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Dodder is a parasitic weed that causes a lot of damage to citrus production in the south of Kerman province, Iran. Introducing cultivars which tolerant to this parasite can be considered a very effective step in controlling it. Therefore, to evaluate the tolerance of seven important citrus species to dodder, an experiment was conducted in a randomized complete block design with three replicates in greenhouse conditions for two years (2016-2017). In this experiment, the reaction of orange, local, and Kara tangerine, grapefruit, Valencia orange, local orange, and lemon seedlings to dodder infestation was investigated. The infestation was done artificially by placing 10 dodder’s thallus on the seedlings of each of the mentioned species. After the successful establishment of the parasite (during 4 months), chlorophyll content, number of stems on citrus species shoots, number of capsules in infested seedlings, and seed weight on each seedling were measured and recorded. The results of this study revealed that different species of citrus showed very different reactions to the presence of dodder so that these species can be based on the success rate of its attachment to them into tolerant and sensitive species. According to the results, Valencia oranges and Bitter orange were tolerant to dodder, but lemon and tangerines (local and Kara) showed high sensitivity. A cross-sectional of plant tissues showed that concerning anatomic view, there was no difference in haustorium penetration between the different citrus species. As a result, it is recommended to use physiological, genetical, and biochemical analysis to distinguish the differences.

Se irradiaron inflorescencias de maíz con rayos gamma de cobalto-GO, exponiéndolas a una dosis que fluctuó entre 2.50 y 20,000 roentgenios. Veinticuatro y 18 horas después de irradiadas, se recobró el polen para fertilizar las mazorcas. Se obtuvieron los siguientes datos: número de semillas buenas, o sea, semillas bien desarrolladas; porcentaje de germinación de la semilla buena, y altura de las plantas a los 7 y 14 días después de haber germinado la semilla. No se obtuvo semilla, de la que se irradió con una dosis en exceso de 1,000 roentgenios. El polen que se trató por 24 horas afectó poco los caracteres que se midieron, al compararse con el que se trató por 18 horas. La reacción fue general en cuanto a la cantidad de buena semilla producida por mazorca y a su porcentaje de germinación. Las dosis altas disminuyeron tanto la cantidad de semilla buena como el porcentaje de germinación. No hubo evidencia cuanto a la reacción de las plantas irradiadas con referencia a su altura. Si la semilla germina, su crecimiento es igual sin importar la dosis aplicada.

Crop infestation species have acquired resistance to herbicides, stimulating the search for new control methods. Plants secondary metabolites can hold more sustainable alternatives, as they can be used for development of natural herbicides. This study evaluated phytotoxic effects of aqueous extracts of Ilex paraguariensis leaves on Conyza bonariensis, an infesting species of Brazilian crops. Different concentrations of decoction and infusion extracts were tested in germination and growth bioassays. Adult plants were evaluated for leaf anatomy effects caused by the yerba mate extract. HPLC analysis was used to quantify the three major chemical constituents. The most effective aqueous extract (decoction 1.0%) decreased the percentage of seed germination, germination speed index, and percentage of germination-derived seedling formation, and increased the time for seedling formation. Shoot and root growth were not affected by this extract. In adult plants, the same extract damaged epidermis and palisade/lacunous parenchyma six hours after exposure. Caffeine was found as the major compound of this extract, followed by rutin and quercetin. Therefore, aqueous extract by decoction 1.0 % of I. paraguariensis leaves showed potential for control of C. bonariensis infestation and rather promising for the development of a natural herbicide.

Saline–alkaline (SA) stress is characterized by high salinity and high alkalinity (high pH), which severely inhibit plant growth and cause huge losses in crop yields worldwide. Here we show that a moderate elevation of endogenous abscisic acid (ABA) levels by RNAi-mediated suppression of OsABA8ox1 (OsABA8ox1-kd), a key ABA catabolic gene, significantly increased tolerance to SA stress in rice plants. We produced OsABA8ox1-kd lines in two different japonica cultivars, Dongdao 4 and Nipponbare. Compared with non-transgenic control plants (WT), the OsABA8ox1-kd seedlings accumulated 25.9%–55.7% higher levels of endogenous ABA and exhibited reduced plasmalemma injury, ROS accumulation and Na+/K+ ratio, and higher survival rates, under hydroponic alkaline conditions simulated by 10, 15, and 20 mmol L−1 of Na2CO3. In pot trials using SA field soils of different alkali levels (pH 7.59, 8.86, and 9.29), OsABA8ox1–kd plants showed markedly higher seedling survival rates and more vigorous plant growth, resulting in significantly higher yield components including panicle number (85.7%–128.6%), spikelets per panicle (36.9%–61.9%), branches (153.9%–236.7%), 1000–kernel weight (20.0%–28.6%), and percentage of filled spikelets (96.6%–1340.8%) at harvest time. Under severe SA soil conditions (pH = 9.29, EC = 834.4 μS cm−1), OsABA8ox1-kd lines showed an 194.5%–1090.8% increase in grain yield per plant relative to WT plants. These results suggest that suppression of OsABA8ox1 to increase endogenous ABA levels provides a new molecular approach for improving rice yield in SA paddies.

Microbial communities are essential for soil health, but fungicide application may have significant effects on their structure. It is difficult to predict whether nontarget pathogens of applied fungicides in the soil will cause crop damage. Tebuconazole is a triazole fungicide that can be used as a seed treatment and, thereby, introduced to the soil. However, seed-applied tebuconazole has a potential risk of causing poor emergence of corn (Zea mays) seedlings. Using soil with a history of poor corn seedling emergence, we demonstrate through TA cloning and isolation that the poor emergence of corn seedlings from tebuconazole-coated corn seeds was primarily because of infection by surviving soil pathogens, specifically Pythium species that are not targeted by tebuconazole, rather than the phytotoxic effects of tebuconazole. Bioassay tests on tebuconazole-amended media showed that tebuconazole can suppress soil fungi while allowing Pythium to grow. Pythium species primarily contributing to the corn seed rot were more pathogenic at cooler temperatures. Furthermore, the nontarget biocontrol agent of Trichoderma spp. was strongly inhibited by tebuconazole. Taken together, the nontarget effects of tebuconazole are likely not significant under favorable plant growing conditions but are considerable because of low-temperature stress.

Drought stress adversely affects plant health and productivity. Recently, drought-resistant bacterial isolates are used to combat drought resistance in crops. In this in vitro study, 20 bacterial isolates were isolated from harsh soil; their drought tolerance was evaluated using four concentrations of polyethylene glycol (PEG) 6000. The two most efficient isolates (DS4 and DS9) were selected and identified using 16S rRNA genetic sequencing. They were registered in the NCBI database and deposited under accession numbers MW916285 and MW916307 for Bacillus cereus (DS4) and Bacillus albus (DS9), respectively. These isolates were screened for plant growth-promoting properties compared to non-stressed conditions. Biochemical parameters; Proline, salicylic acid, gibberellic acid (GA), indole acetic acid (IAA), antioxidant activity, and antioxidant enzymes were measured under the same conditions, and in vitro seed germination was tested under stress conditions and inoculation with selected isolates. The results showed that under the harsh conditions of PEG6000, DS4 produced the highest amount of IAA of 1.61 µg/ml, followed by DS9 with 0.9 µg/ml. The highest amount of GA (49.95 µg/ml) was produced by DS9. On the other hand, the highest amount of siderophore was produced from DS4 isolate followed by DS9. Additionally, DS4 isolate recorded the highest exopolysaccharide (EPS) content of 3.4 mg/ml under PEG (-1.2 MPa) followed by DS9. The antioxidant activity increased in PEG concentrations depending manner, and the activity of the antioxidant enzymes increased, as catalase (CAT) recorded the highest activity in DS4 with an amount of 1.095 mg/ml. additionally, an increase in biofilm formation was observed under drought conditions. The isolated mixture protected the plant from the harmful effects of drought and showed an increase in the measured variables. Under unstressed conditions, the highest rates of emulsification index (EI 24%) were obtained for DS4 and DS9, at 14.92 and 11.54, respectively, and decreased under stress. The highest values of germination, total seedling length, and vigor index were obtained upon inoculation with the combination of two strains, and were 100%, 4.10 cm, and 410, respectively. Therefore, two strains combination is an effective vaccine capable of developing and improving drought tolerance in dryland plants.

