalene. The possible involvement of saturated FAs, ABA, and squalene in various exudate functions, as well as their potential relationship on the stigma, is discussed. [ABSTRACT FROM AUTHOR]

Flowering and fruiting phenology have been infrequently studied in the ever‐wet hyperdiverse lowland forests of northwestern equatorial Amazonía. These Neotropical forests are typically called aseasonal with reference to climate because they are ever‐wet, and it is often assumed they are also aseasonal with respect to phenology. The physiological limits to plant reproduction imposed by water and light availability are difficult to disentangle in seasonal forests because these variables are often temporally correlated, and both are rarely studied together, challenging our understanding of their relative importance as drivers of reproduction. Here we report on the first long‐term study (18 years) of flowering and fruiting phenology in a diverse equatorial forest, Yasuní in eastern Ecuador, and the first to include a full suite of on‐site monthly climate data. Using twice monthly censuses of 200 traps and >1000 species, we determined whether reproduction at Yasuní is seasonal at the community and species levels and analyzed the relationships between environmental variables and phenology. We also tested the hypothesis that seasonality in phenology, if present, is driven primarily by irradiance. Both the community‐ and species‐level measures demonstrated strong reproductive seasonality at Yasuní. Flowering peaked in September–November and fruiting peaked in March–April, with a strong annual signal for both phenophases. Irradiance and rainfall were also highly seasonal, even though no month on average experienced drought (a month with <100 mm rainfall). Flowering was positively correlated with current or near‐current irradiance, supporting our hypothesis that the extra energy available during the period of peak irradiance drives the seasonality of flowering at Yasuní. As Yasuní is representative of lowland ever‐wet equatorial forests of northwestern Amazonía, we expect that reproductive phenology will be strongly seasonal throughout this region. [ABSTRACT FROM AUTHOR]

Hybridization plays an indispensable role in creating the diversity associated with plant evolution and genetic improvement of crops. Production of hybrids requires control of pollination and avoidance of self-pollination for species that are predominantly autogamous. Hand emasculation, male sterility genes or male gametocides have been used in several plant species to induce pollen sterility. However, in cowpea (Vigna unguiculata (L.) Walp), a self-pollinated cleistogamous dryland crop, only hand emasculation is used, but it is tedious and time-consuming. In this study, male sterility was effectively induced in cowpea and two dicotyledonous model species (Arabidopsis thaliana (L.) Heynh. and Nicotiana benthamiana Domin) using trifluoromethanesulfonamide (TFMSA). Pollen viability assays using Alexander staining showed that 30 ml of 1000 mg/l TFMSA with two-time treatments of one-week interval at the early stage of the reproductive phase under field or greenhouse conditions induced 99% pollen sterility in cowpea. TFMSA treatment induced non-functional pollen in diploid A. thaliana at two-time treatment of 10 ml of 125–250 mg/l per plant and N. benthamiana at two-time treatment of 10 ml of 250–1000 mg/l per plant. TFMSA-treated cowpea plants produced hybrid seeds when used as the female parent in crosses with non-treated plants used as male parents, suggesting that TFMSA had no effect on female functionality in cowpea. The ease of TFMSA treatment and its effectiveness to induce pollen sterility in a wide range of cowpea genotypes, and in the two model plant species tested in this study, may expand the scope of techniques for rapid pollination control in self-pollinated species, with potential applications in plant breeding and plant reproduction science. [ABSTRACT FROM AUTHOR]

Flowering is the transition from vegetative to reproductive growth and is critical for plant adaptation and reproduction. FLOWERING LOCUS C (FLC) plays a central role in flowering time control, and dissecting its regulation mechanism provides essential information for crop improvement. Here, we report that DECAPPING5 (DCP5), a component of processing bodies (P-bodies), regulates FLC transcription and flowering time in Arabidopsis (Arabidopsis thaliana). DCP5 and its interacting partner SISTER OF FCA (SSF) undergo liquid–liquid phase separation (LLPS) that is mediated by their prion-like domains (PrDs). Enhancing or attenuating the LLPS of both proteins using transgenic methods greatly affects their ability to regulate FLC and flowering time. DCP5 regulates FLC transcription by modulating RNA polymerase II enrichment at the FLC locus. DCP5 requires SSF for FLC regulation, and loss of SSF or its PrD disrupts DCP5 function. Our results reveal that DCP5 interacts with SSF, and the nuclear DCP5–SSF complex regulates FLC expression at the transcriptional level. The P-body component DCP5 regulates FLC transcription and is dependent on SSF in Arabidopsis thaliana. [ABSTRACT FROM AUTHOR]