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[Objective] This paper aims to investigate the characteristics of Primulina guizhongensis pollen and the influence of the breeding system on its sexual reproduction, to uncover its reproduction mechanism and providing theoretical references for the conservation and development of Primulina. [Methods] Using P . guizhongensis as the material, we observed the floral characteristics of P . guizhongensis, screened the pollen isolation medium and the best pollen viability detection method, explored optimal pollen storage conditions, as well as determined the type of its breeding system. [Results] (1) P . guizhongensis was dichogamy, with stamens ripening before pistils. It was herkogamy, with pistils higher than stamens. (2) The optimum medium for culture of the isolated pollen germination was 40 mg/mL boric acid + 10% sucrose + 7 g/L agar, for two hours. (3) Pollen maintained a high germination rate after 7 d of storage at both -20 ℃ and -80 ℃. (4) The stigmas of P . guizhongensis were most fertile at 2-4 d of flowering. (5) P/O was 518.36-782.75, and OCI was 5. (6) P . guizhongensis had a high self-fertilization affinity and was unable to undergo fusionless reproduction. [Conclusion] In vitro germination method is the most intuitive and accurate way to detect pollen viability. Low temperature is conducive to pollen storage of P . guizhongensis, and the breeding system is predominantly heterogametic.

Insufficient pollination is one of the direct causes of flower and fruit drop in goji berries. Aiming to determine the flowering characteristics, 'Ningqi 10' was taking as material to analyze flowering period, including flower color, stigma receptivity, pollen vitality, and nectar secretion at different stages. The study also analyzed the pollination characteristics of common pollinating insects, such as the duration of a single visit to flowers and the number of pollen deposition on the stigma. The results showed that during 12~24 h after flowering and the petal color changed to light purple and white purple, the stigma receptivity, pollen vitality, and nectar secretion were the highest, with significant differences (P<0.05) compared to other stages. The number of pollen deposition on the stigma of common pollinating insects after a single visit (moths>bees>non cushioned bees) showed significant differences compared to natural pollination. The average duration of bees visiting purple flowers was 4.1 s, and the difference was extremely significant (P<0.01) compared to the duration of bees visiting yellow flowers (average 1.7 s). The number of pollen deposition on the stigma of common pollinating insects after a single visit to flowers (moths>bees>non cushioned bees) showed significant differences compared to natural pollination. However, in terms of overall efficiency and the number of pollinating insect visits, it was recommended to introduce pollinating insects (such as bees) to enhance the assisted pollination of goji berries and improve the fruit setting and seed setting of 'Ningqi 10'. The research results provided scientific basis for the development of assisted pollination measures for goji berries. [ABSTRACT FROM AUTHOR]

Annona hybrid Arka Sahan has become a commercially important fruit in recent times and it needs an assisted pollination to get good size. Studies on floral biology of Annona hybrid Arka Sahan revealed that major bloom occurs during March-April. Most of the flowers start opening during the afternoon and continued till 7.00 pm, while, pollen dehiscence mainly occurred in early morning in the following day. The maximum stigma receptivity was recorded on the day of anthesis. Completely pendulous petal was more common in Arka Sahan flowers resulting improper pollination. The minimum number of beetles and bees were observed between 7.00 to 8.00 am. Pollen germination and viability were lower at anthesis (5.8% and 44%, respectively) and declined as the day progressed. The pendulous nature of petals eventually brings some un-pollinated stigmas potentially resulting in delayed selfing leading to misshaped fruits. [ABSTRACT FROM AUTHOR]

Pollination in angiosperms depends on complex communication between pollen grains and stigmas, classified as wet or dry, depending on the presence or absence of secretions at the stigma surface, respectively. In species with wet stigma, the cuticle is disrupted and the presence of exudates is indicative of their receptivity. Most stigma studies are focused on a few species and families, many of them with self-incompatibility systems. However, there is scarce knowledge about the stigma composition in Fabaceae, the third angiosperm family, whose stigmas have been classified as semidry. Here we report the first transcriptome profiling and DEGs of Vicia faba L. styles and stigmas from autofertile (flowers able to self-fertilize in the absence of manipulation, whose exudate is released spontaneously) and autosterile (flowers that need to be manipulated to break the cuticle and release the exudates to be receptive) inbred lines. From the 76,269 contigs obtained from the de novo assembly, only 45.1% of the sequences were annotated with at least one GO term. A total of 115,920, 75,489, and 70,801 annotations were assigned to Biological Process (BP), Cellular Component (CC), and Molecular Function (MF) categories, respectively, and 5918 differentially expressed genes (DEGs) were identified between the autofertile and the autosterile lines. Among the most enriched metabolic pathways in the DEGs subset were those related with amino acid biosynthesis, terpenoid metabolism, or signal transduction. Some DEGs have been related with previous QTLs identified for autofertility traits, and their putative functions are discussed. The results derived from this work provide an important transcriptomic reference for style-stigma processes to aid our understanding of the molecular mechanisms involved in faba bean fertilization. [ABSTRACT FROM AUTHOR]

Reproductive barriers are the single largest impediment in breeding of Solanum aethiopicum (Shum and Gilo cultivars). Knowledge of these barriers is important for prudent germplasm utilization and genetic improvement of the species. This study investigated compatibility barriers between S. aethiopicum and its relatives. A randomized complete block design and a full diallel mating method were used to evaluate crossability and floral traits of six genotypes of four different species (S. aethiopicum, S. macrocarpon, S. anguivi and S. incanum) across two seasons. Parameters assessed were petal opening time, stigma receptivity, anther dehiscence, pollen quantity, pollen viability and crossing success. Most flowers for all parental genotypes were opened by 08:00 am. Mean number of open flowers was higher (12 ± 6) for S. aethiopicum Shum (N11) and lowest (n = 3 ± 1) for S. macrocarpon (E12; (p < 0.001), with other genotypes being intermediate. Stigma receptivity differed (p < 0.001) among genotypes and seasons and was highest for N11 at 3.31 ± 1.32 and lowest for S. incanum (In1) at 2.24 ± 1.27; other genotypes were intermediate. All genotypes possessed high pollen viability (µ > 80%) though species differed (p < 0.01). All genotypes exhibited self-compatibility to varying degrees with N11 showing the highest fruit success (67.9 ± 15.6%), seeds per fruit (82 ± 51), and F1 germination rate (79 ± 18%). Interspecific crosses using S. macrocarpon, S. anguivi and S. incanum as females showed poor or no fruit and seed. N11 (S. aethiopicum Shum) was the top performer as a female; crosses with S. macrocarpon (N11xE12) showed highest fruit success (65.9 ± 26.5), with S. anguivi (N11xA1) showing the highest seed set (n = 56 ± 34) and S. incanum (N11xIN1) showing the highest F1 germination (64 ± 19). The F1 intraspecific cross between S. aethiopicum Shum (N4) and S. aethiopicum Gilo (G4) did not germinate. Female parent functioning may be a key feature for the failure of interspecific crosses where S. aethiopicum is a donor as observed by the unilateral incompatibility. [ABSTRACT FROM AUTHOR]

The andromonoecy is an unusual sex expression in trees in which an individual plant bears both functionally staminate and hermaphrodite flowers on the inflorescences. This study aims to investigate the effect of crown layers on the floral biology and reproductive effort of Aesculus indica (Wall. ex Camb.) Hook. The results revealed that the peak period of anthesis was between 06:00 and 08:00 h of the day. Male flower production was predominantly higher as compared to the perfect flowers on the inflorescences. There was no significant variation between total pollen production in staminate and perfect flowers. Features like protogyny and inter-level asynchrony promote xenogamy; however, intra-level asynchrony results in geitonogamy. Controlled pollination treatments revealed the existence of self-incompatibility in flowers. Pollination syndromes in flowers support ambophily. A trend of consistent improvement in reproductive success from lower canopy layers to upper crown layers in the analyzed trees was recorded. The crown layers have a significant impact on flower production, fruit, and seed set. An increase in male flower production due to the increment in the crown is a mechanism of reproductive assurance as a pollen donor and pollinator recipient and also due to the differential cost of expenditure of reproduction in crown layers. Andromonoecy in A. indica promotes self-incompatibility, and there was a tapering trend of reproductive success in the crown layers. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The genus Sphaeralcea belongs to the Malvaceae family and has native species from South America. Their attractive morphological characteristics with ornamental value have not yet been explored. The objective of this work was to know the viability of pollen, stigma receptivity, type of pollination and combining ability of four Sphaeralcea species (S. australis, S. bonariensis, S. crispa and S. mendocina), with the aim to develop new ornamental varieties. Fructification, fertility, seed germination and survival seedlings on intraspecific and reciprocal interspecific offspring were assessed. The highest values ​​of stigma receptivity and pollen viability were obtained at 2:00 pm for the four species. S. mendocina also showed high values ​​of pollen viability at 4:00 pm. The species proved to be self-incompatible and allogamous, with different degrees of reproductive compatibility. The interspecific crosses of S. mendocina and the intraspecific of S. crispa did not produce descendants. The crosses between S. australis and S. bonariensis as maternal parent presented the best combining ability with good fruit production, seed germination and survival. This research provides useful information for the formulation and implementation of breeding strategies, to improve pollination efficiency, and to breed new Sphaeralcea varieties with ornamental potential.

Exacum bicolor (Roxb.) is an herbaceous perennial endemic to peninsular India and enlisted as an endangered plant species. Since a thorough insight into the reproductive biology of a species is necessary to aid conservation and crop improvement, the present study was formulated to assess the floral biology and reproductive behaviour of the plant. It was found that the bisexual flowers of this plant possess pollen grains that remain viable for nine days after anthesis exhibiting maximum viability on the first day of anthesis (84.61%) and 84.18 per cent viability on the previous day of anthesis. Stigma was found to be receptive upto four days after anthesis. Maximum seed weight per capsule (17.21 mg) was realised from flowers pollinated on the third day of flower opening. There was 100 per cent fruit set in flowers that were open pollinated as well as in the flowers which were either controlled out-crossed or self-pollinated under control. Fruit set was not observed on bagging the flowers to avoid natural out-crossing, and on open pollination. Hence, it became evident that Exacum bicolor (Roxb.) is primarily a cross-pollinated species, although no self-incompatibility mechanism operates in the species. Also, natural self-pollination is not favoured for procreation; reproduction via apomixis is absent in the species. [ABSTRACT FROM AUTHOR]

• Comprehensive phenology from the onset of the primordial bud to the senescence phase, is documented for Macrotyloma uniflorum. • Floral organs exhibits ultrastructural variation in Macrotyloma uniflorum. • Macrotyloma uniflorum accessions from Republic of Benin are non-echinate; other accessions exhibit spinuliferous pollen. • There is a positive correlation between days to flowering and most floral traits. • Pollens of Macrotyloma uniflorum are viable during the day. The absence of information on the reproductive biology of some nutritive legumes has been an obstacle to their genetic improvement. Gathering information on reproductive biology contributes significantly to the interest of breeders to have adequate tools for initiating the improvement program through crosses among high performing genotypes. To contribute to this, we examined the flowering phenology, pollen biology, stigma receptiveness at bud dehiscence and anthesis phases, and the in-vitro germination of the pollens in horsegram (Macrotyloma uniflorum). Pollens of horsegram were found to be either tricolporate or triporate, echinates in all accessions except in the collections from Benin. Ovaries in horsegram showed great variation in the number of ovules and activities of peroxidase indicated the receptiveness of stigma at bud dehiscence phase and during anthesis. A high number of ovules per ovary was found in accessions from Australia (Leichardt 1 and 2), Mali (LeichardtMali) and India (CPI22679). Pollen viability analysis implies the possibility of better results when pollinating during the day and immediately after the flower opens. The study provides information on the reproductive biology of horsegram for future hybridization program in order to enhance the performance of the crop and increase production. It also reveals differences in accessions from Benin compared with all other accessions from Mali, India or Australia. [ABSTRACT FROM AUTHOR]

The genus Sphaeralcea belongs to the Malvaceae family and has native species from South America. Their attractive morphological characteristics with ornamental value have not yet been explored. The objective of this work was to know the viability of pollen, stigma receptivity, type of pollination and combining ability of four Sphaeralcea species (S. australis, S. bonariensis, S. crispa and S. mendocina), with the aim to develop new ornamental varieties. Fructification, fertility, seed germination and survival seedlings on intraspecific and reciprocal interspecific offspring were assessed. The highest values of stigma receptivity and pollen viability were obtained at 2:00 PM for the four species. S. mendocina also showed high values of pollen viability at 4:00 PM. The species proved to be self-incompatible and allogamous, with different degrees of reproductive compatibility. The interspecific crosses of S. mendocina and the intraspecific of S. crispa did not produce descendants. The crosses between S. australis and S. bonariensis as maternal parent presented the best combining ability with good fruit production, seed germination and survival. This research provides useful information for the formulation and implementation of breeding strategies, to improve pollination efficiency, and to breed new Sphaeralcea varieties with ornamental potential. [ABSTRACT FROM AUTHOR]

Pollination in angiosperms depends on complex communication between pollen grains and stigmas, classified as wet or dry, depending on the presence or absence of secretions at the stigma surface, respectively. In species with wet stigma, the cuticle is disrupted and the presence of exudates is indicative of their receptivity. Most stigma studies are focused on a few species and families, many of them with self-incompatibility systems. However, there is scarce knowledge about the stigma composition in Fabaceae, the third angiosperm family, whose stigmas have been classified as semidry. Here we report the first transcriptome profiling and DEGs of Vicia faba L. styles and stigmas from autofertile (flowers able to self-fertilize in the absence of manipulation, whose exudate is released spontaneously) and autosterile (flowers that need to be manipulated to break the cuticle and release the exudates to be receptive) inbred lines. From the 76,269 contigs obtained from the de novo assembly, only 45.1% of the sequences were annotated with at least one GO term. A total of 115,920, 75,489, and 70,801 annotations were assigned to Biological Process (BP), Cellular Component (CC), and Molecular Function (MF) categories, respectively, and 5918 differentially expressed genes (DEGs) were identified between the autofertile and the autosterile lines. Among the most enriched metabolic pathways in the DEGs subset were those related with amino acid biosynthesis, terpenoid metabolism, or signal transduction. Some DEGs have been related with previous QTLs identified for autofertility traits, and their putative functions are discussed. The results derived from this work provide an important transcriptomic reference for style-stigma processes to aid our understanding of the molecular mechanisms involved in faba bean fertilization.

It is generally agreed that many Vitis vinifera L. cultivars are self-fertile, where self-pollination often occurs before capfall in a process called cleistogamy. Therefore, it is difficult to identify the right time to remove stamens before self-pollination during the cross-breeding of grape. For this paper, we observed the process of grape flowering and measured the pollen viability and stigma receptivity of grape flowers of 'Shine Muscat' in order to identify the starting time of self-pollination before capfall and to provide useful information for improving the efficiency of cross-breeding. The results demonstrate that the anther is not cracked during the visible clusters and separated clusters stages. Meanwhile, in the separated floral buds, flowering begins, and full bloom stages, the pollen viability is 60.7%, 73.2% and 80.3%, respectively; however, at the berry set stage, pollen viability drops to zero. The top of the mature stigma is composed of a layer of nearly cylindrical papillary cells, and the stigma receptivity for pollen changes with the development of flowers: in particular, no reaction was observed in the visible clusters stage; weak positive reaction at the separated clusters stage; strong positive reaction at the separated floral buds, flowering begins, and full bloom stages; and no reaction at the berry set stage. In the separated floral buds stage, pollen tubes were seen germinating in the style. In the flowering begins stage, more pollen tubes were observed at the entry of the ovary. During the full bloom stage, most pollen tubes elongated into the ovary base and some entered the pearl hole. At the berry set stage, newborn endosperm nucleus could be seen in the ovule. From the above, we can conclude that the initiation time of closed fertilization for 'Shine Muscat' grape can be judged as the separated floral buds stage, and it is best to discard the stamen before the separated floral buds stage when conducting cross-breeding. [ABSTRACT FROM AUTHOR]

Commelinaceae is an important component of the Atlantic Forest and its analysis can provide information on the conservation of that species. This study had the objective of analyzing the phenology and floral and reproductive biology of Dichorisandra rhizantha, growing in an Atlantic Forest fragment, to obtain data related to the form of reproduction and pollination mechanism of this species. We monitored the phenophases and reproductive biology of the D. rhizantha in the area studied using different methodologies and microscopy techniques (LM, SEM and FM). The flowering period occurs during the dry season. The species is andromonoecious and has daytime anthesis (4:30 a.m.–1:30 p.m.). It has purple zygomorphic flowers and rimose but functionally poricidal anthers. The pollen viability was 97.6% and the two floral morphs investigated contained a large quantity of pollen grains. The time of greatest stigma receptivity (anthesis) coincided with the pollen viability. Cross‐pollination was the only efficient reproductive system of the species, with observation of gametophytic self‐incompatibility and pollen tubes growth only as far as the middle or lower third of the pistil. We observed bee species of the genera Xylocopa and Euglossa visiting the flowers and acting as effective pollinators. The immature fruits were formed after about 3.25 ± 1 days, and the presence was noted of ants of the genus Cephalotes acting as dispersers of the seeds, with aril serving as the reward. Although the natural reproductive system is efficient, D. rhizantha is endangered, mainly due to fragmentation of habitat caused by deforestation and urban encroachment. [ABSTRACT FROM AUTHOR]

• We present a new proposal, the so-called reproductive efficiency, which measures plants' efficiency in fertilizing their eggs. • We apply microsurgeries to the corolla tube to enable artificial self-fertilization. • Catharanthus roseus presents the mixed reproduction mode, namely: allogamy and autogamy, simultaneously. • We conclude that allogamy is the main pollination strategy. • Autogamy is a reproduction guarantee mechanism (back-up plan) that can be reinforced by cleistogamy. Despite the medicinal importance of Catharanthus roseus [L.] G. Don., the literature is still controversial about its mode of reproduction. The breeding of species depends on this information. The purpose of this study was to ascertain the preferential reproduction mode of C. roseus by using different genotypes of this species. We also sought to verify the relative importance of allogamy and autogamy on the species reproduction. Therefore, it was necessary to estimate the pollen:ovule ratio, the rates of open pollination and natural self-fertilization, the efficiency of allogamy and autogamy, and pollen viability and stigma receptivity. Furthermore, we applied fluorescence microscopy to analyze the emission and development of pollen tubes in vivo in floral buds and investigated the histochemistry of the pollen grains. Finally, through ISSR markers, we estimated the genetic diversity of the genotypes. In general, C. roseus has a mixed reproduction mode, with the possible simultaneous occurrence of allogamy and autogamy. However, allogamy was much more prevalent, and it was also more efficient as a reproductive strategy in the genotypes. The high magnitude of genetic diversity found corroborates allogamy as the most prevalent mode of reproduction. Nevertheless, autogamy occurred in all the genotypes, although the seed production efficiency was low. Autogamy can be understood as a supposed reproductive guarantee mechanism by C. roseus. [ABSTRACT FROM AUTHOR]

• The pollen viability, storage and germination results showed significant differences among the species of Casuarina and between stains (acetocarmine and aniline blue), storage duration, temperature and germination media (BA and BK medium). • The female flowers had a life span of about 10 days, and the stigma receptivity started 3 days after anthesis and peaked between the fourth and sixth days. • The receptivity period was linked to distinct morphological characteristics of the stigma, which can be used as a guide for hand pollination. • Successful storage of pollen and knowledge of the stigma receptivity time help breeders perform controlled pollination, leading to a high level of fruit and seed set. Casuarina species (Casuarinaceae) are nitrogen-fixing multipurpose trees planted extensively throughout the tropics for wood production and environmental services. Increasing productivity of plantations through breeding is underway in China, India and Thailand. The current focus of breeding is to produce interspecific hybrids possessing a combination of specifies-specific characters of forestry importance. Earlier hybridization attempts were less successful mainly due to insufficient knowledge on floral and pollen biologyand lack of efficient hand pollination techniques. The differences in the floral characters and their influence on pollen and seed output in three Casuarina species (C. equisetifolia, C. junghuhniana and C. cristata) were studied. Pollen from six clones were stored at three temperature levels and tested for viability from 3 to 45 days after storage using acetocarmine and aniline blue stains. In vitro germination of stored pollen was testedwith two germination media from 3 to 30 days. Female flowers were control pollinated from 1 to 7 days after anthesis and stigma receptivity was determined based on presence of germinating pollen. There was a significant effect of clone, stain, storage temperature and storage period on the viability of pollen. Pollen viability and in vitro germination reduced drastically when stored at room temperature for three days but was high under low temperature storage. While the viability of pollen stored at 4°C and -20 °C comparable up to 15 days of storage, freezer storage showed better viability at 45 days. In vitro germination was higher with the broad-based Brewbaker-Kwack medium than the basic sucrose-boron medium. The stigma was receptive from the third to seven days after anthesis and the peak period was on fourth and fifth days for C. equisetifolia and C. junghuhniana and fifth and sixth days for C. cristata. The receptivity level of the stigma was associated with distinct morphological features during lifespan of the female flower. Pollen stored under low temperatures can be used to cross parents with dissimilar flowering phenology within the same flowering season and conducting hand pollination during when the stigma is at its peak receptivity will increase hybridization success. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract To produce pitaya (Hylocereus spp.), it is essential that pollination occur, either artificially or by pollinating agents. This study evaluated the viability of self-pollination, cross-pollination, and natural pollination, as well as pollen viability, stigma receptivity and ideal pollination window in pitaya flowers (Hylocereus spp.). An experiment was conducted with a randomized block design consisting of four treatments: T1: manual self-pollination; T2: nocturnal open pollination; T3: diurnal open pollination; and T4: manual cross-pollination - red-fleshed pitaya [ Hylocereus polyrhizus] pollen placed on white-fleshed pitaya [ Hylocereus undatus] stigma. The experiment had four replicates, with two plants per replicate (two flowers per plant), totaling 16 flowers per treatment. The analyzed variables were fruit weight, length, diameter, titratable acidity, pH, soluble solids, and SS/TA ratio; the germination percentage of pollen grains; and the receptivity of stigmas. Artificial pollination (self- and cross-pollination) of white-fleshed pitaya (Hylocereus undatus) is viable, resulting in larger fruits than natural pollination, with cross-pollination being the most recommended. Throughout the floral opening period, the pitaya flower (Hylocereus spp.) has receptive stigma capable of receiving pollen. The flowers exhibit the highest pollen germination rate at 7 p.m, which is the ideal pollination window for pitaya.

Alfalfa (Medicago sativa L.) is an important forage in intercropping or rotation ecosystem, and shading is the principal limiting factor for its growth under the crop or forest. Agronomic studies showed that shading would systematically reduce the biomass of alfalfa. However, little is known about the reproduction of alfalfa under shading conditions. In order to study the effect of shading on the reproductive characteristics of alfalfa, two alfalfa cultivars ("Victoria" and "Eureka") were used to study the effect of shading levels (full light, 56.4% shade, and 78.7% shade) on alfalfa flowering phenology, pollen viability, stigma receptivity, and seed quality. Results showed that shading delayed flowering phenology, shortened the flowering stage, faded the flower colors, and significantly reduced pollen viability, stigma receptivity, the number of flowers, quantity, and quality of seeds. Under shading conditions, seed yield per plant was obviously positively correlated with germination potential, germination rate, pollen viability, and 1,000-seed weight. The number of flower buds, pollen viability, 1,000-seed weight, and germination rate had the greatest positive direct impact on seed yield per plant. Our findings suggested that delayed flowering and reducing reproduction growth were important strategies for alfalfa to cope with shading and pollen viability was the key bottleneck for the success of alfalfa reproduction under shading. However, given that alfalfa is a perennial vegetative-harvest forage, delaying flowering in a weak light environment was beneficial to maintain the high aboveground biomass of alfalfa. Therefore, this should be taken into account when breeding alfalfa cultivars suitable for intercropping. Future research should further reveal the genetic and molecular mechanism of delayed flowering regulating the accumulation and distribution of assimilates between vegetative and reproductive organs of alfalfa under shading, so as to provide a theoretical basis for breeding of shade-tolerant alfalfa cultivars. [ABSTRACT FROM AUTHOR]

Hand pollination is a necessary assisting method for pitaya (Selenicereus spp.) production to achieve a high yield. With the cultivated area increasing at an exponential rate in recent years, a comprehensive study of the pollination process was conducted. We developed an ideal medium for pitaya pollen in vitro germination in this study, then tested the activity of pollen collected from or stored for various time periods. We discovered that those collected between 2 h before blooming and 6 h after blooming had the higher germination rates (27.2–65.1%), the highest activity of pollen occurred between 2 h and 4 h after blooming, and that storing them at 4°C for 24 h reduces their germination rate from 65.2 percent to 35.5 percent and their production to about 82%. As a result, pollinating plants with pollen that has been held for more than 24 h is not recommended unless a breakthrough in pollen storage is achieved. We also discovered that stigma receptivity and pollen activity are synchronized, which together determines the rate of fruit setting and the size of the fruit. Pollination within 6 h after flowering offers the optimum fruit setting percentage and size, while pollination at 6:00 pm, 2 h before blooming, is also a good alternative; however, pollination at 6:00 am the next morning is expected to result in a 23% drop in the fruit size. These findings will be beneficial for reproductive biology research, as well as laying the groundwork for hand pollination to boost pitaya output and breeding efficiency. [ABSTRACT FROM AUTHOR]

Climate change is being felt in all vineyards around the world, opening up new perspectives for regions with a growing winemaking industry. In this study, 11 hybrid grapevines grown in cold climates were assessed in terms of flowering biology and pollination efficiency. The flowers were evaluated for the number of anthers and pollen grains in the flower; pollen viability and pollen grain size, the number of ovules in the ovary, and, consequently, the size and the weight of berries and the number of seeds in the berries were also analyzed. The flowers of Vitis vinifera L. usually have 5 stamens and 5 petals in their structure; this number for hybrid varieties ranged from 4 to 7, and in the case of the variety 'Seyval Blanc', it was 4 to 11 stamen and petals. Pollen grain size varied and ranged from 17.01 to 22.25 μm, while pollen grain pro-duction in flowers ranged from 5073 to 34,976 grain, which was calculated using a Bürker hemocytometer. The number of ovules in the ovary for the cultivars in question was highly variable, ranging from 3 to 7. One of the most important factors affecting flower pollination is stigma receptivity. Stigma receptivity appeared when the cap starts to fall off and disappeared at the browning of the cap. In connection with climatic changes, grapevine production is expanding to cool-climate countries. The aim of this study was to expand our knowledge about the flower morphology of 11 hybrid grapevine varieties most commonly cultivated in Poland. Knowledge of the flowering process can be important for improving yield and its quality. [ABSTRACT FROM AUTHOR]

Cultivated yam (D. rotundata) is a staple tuber crop in West Africa whose sexual reproduction control remains largely unknown despite its importance for plant breeding programs. In this paper, we compared self-pollination, intracultivar cross-pollination and intercultivar cross-pollination in three monoecious cultivars (Amoula, Heapala and Yassi). Results showed that pollen viability (49%) and stigma receptivity (40%) were similar in monoecious and dioecious plants, suggesting that autogamy could occur in monoecious plants. However, fruit and seed sets were significantly lower after self-pollination compared to cross-pollination. Overall, autogamy reached 11% and pollen lability was almost zero (<1%). The low percentage of pollen grains germinating on the stigma (37%) and pollen tubes reaching the ovules (25%) after self-pollination partly explained the low seed set. Strong inbreeding depression was observed after self-pollination and almost all fruits and about 75% of the seeds resulting from self-pollination showed malformations. Seed germination was also 20 times lower after self-pollination compared to cross-pollination. Sexual reproduction remained low in D. rotundata even after cross-pollination as fruit and seed set did not exceed 18% and 13% respectively. Moreover, comparison between intracultivar cross-pollination and self-pollination revealed intravarietal genetic diversity inside the analyzed yam cultivars. Overall, our results showed that D. rotundata has a very low tolerance to autogamy in monoecious cultivars and has developed pre- and postzygotic mechanisms to limit selfing. [ABSTRACT FROM AUTHOR]

Alfalfa (Medicago sativa L.) is an important forage in intercropping or rotation ecosystem, and shading is the principal limiting factor for its growth under the crop or forest. Agronomic studies showed that shading would systematically reduce the biomass of alfalfa. However, little is known about the reproduction of alfalfa under shading conditions. In order to study the effect of shading on the reproductive characteristics of alfalfa, two alfalfa cultivars (“Victoria” and “Eureka”) were used to study the effect of shading levels (full light, 56.4% shade, and 78.7% shade) on alfalfa flowering phenology, pollen viability, stigma receptivity, and seed quality. Results showed that shading delayed flowering phenology, shortened the flowering stage, faded the flower colors, and significantly reduced pollen viability, stigma receptivity, the number of flowers, quantity, and quality of seeds. Under shading conditions, seed yield per plant was obviously positively correlated with germination potential, germination rate, pollen viability, and 1,000-seed weight. The number of flower buds, pollen viability, 1,000-seed weight, and germination rate had the greatest positive direct impact on seed yield per plant. Our findings suggested that delayed flowering and reducing reproduction growth were important strategies for alfalfa to cope with shading and pollen viability was the key bottleneck for the success of alfalfa reproduction under shading. However, given that alfalfa is a perennial vegetative-harvest forage, delaying flowering in a weak light environment was beneficial to maintain the high aboveground biomass of alfalfa. Therefore, this should be taken into account when breeding alfalfa cultivars suitable for intercropping. Future research should further reveal the genetic and molecular mechanism of delayed flowering regulating the accumulation and distribution of assimilates between vegetative and reproductive organs of alfalfa under shading, so as to provide a theoretical basis for breeding of shade-tolerant alfalfa cultivars.

Neoregelia cultivars have been used in many areas for landscaping and indoors in a variety of creative ways, but scientific reports of their pollination and hybridization are presently limited. Cross-combinations of Neoregelia cultivars were created to define conditions for pollination timing and to evaluate cross-compatibility. Neoregelia cultivars have short-lived flowers. Hybrid seeds were obtained only when cross-pollination was performed before 1200 hr. Results of 19 cross-combinations including six reciprocal crosses revealed that hybrid seeds were obtained in the female parents with a 1.9- to 2.0-cm style length, but not in those with a 2.6- to 3.0-cm style length. The pollen tube penetrated the ovule as early as 1 day after pollination in the compatible cross, whereas swollen pollen tubes were observed at half and two-thirds of the style in the incompatible cross. Removal of 50% of the style length of the female parents could overcome the fertilization barrier for those incompatible crosses and hybrid seeds could be successfully obtained.

Copyright of Acta Scientiarum Naturalium Universitatis Sunyatseni / Zhongshan Daxue Xuebao is the property of Sun-Yat-Sen University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Information regarding efficient pollen viability testing methods and the most favourable pollen storage conditions for internationally important date palm cultivars is limited. No such information has been reported on Australian male selections. The in vitro pollen germination of three elite Australian male selections, "Big pod", "Campbell" and "Tanunda", was estimated using a modified Brewbaker and Kwack (BK) medium with combinations of various chemicals. Germination was maximized when 75 mg/l H3BO4, 400 mg/l Ca (NO3)2.4H2O, 100 mg/l KNO3, 50 mg/l MgSO4.7H2O and 15% (w/v) sucrose were used in a medium at pH 5.4. The viability of pollen of these three genotypes following storage in a refrigerator at 4°C was tested every 3 mo for 12 mo. Significant pollen viability was maintained after 9 mo of storage and the highest germinability (60.3%) was observed for the genotype "Tanunda". Six tests for determining viability, including TTC (2,3,5-triphenyltetrazolium chloride), IKI (iodine potassium iodide), lactophenol cotton blue (LPCB), acetocarmine, fluorescein diacetate (FDA) and Alexander's differential stain were evaluated and correlations between these pollen viability tests and in vitro germination were determined. A highly positive correlation between in vitro germination and the FDA viability test was observed. The metaxenic effect induced by pollinating the cultivar "Barhee" with three sources of pollen was investigated by assessing changes in the levels of malic acid, citric acid, fructose, glucose, sucrose, l-proline and myo-inositol during fruit development. The pollen source had a significant influence on the concentrations of these chemicals (metaxenic effect). Pollen of the genotype "Tanunda" significantly increased fruit size, fresh weight and seed size in comparison with other pollen sources. [ABSTRACT FROM AUTHOR]

Artificial hybridization in Phaseolus lunatus L. is still little used in genetic improvement programs in Brazil due to the low establishment percentages. This work aimed to evaluate pollen viability and stigma receptivity in different Lima bean genotypes throughout the day. Accessions 'Roxinha -MT' and 'Cana Longa-PB' were used in the experiment. Five flower buds were collected from each genotype at 6:00 a.m., 10:00 a.m., 2:00 p.m., and 6:00 p.m. The stigma receptivity was determined using 3% hydrogen peroxide, whereas pollen viability was determined with 2% acetocarmine colouration. The genotype and time factors acted independently on the percentage of viable and non-viable pollen grains and stigma receptivity. The genotype 'Roxinha' presented 88.54% viable pollen grains, a value 84.27% higher than that of the 'Cana Longa' genotype. This percentage varied as a function of time, with the highest means observed at 6:00 a.m. Stigma receptivity was influenced only by the time of the day, undergoing a great reduction in receptivity, from 88% in the early morning to slightly more than 40% around noon. These results indicate that 6:00 a.m. is the most suitable time to perform artificial crosses in Lima bean plants. [ABSTRACT FROM AUTHOR]

In Nicotiana tabacum, female gametophytes are not fully developed at anthesis, but flower buds pollinated 12 h before anthesis produce mature embryo sacs. We investigated several pollination-associated parameters in N. tabacum flower buds to determine the developmental timing of important events in preparation for successful fertilization. First, we performed hand pollinations in flowers from stages 4 to 11 to study at which developmental stage pollination would produce fruits. A Peroxtesmo test was performed to correlate peroxidase activity on the stigma surface, indicative of stigma receptivity, with fruit set. Pollen tube growth and female gametophyte development were microscopically analyzed in pistils of different developmental stages. Fruits were obtained only after pollinations of flower buds at late stage 7 and older; fruit weight and seed germination capacity increased as the developmental stage of the pollinated flower approached anthesis. Despite positive peroxidase activity and pollen tube growth, pistils at stages 5 and 6 were unable to produce fruits. At late stage 7, female gametophytes were undergoing first mitotic division. After 24 h, female gametophytes of unpollinated pistils were still in the end of the first division, whereas those of pollinated pistils showed egg cells. RT-qPCR assay showed that the expression of the NtEC1 gene, a marker of egg cell development, is considerably higher in pollinated late stage 7 ovaries compared with unpollinated ovaries. To test whether ethylene is the signal eliciting female gametophyte maturation, the expression of ACC synthase was examined in unpollinated and pollinated stage 6 and late stage 7 stigmas/styles. Pollination induced NtACS expression in stage 6 pistils, which are unable to produce fruits. Our results show that pollination is a stimulus capable of triggering female gametophyte development in immature tobacco flowers and suggests the existence of a yet undefined signal sensed by the pistil.

Objective: To determine the stigma receptivity and the pollen viability in order to make manual crosses and obtain viable progeny in castor bean (Ricinus communis L.). Design/Methodology/Approach: Pollen viability tests were made on breeding materials by staining with acetocarmine solution. In elite materials, the receptivity of the stigma was evaluated with hydrogen peroxide. From the inflorescences, the male ones were removed and the female ones were preserved, which were covered with a glassine bag. After six days, they were checked and when they were considered receptive, manual pollinations were carried out between viable pollen materials and receptive stigma. The pollen of the male parent was impregnated in the stigmas and the inflorescence was covered again. Results: The breeding materials exhibited viable pollen since they were stained red. Whereas, the application of hydrogen peroxide to the stigmas of the elite materials showed bubbling, indicative that they were receptive. In 2014, 400 inflorescences were pollinated with 8 flowers on average and a fruit pollinated percentage of 61.21. In 2015, 245 inflorescences with 12 flowers on average and 61.24% of fruit were pollinated. Study Limitations/Implications: Temperature and relative humidity were fundamental factors for the success of castor bean fertilization. Findings/Conclusions: The elite castor bean materials presented receptive stigmas and the improved viable pollen materials. Manual crosses produced fruits and seeds. The fruits pollinated were 61%. [ABSTRACT FROM AUTHOR]

Climate change is being felt in all vineyards around the world, opening up new perspectives for regions with a growing winemaking industry. In this study, 11 hybrid grapevines grown in cold climates were assessed in terms of flowering biology and pollination efficiency. The flowers were evaluated for the number of anthers and pollen grains in the flower; pollen viability and pollen grain size, the number of ovules in the ovary, and, consequently, the size and the weight of berries and the number of seeds in the berries were also analyzed. The flowers of Vitis vinifera L. usually have 5 stamens and 5 petals in their structure; this number for hybrid varieties ranged from 4 to 7, and in the case of the variety ‘Seyval Blanc’, it was 4 to 11 stamen and petals. Pollen grain size varied and ranged from 17.01 to 22.25 μm, while pollen grain pro-duction in flowers ranged from 5073 to 34,976 grain, which was calculated using a Bürker hemocytometer. The number of ovules in the ovary for the cultivars in question was highly variable, ranging from 3 to 7. One of the most important factors affecting flower pollination is stigma receptivity. Stigma receptivity appeared when the cap starts to fall off and disappeared at the browning of the cap. In connection with climatic changes, grapevine production is expanding to cool-climate countries. The aim of this study was to expand our knowledge about the flower morphology of 11 hybrid grapevine varieties most commonly cultivated in Poland. Knowledge of the flowering process can be important for improving yield and its quality.

• Kersting's groundnut flowers are bisexual and incompletely protogynous. • The flowers are of 'pre-anthesis cleistogamous' type. • Spontaneous self-pollination occurs in the flower, facilitated by style bending. • Emasculation may be done on one-day buds to prevent unwanted self-pollination. Knowledge gap on the reproductive biology of orphan crops is a major challenge to their cultivar development and genetic improvement. This study described the reproductive organs and phenology, assessed receptivity of stigma versus anther dehiscence, and examined pollen viability and germination in Kersting's groundnut. Experiments were conducted on nine morphotypes in a randomized complete block design with three replications in a screenhouse. Phenological observations were made on 1026 flower buds. Anther dehiscence was determined through microscopic observations while receptivity of the stigma was assessed using the hydrogen peroxide test. Pollen viability was assayed using histochemical staining. In vitro germination and pollen tube growth were assessed for up to 72h. Flowers were bisexual and incompletely protogynous, and spontaneous self-pollination was favoured by style bending. Flowering and fruiting were classified into six developmental stages each. Timing of all stages differed significantly (P<0.001) among morphotypes. The stigma was receptive 1-2 days before anther dehiscence and remained so until each flower wilted. Anthesis started 3 days from young bud appearance and lasted between 2–4 days depending on the morphotype. Pollen viability rates were very high (88–98%) and differed among morphotypes (P< 0.001). Pollen germination rates were low (8–37%) and varied among morphotypes and anthesis stages (P <0.05). Pollen tube growth varied significantly among morphotypes, anthesis stages and incubation time. The morphotype ZHLA-2 exhibited the highest reproductive vigour and could be recommended as pollen donor for hybridization. The study provides information on the best time and stage for emasculation and is expected to help breeders optimise a hybridisation protocol. [ABSTRACT FROM AUTHOR]

The determination of the optimum pollination period was the key technology in the implementation of Popu.lus davidiana directive breeding project, which can guide the hybrid pollination of populus dafJidiana and improve the breeding efficiency. Choosing Populus dafJUiiana single plants selected from superior provenances as the research object, the stigma receptivity and optimal pollination period of Populus davidiana were studied by testing benzidine - ~ 02 method and morphological observations. At the same time, female flowering branches with different lengths and diameters were treated with different leaf buds and flower bud number to observe and analyze inflorescence length, 1 000 - grain weight and other indexes, to explore the influence of female flowering branches quality on flower bud development. The results showed that under a greenhouse condition, the stigma of the optimal receptivity stage of Populll.f davidiana was 3 d. The external morphological characteristics of the pistil stigma had a certain correlation with the receptive period. The optimal pollination period of Populus dafJUiiana was when the inflorescence was loose and elongated, the stigma could all protrude out of bud scales, the cracking angle was about 180° and the stigma was red and secreated a lot of crystal clear mucus, benzidine - ~ 02 staining appeared a lot of bubbles, and the stigma changed to deep blue. The morphological characteristics of stigma fully exposed, moist and secreting a lot of mucus could be used as a signal of the optimal pollination period of Populll.f davidiana, which could be used to guide the cross breeding and pollination of Populus davidiana. There was the best for flower bud and seed development that flower shoot retain 2 to 3 inflorescences and retain the only one pair leaf bud at the top with the bottom diameter was 2 cm and length was 2 m. [ABSTRACT FROM AUTHOR]

【Objective】 To reveal the effects of different exogenous hormones on the seed number and photosynthetic performance in common buckwheat.【Methods】 Varieties of “BZS” and“CT1” as experimental materials and treated with different concentrations(100,150,200 mg/L) of paclobutrazol(PP333) and 6-benzyl adenine(6-BA) at different time of seedling stage to study the effects of different treatments on pollen fertility,stigma receptivity,photosynthetic parameters,flowering number and the seed number of common buckwheat.【Results】 Compared with the control(water),PP333 treatment at 100 mg/L and 6-BA at 150 mg/L,the seed numbers reached maximum increased respectively 20.3% and 47.9%. The net photosynthetic rate and intercellular CO2 concentration during full booming stage were both increased when spraying PP333 and 6-BA compared with CK at different stage of common buckwheat. The transpiration rate was increased and stomatal conductivity was decreased when spraying PP333 compared with CK but the effect of spraying 6-BA was opposite to that of spraying PP333.【Conclusion】 In the second true leaf stage of common buckwheat,PP333 100 mg/L or 6-BA 150 mg/L treatments could improve pollen fertility,stigma receptivity,seed number per plant,and photosynthetic performance. [ABSTRACT FROM AUTHOR]

The reproductive traits in Gagea are affected by both abiotic and biotic environmental factors. However, further intrinsic drivers, like the ploidy level, could also have a significant influence on the sexual efficiency of these geophytes. Here, we present a comparative study involving the reproductive biology of five species of Gagea occurring in southern Italy, and representing different ploidy levels. The experimental investigations included flower phenology, pollen quality (i.e., morphology, viability, and germination), and stigma receptivity. Such data were then combined with information on seed-set available from previous work. All the studied species showed a gradual pollen presentation, and an early and durable stigma receptivity. Such traits represent effective functional adaptations to prevent pollen limitation under the unpredictable weather dynamics typical of the early blooming season of these plants. The use of a diluted substrate favoured the rate of pollen germination in vitro and, likely, it represents a further adaptation versus adverse environmental conditions (i.e., rain damage on exposed pollen). However, the rates of pollen viability and germination were generally low and appeared related to the ploidy level. Data inherent pollen quality (i.e. morphology, viability and germination) and seedset indicated the hexaploid G. lutea as the most fertile species, while the heptaploid G. fragifera had the lowest scores for all the considered traits. Finally, by considering the isolation and reduced size of the studied population, the unexpected low fertility found in the diploid G. minima was possibly due to inbreeding depression related to the relict status of this species in southern Italy. [ABSTRACT FROM AUTHOR]

Pongamia pinnata, is an important biodiesel plant in India. The seed is an economic part of the plant used for extraction of biodiesel. The reproductive biology of P. pinnata is important for determining barriers in setting pods. The study has been carried out at Central Agroforestry Research Institute, Jhansi, India, during 2017–2019. The observations were made on the floral biology and pollinator activity in P. pinnata for 2 years. Anthesis was noticed between 0800 and 1000 h with peak anthesis between 0800 and 0830 h. Flower longevity was only 1 day. