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One of the first cellular locations of the calreticulin (CRT) chaperone in eukaryotic cells, apart from its obvious localization in the endoplasmic reticulum (ER), was the cell nucleus (Opas et al. 1991). The presence of CRT has been detected inside the nucleus and in the nuclear envelope of animal and plant cells, and a putative nuclear localization signal (NLS) in the CRT amino acid sequence has been mapped in several animal and plant species. Over the last 30 years, other localization sites of this protein outside the ER and cell nucleus have also been discovered, suggesting that CRT is a multifunctional Ca2+-binding protein widely found in various cell types. In our previous studies focusing on plant developmental biology, we have demonstrated the presence of CRT inside and outside the ER in highly specialized plant cells, as well as the possibility of CRT localization in the cell nucleus. In this paper, we present a detailed analysis of immunocytochemical localization of CRT inside nuclei of the pistil transmission tract somatic cells before and after pollination. We show a similar pattern of the nuclear CRT localization in relation to exchangeable Ca2+ for two selected species of angiosperms, dicotyledonous Petunia and monocot Haemanthus, that differ in anatomical structure of the pistil and discuss the potential role of CRT in the cell nucleus. [ABSTRACT FROM AUTHOR]

Based on morphological observations, molecular phylogenetic analyses and literature consultations, a new species of Gesneriaceae, Petrocodon mirus, is described and illustrated here. This new species exhibits morphological similarity with P. pulchriflorus and P. hechiensis, but is easily distinguished from the latter two by its slightly leathery leaf blade, liner to ligulate‐oblong lip lobes, and shorter tube with constriction at middle. In addition, the new species differs from P. pulchriflorus by its reflexed adaxial lip lobes, and from P. hechiensis by its included stamen and pistil. However, the stigma of P. mirus is much similar to the chiritoid stigma diagnostic for ChiritaBuch.‐Ham. ex Don (now mostly included in Primulina); based on this observation a new hypothesis for the evolution of the chiritoid stigma is proposed. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a complex mechanism that prevents plants from self-fertilizing to preserve and promote genetic variability. The angiosperm species have developed two different SI systems, the sporophytic (SSI) and the gametophytic (GSI) systems. SI is a significant impediment to steady fruit production in fruit tree species of the Rosaceae. In Rosaceae, GSI is genetically regulated via a single locus, named the 'S-locus', which includes a minimum of two polymorphic and relatively intercorrelated S genes: a pistil-expressed S-RNase gene and several pollen-expressed SFBB (S-locus F-Box Brothers) or SFB (S haplotype-specific F-box protein). This necessitates the interaction of S-RNases with the male determinants. Although genetic and molecular analyses of S genes have shown that mutations in both pistils and pollen-specific components induce self-compatibility in many species and cultivars, other genes or molecules outside the S-locus can co-participate in the male gamete rejection in GSI. However, we highlight and synthesize the most recent knowledge on different mechanisms of GSI in Rosaceae in this current review. [ABSTRACT FROM AUTHOR]

Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F 5:6 generation plants derived from inter-subspecific crosses (Nipponbare × KDML105) with low (LS) and high seed-setting rates (HS), in which normal pollen fertility was observed. However, LS plants showed a reduced number of pollen grains adhering to the stigma and fewer pollen tubes reaching the ovules at 4‒5 h post-pollination, compared with HS plants. Bulked segregant RNA-Seq analysis of pollinated pistils from the HS and LS groups revealed 249 and 473 differentially expressed genes (DEGs), respectively. Kyoto Encyclopedia of Genes and Genomes analysis of the HS and LS- specific DEGs indicated enrichment in metabolic pathways, pentose and glucuronate interconversions, and flavonoid biosynthesis. Several of these DEGs exhibited co-expression with pollen development genes and formed extensive clusters of co-expression networks. Compared with LS pistils, enzyme genes controlling pectin degradation, such as OsPME35 and OsPLL9 , showed similar expression patterns, with higher levels in HS pistils pre-pollination. Os02g0467600 , similar to cinnamate 4-hydroxylase gene (CYP73), involved in flavonoid biosynthesis, displayed higher expression in HS pistils post-pollination. Our findings suggest that OsPME35 , OsPLL9 , and Os02g0467600 contribute to prezygotic isolation by potentially modifying the stigma cell wall (OsPME35 and OsPLL9) and controlling later processes such as pollen-stigma adhesion (Os02g0467600) genes. Furthermore, several DEGs specific to HS and LS were co-localized with QTLs and functional genes associated with spikelet fertility. These findings provide valuable insights for further research on rice spikelet fertility, ultimately contributing to the development of high-yielding rice varieties. [ABSTRACT FROM AUTHOR]

Periwinkle (Catharanthus roseus (L.) G. Don) is renowned for its diverse colors and resilience to harsh climates. Still, most commercial cultivars predominantly display flat petals. Using cultivars representing non-wavy, medium-wavy, and extreme-wavy flower forms, we examined morphological differences in both their mature leaves and floral organs. Phenotypes of self-pollinated (S1) and cross-pollinated (F1, F2) populations further underscored their morphological distinctions. Specifically, the extreme-wavy type displayed elliptical leaves, broader than the non-wavy type, with a pronounced acute apex and a notably wrinkled blade surface. The non-wavy type also bore intensely wavy petal margins and exhibited a smaller flower diameter, with a notable absence of a functional pistil, indicating female sterility. The insights gained allowed for early differentiation during the seedling period. This study suggests that the inheritance of these flower forms is regulated by an allele WAVY (Wv), which exhibits incomplete dominance. Concretely, the non-wavy form arises from a recessive homozygous expression (wvwv), the extreme-wavy from a dominant homozygous expression (WvWv), and the medium-wavy from a heterozygous expression (Wvwv). This study provides clarity on morphological descriptions and inheritance patterns of wavy flower forms, facilitating strategic breeding of diverse flower forms in periwinkle. [ABSTRACT FROM AUTHOR]

Primulina guarouba, a new species from the limestone area of northern Guangxi, China, is described and illustrated. According to the maximum likelihood (ML) and Bayesian inference (BI) analysis, it nests in a strongly supported clade (BP = 99%) that includes P. cordifolia, P. repanda and P. huangii. Of these, P. guarouba is similar to the P. cordifolia in morphology, but it is easily distinguished from the latter by some of the distinct characters in leaf blade, peduncles, bracts, calyx, corolla, pistil. [ABSTRACT FROM AUTHOR]

The article explores the process of ovule abortion and its implications for the invasiveness and seed dispersal of Hyptis suaveolens Lamiaceae Poit species. The study examines the anthesis and dehiscence of anthers, stigma receptivity, path of pollen tubes under fluorescence microscope, pollen-ovule ratio, and time and duration of visits of insects on the flower. It evaluates the total number of pistils with ovule abortion and floral morphology.

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Cherry (Prunus avium) fruits are important sources of vitamins, minerals, and nutrients in the human diet; however, they contain a large stone, making them inconvenient to eat 'on the move' and process. The exogenous application of gibberellic acid (GA3) can induce parthenocarpy in a variety of fruits during development. Here, we showed that the application of GA3 to sweet cherry unpollinated pistils acted as a trigger for fruit set and permitted the normal formation of fruit up to a period of twenty-eight days, indicating that gibberellins are involved in the activation of the cell cycle in the ovary wall cells, leading to fruit initiation. However, after this period, fruit development ceased and developing fruit began to be excised from the branch by 35 days post treatment. This work also showed that additional signals are required for the continued development of fully mature parthenocarpic fruit in sweet cherry. [ABSTRACT FROM AUTHOR]

Pitaya flower, a medicinal and edible plant commonly used in tropical and subtropical regions, was the focus of this study, which compared the effects of hot-air drying (HAD) and vacuum drying (VD) on phytochemical profiles and biological activities of its four parts: calyx, petals, stamens, and pistils. Both drying methods significantly increased the total phenolic content (TPC) of pitaya flowers, with values ranging from 1.86 to 3.24 times higher than those of fresh samples. Twelve flavonoid compounds were identified in pitaya flowers, with the glycoside derivatives of three flavonols (kaempferol, isorhamnetin, and quercetin) being the most abundant. VD resulted in 1.15 times higher total flavonoid glycoside content than HAD, whereas in petals, HAD yielded a total flavonoid glycoside content 1.21 times higher than VD. Both HAD and VD effectively increased the antioxidant capacities of pitaya flowers, though the difference between the two methods was not significant. Additionally, both drying methods enhanced the antiproliferative activity of pitaya flowers, with HAD showing a more significant effect than VD. The present study emphasized the efficacy of drying methods for enhancing flavonoids in pitaya flowers and provided insights for functional products' innovation with different parts of pitaya flowers. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a crucial mechanism that prevents self-fertilization and inbreeding in flowering plants. Citrus exhibits SI regulated by a polymorphic S -locus containing an S-RNase gene and multiple S -locus F-box (SLF) genes. It has been documented that S-RNase functions as the pistil S determinant, but there is no direct evidence that the SLF genes closely linked with S-RNase function as pollen S determinants in Citrus. This study assembled the genomes of two pummelo (Citrus grandis) plants, obtained three novel complete and well-annotated S -haplotypes, and isolated 36 SLF or SLF-like alleles on the S -loci. Phylogenetic analysis of 138 SLFs revealed that the SLF genes were classified into 12 types, including six types with divergent or missing alleles. Furthermore, transformation experiments verified that the conserved S6-SLF7a protein can lead to the transition of SI to self-compatibility by recognizing non-self S8-RNase in 'Mini-Citrus' plants (S 7 S 8 and S 8 S 29 , Fortunella hindsii), a model plant for citrus gene function studies. In vitro assays demonstrated interactions between SLFs of different S haplotypes and the Skp1–Cullin1–F-box subunit CgSSK1 protein. This study provides direct evidence that SLF controls the pollen function in Citrus , demonstrating its role in the 'non-self recognition' SI system. [ABSTRACT FROM AUTHOR]

The objective of this study was to characterize the reproductive compatibility among cultivars and selections of Japanese plum through controlled pollination, both in vivo and in situ, to obtain a profile of reproductively compatible cultivars. In situ and in vivo self-pollinations were carried out in an F1 population of Japanese plum, and in vivo pollinations were conducted on the pollen-grain receptor cultivars: Laetitia, Zafira and Fortune, and the pollen-grain donor cultivars: Piamontesa, Selection Plum 86-13, Harry Pickstone, Black Amber, Bruce, SC-17, Laetitia, SC-15, SC 7, Zafira, Amarelinha, América, Reubennel and Fortune, to verify the percentage of germination of pollen grains and growth of pollen tubes in the pistils of the recipient plants. The in situ and in vivo assays for the F1 population confirm the self-compatibility of genotypes 13 and 35. The Laetitia cultivar is self-incompatible; however, it is compatible with the Selection 'Plum 86-13'. 'Zafira' is self-incompatible. 'Fortune' is compatible with 'Amarelinha', 'SC-7', 'America', 'Harry Pickstone' and 'Reubennel', but it is self-incompatible. [ABSTRACT FROM AUTHOR]

The development of Ceanothus perplexans Trelease (Rhamnaceae) flowers was observed during April in 2023 and 2024 in the Cerbat Mountains of western Arizona. Flowers are strongly protandrous, with anthers dehiscing inside flower buds. Nectar is produced when flowers begin to open; the anthers are exposed; and the pistil is short and blue or purple. Fully open flowers lack most pollen and produce abundant nectar surrounding an elongated, pale pistil with blue or purple stigmas. Most flowers begin opening during the morning and become fully open during midday. Flowers in each inflorescence open on different days within a 4-day time span, and inflorescences on each shrub flower at around the same time. Flower development resembles other species in the family, except for differences in the timing of pollen and nectar production, and separates pollen acquisition and deposition by pollinating insects. [ABSTRACT FROM AUTHOR]

Previous studies have shown that ethylene levels in flower buds are key to sex determination in plants. However, the roles of ethylene in wheat flower development are poorly understood. In this study, pistillody wheat HTS-1 (three-pistil trait), CM28TP (three-pistil trait), CS (one-pistil trait), and CM28 (one-pistil trait) were used as experimental materials. The effect of exogenous ethephon (ETH) and 1-methylcyclopropene (1-MCP) on the morphology of wheat flowers and candidate genes in the ethylene signaling pathway was investigated. The results revealed that exogenous ETH or 1-MCP treatment had a strong effect on the stamens but not on the pistils of wheat. Specifically, after treatment with ETH, the stamens of CS and CM28 became significantly shorter, while in CM28TP, 71.38% of stamens were homologously transformed into pistils or pistil-like structures (pistillody). Moreover, after treatment with 1-MCP, the pistillody stamens of HTS-1 were transformed back into stamens, and the pistillody rate decreased from 73.61 to 55.25%. Furthermore, pistillody occurred in three-pistil wheat but not in one-pistil wheat, so the three-pistil trait was closely related to the occurrence of pistillody. In addition, the expression of the ethylene transduction genes TaETR1, TaCTR1, and TaEIN2 and the ethylene response gene TaERF was upregulated under pistillody. Among them, TaCTR1 presented the highest level under pistillody, being 150 times in HTS-1 and 103 times higher in CM28TP treated with ETH than in CM28TP. Moreover, the ERELEE4 cis-acting element was found upstream of the TaCTR1 gene promoter and could facilitate homologous transformation of stamens into pistils or pistil-like structures. The results lay a theoretical foundation for analyzing the effect of ethylene on wheat flower development and supply important information for wheat hybrid breeding. [ABSTRACT FROM AUTHOR]