Cotton architecture is partly determined by shoot branching and flowering patterns. GhBRC1 was previously identified by RNA-seq analysis of nulliplex-branching and normal-branching cotton. However, the roles of GhBRC1 in cotton remain unclear. In the present study, investigations of nuclear localization and transcriptional activity indicated that GhBRC1 has characteristics typical of transcription factors. Gene expression analysis showed that GhBRC1 was highly expressed in axillary buds but displayed different expression patterns between the two branching types. Overexpression of GhBRC1 in Arabidopsis significantly inhibited the number of branches and promoted flowering. In contrast, silencing GhBRC1 in cotton significantly promoted seedling growth. GhBRC1 was induced by multiple hormones, including strigolactones, which promoted seedling growth and seed germination of Arabidopsis plants overexpressing GhBRC1. Consistent with these findings, RNA-seq analysis of virus-induced gene silencing treated cotton revealed that a large number of genes were differentially expressed between GhBRC1-silenced and control plants, and these genes were significantly enriched in plant hormone signalling pathways. Together, our data indicates that GhBRC1 regulates plant branching and flowering through multiple regulatory pathways, especially those regulating plant hormones, with functions partly differing from those of Arabidopsis BRC1. These results provide insights into the molecular mechanisms controlling plant architecture, which is important for breeding cotton with ideal plant architecture and high yield.

Spot blotch caused by Cochliobolus sativus has become an important disease in the wheat-growing regions in China that has resulted from changes in the regional climate, agricultural cultivation patterns, and the susceptible wheat varieties that are widely grown. Little information is available about virulence variability and pathogenic specialization of the C. sativus isolates from major wheat-growing regions in China. Here, 12 representative wheat varieties and foundation breeding stocks were selected to characterize the pathotypes of C. sativus isolates from infected wheat plants. Based on the infection phenotypes in the 12 differential genotypes at the seedling stage, 70 Chinese pathotypes were identified from 110 isolates and clustered into three virulence groups. The high virulence isolates were collected from wheat leaves, crowns, and roots, with most (10 of 14) from the Henan province in the Huang-Huai plain. No relationship was evident between virulence variability of C. sativus isolates and their geographic origins or types of diseased wheat tissues. C. sativus showed a significant pathogenic specialization in hosts of wheat and barley. Most of the wheat isolates (50 of 65) were avirulent to all the differential barley genotypes, and a few were virulent only to highly susceptible barley genotypes. These results indicated that C. sativus isolates from the wheat-growing regions in China varied considerably for their virulence in wheat varieties, and showed significant pathogenic specialization to the wheat and barley hosts.

Like other plant compartments, the seed harbors a microbiome. The members of the seed microbiome are the first to colonize a germinating seedling, and they may initiate the trajectory of microbiome assembly for the next plant generation. Therefore, the members of the seed microbiome are important for the dynamics of plant microbiome assembly and the vertical transmission of potentially beneficial symbionts. However, it remains challenging to assess the microbiome at the individual seed level (and, therefore, for the future individual plants) due to low endophytic microbial biomass, seed exudates that can select for particular members, and high plant and plastid contamination of resulting reads. Here, we report a protocol for extracting microbial DNA from an individual seed (common bean, Phaseolus vulgaris) with minimal disruption of host tissue, which we expect to be generalizable to other medium- and large-seed plant species. We applied this protocol to determine the 16S ribosomal RNA (rRNA) V4 and rRNA internal transcribed spacer 2 amplicon composition and examine the variability of individual seed harvested from replicate common bean plants grown under standard, controlled conditions to maintain health. Using DNA extractions from individual seeds, we compared seed-to-seed, pod-to-pod, and plant-to-plant microbiomes, and found the highest microbiome variability at the plant level. This suggests that several seeds from the same plant could be pooled for microbiome assessment, given experimental designs that apply treatments at the parent plant level. This study adds protocols and insights to the growing toolkit of approaches to understand the plant-microbiome engagements that support the health of agricultural and environmental ecosystems.

The present study aims to understand the physiological and biochemical changes occurring in Moringa (Moringa oleifera Lam.) seeds from development to maturation. The flowers of ten uniform plants (1.5 years old) were first tagged, and the growth of the pod and seeds was monitored from 7 days after anthesis (DAA) to 70 DAA (maturity) during 2016–17 and 2017–18. Results showed that the moisture content of seeds increased significantly from 14 to 28 DAA. Following that, it decreased gradually from 28 to 49 DAA and drastically from 49 to 70 DAA. The dry weight of the seeds increased substantially until 70 DAA due to increase in carbohydrates, proteins, and oils in developing seed. Seeds acquired germinability at 49 DAA but attained desiccation tolerance only after 56 DAA. Seeds harvested at 70 DAA showed maximum germination, seedling length, seedling dry weight, vigor index-I, vigor index-II, and maximum dry weight. Thus, this stage could be considered as the most suitable stage for harvesting. Furthermore, high dehydrogenase activity and lower electrical conductivity with a decrease in total soluble sugars and total soluble proteins in seed leachate indicate higher vigor and better physiological status of the seed during the later stages of development and maturation. A proper understanding of seed maturity will boost seed-based cultivation, improve seed storability and germination percentage, reduce seed shattering, and promote commercial cultivation.

Vachellia karroo (Hayne) Banfi & Galasso (formerly Acacia karroo) is the most widespread tree in southern Africa, and exhibits wide morphological variation such that the phenotypes have been considered as separate species. We sought to determine whether local adaptation was occurring in two neighboring Vachellia karroo populations (ca. 15 km apart) in South Africa that show tremendous size variation as adults. We examined seedling and sapling performance of genotypes grown in reciprocal environments that differ in climatic and edaphic conditions. We used a field reciprocal transplant experiment at Richards Bay and Empangeni, and complemented this with a common garden study. We measured total height, stem diameter, thorn length, leaf area, leaf weight, plant aboveground dry weight and specific leaf area after 4 months and 16 months for common garden and field-grown plants, respectively. For greenhouse-grown plants, root dry weight was also measured. Phenotypes of seedlings and saplings from the two populations maintained their differences in the greenhouse and in the field. Greenhouse-grown plants showed lower proportional root allocation for Richards Bay than Empangeni (i.e. root mass fraction: 0.20 ± 0.01 vs 0.60 ± 0.02). In the field, there were significant genotype-by-environment interactions for two of the seven performance traits for reciprocally-transplanted populations. We found limited evidence for local adaptation that is attributed to variation in edaphic conditions. Local adaptation was evident in two leaf traits (leaf area and leaf dry weight) that showed a genotype-by-environment interaction. These two traits clearly have important fitness consequences for photosynthesis. However, plants from one population grew taller and had longer thorns at both sites. We conclude that the magnitude of divergent selection in the two populations is relatively low and may be accompanied by processes such as genetic drift, leading to limited local adaptation and genetic differentiation.

Rice false smut (RFS) is a destructive disease of rice worldwide caused by Ustilaginoidea virens. Nevertheless, there is a lack of efficient and stable artificial inoculation method to simulate the natural infection of U. virens, which is an important factor limiting further research on the pathogen. The purpose of this study was to establish an artificial inoculation method, which can simulate the natural infection process of U. virens without destroying the panicle sheath structure of rice. In this research, rice plants were inoculated by soaking roots at the seedling stage, spraying at the tillering stage, injecting at the booting stage, and again spraying at the flowering stage to determine the appropriate artificial inoculation time. Meanwhile, the panicle sheath instillation method and the injection inoculation method were compared. The results show that stages 6 to 8 of young panicle differentiation are an important period for U. virens infection. There were no significant differences in the mean rates of infected panicles, mean rates of infected grains, and maximum infected grains per panicle between the two inoculation methods. However, the frequency of RFS ball occurrence at the upper part of the panicles was significantly higher on the spikelets inoculated by the injection method than that of spikelets inoculated by natural infection and panicle sheath instillation. Therefore, panicle sheath instillation method was more similar to the natural infection of U. virens in the field. This research exhibited an innovative artificial inoculation method for identification of U. virens pathogenicity and evaluation of rice resistance against RFS.

Abscisic acid (ABA) plays an important role in seed germination, stomatal closure, and seedling growth inhibition in plants. Among downstream genes whose expression levels are regulated by AFA1 (Arabidopsis F-box Protein Hypersensitive to ABA 1), one gene, AtHAD1 upregulated by ABA was selected from Arabidopsis. AtHAD1 was induced by drought and salt stresses as well as by ABA and was found in dry seeds. Its loss-of-function mutants exhibited increased ABA-sensitivity in germination, seedling growth, and stomatal closure. In addition, the mutants displayed a lower water loss rate and higher survival rate under drought stress than the wild-type plants, indicating that a loss of AtHAD1 leads to enhanced drought tolerance. These results show that AtHAD1 has an inhibitory role in ABA response and ABA-mediated drought tolerance. The expression levels of several ABA-responsive genes in athad1 were higher than those in the wild-type under the ABA treatment, suggesting that AtHAD1, as a negative regulator in ABA response, could be associated with the downregulation of the ABA-responsive genes. The phosphatase assay showed that AtHAD1 exhibits phosphatase activity. Monitoring of the subcellular localization of GFP-fused AtHAD1 proteins indicated that AtHAD1 exists in the nucleus and cytoplasm. Overall, this study shows that Arabidopsis HAD1 as an intracellular phosphatase negatively functions in the ABA-mediated cellular responses. This research could serve as a research basis to understand the functional link between ABA signaling and the regulation process of the cellular phosphate level.

Interactions between endophytic fungi (EFs) and their host plants range from positive to neutral to negative. The results of such interactions can vary depending on the organ of the infected host plant. EFs isolated from the leaves of some species of plants have potential for use as agents to inhibit seed germination and control invasive plants. The objectives of this study were to identify EFs present in the leaves of Copaifera oblongifolia and to evaluate the role of these fungi in seed germination and seedling development. A total of 11 species of EFs were isolated, which were identified using the internal transcribed spacers (ITS) sequence of the nuclear ribosomal DNA. The isolated species of EFs are generalists and probably are transmitted horizontally. Laboratory tests revealed that filtrates of these fungal isolates differently affect seed germination and seedling development of C. oblongifolia. The species Curvularia intermedia, Neofusicoccum parvum, Pseudofusicoccum stromaticum and Phomopsis sp. negatively affected seed germination, with N. parvum standing out for its negative effects, inhibiting seedling germination and survival in 89 and 222%, respectively. In addition, Cochliobolus intermedius negatively affected seedling development. Thus, the combined use of N. parvum and C. intermedius, or products from the metabolism of these microorganisms, in the control of invasive plants deserves attention from future studies. Resumo As interações entre fungos endofíticos (FEs) e suas plantas hospedeiras variam de positivas, neutras a negativas. Os resultados destas interações podem variar dependendo do órgão da planta hospedeira infectada. FEs isolados de folhas de algumas espécies de plantas têm potencial para serem usados como agentes inibidores da germinação de sementes e no controle de plantas invasoras. Os objetivos deste estudo foram identificar os FEs presentes nas folhas de Copaifera oblongifolia e avaliar o papel destes fungos na germinação das sementes e no desenvolvimento das plântulas. Um total de 11 espécies de FEs foi isolado das folhas de C. oblongifolia e identificado através da sequência dos espaçadores internos transcritos do DNA ribossomal nuclear. As espécies de FEs isoladas são generalistas e provavelmente devem ser transmitidas horizontalmente. Os resultados dos testes de germinação mostraram que filtrados destes isolados fúngicos podem afetar diferentemente a germinação das sementes e o desenvolvimento das plântulas de C. oblongifolia. As espécies Curvularia intermedia, Neofusicoccum parvum, Pseudofusicoccum stromaticum e Phomopsis sp. afetaram negativamente a germinação das sementes de C. oblongifolia. Dentre estas espécies devemos destacar que N. parvum reduziu a germinação e a sobrevivência das plântulas em 89 e 222%, respectivamente. Além disso, Cochiliobolus intermedius afetou negativamente o desenvolvimento das plântulas. Assim, o uso combinado de N. parvum e C. intermedius, ou de produtos do metabolismo destas espécies de fungos, têm potencial para serem usados no manejo de plantas invasoras.

Seed regeneration is a critical stage in the life histories of plants, affecting species' abilities to maintain local populations, evolve, and disperse to new sites. In this study, we test for local adaptations to drought in germination and seedling growth of two alpine forbs with contrasting habitat preferences: the alpine generalist Veronica alpina and the snowbed specialist Sibbaldia procumbens. We sampled seeds of each species from four populations spanning a precipitation gradient from 1200 to 3400 mm/year in western Norway. In a growth chamber experiment, we germinated seeds from each population at 10 different water potentials under controlled light and temperature conditions. Drought led to lower germination percentage in both species, and additionally, slower germination, and more investment in roots for V. alpina. These responses varied along the precipitation gradient. Seeds from the driest populations had higher germination percentage, shorter time to germination, and higher investments in the roots under drought conditions than the seeds from the wettest populations – suggesting local adaption to drought. The snowbed specialist, S. procumbens, had lower germination percentages under drought, but otherwise did not respond to drought in ways that indicate physiological or morphological adaptions to drought. S. procumbens germination also did not vary systematically with precipitation of the source site, but heavier-seeded populations germinated to higher rates and tolerated drought better. Our study is the first to test drought effects on seed regeneration in alpine plants populations from high-precipitation regions. We found evidence that germination and seedling traits may show adaptation to drought even in populations from wet habitats. Our results also indicate that alpine generalists might be more adapted to drought and show more local adaptations in drought responses than snowbed specialists. publishedVersion

Murray-Darling Freshwater Research CentreMDFRC item.(1) Causes of seedling mortality in Diplachne fusca were investigated, and the flooding tolerance of seedlings was examined in field and glasshouse experiments in temperate New South Wales, Australia. (2) Seedlings growing under non-flooded conditions in rice crops sown in unflooded soils, were susceptible to water stress, with up to 65% dying. Seedlings emerging in autumn after rain also became water stressed. Those surviving were stunted by cold temperatures or killed by frost or site disturbance. (3) Under controlled flooding conditions, continuous submergence resulted in greater germination than brief irrigations. Delaying permanent flooding gave less germination but fewer deaths after the onset of flooding compared with flooding for the duration of the experiment. Significantly more seedlings established in 4 cm deep permanent floodwater than in 12 cm. (4) In the glasshouse, single-leaved seedlings could establish in 20 cm deep water with no mortality. Submerged seedlings emerged above water level by rapid elongation of the fourth and fifth leaves. (5) A strategy for the control of D. fusca in rice fields is described, using the results of this and previous studies.

BACKGROUND Tobacco sore shin caused by Rhizoctonia solani Kuhn is a major soil-borne fungal disease of tobacco, gradually causing infected stems to become thin and dry, leading to great losses to China's tobacco industry. Fungicides with phloem mobility are needed for application to foliage to effectively control root or vascular system pathogens. In this study, phenazine-1-carboxylic-valine (PCA-Val) conjugate with strong phloem mobility was tested for control of tobacco sore shin. In vitro fungicidal activity, systemicity, and in vivo efficacy of PCA-Val conjugate against R. solani in tobacco seedling were evaluated. RESULTS In vitro fungicidal activity of PCA-L-Val against R. solani was lower than that of PCA or PCA-D-Val, but the in vivo protective activity and curative activity of PCA-L-Val was the highest among these chemicals tested. The systemicity tests in tobacco seedlings revealed that PCA did not possess phloem mobility, while PCA-L-Val and PCA-D-Val exhibited strong phloem mobility and could be transported and accumulated in the lower part of the seedling as well as throughout the phloem. In addition, we also found that, just like reported hormone amino acid conjugates, PCA-L-Val could be hydrolyzed by tobacco seedlings, to release free PCA. CONCLUSIONS The current research results indicated that PCA-L-Val possess good phloem transport in tobacco and promising in vivo antifungal activity against R. solani, which can be used as a phloem-mobile fungicide against tobacco sore shin in production practice. This article is protected by copyright. All rights reserved.

Seed dormancy-break via cold stratification is of fundamental importance for plant adaptation to environmental conditions and response to climate change through timing germination, seedling emergence and consequently community dynamics. Although cold stratification requirements for dormancy break vary among species, it is not known if this variation is determined by the environmental conditions experienced by seeds or by differences among species. We determined the soil moisture content and duration of cold stratification required for seed dormancy-break of species from alpine and desert habitats (soil moisture content: 20 and 18 species from alpine and desert habitats, respectively; duration: 16 and 16 species from the alpine and desert, respectively), and examined the correlation between environmental conditions (soil moisture content and duration of cold stratification) required for dormancy-break and seed traits. Seed germination increased and then decreased as soil moisture content or duration of cold stratification increased. The optimal and critical soil moisture content for seed dormancy-break were higher for alpine species than desert species. A positive correlation between optimal soil moisture content and seed shape was found. However, the duration of cold stratification required for dormancy-break was not related to habitat, seed mass or seed shape. Our results suggest that soil moisture content rather than duration of cold stratification resulting from climate change could affect seed germination and consequently seedling emergence and establishment, especially for desert species.

Rapeseed, a major oil crop in the world, is easily affected by low-temperature stress. A low temperature delays seed germination and increases seedling mortality, adversely affecting rapeseed growth and production. In the present study, a tolerant cultivar (Huyou21) was crossed with a susceptible genotype (3429) to develop a mapping population consisting of 574 F2 progenies and elucidate the genetic mechanisms of seed germination under low temperatures. Two quantitative trait loci (QTL) for low-temperature germination (LTG) were detected, one on chromosome A09 (named qLTGA9-1) and the other on chromosome C01 (named qLTGC1-1), using the QTL-seq approach and confirmed via linkage analysis in the mapping population. Further, qLTGA9-1 was mapped to a 341.86 kb interval between the SSR markers Nys9A212 and Nys9A215. In this region, 69 genes including six specific genes with moderate or high effect function variants were identified based on the Ningyou7 genome sequence. Meanwhile, qLTGC1-1 was mapped onto a 1.31 Mb interval between SSR markers Nys1C96 and Nys1C117. In this region, 133 genes including five specific genes with moderate effect function variants were identified. These specific genes within the two QTL could be used for further studies on cold tolerance and as targets in rapeseed breeding programs.

Wheat stem rust caused by Puccinia graminis f. sp. tritici is a widespread and recurring threat to wheat production. Emerging P. graminis f. sp. tritici variants are rapidly overcoming major gene resistance deployed in wheat cultivars and new sources of race-nonspecific resistance are urgently needed. The National Small Grains Collection (NSGC) contains thousands of wheat landrace accessions that may harbor unique and broadly effective sources of resistance to emerging P. graminis f. sp. tritici variants. All NSGC available facultative and winter-habit bread wheat landraces were tested in a field nursery in St. Paul, Minnesota, against a bulk collection of six common U.S. P. graminis f. sp. tritici races. Infection response and severity data were collected on 9,192 landrace accessions at the soft-dough stage and resistant accessions were derived from single spikes. Derived accessions were tested in St. Paul a second time to confirm resistance and in a field nursery in Njoro, Kenya against emerging races of P. graminis f. sp. tritici with virulence to many known resistance genes including Sr24, Sr31, Sr38, and SrTmp. Accessions resistant in the St. Paul field were also tested at the seedling stage with up to 13 P. graminis f. sp. tritici races, including TTKSK and TKTTF, and with 19 molecular markers linked with known stem rust resistance genes or genes associated with modern breeding practices. Forty-five accessions were resistant in both U.S. and Kenya field nurseries and lacked alleles linked with known stem rust resistance genes. Accessions with either moderate or strong resistance in the U.S. and Kenya field nurseries and with novel seedling resistance will be prioritized for further study.

Clubroot, caused by Plasmodiophora brassicae, is a soilborne disease that occurs in cruciferous crops worldwide. P. brassicae usually exists as a mixture of several pathotypes, which has hampered the research on resistance mechanisms of cruciferous crops against P. brassicae. In this study, clubroot galls were collected from a field in Shenyang, China, as a pathogen source to develop an efficient protocol for a single-spore isolation system of P. brassicae by optimizing the seedling age for inoculation, host inoculation method, and plant culture method. The operational steps of the single-spore isolation method were optimized as follows: the use of 2-day-old seedlings for inoculation, substituting a cryobox (100 × 2.0-ml vials) for culture dishes, the addition of nutrient solution culture, and microscopic observations of single spores. The rate of infection success was substantially improved, and single-spore isolates of four pathotypes (4, 8, 9, and 11) were acquired in this system. Subsequently, the optimized system was used to isolate and characterize the pathotypes of single-spore isolates of P. brassicae collected from five fields in regions in China. Approximately four to nine pathotypes were isolated from each region. Among these, pathotype 4 was the most prevalent. This study provides a source of valuable information that can eventually be used for the genetic analysis of host–P. brassicae interaction.

To evaluate seed vigor, electrical conductivity and ethanol tests are fast and efficient methodologies. They have the potential to be used in several species, such as red rice. However, there are no protocols or information about their efficiency. Thus, the objective was to evaluate the efficiency, and define parameters of execution for electrical conductivity and ethanol tests, to evaluate the vigor of red rice seeds. The study was conducted using four lots of ‘BRS 901’ red rice, which was subjected to a germination test, as well as first count, accelerated aging, and field seedling emergence tests. The electrical conductivity test was performed with 25, 50, and 100 seeds soaked in 50 mL and 75 mL of water, at 25 °C and 30 °C, for 3, 6, 20, and 24 hours, respectively. The ethanol test was performed with 50 and 100 seeds soaked in a volume of water equivalent to 1.0, 1.5, 2.0, 2.5, and 3.0× the mass of the seed sample. To assess the vigor of red rice seeds, the electrical conductivity test is an efficient method when conducted with 50 seeds soaked in 50 mL of water at 25 °C for 20 hours. Meanwhile, the ethanol test is most effective when performed with 50 seeds, in a volume of water that is 2.5× the mass of the sample, at 40 °C for 24 hours.

Experiments of two seasons (2019/2020 and 2020/2021) were carried out in greenhouse at Department of Plant Pathology, Faculty of Agriculture, Ain Shams University. While, field experiments were carried out at El-Kanater Horticulture Research Station (El-Kaluobia Governorate), Horticulture Research Institute, Agriculture Research Center (ARC), Egypt.Compared with untreated infected strawberry plants Festival cultivar, all applications with chitosan at 500 ppm, methionine at 20 ppm and ascorbic acid at 20 mM via seedling root soaking, foliar spray, and combining the root soaking with foliar spray, or seedling root soaking with Rhizolex (1g/L) showed significant decrease in root rot incidence caused by Rhizoctonia solani. The combining of root soaking with foliar spray of chitosan or methionine resulted the highest significant decreases of disease incidence under greenhouse and field conditions. However, all applications except Rhizolex resulted in significant increases in phenolic compounds, oxidative enzymes activity i.e., PPO, SOD and CAT in roots during the two growing seasons. Obtained results showed that soaking plus foliar spraying with chitosan at 500ppm, methionine at 20 ppm and ascorbic acid at 20 mM significantly increased all vegetative growth characters, N, P, K and total carbohydrate in plant foliage, fruit yield and its components as well as physical and chemical fruit quality.

Seedling vigor and regrowth ability are important traits for the forage production of winter wheat. The objectives of this study were to map quantitative trait loci (QTL) associated with seedling vigor and regrowth vigor traits using a genome-wide association mapping study (GWAS). Seedling vigor and regrowth vigor were evaluated with shoot length, the number of shoots per plant and shoot dry weight per plant 45 days after planting and 15 days after cutting. A large phenotypic variation was observed for all the traits studied. In total, 12 significant QTL for seedling vigor and 16 for regrowth vigor traits were detected on various chromosomes. Four QTL on chromosomes 2B, 4B, 5A and 7A for seedling vigor co-localized with QTL for regrowth vigor due to significant correlations between corresponding traits of the initial growth and regrowth. A BLAST search using DNA sequences of the significant loci revealed candidate genes playing roles in vegetative and reproductive development in different crop species. The QTL and single-nucleotide polymorphism (SNP) markers identified in this study will be further validated and used for marker-assisted selection of the traits during forage wheat breeding.

Longer photoperiod in form of continuous light (24-h photoperiod without dark interruption) can alter the various physiological and biochemical processes of the plant. This study aimed to evaluate the effects of continuous light on various biochemical parameters associated with the growth and development of Vigna radiata L. (mung bean). The findings showed that leaf size and chlorophyll content of seedlings grown under continuous light were significantly greater than control plants subjected to 12 h light/12 h dark (12/12 h). The activity of antioxidant enzymes superoxide dismutase (SOD, 30.81%), catalase (CAT, 16.86%), guaiacol peroxidase (GPOD, 12.27%), malondialdehyde, (MDA, 39.31) and proline (14.81%) were notably higher in 24/0 h light period than 12/12 h light period grown seedling at an early stage (on Day 6) while they were constant at the later stage of development. Increased activity of amylase and invertase reveals higher assimilation and consumption of photosynthetic products. This study revealed that plants were stressed at first. However, they gradually became acclimated to continuous light and efficiently used the excess light in carbon assimilation.

Rice seedlings were treated with different concentrations of Pb solutions or /and CO2 (Pb 0 μM + CO2 400 ± 20 μmol/mol, AC; Pb 0 μM + 800 ± 20 µmol/mol, EC; Pb 50 μM + CO2 400 ± 20 μmol/mol, L; Pb 150 μM + CO2 400 ± 20 μmol/mol, H; Pb 50 μM + CO2 400 ± 20 μmol/mol, EC + L; Pb 150 μM + CO2 800 ± 20 μmol/mol, EC + H;), so as to study the effects of Pb stress and/or elevated CO2 on growth, photosynthesis, and endogenous hormones. We measured the biomass, photosynthetic gas exchange parameters, fluorescence parameters and their curves (O-J-I-P, Variable fluorescence) and the contents and ratio of endogenous hormones in rice seedlings. The results show that: (1) Both L and H had negative effects on the growth of rice seedlings. However, H treatment had a significant negative effect on PSII of rice seedlings, but L treatment had no significant effect. In addition, JA (jasmonic acid) and ABA (abscisic acid) were significantly associated with the decrease of GS in Rice under Pb stress. (2) Under EC treatment, the secretion of growth hormones increased significantly. More importantly, the content of JA increased significantly while GS decreased, but ABA did not, which may mean that JA is more sensitive to stomatal regulation under EC. (3) Compared with L and H, EC + L and EC + H manifested in the enhancement of photosynthetic performance and adjustment of hormone ratio. Compound treatment significantly increased the ratio of “promoting-hormone to ABA” compare with L and H treatment. The biomass accumulation of rice seedlings increased significantly after being affected by changes in hormone ratios and enhanced photosynthesis. Therefore, the high concentration CO2 reduces the harm of Pb to a certain extent. However, this relief is also limited. Compared with H, EC + H has no alleviating effect on rice seedling most growth and photosynthetic parameters.

Heather, Calluna vulgaris, is a key species of European dry heath and central determinant of its conservation status. The established Calluna life cycle concept describes four phases—pioneer, building, mature, and degeneration—distinguishable by growth and vitality characteristics of undisturbed plants grown from seeds. However, little is known about the life cycle and ageing of plants subjected to severe disturbance, although measures to this effect (burning, mowing) are common in heathland management. We studied the vitality of over 400 heather plants by examining multiple morphological (plant height, long shoot and inflorescence lengths, flowering activity), anatomical (growth rings) and environmental (management, nitrogen deposition, climate) attributes. We found Calluna vitality to be mainly determined by the aboveground stem age, and that severe disturbances promote vigorous vegetative regeneration. Ageing-related shifts in the habit and vitality of plants resprouting from stem-base buds is similar to that of seed-based plants, but the former revealed higher vitality when young, at the cost of a shorter life span. In contrast, plants originating from decumbent stems resemble building-stage plants but apparently lack the capacity to re-enter a cycle including stages other than degeneration-type. As a consequence, we supplemented the established heather life cycle concept with a post-disturbance regeneration cycle of plants derived from resprouting. We conclude that management of dry lowland heathlands should include rotational small-scale severe disturbance to support both seed germination and seedling establishment as well as vegetative regeneration chiefly of young heather plants capable of resprouting from buds near rootstock.

Fluid-feeding herbivores directly affect host plants through sap consumption. Moreover, they establish mutualistic relationships with ants, which might generate additional reproductive costs related to pollinator repellence. Here we studied the drivers of variation in the outcomes of these interactions from the perspective of Psittacanthus robustus, a hummingbird-pollinated mistletoe. We hypothesized that associations between fluid-feeding insects and ants should indirectly decrease mistletoe reproduction by repelling pollinators, and directly by reducing seed size, germination, and establishment of plants presenting denser herbivore aggregations. First, we manipulated the presence of the ant Camponotus rufipes on mistletoe inflorescences to assess their effects on visitation behavior of pollinators. We correlated fruit production and fruit and seed size to abundance of fluid-feeding insects on plants. Moreover, we conducted a field experiment assessing the effects of aggregation size of fluid-feeding herbivores on seed germination and seedling establishment. Ant presence on inflorescences did not affect the visitation rates of the main pollinator, the hummingbird Eupetomena macroura. Abundance of fluid-feeding herbivores did not explain variation in fruit crop size. However, we observed a significant reduction in seed size in those plants hosting larger aggregations of fluid-feeding herbivores. The reduction in seed size did not translate into a significant decrease in seed germination nor a decrease in seedling establishment. Our results dispute previous studies highlighting negative indirect effects on plant–pollinator interactions mediated by the presence of ant–trophobiont mutualisms. Likewise, our study underscores the need of assessing fluid-feeding herbivore effects on crucial stages of the host plant life cycle to clarify fitness consequences of multitrophic interactions.

An experiment was conducted to investigate the effect of different levels of cadmium (Cd) stress on germination, morphology, physiology and yield of rice. There were five treatments, viz. control (no Cd), 0.5 mM CdCl2, 1 mM CdCl2, 1.5 mM CdCl2 and 2 mM CdCl2, carried out by a randomized complete block design (RCBD) with three replications. Cadmium stress caused a significant reduction of plant height and tillers hill-1 in a dose-dependent manner. The highest decline of relative water content and SPAD value was found at 1.5 mM (11 and 16%) and 2 mM (14 and 19%) Cd stress compared to the control. The number of effective tillers hill-1, filled grains panicle-1, 1000-grain weight, length of panicle, grain yield and straw yield reduced significantly by 44, 32, 15, 24, 37 and 45%, respectively, over the control. Germination and seedling-related parameters were recorded 10 days after germination. The lowest germination percentage (27%), germination index (27%) and seedling vigour index (49%) were observed at the highest level of Cd stress in comparison to the control. Cadmium stress resulted in maximum abnormal seedlings and markedly reduced length of root and shoot as well as their fresh and dry weight. Root shoot ratio showed differential responses to Cd stress. Thus, it can be concluded that a higher level of Cd in soil has a detrimental effect on seed germination, morphology, physiology and yield of rice.

Scots pine (Pinus sylvestris L.) seeds have variable levels of primary dormancy which reflect within-species adaptation to local environments. The objective of this study was to use a thermal time approach to determine whether primary dormancy levels in seeds were correlated with mean ambient temperature during temperature-sensitive phases of the reproductive cycle. Seedlots were obtained from a single open-pollinated clonal seed orchard in five crop years and germinated over a wide temperature range (7–35 °C) to calculate base temperature for germination with and without pre-chills (4 and 8 weeks). Primary dormancy levels varied amongst seedlots collected in different crop years (CY). Unchilled seeds were the most dormant for CY2007 (Tb = 10.9 °C) and least dormant for CY2012 (Tb = 5.6 °C). Base temperatures for germination were correlated with mean ambient temperature during different phases of the reproductive cycle. There was a strong positive correlation between base temperature for germination of unchilled seeds and mean temperature during pollination and early pollen tube growth. This suggests that maternal environmental effects during this phase could potentially select for dormant or non-dormant seeds, which has implications for tree breeding and seedling production in forest nurseries.

Stored tree seed collections are essential resources for seedling production and conserving unique germplasm. As stored seeds age, however, seed viability and seedling vigor can decline. This study tests how age and seed mass correspond to germination dynamics and seedling vigor in four white spruce collections from the upper midwestern United States. Using two seedling growth experiments, this study demonstrates that white spruce seeds stored for >30 years have low seed viability and slower seedling growth rates compared with seeds from more recent (≤10 years) white spruce collections. Seed mass also predicted seedling growth rate regardless of collection age, suggesting larger seeds from older collections generate faster growing seedlings.

Unlike animals, plant development is plastic and sensitive to environmental changes. For example, Arabidopsis thaliana seedlings display distinct growth patterns when they are grown under different light or temperature conditions. Moreover, endogenous plant hormone such as ethylene also impacts seedling morphology. Ethylene induces hypocotyl elongation in light-grown seedlings but strongly inhibits hypocotyl elongation in etiolated (dark-grown) seedlings. Another characteristic ethylene response in etiolated seedlings is the formation of exaggerated apical hooks. Although it is well known that high ambient temperature promotes hypocotyl elongation in light-grown seedlings (thermomorphogenesis), ethylene suppresses thermomorphogenesis. On another side, high ambient temperature also inhibits the ethylene-responsive hypocotyl shortening and exaggerated hook formation in etiolated seedlings. Therefore, the simplest phytohormone ethylene exhibits almost the most complicated responses, depending on temperature and/or light conditions. In this review, we will focus on two topics related to the main theme of this special issue (response to high temperature): (1) how does high temperature suppress ethylene-induced seedling morphology in dark-grown seedlings, and (2) how does ethylene inhibit high temperature-induced seedling growth in light-grown seedlings. Controlling ethylene biosynthesis through antisense technology was the hallmark event in plant genetic engineering in 1990, we assume that manipulations on plant ethylene signaling in agricultural plants may pave the way for coping with climate change in future.

Recolonization of wind-dispersed tree species in degraded areas may decline with distance from remnant forest fragments because seed rain frequently decreases with distance from the seed source. However, regeneration of these species may be even more limited to sites close to the seed source if dispersal distance is negatively affected by seed mass, and germination probability is positively affected by seed mass. We evaluated these hypotheses in a Mediterranean-type ecosystem of central Chile, using the wind-dispersed tree species Quillaja saponaria. We assessed the seed rain curve in a degraded open area adjacent to a remnant forest fragment of this species, and related seed mass with dispersal distance from the seed source. Then, we evaluated the relationship between seed mass, germination, and seedling growth, and if seeds that fall nearer the seed source have greater germination probability. We found a decreasing seed rain with the distance from the seed source. Seed mass was not related to dispersal distance, although seeds with higher wing area dispersed further. Germination probability was significantly and positively related to the seed mass. We observed no significant relationship between distance and germination probability. We conclude that germination probability of this species does not vary along the seed rain curve, and that the recruitment density would be greater near the seed source only due to decreasing seed rain with distance. Our results suggest that this species has the potential to be passively restored in degraded areas, especially within the first 70 m from the remnant forest fragments.

Mungbean is one of the important grain legumes and considered as ‘Green Pearl’ due to its nutritional significance. It is an excellent source of proteins and micronutrients and readily accessible to low income groups in arid and semi-arid regions of Africa and Asia. However, poor nutritional status of the soils in these regions limits the productivity and grain nutritional properties of mungbean. Seed priming with nutrient solutions was identified as viable and cost effective alternative to increase the crop productivity and grain nutritional properties and hence, an in-vitro experiment was conducted for optimizing the concentration of nano iron oxide (FeO) for seed priming in mungbean at Agricultural College, Bapatla, Acharya N.G.Ranga Agricultural University, Andhra Pradesh during 2018. Different concentrations of nano iron oxide were tested in completely randomized block design with three replications. The results revealed that, the nano iron oxide 50 ppm was found effective in increasing the germination percent, shoot length, root length, seedling vigour index and speed of germination of mungbean and has been considered as an optimum concentration for seed priming in mungbean.

Seedling transplanting is widely used in rice cultivation. Systemic insecticides can be delivered to seedling roots by application through rice seedling boxes before transplanting. The most challenging aspect is to provide long-term control of rice pests and overcome transplanting shock. Precise control of the release rate of insecticide can meet these requirements. Pymetrozine is a promising insecticide used for the control of rice planthoppers resistant to neonicotinoid insecticides.In this study, four controlled-release granular formulations of pymetrozine were prepared based on a mixture of cost-effective and biodegradable kaolin and xanthan gum or a mixture of calcined kaolin and xanthan gum. Fluorescence images showed that different 3D networks were formed in the four granular formulations. The four granular formulations showed different water uptake rates and release rates of pymetrozine in water. Pymetrozine release rate was positively correlated with the water uptake capacity, rather than the water uptake rate of granules. Diffusion was the dominant mechanism for the release of pymetrozine from granules. Pymetrozine was found to reduce the survival of transplanted rice seedlings suffering from transplanting shock. Incorporating pymetrozine in controlled-release granules alleviated this phytotoxicity. The survival rate of rice seedlings in granular pymetrozine treatments ranged 68.8-85.0%, whereas the survival rate was50% for powdered pymetrozine treatments. Additionally, four prepared granule formulations had a significant control effect on rice planthopper with efficacies ranging from 76.7% to 98.0% 40 days after seedling box treatment.The granule with an intermediate release rate of pymetrozine was shown to be more suitable for seedling box treatment than field application and traditional liquid spraying for the long-term control of paddy planthoppers. © 2021 Society of Chemical Industry.

Arabidopsis Cytochrome P450 85A2 (AtCYP85A2) was introduced to Arabidopsis thaliana seeds using a seed-specific promoter, pAt5g54000. GUS (β-Glucuronidase) activity and RT-PCR analysis demonstrated that AtCYP85A2 overexpression only occurred in seeds of a transgenic plant, pAt5g54000-AtCYP85A2::Col-0. A crude enzyme solution prepared pAt5g54000-AtCYP85A2::Col-0 seeds successfully catalyzed the conversion of castasterone (CS) to brassinolide (BL), which was not detected in wild-type seeds. Furthermore, a higher level of CS and BL was detected in pAt5g54000-AtCYP85A2::Col-0 seeds compared to untransformed seeds, thus demonstrating that seed-specific overexpression of AtCYP85A2 efficiently encoded a bi-functional enzyme for brassinosteroids 6-oxidase/brassinolide synthase to generate CS and BL in seeds of pAt5g54000-AtCYP85A2::Col-0. Compared to the wild type, pAt5g54000-AtCYP85A2::Col-0 produced substantially larger seeds with a high concentration of nutrients due to an enhancement in brassinosteroids signaling. Additionally, pAt5g54000-AtCYP85A2::Col-0 exhibited superior seed germination, seedling and rosette plant growth, and flower and silique formation, indicating that seed-specific AtCYP85A2 expression activates overall vegetative and reproductive growth and development in A. thaliana.

Azospirillum spp. are plant-growth-promoting rhizobacteria. The surface lectins of A. brasilense strain Sp7 and A. baldaniorum strain Sp245 can attach to specific carbohydrates, and ensure the binding of the bacteria to the root surface. We investigated possible effects of A. brasilense Sp7 and A. baldaniorum Sp245 lectins on the activities of antioxidant enzymes and on the content of low-molecular-weight antioxidants in the roots of 4-day-old wheat seedlings. The roots were exposed to a number of simulated abiotic stresses: hypothermic, hyperthermic, drought, and salinity stresses. Under all stresses, both lectins increased peroxidase and superoxide dismutase activities and decreased catalase activity. The lectins differed in the intensity of induction of changes in the amounts of the low-molecular-weight antioxidants in wheat roots. They also differed in functional activity owing to their different carbohydrate specificities and structures. The data suggest broader possibilities of lectins in terms of the effect on the metabolism of host plants, and they permit adjustments to be made to the current understanding of the mechanisms that control the associative interactions between plants and bacteria.

The famous Mexican proverb says “They tried to bury us, they did not know we were seeds”. Seeds buried under the soil find their way through the soil particles and emerge out. The mechanical pressure of the soil cover induces the production of the gaseous hormone ethylene in plants. Ethylene promotes formation of an apical hook to protect the plant tip when seedlings try to penetrate through the soil. The dark environment under the soil cover also promotes apical hook formation. Once the seedlings reach the soil surface the apical hook opens to expose the meristem and initiate the development of aerial parts. Recent studies suggest the integration of the ethylene and light signaling pathway to regulate soil emergence. Here we summarize our current understanding of how light and ethylene signals coordinate to optimize seedling establishment. This might contribute towards crop improvement programs as successful emergence is critical for survival of seeds plants in natural environments and agricultural fields.

The experiment was conducted in Seed Testing Laboratory, Department of Genetics and Plant Breeding, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.) during kharif season 2019-2021, so as to standardize the acceptable seed treatments for sorghum (Paiyur-2).Different seed priming treatments were taken into the study viz., were evaluated T1 – Zinc Sulphate @ 0.5% up to 3hours, T2 – Zinc Sulfate@1% at 4 hours, T3 – Zinc Sulfate@1.5% at 6 hours, T4 – Thiourea @ 0.5% at 3 hours, T5 – Thiourea @ 1% at 4 hours, T6 – Thiourea @ 1.5% at 6 hours, T7 – KNO3@ 0.5% at 3 hours, T8 – KNO3 @ 1% at 4 hours, T9 – KNO3 @ 1.5% at 6 hours, T10 – Moringa Leaf extract @ 3% at 8 hours, T11 – Neem leaf extract @ 3% at 8 hours, T12 – Thiourea @0.5% with Zinc Sulphate(ZnSo4) @ 0.5% at 6 hours. During this study it had been found that maximum germination percent, seedling length and vigour attributes was observed when seed treated with T10- Moringa leaf extract @ 3% followed by T9 – KNO3 @ 1.5% and minimum observed in Control (Untreated seed). Seed treatment with Moringa leaf extract @ 3% enhances germination on seedling characters and it is a simple method and no requirement for expensive equipment and chemical might be used for overcoming challenges associated with a poor germination and seedling establishment.

This study investigated the effects of potting media on seed germination and early seedling growth of Pterocarpus erinaceus Poir at the Forestry Nursery in Jos, Nigeria. Using Completely Randomized Design (CRD) with three replicates, laboratory-tested soil samples, top soil, sharp sand, sharp sand + top soil, sharp sand + top soil + cow dung and sharp sand + top soil + poultry droppings were used in various combinations to assess the growth parameters of P. erinaceus (germination percentage, emergence, plant height, number of leaves, length of leaves and stem diameter) for 12 weeks. Descriptive and inferential statistics were employed to analyze collected data. Result indicated that sharp sand + top soil + poultry droppings had the highest nitrogen concentration (2.19%), sharp sand + top soil + cow dung (2.07%), sharp sand + top soil (1.50%), top soil (0.72%) and Sharp sand (0.38%). Potting media with poultry droppings recorded an overall higher percentage germination of 42.9% by the end of the germination period. Analysis of variance (ANOVA) of collected data on combined soil aggregate on growth parameters indicated a significant (p

A new direction in pre-sowing seed preparation is environmentally friendly and energyefficient ultraviolet irradiation, which increases germination, reduces seed infection, and improves growth force. In this regard, the experiment of studying the effect of UV irradiation on the sowing qualities and morphophysiological parameters of the seeds of the birds-foot trefoil and awnless brome was laid at the UdmFRC UB RAS in 2019. Use of UV rays of range A with a wavelength of 315–400 nm for 5 min reduced the infection of the birds-foot trefoil seeds by 3.2%, increased the length of the sprout by 0.81 cm and the strength of growth — by 5.4% in comparison with untreated seeds. There was also a tendency for a decrease in seed hardness by 2.5%, an increase in root length by 0.41 cm, and the degree of seedling development by 0.12 points. The most effective for awnless brome seeds was UV treatment for 35 minutes, which led to an increase in germination by 14.5%, a decrease in seed infection by 5.8%. There was also a tendency to improve the morphological parameters of seedlings: the length of the sprout increased by 0.9 cm, the length of the root — by 0.88 cm, the length of the coleoptile — by 0.30 cm. The strength of growth in this variant was 9.3% higher than in the control without treatment. In general, the treatment of perennial grasses seeds with ultraviolet light reduced infection, increased laboratory germination and strength of growth, and reduced seed hardness.

Paddy fields contaminated with cadmium (Cd) present decreased grain yield and produce Cd-contaminated grains. Screening for low-Cd-accumulating cultivars is a useful method to reduce the amount of Cd in the grains. The present study aimed to examine the roles of the root morphology and anatomy in Cd translocation and accumulation in rice plants. Twenty-two rice cultivars were used in the first experiment, after which two cultivars [Zixiangnuo (ZXN) and Jinyou T36 (JYT36)] were selected and used in subsequent experiments under hydroponic conditions. The results showed that there were significant differences in Cd concentrations in the shoots (ranging from 4 to 100 mg/kg) and the Cd translocation rates (shoot/root) (from 7% to 102%) among the 22 cultivars, and the shoot Cd concentration was significantly correlated with the Cd translocation rate of the 22 cultivars under 0.1 mg/L Cd treatment. Compared with cultivar ZXN, JYT36 had greater root Cd uptake and accumulation but lower shoot Cd accumulation and Cd translocation rate. The number of root tips per surface area of cultivar ZXN was greater than that of JYT36, while the average root diameter was lower than that of JYT36. Compared with ZXN, JYT36 had stronger apoplastic barriers, and the Casparian bands and suberin lamellae in the root endodermis and exodermis were closer to the root apex in both the control and Cd treatments, especially for suberin lamellae in the root exodermis with Cd treatments, with a difference of 25 mm. The results also showed that, compared with ZXN, JYT36 had greater percentages of Cd bound in cell walls and intracellular Cd but lower Cd concentrations in the apoplastic fluid under the Cd treatment. The results suggested that Cd translocation, rather than root Cd uptake, is a key process that determines Cd accumulation in the rice shoots. The root morphological and anatomical characteristics evidently affect Cd accumulation in the shoots by inhibiting Cd translocation, especially via the apoplastic pathway. It was possible to pre-screen low-Cd-accumulating rice cultivars on the basis of their root morphology, anatomical characteristics and Cd translocation rate at the seedling stage.

This study investigated the effects of illumination time and soil moisture on seed germination and seedling establishment of Magnolia sprengeri Pamp. to improve the seed germination percentage and seedling survival percentage of M. sprengeri. It is of great significance for rapid propagation, seedling regeneration, field management, and artificial high-efficiency cultivation of M. sprengeri. In this study, the seeds of natural M. sprengeri populations from original habitat were used as test materials. Seed germination and seedling establishment of M. sprengeri were performed under different illumination time and soil moisture treatments in artificial climate incubator. The study found that there were significant differences among various key parameters related to seed germination and seedling establishment under different treatments (P < 0.05). Germination percentage, germination potential, germination index, vigor index, germination rate, plant height, number of leaves, base diameter, taproot length, number of lateral roots, maximum lateral root length, single plant leaf area, fresh weight, and seedling survival rate reached the maximum at continuous illumination and 13% of soil moisture, respectively. By the integrative evaluation for the influence of these two factors on seed germination and seedling establishment, soil moisture is a dominant factor affecting seed germination and seedling establishment, whereas illumination is an important promoting factor for seedling establishment of M. sprengeri. Continuous illumination and 13% of soil moisture content is suitable for seed germination and seedling establishment of M. sprengeri.

A new phosphatidylinositol transporter gene was isolated from the T-DNA insertion mutant libraries of rice. The RT-PCR and GUS staining showed that it belonged to embryo specific expression gene. The phonotype of growth and development revealed that the growth was slower and leaf yellowing than that of wild type before 5-leaf stage in rice seedlings, and it was completely restored until to 5-leaf stage. Further, the transcriptome sequencing results showed that the gene affected the nitrogen metabolism signal pathway between mutant and wild type. In addition, our study revealed an important phosphatidylinositol transporter protein which can control the growth development and promote nitrate transporter and absorption in rice seedling stage.

Graphical abstract, Introduction Sunflower seeds possess higher oil content than do cereal crop seeds. Storage of sunflower seeds is accompanied by loss of seed vigor and oxidation of storage and membrane lipids. Objectives This study first reported that compound sodium nitrophenolate (CSN), a new plant growth modulator, improved the germination and seedling emergence of aged sunflower seeds. The present study provide a future reference as to the potential applications of CSN and the regulation mechanism of exogenous substances in increasing aged crop seed vigor. Methods Phenotypic analysis was performed to investigate the effect of CSN on germination and seedling emergence from naturally- and artificially-aged sunflower seeds. The biochemical and enzyme activity analysis were conducted to test the CSN-induced effect on glycometabolism, fatty acid and abscisic acid metabolism. Meanwhile, gene expression analysis was carried out to detect the changes in the transcription level of sunflower seeds during early germination period after CSN treatment. Results CSN application significantly increased the germination rate and seedling emergence rate of sunflower seeds under natural and artificial aging. Biochemical analysis indicated that, CSN treatment significantly enhanced the sucrose and fructose contents in aged sunflower seeds during early germination period. Moreover, the contents of several different fatty acids in CSN-treated sunflower seeds also significantly increased. Enzyme activity analysis revealed that CSN treatment remarkably up-regulated the activities of several critical enzymes related to triacylglycerol hydrolysis. Consequently, the transcription levels of the above key enzymes-related synthetic genes were also significantly up-regulated in CSN treatment. Furthermore, CSN treatment significantly decreased abscisic acid (ABA) content through the regulation of the gene expressions and activities of metabolism related-enzymes. Conclusion Taken together, the contribution of CSN to the improvement of aged sunflower seed germination and seedling emergence might be closely related to the fatty acid, glycometabolism, and ABA metabolism.

Water deficit inhibits maize (Zea mays L.) seedling growth and yield. Application of exogenous melatonin can improve drought tolerance of corn, but little is known regarding the transcriptional mechanisms of melatonin-mediated drought tolerance in maize. Increased understanding of the effects of melatonin on maize plants under drought stress is vital to alleviate the adverse effects of drought on food production in the future. The aim of this investigation was to use physiological and transcriptome analyses for exploring the possible mechanisms of exogenous melatonin against drought stress in maize. In this study, maize seedlings were subjected to drought stress and some were treated with exogenous melatonin. The physiological results showed that melatonin inhibited H2O2 accumulation and promoted the scavenging of excessive reactive oxygen species to reduce oxidative damage in maize leaves. Transcriptomic analysis identified 957 differentially expressed genes between melatonin and non-melatonin treatment groups. Further detailed analyses suggested that melatonin-regulated genes are mainly related to glutathione metabolism, calcium signaling transduction, and jasmonic acid biosynthesis. Some transcription factor families, such as WRKY, AP2/ERF-ERF, MYB, NAC, and bZIP, were also activated by exogenous melatonin. Moreover, crosstalk between melatonin and other hormones that mediate drought tolerance was observed. In conclusion, the combination of physiological and transcriptome analyses revealed some mechanisms underlying the role of melatonin in alleviating drought; knowledge of these mechanisms may assist in successful maize cultivation under drought stress.

Fluensulfone (FSF) becomes increasingly popular because of its nonfumigation application method. However, studies on the metabolic mechanism of FSF in plants are lacking. Here, tomato seedling was cultivated in hydroponic media to investigate the connection among FSF's metabolism in tomato, the regulation of tomato endogenous glycosides, and the elimination of hydrogen peroxide in tomato cells. The accumulation of FSF was only detected in the lower stems of tomatoes; FSF was mainly metabolized into S-glycosylated conjugates in the roots, and the roots were the tissues with the highest metabolite content; and no FSF and metabolites were detected in the upper leaves. In response to FSF stress (2 mg/L for 7 d), the content of sugar and glycosides in the stems of tomato seedlings significantly increased. The amount of some compounds on the pathway related to glucose was affected by FSF. The three precursor compounds (homomethioine, isoleucine, and l-tyrosine) in the pathway of glucosinolate biosynthesis increased significantly under the stress of FSF, which indicates that FSF may compete with them for UGT74B1. Besides, FSF-induced flavonoid glycosides may play a role in the process of removing hydrogen peroxide. This research provides inspiration for the fate of many xenobiotics containing sulfonyl groups in plants.

The inessential heavy metal/loids cadmium (Cd) and arsenic (As), which often co-occur in polluted paddy soils, are toxic to rice. Silicon (Si) treatment is known to reduce Cd and As toxicity in rice plants. To better understand the shared mechanisms by which Si alleviates Cd and As stress, rice seedlings were hydroponically exposed to Cd or As, then treated with Si. The addition of Si significantly ameliorated the inhibitory effects of Cd and As on rice seedling growth. Si supplementation decreased Cd and As translocation from roots to shoots, and significantly reduced Cd- and As-induced reactive oxygen species generation in rice seedlings. Transcriptomics analyses were conducted to elucidate molecular mechanisms underlying the Si-mediated response to Cd or As stress in rice. The expression patterns of the differentially expressed genes in Cd- or As-stressed rice roots with and without Si application were compared. The transcriptomes of the Cd- and As-stressed rice roots were similarly and profoundly reshaped by Si application, suggesting that Si may play a fundamental, active role in plant defense against heavy metal/loid stresses by modulating whole genome expression. We also identified two novel genes, Os01g0524500 and Os06g0514800, encoding a myeloblastosis (MYB) transcription factor and a thionin, respectively, which may be candidate targets for Si to alleviate Cd and As stress in rice, as well as for the generation of Cd- and/or As-resistant plants. This study provides valuable resources for further clarification of the shared molecular mechanisms underlying the Si-mediated alleviation of Cd and As toxicity in rice.

Improving germination and seedling establishment can effectively increase crop yields. Cold plasma (CP) seed priming can be used as an emerging tool to improve germination efficiency and increase seedling growth. The effects of CP seed priming for different time periods (5 and 10 min) on germination, seedling growth, seedling root morphology, photosynthetic pigments, antioxidant defense system and nutrient uptake of Cuminum cyminum L. (cumin) were investigated. Seed priming with 5 and 10 min CP improved the germination efficiency and germination index by increasing the water absorption capacity of the seeds. CP seed priming for 5 min induced growth, biomass production, proline content and antioxidant defense system of cumin seedlings. Seed pretreatment with 5 min CP enhanced nutrient uptake by increasing root growth, volume and area surface and, consequently, improved photosynthetic pigment contents and growth of cumin seedling. However, 10 CP pretreatment induced oxidative stress and damage to membrane lipids by excessively increasing the level of active species (H2O2 and superoxide anion), resulting in reduced seedling growth and biomass compared to control ones. Therefore, seed priming with CP at the appropriate time duration can be a promising tool to increase germination efficiency and improve seedling establishment in aromatic and medicinal plants.

Seed-borne Streptomyces can transmit vertically from generation to generation and be a mutualism between the endosymbionts and hosts. The aim of this study was to isolate and characterize endophytic Streptomyces strains from wheat sprouts, and to investigate their protection against wheat seed pathogenic fungi Penicillium. Endophytic Streptomyces sp. F6 and Streptomyces sp. F39 were isolated from wheat sprouts germinated under sterile conditions. Both Streptomyces strains could produce siderophores, and showed antagonistic activities against the seed pathogenic fungi Penicillium sp. Z17. The inoculation of Streptomyces sp. F39 and F6 could protect wheat seed germination and promote seedling growth under Penicillium sp. Z17 infection. However, the protection efficiency was impacted by the Streptomyces spore concentrations, the concentration ratios of Streptomyces spores to pathogen spores, and inoculation methods. The results suggested that wheat sprouts harbored diverse endophytic Streptomyces species which derived from wheat seeds, these strains should be more likely transmitted to the next generation, and confer competitive ability to pathogens on the offspring. Owing to the more intimate correlation between sprout endophytic flora with host plants, these strains are more suitable for mature plant interiors compared with those from rhizosphere soils and root interiors.