Search Results (341)

To elucidate the molecular mechanisms underlying anther abortion in celery male sterile lines, this study investigates the morphological differences of floral organs and differential gene expression patterns between two lines at the flowering stage. Using the male sterile line of celery ‘QCBU-001’ and the fertile line ‘Jinnan Shiqin’ as materials, anther structure was analyzed by paraffin sections, and related genes were detected using transcriptome sequencing and qRT-PCR. The results indicated that the anther locules were severely shrunken at maturity in the sterile lines. The callose deficiency led to abnormal development of microspores, preventing the formation of mature pollen grains and ultimately leading to complete anther abortion. The transcriptome results revealed that 3246 genes were differentially expressed in sterile and fertile lines, which were significantly enriched in pathways such as starch and sucrose metabolism and phenylpropanoid biosynthesis. Additionally, differential expression patterns of transcription factor families (MYB, bHLH, AP2, GRAS, and others) suggested their potential involvement in regulating anther abortion. Notably, the expression level of callose synthase gene AgGSL2 was significantly downregulated in sterile anthers, which might be an important cause of callose deficiency and pollen sterility. This study not only provides a theoretical basis for elucidating the molecular mechanism underlying male sterility in celery but also lays a foundation for the utilization and improvement of male sterile lines in vegetable hybrid breeding. Full article

Actinidia arguta is a dioecious plant, and the selection of superior male germplasm is crucial for ensuring effective pollination of female cultivars, maximizing their economic traits, and achieving high-quality yields. This study evaluated 30 male germplasms for pollen quantity, germination capacity, storage characteristics, and ultrastructural features. Results revealed significant variation in pollen germination rates (1.56–96.57%) among germplasms, with ‘Lvwang’, ‘TL20083’, and ‘TG06023’ performing best (all >90% germination). The storage characteristics study demonstrated that −80 °C is the optimal temperature for long-term pollen storage in A. arguta. Significant variations were observed in storage tolerance among different germplasms. Among them, Lvwang exhibited the best performance, maintaining a germination rate of 97.40% after 12 months of storage at −80 °C with no significant difference from the initial value, followed by TT07063. Pollen morphology was closely correlated with fertility. High-fertility pollen grains typically exhibited standard prolate or ultra-prolate shapes, featuring a tri-lobed polar view and an elliptical equatorial view, with neat germination furrows and clean surfaces. In contrast, low-fertility pollen grains frequently appeared shrunken and deformed, with widened germination furrows and visible exudates. Based on these findings, the following recommendations are proposed: ① Prioritize the use of germplasms with pollen germination rates >80% as pollinizers; ② Establish a rapid screening system based on pollen morphological characteristics. This study provides important scientific basis for both male germplasm selection and efficient cultivation practices in A. arguta (kiwiberry). Full article

Nectar robbing typically reduces nectar availability to pollinators, damages flower structure, and/or induces secondary robbing. Consequently, it may reduce pollen deposition and seed set, increase pollination efficiency and outcrossing, and/or not affect reproduction in some species. However, spatiotemporal variations in nectar robbing and their effects on plant reproduction have received little attention. In this study, we assessed the effects of nectar robbing on floral visits, seed set, nectar volume and concentration, and flower longevity in two populations of Salvia castanea Diels (Lamiaceae) in the Himalayan region of Southwestern China in 2014–2020. We also examined whether one or a few visits by pollinators can result in the stigma receiving sufficient pollen to fertilize all ovules of S. castanea. We found that significant differences in the nectar robbing rate did not affect seed set in any of the years for either population of S. castanea. In the robbed and unrobbed flowers, nectar was consistently replenished every night at higher concentrations. Bagging, nectar robbing, and sufficient pollination did not affect flower longevity. Salvia castanea required only 5–10 pollen grains to achieve the maximum seed set. However, pollinators depositing more than 10 pollen grains after a single visit ensured a high seed set of >80%. Our results suggest that nectar availability, floral longevity maintenance, and sufficient pollen deposition mitigate the effects of nectar robbing on the reproductive success of S. castanea. These results are expected to further our understanding of plant–animal interactions and the ecological consequences of nectar robbing. Full article

The pollen coat is the outermost layer of pollen and plays a key role in successful pollination and environmental adaptation. It consists of lipids, proteins, and phenolic compounds that protect pollen from environmental stress, promote hydration, and enable a proper interaction with the stigma. However, many questions remain unanswered, such as what the components of the pollen coat are and how they are formed, as well as how defects in the pollen coat affect the normal function of pollen. This review highlights the molecular mechanisms behind the biosynthesis and transport of pollen coat components and their contributions to pollen hydration, pollination compatibility, and fertility. Moreover, we discuss the role of selected gene families in pollen coat formation and their potential impact on agricultural breeding, paving the way for the breeding of more efficient crops. Full article

This study evaluated the influence of different male date palm cultivars, distinguished by their chloroplast haplotypes, on pollen quality, pollination efficiency, metaxenia effects, and gene expression during fruit development. Chloroplast DNA analysis of 37 male trees revealed multiple haplotypes, from which cultivars B25, P8, C22, and B46 were selected for further investigation. Pollen viability varied significantly among cultivars, with P8 and B25 exhibiting the highest germination rates and pollen tube elongation, while C22 showed the lowest. These differences correlated with pollination success: P8 and B25 achieved fertilization rates near 99%, whereas C22 remained below 43%. Pollination outcomes also varied in fruit traits. Despite its low pollen performance, C22 induced the production of larger fruits at the Bleh (Kimri) stage, potentially due to compensatory physiological mechanisms. Phytochemical profiling revealed significant cultivar effects: fruits from B25-pollinated trees had with lower moisture and polyphenol content but the higher sugar levels and soluble solids, suggesting accelerated maturation. Ripening patterns confirmed this finding, with B25 promoting the earliest ripening and B46 causing the most delayed. Gene expression analysis supported these phenotypic differences. Fruits pollinated by P8, B25, and B46 exhibited elevated levels of cell-division-related transcripts, particularly the PdCD_1 gene (PDK_XM_008786146.4, a gene encoding a cell division control protein), which was most abundant in P8. In contrast, fruits from C22-pollinated trees had the lowest expression of growth-related genes, suggesting a shift toward cell expansion rather than division. Overall, the results show the critical role of male genotype in influencing fertilization outcomes and fruit development, offering valuable insights for targeted breeding strategies at enhancing date palm productivity and fruit quality. Full article

A combination of high potential productivity and ecological stability is essential for current cultivars, which is achievable by breeding. Interspecific/intergeneric hybridization remains a key approach to producing new high-yielding and resistant cultivars. Interspecific reproductive barriers (IRBs) appear in the interaction between the pollen and pistil of interspecific/intergeneric hybrids. The mechanisms underlying these hybridization barriers are to a considerable degree unknown. The pollen–pistil interaction is decisive because the pollen of distantly related plant species either is not recognized by stigma cells or is recognized as foreign, preventing pollen tube (PT) germination and/or penetration into the stigma/style/ovary. This review mainly focuses on (1) the pollen–pistil system; (2) IRB classification; (3) similarity and differences in the function of self-incompatibility (SI) barriers and IRBs; and (4) physiological and biochemical control of IRBs and their overcoming. The main goal is to illuminate the physiological, biochemical, and molecular mechanisms underlying the growth arrest of incompatible PTs and their death. In general, this review consolidates the current understanding of the interaction of the male gametophyte with the sporophyte tissues of the pistil and outlines future research directions in the area of plant reproductive biology. Full article

The undertaking of distant hybridization holds paramount significance for the innovation of tea germplasm resources and the cultivation of superior, specialized tea varieties. However, challenges manifest during the process of tea plant distant hybridization breeding, with reproductive barriers impeding the successful acquisition of hybrid progeny; the precise stages at which these barriers occur remain unclear. In this study, utilizing Camellia sinensis cv. Jinxuan as the maternal parent, as well as C. gymnogyna Chang and C. sinensis cv. Yinghong No.9 as the paternal parents, interspecific distant hybridization (DH) and intraspecific hybridization (IH) were conducted. The investigation involved the observation of pollen germination and pollen tube behavior on the stigma, the scrutiny of the developmental dynamics of the ovary post-hybridization, and the examination of the stages and reasons for reproductive disorders during tea tree distant hybridization. The findings indicate that both IH and DH exhibit pre-fertilization barriers. The pre-embryonic development of hybrids obtained from DH is normal, but there is a significant fruit drop during the stage of fruit development. The germination rate of mature seeds obtained from DH is low, and there are pronounced post-fertilization disorders, which are the primary reasons for the difficulty in achieving successful tea plant distant hybridization. An analysis of the genetic variation in phenotypes and chemical components in the progeny after distant hybridization revealed widespread variation and rich genetic diversity. The identification of progeny with a high amino acid and caffeine content holds promise for future production and breeding, providing valuable theoretical references for the selection of parents in the creation of low-caffeine-content tea germplasm resources. Full article

The gene flow rate in rice (Oryza sativa L.) is a critical factor for establishing safe isolation distances between genetically modified (GM) and non-GM varieties and for ensuring varietal purity in rice breeding programs. This study refines existing gene flow models by disentangling two key components of rice pollen dynamics: quantitative pollen competition and genetic competitiveness. We define B as the proportion of GM pollen within mixed pollen, representing quantitative pollen competitiveness. The outcrossing parameter C_b reflects the likelihood of successful fertilization and seed development by foreign pollen, while the hybrid compatibility parameter C_p captures the relative fertilization success of GM versus non-GM pollen within the same pollen pool. Together, C_b and C_p characterize the genetic competitiveness of rice pollen. Our findings reveal a nonlinear relationship between B and the observed GM pollen rate G, which may exhibit either upward or downward curvature. A nonlinear model provides a significantly better fit to this relationship than a linear model, improving R² by 4.1–21.4% and reducing RMSE by 9.9–47.8%. The parameters C_b and C_p play central roles in determining gene flow; higher values correspond to stronger GM pollen competitiveness, resulting in higher gene flow rates and greater dispersal distances. Specifically, C_b sets the range of the B–G curve, while C_p determines its curvature. Full article

Cotton exhibits indeterminate growth potential at its apical meristem. In field cultivation, it is often necessary to restrict plant height by the foliar application of plant growth regulators or artificial topping. The genetic engineering of cotton architecture offers an efficient, environmentally friendly, and low-cost alternative to current field management. Our study aimed to improve the plant architecture of transgenic cotton by the suppression of GhSP, a key flowering repressor, via the RNA interference method. Sixteen independent transgenic lines were generated and classified as mildly, moderately, and severely suppressed, according to GhSP expression levels. Field evaluation revealed the dose-dependent effects of GhSP silencing on plant height. The mildly suppressed line GhSPi-#5 exhibited a semi-dwarf phenotype of approximately 70~100 cm in height. Negative phenotypes, including excessive dwarf plant architecture and inferior fiber quality and yield traits, were observed in severely GhSP-suppressed transgenic lines. Notably, the mild silencing of GhSP in GhSPi-#5 did not negatively affect leaf and flower organ growth, pollen fertility, major agronomic traits, or fiber quality compared with the wild type. These observations demonstrate the feasibility of manipulating the architecture of transgenic cotton via GhSP silencing. Full article

N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) and N-phenyl-1,2,3-thidiazole-5ylurea (TDZ) are plant growth regulators used for seedless treatment in grape. In this study, the flowers of ‘Shine Muscat’ (Vitis labruscana Bailey × V. vinifera L.) were treated with 3, 5, and 10 mg/L CPPU and TDZ one week before flowering. The results showed that both CPPU and TDZ treatments reduced the pollen germination rate and caused abnormal stamen and pollen grain phenotypes, resembling the male sterility observed in ‘Y_14’ (a novel grapevine germplasm derived from the self-progeny of ‘Shine Muscat’). Using RNA-seq technology, the stamens of flowers treated with 10 mg/L CPPU (CPPU_10), 10 mg/L TDZ (TDZ_10), and the control (CK) were analyzed. A total of 520 and 722 differentially expressed genes (DEGs) were identified in CPPU and TDZ treatments, respectively. GO and KEGG analyses revealed that the common pathways leading to pollen abortion in both treatments were primarily associated with hydrolase activity (acting on glycosyl bonds), phenylpropanoid biosynthesis, pentose and glucuronate interconversions, and ABC transporters. By comparing the DEGs across the three groups (Y_14 vs. SM, CPPU_10 vs. CK, TDZ_10 vs. CK), 16 DEGs exhibited similar expression patterns. Further tissue-specific expression analysis identified nine genes that were highly expressed in stamens and shared the same expression pattern in sterile lines. These findings provide a foundation for further studies on the impact of CPPU and TDZ treatments on grape stamen fertility. Full article

Amberboa moschata (L.) DC. (Asteraceae) is an endangered species, listed in the Red Book of Plants of the Republic of Armenia. The restricted extent of occurrence and habitat degradation necessitate conservation measures of this species, not only in the wild but also through ex situ cultivation. This study examines the comprehensive morpho-phenological, karyological, palynological, eco-physiological, and ornamental characteristics of A. moschata in the context of ex situ conservation. A. moschata plants cultivated ex situ demonstrated high adaptive traits, undergoing a full development cycle and experiencing less water stress compared to wild populations. The diploid cytotype has been found for the species to be 2n = 32, the karyotype is asymmetric, with chromosomes, 0.77–1.91 µm in size. The average pollen fertility of A. moschata is high, 96.7–96.9% in both natural and cultivated samples. A scale of decorativeness was developed, which includes 15 characteristics of the plant, providing an objective means to assess its visual appeal. The scale can be useful for integrating A. moschata into various landscaping schemes. Under cultivation, the total ornamental period lasts approximately 98 days, with the peak ornamental effect observed during the flowering phase, which spans 68–70 days. The study recommends A. moschata for inclusion in living collections in botanical gardens and for use in ornamental gardening and landscaping as part of its ex situ conservation strategy. A map, original photographs, and tables illustrate the article. Full article

Agroforestry systems are essential in sustainable land use in the face of the growing global food demand and climate change. The southern region of Bahia, Brazil, is one of the places in the world where the tree species is particularly in abundance, primarily in cocoa agroforestry systems, contributing to biodiversity conservation. Understanding their reproductive patterns is crucial for the survival and sustainability of these trees. This study dealt with Lecythis pisonis (Sapucaia) trees by applying microsatellite markers for mixed-mating mode and paternity analyses for pollen dispersal. In particular, it was found that Lecythis pisonis offspring are produced through outcrossing, as the case may be, while random crossings and no nearby tree fertilization are the remaining factors that play a crucial role in myriad genetic diversity inversions. This phenomenon was indicated by paternity in nine offspring, with full siblings being from the same parents. The average distance of pollen flow was 6 km, which is why the pollinator, the bee Xylocopa frontalis, has a flight range aligning with distance. These data show the influence of habitat fragmentation, the function of Cabruca, and the conservation strategy. Full article

Heat stress during the flowering stage induces a remarkable decrease in rice spikelet fertility, mainly due to poor pollination manifesting as insufficient pollen deposited on the stigma. It is hypothesized that stigma exsertion, which confers a pollination advantage, may enhance pollen reception and improve female reproductive success under heat stress. The present study aimed to investigate the role of stigma exsertion in spikelet fertility under nocturnal heat. Four rice cultivars exhibiting distinct heat tolerance and twenty rice cultivars with varying degrees of stigma exsertion were grown and subjected to high nighttime temperature treatment at anthesis, in 2023 and 2019, respectively. Heat-tolerant rice cultivars had a relatively low percentage of spikelets with exserted stigmas, and vice versa. Under nocturnal heat stress, rice cultivars exhibiting higher stigma exsertion showed significantly greater reductions in spikelet fertility compared to lower stigma exsertion cultivars. The spikelet fertility of rice cultivars with a higher degree of stigma exsertion was reduced more seriously than that of cultivars with a lower degree of stigma exsertion. Rice spikelet fertility positively correlated with the percentage of hidden stigmas, and exogenous substance-induced increased stigma exsertion led to reduced spikelet fertility under nocturnal heat. These results indicate that a hidden stigma contributes to higher spikelet fertility, while increased stigma exsertion aggravates spikelet sterility in rice cultivars under nocturnal heat conditions. It is proposed that hidden stigmas could serve as a novel breeding trait for sustaining rice spikelet fertility against nocturnal heat stress. Full article

Pollination is essential for producing temperate-zone tree fruits like apples (Malus × domestica). While traditionally considered insect-dependent, this view may result from orchard designs tailored to European honeybees. Previous research showed that low-seed apples could develop in insect exclusion nets, suggesting wind as an alternative pollinator. This study investigated the paternal origin of seeds and fruit set under nets compared to open canopies. Netted canopies of ‘Gala’, Fuji’, and ‘Honeycrisp’ set commercial fruit numbers without manual thinning. To determine the parental source of seeds, genotyping was performed using 16 SNP markers tailored for distinguishing apple cultivars, with primer design and genotyping conducted via the KASP™ system. Results showed significant genetic overlap between seeds from netted and non-netted fruits and nearby pollinizers, ruling out self-pollination. Netted canopies retained fruits with similar or fewer seeds compared to abscised fruits in open canopies, indicating fruit set depends on the population’s seed content rather than individual fruit seed count. These findings supporting the hypothesis that apple trees are adapted to utilize both wind and insect pollination. While wind pollination offers a sustainable approach, it requires adjustments in orchard design to ensure sufficient pollen transfer for reliable fertilization and yield. Full article

Apple production in Western Norway faces challenges due to climatic constraints and varying phenology. It is essential for cultivars to adapt to regional ecological factors, while suitable pollinators are necessary for successful cultivation. This study examined the reproductive biology of two newly introduced apple cultivars, ‘Eden’ (Wursixo) and ‘Fryd’ (Wuranda), over two years (2022–2023). Key qualitative and quantitative parameters of reproductive biology were analyzed, including in vitro pollen germination, pollen tube growth within the style and ovary locules, flowering overlap time, and fruit set. The study involved cross-pollination between the pollen recipient cultivars ‘Eden’ and ‘Fryd’, with various pollenizers: ‘Rubinstep’, ‘Red Aroma’, ‘Elstar’, ‘Asfari’ and ‘Professor Sprenger’, as well as self-pollination and open pollination. According to the results from the progamic phase of fertilization and fruit set, the cultivars ‘Rubinstep’, ‘Asfari’, and ‘Fryd’ were the best pollenizers for ‘Eden’. In contrast, ‘Rubinstep’, ‘Eden’, and ‘Elstar’ were the best pollenizers for ‘Fryd’. Looking only at the overlapping of the flowering time between pollen recipient and pollen donor, ‘Professor Sprenger’ and ‘Fryd’ were the best pollenizers for ‘Eden’, while ‘Professor Sprenger’ and ‘Eden’ were good pollenizers for ‘Fryd’. Full article