[Objective] The present study aimed to provide key information for an in-depth exploration of the reasons behind the low yield of Prunus salicina var. Fengtangli by analyzing the process of flower bud differentiation and flowering in Fengtangli. [Method] A relatively high- yielding plum variety, Mili No. 1, was selected as the control. The external characteristics and size of flower buds in Fengtangli and Mili No. 1 were observed. The anatomical structure, deformities and the number of flower primordia were studied using the paraffin section method. The flowering process, flower quantity and the occurrence of abnormal flowers were also investigated. (Result) Both Fengtangli and Mili No. 1 plums experienced undifferentiated, initial differentiation, sepal primordia differentiation, petal primordia differentiation, stamen primordia differentiation, and pistil primordia differentiation phases during flower bud differentiation. Although the initiation time of flower bud differentiation in Fengtangli was similar to Mili No. 1, the peak period of differentiation in Fengtangli occurred relatively early, mainly concentrated from mid-September to the end of October. Furthermore, Fengtangli exhibited a higher occurrence of abnormal flower buds during the peak period, with fewer flower primordia differentiated in each bud. During the flowering period, the flower quantity of Fengtangli was significantly lower than that of other plum varieties, and a higher frequency of short pistils and double pistils in abnormal flowers was observed. Continued observation revealed that late-stage double pistil flowers could develop into deformed double fruits. [Conclusion] The peak period of flower bud differentiation and the occurrence of abnormal flower buds in Fengtangli are from mid-September to the end of October. Fengtangli has a higher proportion of deformities in flower buds, and each flower bud differentiates fewer flower primordia. These factors contribute to the higher occurrence of abnormal flowers and lower flower quantity during flowering, potentially explaining one of the reasons for the low yield of Fengtangli plum. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a complex mechanism that prevents plants from self-fertilizing to preserve and promote genetic variability. The angiosperm species have developed two different SI systems, the sporophytic (SSI) and the gametophytic (GSI) systems. SI is a significant impediment to steady fruit production in fruit tree species of the Rosaceae. In Rosaceae, GSI is genetically regulated via a single locus, named the ‘S-locus’, which includes a minimum of two polymorphic and relatively intercorrelated S genes: a pistil-expressed S-RNase gene and several pollen-expressed SFBB (S-locus F-Box Brothers) or SFB (S haplotype-specific F-box protein). This necessitates the interaction of S-RNases with the male determinants. Although genetic and molecular analyses of S genes have shown that mutations in both pistils and pollen-specific components induce self-compatibility in many species and cultivars, other genes or molecules outside the S-locus can co-participate in the male gamete rejection in GSI. However, we highlight and synthesize the most recent knowledge on different mechanisms of GSI in Rosaceae in this current review.

The interaction between miRNAs (microRNAs) and target genes plays an important role in plant pistil development. MiRNAs related to pistils were explored in pomegranate. The differentially expressed miRNAs were screened at different developmental stages of pomegranate pistils, and their target differentially expressed mRNAs were further identified to clarify the regulatory effect of miRNAs on pistil development. In our study, 61 conserved miRNAs were identified in 30 families, including miR395, miR394, miR393, miR161, miR162, and miR168. Among them, miR156, miR157, miR159, miR160, miR164, miR165, miR166, miR167, miR169, and miR172 were involved in the development of flower organs. Eight miRNAs were randomly selected and verified for qRT-PCR analysis. The result analysis indicated that miR160, miR164, and miR172 might be positive factors in the regulation of pomegranate pistil development. MiR156 and miR166 might be involved in regulation of pomegranate pistil development as negative factors. [ABSTRACT FROM AUTHOR]

Floral fragrance, as one of the evaluation indicators for ornamental plants, influences people's perception of these plants. To explore the volatile compounds and their application value in different parts of Iris typhifolia and to investigate the contributions of each part to the floral aroma, an AIRSENSE electronic nose, principal component analysis (PCA), linear discriminant analysis (LDA), and loading analysis (Loading) are employed to study the differences in floral components among the various parts. Samples from the stamen, pistil, flag petal, and pendant petal are qualitatively and quantitatively analyzed using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC-MS) techniques, combined with spectral library retrieval, cluster analysis, and Odor Activity Value (OAV) calculation. The results show that the electronic nose significantly distinguished the aromas from different parts, and there are significant differences in aroma composition. Through cluster analysis and OAV calculation, it is found that the pistil makes the primary contribution to the floral profile of Iris typhifolia, due to the presence of caproaldehyde, 2-methoxy-3-sec-butylpyrazine, and abundant terpenes. This research provides a valuable reference for reconstructing the floral aroma profile, extracting bioactive substances, and exploring aromatherapy with Iris typhifolia. [ABSTRACT FROM AUTHOR]

Sulforaphene is an isothiocyanate which is produced by the hydrolysis from glucoraphenin, one of glucosinolates mostly found in radish plant. This study evaluates the genetic diversity of sulforaphene contents from the seedlings of 29 radish genotypes in an attempt to find a variety with a high extraction yield and which can be used as a breeding source of intergeneric hybrid vegetable Baemuchae. The sulforaphene content was highest in the seedlings of 'Cheongwoonplus' (1,426.8 mg kg− 1 FW) and 'Taebaek' (1,363.3 mg kg− 1 FW) cultivars and lowest in the 'Matchuimbom' (328.7 mg kg− 1 FW) cultivar. The sulforaphene contents of four radish cultivars and three Baemuchae varieties sharply decreased during seedling growth; however, they were much higher in the seedlings of radish cultivars than in Baemuchae varieties. The sulforaphene contents in unpollinated pistil tissues were not affected by species, whereas they responded differently to the cultivar or variety. After pollination, the sulforaphene content gradually increased in radish cultivars during seed development, but relatively much less in Baemuchae varieties. These results indicated that the sulforaphene content varied widely in the seedlings of radish cultivars. Sulforaphene gradually accumulated after pollination during seed development in radish cultivars, but not much in Baemuchae varieties. However, not much difference was observed in the sulforaphene contents of unpollinated pistil tissues of radish and baemoochae. [ABSTRACT FROM AUTHOR]

The ultrastructure of stigmatic and stylar secretory tissues was studied in one cultivar of Pyrus communis and six cultivars of Pyrus pyrifolia var. culta (the so-called Nashi pear) using standard light, scanning, and transmission electron microscopy methods. Although both tissues secreted an extracellular fluid necessary for the development of male gametophyte, they differed markedly in the ultrastructure of the extracellular matrix and in the distribution and ultrastructure of organelles. The difference was most evident in regard to the endoplasmic reticulum, which represented the rough, smooth, and vesicular type in stigmatic papillate epidermis and distal stigmatoid tissue cells and occurred mainly as the rough type in form of expanded cisternae filled with fine-fibrillar content in the transmitting tissue of the style.

SUMMARY: Switch defective/sucrose non‐fermentable (SWI/SNF) chromatin remodeling complexes are evolutionarily conserved, multi‐subunit machinery that play vital roles in the regulation of gene expression by controlling nucleosome positioning and occupancy. However, little is known about the subunit composition of SPLAYED (SYD)‐containing SWI/SNF complexes in plants. Here, we show that the Arabidopsis thaliana Leaf and Flower Related (LFR) is a subunit of SYD‐containing SWI/SNF complexes. LFR interacts directly with multiple SWI/SNF subunits, including the catalytic ATPase subunit SYD, in vitro and in vivo. Phenotypic analyses of lfr‐2 mutant flowers revealed that LFR is important for proper filament and pistil development, resembling the function of SYD. Transcriptome profiling revealed that LFR and SYD shared a subset of co‐regulated genes. We further demonstrate that the LFR and SYD interdependently activate the transcription of AGAMOUS (AG), a C‐class floral organ identity gene, by regulating the occupation of nucleosome, chromatin loop, histone modification, and Pol II enrichment on the AG locus. Furthermore, the chromosome conformation capture (3C) assay revealed that the gene loop at AG locus is negatively correlated with the AG expression level, and LFR‐SYD was functional to demolish the AG chromatin loop to promote its transcription. Collectively, these results provide insight into the molecular mechanism of the Arabidopsis SYD‐SWI/SNF complex in the control of higher chromatin conformation of the floral identity gene essential to plant reproductive organ development. Significance Statement: This study provides insight into the molecular mechanism of the Arabidopsis SYD‐SWI/SNF complex in the control of higher chromatin conformation of the floral identity gene essential to plant reproductive organ development. [ABSTRACT FROM AUTHOR]

Leucojum aestivum is a perennial bulbous plant belonging to the Amaryllidaceae family. Climate change causes an increase in the danger of plant species extinction by producing negative effects on biodiversity and geographical distribution of species. In this study, phenological observations were obtained from L. aestivum populations, which are naturally distributed in Bursa Karacabey, then the morphological characteristics were determined. Also, MaxEnt programme was used to determine the current and future potential distribution areas of the L. aestivum populations in terms of climate change. The plant height of L. aestivum was determined to be an average of 60.92 土 10.38 cm. The width of the bulbs was 31.30 土 6.77 mm on average, and also the mean length was 34.67 土 6.22 mm. The mean weight was 21.35 土 11.74 g. The mean width of the broad linear leaves is 12.61 土 3.50 mm and also 51.53 土 15.38 cm for their mean length. The mean width of the white flowers was 22.97 土 4.01 mm and mean length was 20.56 土 1.80 mm. The mean flower stalk length was found to be 36.62 土 17.33 mm. The number of flowers was an average of 5.54 土 1.21. The mean anther length was 8.98 土 1.01 mm. The mean length of the pistil was found to be 11.93 土 0.84 mm. The mean width of the fruits was 20.86 土 3.62 mm. The number of fruits was found to be a minimum of 1 and maximum of 7 with an average of 2.12 土 1.61. The mean width of the seeds was 6.58 土 0.50 mm; and also the number of seeds was found to be at least 1 and at most 26 with an average of 8.16 土 4.90. According to the outputs of the two scenarios, which we evaluated as mild or strict, while no situation was present that would endanger the extinction of the species in Turkey over the next 80 years based on the SSP1-2.6 scenario; however serious reductions in the distribution areas of the species based on the SSP5-8.5 scenario. For this reason, in-situ and ex-situ conservation measures should be taken according to the species and their habitat requirements, and it is suggested to impose various conservation based sanctions and restrictions apart from these measures. [ABSTRACT FROM AUTHOR]

Purpose. To study in vitro the morphological and cytological characteristics of anthers, pollen and pistils of plants of the genus Miscanthus. Methods. Preparations of pistils, unpollinated seed buds, anthers and pollen, unstained or stained with a solution of carmine (2%) in acetic acid (45%) or methylene blue solution, were examined by light microscopy. Measurements for plants of different Miscanthus species, as well as counting the number of pollen of different diameters, were made in ten replicates. Results. The morphological and cytological characteristics of the reproductive organs of M. sinensis, M. sacchariflorus and M. giganteus species were studied. It was found that the flower of this plant is monoecious, containing both stamens and a pistil. The color of the anthers is yellow or pinkish-yellow, their tissues consist of elongated cells 70-100 μm long. The pistil has a two-column ovary with long (2.0-2.8 mm) pinnate stigmas which vary in color from white to bright pink. The shape of the pistil feather is moderately branched; length - 160-300 μm; width - 20-30 μm; alternate position; the number of small branches is 10-15 pcs. The pollen of different Miscanthus species differ in qualitative and quantitative characteristics, in particular in M. sinensis and M. sacchariflorus it is characterized by a rounded shape, evenness and uniformity (43-48 μm in diameter), whereas in M. giganteus it is more heterogeneous in size (23-45 μm in diameter). The pollen has a rounded, decorated pore with a diameter of 2.7-4.0 μm. Conclusions. According to the results of the conducted research, the morphological and cytological characteristics of the reproductive organs of M. sinensis, M. sacchariflorus and M. giganteus, namely: pistils, anthers and pollen, were provided. The data obtained should be taken into account in future breeding for the production of di- and triploid Miscanthus hybrids. [ABSTRACT FROM AUTHOR]

The interaction between miRNAs (microRNAs) and target genes plays an important role in plant pistil development. MiRNAs related to pistils were explored in pomegranate. The differentially expressed miRNAs were screened at different developmental stages of pomegranate pistils, and their target differentially expressed mRNAs were further identified to clarify the regulatory effect of miRNAs on pistil development. In our study, 61 conserved miRNAs were identified in 30 families, including miR395, miR394, miR393, miR161, miR162, and miR168. Among them, miR156, miR157, miR159, miR160, miR164, miR165, miR166, miR167, miR169, and miR172 were involved in the development of flower organs. Eight miRNAs were randomly selected and verified for qRT-PCR analysis. The result analysis indicated that miR160, miR164, and miR172 might be positive factors in the regulation of pomegranate pistil development. MiR156 and miR166 might be involved in regulation of pomegranate pistil development as negative factors.

Abstract Heat stress during gametogenesis leads to spikelet sterility. To ascertain the role of female reproductive organ (pistil), two rice genotypes N22 and IR64 with contrasting heat stress responses were exposed to control (30 °C) and heat stress (38 °C and 40 °C) during megasporogenesis. Anatomical observations of ovule revealed greater disappearance of megaspore mother cell and nuclei at early stages, and during later stages mature embryo sac without female germ unit, improper positioning of nuclei, and shrunken embryo sac was observed in the sensitive IR64. Under heat stress, a decrease in sugar and starch, increase in H2O2 and malondialdehyde with lower antioxidant enzyme activities were recorded in pistils of both N22 and IR64. Lower accumulation of TCA cycle metabolites and amino acids were noticed in IR64 pistils under heat stress at gametogenesis, whereas N22 exhibited favorable metabolite profiles. At heading, however, N22 pistils had higher carbohydrate accumulation and better ROS homeostasis, suggesting higher recovery after heat stress exposure. In summary, the results indicate that heat stress during megasporogenesis leads to irreversible anatomical and physiological changes in pistil and alters metabolic signatures leading to increased spikelet sterility in rice. Mechanisms identified for enhanced heat tolerance in pistil can help in developing rice varieties that are better adapted to future hotter climate.

High night temperature (HNT) impairs crop productivity through the reproductive failure of gametes (pollen and pistil). Though female gametophyte (pistil) is an equal partner in the seed-set, the knowledge of the antioxidant system(s) and hormonal control of HNT tolerance or susceptibility of pistils is limited and lacking. The objectives of this study were to determine the antioxidant mechanism for homeostatic control of free radicals, and the involvement of abscisic acid (ABA) and gibberellic acid (GA3) in HNT stress protection in the wheat pistils of contrasting wheat genotypes. We hypothesized that HNT tolerance is attributed to the homeostatic control of reactive oxygen species (ROS) and hormonal readjustment in pistils of the tolerant genotype. The ears of two contrasting wheat genotypes—HD 2329 (susceptible) and Raj 3765 (tolerant) were subjected to two HNTs (+5 °C and +8 °C) over ambient, in the absence and presence of dimethylthiourea (DMTU), a chemical trap of hydrogen peroxide (H2O2). Results showed that HNTs significantly increased ROS in pistils of susceptible genotype HD 2329 to a relatively greater extent compared to tolerant genotype Raj 3765. The response was similar in the presence or absence of DMTU, but the H2O2 values were lower in the presence of DMTU. The ROS levels were balanced by increased activity of peroxidase under HNT to a greater extent in the tolerant genotype. Cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) activity was inversely related to H2O2 production within a critical range in Raj 3765, indicating its modulation by H2O2 levels as no change was observed at the transcriptional level. The hormonal status showed increased ABA and decreased GA3 contents with increasing temperature. Our study elucidates the role of H2O2 and GA3 in stress tolerance of pistils of tolerant genotype where GAPC acts as a ROS sensor due to H2O2-mediated decrease in its activity. [ABSTRACT FROM AUTHOR]

Plant specific SHORT INTERNODES/STYLISH (SHI/STY) protein is a transcription factor involved in the formation and development of early lateral organs in plants. However, research on the SHI/STY protein family is not focused enough. In this article, we review recent studies on SHI/STY genes and explore the evolution and structure of SHI/STY. The biological functions of SHI/STYs are discussed in detail in this review, and the application of each biological function to modern agriculture is discussed. All SHI/STY proteins contain typical conserved RING-like zinc finger domain and IGGH domain. SHI/STYs are involved in the formation and development of lateral root, stem extension, leaf morphogenesis, and root nodule development. They are also involved in the regulation of pistil and stamen development and flowering time. At the same time, the regulation of some GA, JA, and auxin signals also involves these family proteins. For each aspect, unanswered or poorly understood questions were identified to help define future research areas. This review will provide a basis for further functional study of this gene family. • The evolution and structure of SHI/STY genes are explored. • The formation and development of lateral root, stem, leaf, nodule, pistil and stamen and flowering are associated with SHI/STYs. • The regulation of GA, JA, and auxin signals also involves these family proteins. [ABSTRACT FROM AUTHOR]

Due to its great medicinal value, the Moldavian dragonhead, belonging to Lamiaceae, is naturally distributed in Europe, Siberia, and Central Asia and planted in different Iranian provinces. This research studied the development of male/female reproductive organs. Flowers and buds in different stages of development were fixed and preserved in order to prepare microtome sections using appropriate solutions and embed them in paraffin. Hematoxylin-eosin was used to stain the slices. Based on the results, despite the relative simultaneity of the formation of stamen primordium and carpel, stamens develop faster than ovules. Nurses' cells in secretory and plasmodium types are rectangular, spindle-shaped, and often mononuclear or more. The microspore's tetrads had tetrahedral ornamentations, and mature pollen grains were hexacolpate with reticulate ornamentation of the exine. The ovules were anatropous, unitegmic, and tenuinucellate. The functional megaspore has a micropillar position, and the embryo sac development belongs to the Polygonum type. [ABSTRACT FROM AUTHOR]

Flower bud differentiation is a key component of plant blooming biology and understanding how it works is vital for flowering regulation and plant genetic breeding, increasing the number and quality of flowering. Red soil is the most widely covered soil type in the world, and it is also the most suitable soil type for crape myrtle planting. The flower buds of crape myrtle (Lagerstroemia indica) planted in red soil were employed as experimental materials in this study, and the distinct periods of differentiation were identified using stereomicroscopy and paraffin sectioning. We optimized the steps of dehydration, transparency, embedding, sectioning and staining when employing paraffin sections. When seen under a microscope, this optimization can make the cell structure of paraffin sections obvious, the tissue structure complete, and the staining clear and natural. The flower bud differentiation process is divided into 7 periods based on anatomical observations of the external morphology and internal structure during flower bud differentiation: undifferentiated period, start of differentiation period, inflorescence differentiation period, calyx differentiation period, petal differentiation period, stamen differentiation period, and pistil differentiation period. The differentiation time is concentrated from the end of May to mid-June. Crape myrtle flower bud differentiation is a complicated process, and the specific regulatory mechanism and affecting elements need to be investigated further. [ABSTRACT FROM AUTHOR]

We present a new interferometer to measure piston, tip and tilt of segmented mirrors, using the combination of an optical grating and a microlens array. Since this interferometer is able to collect all the incident light and to operate with a large spectra bandwidth, it is particularly suitable to operate in low light level conditions, for example for the co-phasing of segmented primary mirrors like James Webb Space Telescope. We tested our new device on a 37-segment deformable mirror and obtained an accuracy better than λ / 100. The measurement is self-referenced and errors can be estimated on the measurement itself thanks to closure relationships. • Error can be evaluated on the measurement itself thanks to closure relationships. • The interferometer is optimized for low-light level applications. • The redundance of reconstruction method increases the signal-to-noise ratio. • The set-up is proposed in two configurations for facilitating technologies choices. [ABSTRACT FROM AUTHOR]

Floral fragrance, as one of the evaluation indicators for ornamental plants, influences people’s perception of these plants. To explore the volatile compounds and their application value in different parts of Iris typhifolia and to investigate the contributions of each part to the floral aroma, an AIRSENSE electronic nose, principal component analysis (PCA), linear discriminant analysis (LDA), and loading analysis (Loading) are employed to study the differences in floral components among the various parts. Samples from the stamen, pistil, flag petal, and pendant petal are qualitatively and quantitatively analyzed using solid-phase microextraction (SPME) and gas chromatography–mass spectrometry (GC-MS) techniques, combined with spectral library retrieval, cluster analysis, and Odor Activity Value (OAV) calculation. The results show that the electronic nose significantly distinguished the aromas from different parts, and there are significant differences in aroma composition. Through cluster analysis and OAV calculation, it is found that the pistil makes the primary contribution to the floral profile of Iris typhifolia, due to the presence of caproaldehyde, 2-methoxy-3-sec-butylpyrazine, and abundant terpenes. This research provides a valuable reference for reconstructing the floral aroma profile, extracting bioactive substances, and exploring aromatherapy with Iris typhifolia.

Abstract Background The fragrant flower plant Osmanthus fragrans has an extremely rare androdioecious breeding system displaying the occurrence of males and hermaphrodites in a single population, which occupies a crucial intermediate stage in the evolutionary transition between hermaphroditism and dioecy. However, the molecular mechanism of androdioecy plant is very limited and still largely unknown. Results Here, we used SWATH-MS-based quantitative approach to study the proteome changes between male and hermaphroditic O. fragrans pistils. A total of 428 proteins of diverse functions were determined to show significant abundance changes including 210 up-regulated and 218 down-regulated proteins in male compared to hermaphroditic pistils. Functional categorization revealed that the differentially expressed proteins (DEPs) primarily distributed in the carbohydrate metabolism, secondary metabolism as well as signaling cascades. Further experimental analysis showed the substantial carbohydrates accumulation associated with promoted net photosynthetic rate and water use efficiency were observed in purplish red pedicel of hermaphroditic flower compared with green pedicel of male flower, implicating glucose metabolism serves as nutritional modulator for the differentiation of male and hermaphroditic flower. Meanwhile, the entire upregulation of secondary metabolism including flavonoids, isoprenoids and lignins seem to protect and maintain the male function in male flowers, well explaining important feature of androdioecy that aborted pistil of a male flower still has a male function. Furthermore, nine selected DEPs were validated via gene expression analysis, suggesting an extra layer of post-transcriptional regulation occurs during O. fragrans floral development. Conclusion Taken together, our findings represent the first SWATH-MS-based proteomic report in androdioecy plant O. fragrans, which reveal carbohydrate metabolism, secondary metabolism and post-transcriptional regulation contributing to the androdioecy breeding system and ultimately extend our understanding on genetic basis as well as the industrialization development of O. fragrans.

Heat stress during gametogenesis leads to spikelet sterility. To ascertain the role of female reproductive organ (pistil), two rice genotypes N22 and IR64 with contrasting heat stress responses were exposed to control (30 °C) and heat stress (38 °C and 40 °C) during megasporogenesis. Anatomical observations of ovule revealed greater disappearance of megaspore mother cell and nuclei at early stages, and during later stages mature embryo sac without female germ unit, improper positioning of nuclei, and shrunken embryo sac was observed in the sensitive IR64. Under heat stress, a decrease in sugar and starch, increase in H2O2 and malondialdehyde with lower antioxidant enzyme activities were recorded in pistils of both N22 and IR64. Lower accumulation of TCA cycle metabolites and amino acids were noticed in IR64 pistils under heat stress at gametogenesis, whereas N22 exhibited favorable metabolite profiles. At heading, however, N22 pistils had higher carbohydrate accumulation and better ROS homeostasis, suggesting higher recovery after heat stress exposure. In summary, the results indicate that heat stress during megasporogenesis leads to irreversible anatomical and physiological changes in pistil and alters metabolic signatures leading to increased spikelet sterility in rice. Mechanisms identified for enhanced heat tolerance in pistil can help in developing rice varieties that are better adapted to future hotter climate. [ABSTRACT FROM AUTHOR]

MADS-box genes play an important role in many developmental processes in plants, especially in flower organogenesis. Yellowhorn (Xanthoceras sorbifolium Bunge) is a monoecious plant, its male and female flowers are formed due to the abortion of flower organs at the later stages of flower development. To investigate the functions of MADS-box genes in flower development, we conducted a comprehensive analysis of MADS-box genes across the yellowhorn genome and discovered 79 XsMADS genes. The analysis of the transcriptome revealed that the XsMADS genes displayed distinct expression patterns during the flower development process. XsSTK showed an upward trend during the critical period for pistil formation and specifically expressed a high level in normal pistil. Moreover, XsSTK over-expression transgenic Arabidopsis exhibited an abnormal phenotype, with swollen ovary, shorter and thicker siliques, suggesting that XsSTK might contribute to ovary development. These findings offer a thorough and organized examination of the MADS-box genes in yellowhorn and lay a foundation for further analyzing the mechanism of sex differentiation in yellowhorn and cultivating new varieties with high-yield and quality. • The kernel oil of yellowhorn is rich of nerve acids, our study is beneficial for increasing the yield of nerve acids. • The first report of a comprehensive and systematic analysis of the yellowhorn MADS-box genes. • It identified the function of XsSTK in ovary development and analyzed the role in sex differentiation of yellowhorn. [ABSTRACT FROM AUTHOR]

• Peliosanthes meghalayensis, a new species from Wari Chora gorge in Meghalaya, NE India, described and illustrated. • Similar to P. pumila from Khasia, NE India, but differs chiefly by knobby rhizome, broader leaf blades, closer transversal veinlets, slightly larger cernuous flowers, and pistils with 6 distinct ridges. • P. subspicata, a rare plant is rediscovered in Assam, NE India, known only by old collections made in NE India and Bangladesh in the 19th century. • Supplemental description and illustration based on living collections provided. • P. bipiniana treated as conspecific with P. subspicata. Peliosanthes meghalayensis , a new species from Wari Chora gorge in Meghalaya, NE India, is described and illustrated. It is similar to P. pumila from Khasia, NE India, in its small habit and having flowers fewer than 10, but differs chiefly by the knobby rhizome, broader leaf blades with closer transversal veinlets, slightly larger cernuous flowers, and pistils with 6 distinct ridges. On the other hand, in Assam, NE India, we rediscovered P. subspicata , which had been known only by old collections made in NE India and Bangladesh in the 19th century. We supplementarily describe and illustrate it based on living collections. We treated P. bipiniana as conspecific with P. subspicata. [ABSTRACT FROM AUTHOR]

Summary: Style length is a major determinant of breeding strategies in flowering plants and can vary dramatically between and within species. However, little is known about the genetic and developmental control of style elongation.We characterized the role of two classes of leaf adaxial–abaxial polarity factors, SUPPRESSOR OF GENE SILENCING3 (SGS3) and the YABBY family transcription factors, in the regulation of style elongation in Mimulus lewisii. We also examined the spatiotemporal patterns of auxin response during style development.Loss of SGS3 function led to reduced style length via limiting cell division, and downregulation of YABBY genes by RNA interference resulted in shorter styles by decreasing both cell division and cell elongation. We discovered an auxin response minimum between the stigma and ovary during the early stages of pistil development that marks style differentiation. Subsequent redistribution of auxin response to this region was correlated with style elongation. Auxin response was substantially altered when both SGS3 and YABBY functions were disrupted.We suggest that auxin signaling plays a central role in style elongation and that the way in which auxin signaling controls the different cell division and elongation patterns underpinning natural style length variation is a major question for future research. [ABSTRACT FROM AUTHOR]

To the better management of spring frost problem in the apricot cultivars, evaluation of biochemical changes in flower and/or flower organs during bud break could be one of the key factors. In this study, the relationship between the biochemical metabolites such as amino acids and minerals in the receptacle and pistil organs of two different apricot cultivars (frost-sensitive and frost-tolerant) and their relative effects on the frost tolerance of the cultivars and their organs were investigated during full blooming stage. In both apricot cultivars, it was found that the cell death points (CDP) of flower receptacle (− 6.3 to − 8.4 °C) were at higher temperatures than the CDP of flower pistil organs (− 13.1 to − 14.5 °C). Receptacle organs in flower, therefore, had less tolerance to spring frost damage. In addition, significant differences in mineral and amino acid contents were detected both between apricot cultivars and between the receptacle and pistil organs of the cultivars. Amino acid and mineral contents were lower both in the freezing-sensitive apricot cultivar ("Mihralibey") and the freezing-sensitive organ (receptacle) in comparison with the freezing-tolerant apricot cultivar ("Iğdır Şalak") and the freezing-tolerant organ (pistil). A significant negative correlation was also observed between the mean CDP values and both amino acid and mineral contents in the receptacle and pistil organs of both apricot cultivars. A negative correlation was found between CDP values and glutamate from amino acids and N, K, and Mg from minerals, and also these were determined that they had positive effects on frost tolerance increase. An important finding from our work revealed that the amount of each mineral and amino acid allocated differently to the receptacle and pistil organs of the apricot cultivars. The understanding of the amino acids and the mineral dynamics may contribute to improving the tolerance of flowers of apricot or other deciduous species to frost damage during spring. In the future, we may conclude that protection strategies such as increasing amino acids and mineral content in the receptacle organ of flowers would be necessary to cope with the negative effects of spring frost. [ABSTRACT FROM AUTHOR]

High night temperature (HNT) impairs crop productivity through the reproductive failure of gametes (pollen and pistil). Though female gametophyte (pistil) is an equal partner in the seed-set, the knowledge of the antioxidant system(s) and hormonal control of HNT tolerance or susceptibility of pistils is limited and lacking. The objectives of this study were to determine the antioxidant mechanism for homeostatic control of free radicals, and the involvement of abscisic acid (ABA) and gibberellic acid (GA3) in HNT stress protection in the wheat pistils of contrasting wheat genotypes. We hypothesized that HNT tolerance is attributed to the homeostatic control of reactive oxygen species (ROS) and hormonal readjustment in pistils of the tolerant genotype. The ears of two contrasting wheat genotypes—HD 2329 (susceptible) and Raj 3765 (tolerant) were subjected to two HNTs (+5 °C and +8 °C) over ambient, in the absence and presence of dimethylthiourea (DMTU), a chemical trap of hydrogen peroxide (H2O2). Results showed that HNTs significantly increased ROS in pistils of susceptible genotype HD 2329 to a relatively greater extent compared to tolerant genotype Raj 3765. The response was similar in the presence or absence of DMTU, but the H2O2 values were lower in the presence of DMTU. The ROS levels were balanced by increased activity of peroxidase under HNT to a greater extent in the tolerant genotype. Cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) activity was inversely related to H2O2 production within a critical range in Raj 3765, indicating its modulation by H2O2 levels as no change was observed at the transcriptional level. The hormonal status showed increased ABA and decreased GA3 contents with increasing temperature. Our study elucidates the role of H2O2 and GA3 in stress tolerance of pistils of tolerant genotype where GAPC acts as a ROS sensor due to H2O2-mediated decrease in its activity.

Background: The fragrant flower plant Osmanthus fragrans has an extremely rare androdioecious breeding system displaying the occurrence of males and hermaphrodites in a single population, which occupies a crucial intermediate stage in the evolutionary transition between hermaphroditism and dioecy. However, the molecular mechanism of androdioecy plant is very limited and still largely unknown. Results: Here, we used SWATH-MS-based quantitative approach to study the proteome changes between male and hermaphroditic O. fragrans pistils. A total of 428 proteins of diverse functions were determined to show significant abundance changes including 210 up-regulated and 218 down-regulated proteins in male compared to hermaphroditic pistils. Functional categorization revealed that the differentially expressed proteins (DEPs) primarily distributed in the carbohydrate metabolism, secondary metabolism as well as signaling cascades. Further experimental analysis showed the substantial carbohydrates accumulation associated with promoted net photosynthetic rate and water use efficiency were observed in purplish red pedicel of hermaphroditic flower compared with green pedicel of male flower, implicating glucose metabolism serves as nutritional modulator for the differentiation of male and hermaphroditic flower. Meanwhile, the entire upregulation of secondary metabolism including flavonoids, isoprenoids and lignins seem to protect and maintain the male function in male flowers, well explaining important feature of androdioecy that aborted pistil of a male flower still has a male function. Furthermore, nine selected DEPs were validated via gene expression analysis, suggesting an extra layer of post-transcriptional regulation occurs during O. fragrans floral development. Conclusion: Taken together, our findings represent the first SWATH-MS-based proteomic report in androdioecy plant O. fragrans, which reveal carbohydrate metabolism, secondary metabolism and post-transcriptional regulation contributing to the androdioecy breeding system and ultimately extend our understanding on genetic basis as well as the industrialization development of O. fragrans. [ABSTRACT FROM AUTHOR]

To boost our understanding of recent frost damage events in apricot trees, we focused on estimating the cell death point in the receptacle and pistil organs of apricots by simulating the unexpected temperature changes occurring in early spring under laboratory-based freezing experiments. The hypothesis also that organic acids (oxalic, propionic, tartaric, butyric, malonic, malic, lactic, citric, maleic, fumaric and succinic acids) and soluble sugar compositions (glucose, fructose, sucrose and total sugar) may directly stimulate the change of the frost tolerance in apricot receptacle and pistil organs was investigated using two apricot (Prunus armeniaca L.) cultivars, one tolerant to frost ('Iğdır Şalak') and the other sensitive to frost ('Mihralibey'). Our results indicated that the mean the cell death point (CDP) of flower pistil (from −13.26 to −14.18 °C) was at lower temperatures than those of flower receptacle (from −6.28 to −8.65 °C) in both apricot cultivars during the full blooming stage. In both apricot cultivars, receptacle organs showed more sensitive changes to the frost tolerance in response to low temperatures compared with pistil organs. In terms of organic acid and soluble sugar contents, significant differences were determined for both apricot cultivars and between the pistil and the receptacle organs of the flowers. Organic acid content was higher in the freezing-tolerant apricot cultivar ('Iğdır Şalak') than the freezing-sensitive apricot cultivar ('Mihralibey'), but it was lower in the freezing-tolerant organ (pistil) in comparison with the freezing-sensitive organ (receptacle). Moreover, fructose concentrations for both 'Mihralibey' and 'Iğdır Şalak' were significantly higher in the receptacle compared to the pistil. A significant negative correlation was also observed between the mean CDP values and both all organic acids and sucrose contents in the pistil and the receptacle organs for both apricot cultivars. There was a positive relationship between the CDP values and fructose content in 'Iğdır Şalak'. Additionally, there was a negative correlation between the CDP values and sucrose in 'Mihralibey'. Overall, the data presented suggest that the high level of sucrose and organic acid content of receptacle and pistil organs contributes to support frost tolerance of organs. The results of this study could help in the understanding of how receptacle and pistil organs of two different apricot cultivars react to frost stress, and how they modulate their soluble sugar and organic acid metabolism. [ABSTRACT FROM AUTHOR]

Abstract Sweet cherry fruit is a tasty and valuable product for consumers. In order to increase the export share of cherry, which is also very important in export, it is beneficial to grow with cherry varieties that mature at different times. The cherries offered to the market in the early period will be more attractive. In this study, morphological and biological features of pistils of early-maturing ‘Cristalina’, ‘Early Lory’, ‘Prime Giant’, fruit set rates and pollen germination status and some chemical applications were investigated. As a result, fruit sets of cultivars were 17.6-28.6% in two years. Significant differences were observed in pistil morphology of the cultivars and ‘Cristalina’ had shorter pistil (14.35-14.51 mm) and style (11.47-11.65 mm) lengths than the other cultivars. Greater deformation was observed in primary ovules of ‘Early Lory’ right after anthesis. There were not significant differences in pollen germination ratios of the cultivars, but boric acid treatments improved pollen germination ratios of all cultivars. Boric acid application increased pollen germination with 21%. This was followed by IAA (8%), GA3 (5%), KNO3 (4%). It was concluded based on present findings that in orchard establishment with the early cultivars, flower biology should momentously be assessed.

Heat stress coinciding with reproductive stage leads to a significant loss in reproductive organs viability, resulting in lower seed‐set and crop productivity. Successful fertilization and seed formation are determined by the viability of male and female reproductive organs. The impact of heat stress on the male reproductive organ (pollen) is studied more often compared to the female reproductive organ (pistil). This is attributed to easier accessibility of the pollen coupled with the notion that the pistil's role in fertilization and seed‐set under heat stress is negligible. However, depending on species and developmental stages, recent studies reveal varying degrees of sensitivity of the pistil to heat stress. Remarkably, in some cases, the vulnerability of the pistil is even greater than the pollen. This article summarizes the current knowledge of the impact of heat stress on three critical stages of pistil for successful seed‐set, that is, female reproductive organ development (gametogenesis), pollen‐pistil interactions including pollen capture on stigma and pollen tube growth in style, as well as fertilization and early embryogenesis. Further, future research directions are suggested to unravel molecular basis of heat stress tolerance in pistil, which is critical for sustaining crop yields under predicted warming scenarios. Heat stress negatively impacts pistil development, pollen‐pistil interactions, fertilization and early embryo development in plants by altering the morpho‐anatomical parameters, transcriptional regulation, sugar and hormonal signaling in the pistil. [ABSTRACT FROM AUTHOR]

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Oilseed rape (Brassica napus L.) is sensitive to heat stress during the reproductive stage, but it is not clear whether the male and female reproductive organs differ in their sensitivity to heat stress. In this study, full diallel crossing experiments were conducted among four genotypes of B. napus under control, moderate and high heat stress conditions for five days immediately before and two days after crossing. General combining ability (GCA), specific combining ability (SCA) and reciprocal effects were analyzed to evaluate the genetic basis of heat stress tolerance in male and female reproductive organs. High female temperature (Tf) and high male temperature (Tm) reduced the number of fertile pods and seeds set per floret, and the significant Tf × Tm interaction indicated that female reproductive organs were more sensitive to heat stress than male reproductive organs. There were no overall GCA, SCA or reciprocal effects across all combinations of Tf and Tm. However, a significant reciprocal × Tf effect was found, suggesting that genotypes differed in their ability to set fertile pods and seeds as Tf increased. The relative heat tolerance of G1 as a female increased as Tf increased, and the relative heat tolerance of G2 as a male decreased as Tf increased. In summary, reciprocal diallel crossing has demonstrated that female reproductive organs of B. napus are more sensitive than male to transient heat stress at the early flowering stage, and genotypes differ in relative heat tolerance in the male and female reproductive organs as Tf increases. [ABSTRACT FROM AUTHOR]

Key message: Pistil AGPs display dynamic localization patterns in response to fertilization in tomato. SlyFLA9 (Solyc07g065540.1) is a chimeric Fasciclin-like AGP with enriched expression in the ovary, suggesting a potential function during pollen–pistil interaction. During fertilization, the male gametes are delivered by pollen tubes to receptive ovules, deeply embedded in the sporophytic tissues of the pistil. Arabinogalactan glycoproteins (AGPs) are a diverse family of highly glycosylated, secreted proteins which have been widely implicated in plant reproduction, particularly within the pistil. Though tomato (Solanum lycopersicum) is an important crop requiring successful fertilization for production, the molecular basis of this event remains understudied. Here we explore the spatiotemporal localization of AGPs in the mature tomato pistil before and after fertilization. Using histological techniques to detect AGP sugar moieties, we found that accumulation of AGPs correlated with the maturation of the stigma and we identified an AGP subpopulation restricted to the micropyle that was no longer visible upon fertilization. To identify candidate pistil AGP genes, we used an RNA-sequencing approach to catalog gene expression in functionally distinct subsections of the mature tomato pistil (the stigma, apical and basal style and ovary) as well as pollen and pollen tubes. Of 161 predicted AGP and AGP-like proteins encoded in the tomato genome, we identified four genes with specifically enriched expression in reproductive tissues. We further validated expression of two of these, a Fasciclin-like AGP (SlyFLA9, Solyc07g065540.1) and a novel hybrid AGP (SlyHAE, Solyc09g075580.1). Using in situ hybridization, we also found SlyFLA9 was expressed in the integuments of the ovule and the pericarp. Additionally, differential expression analyses of the pistil transcriptome revealed previously unreported genes with enriched expression in each subsection of the mature pistil, setting the foundation for future functional studies. [ABSTRACT FROM AUTHOR]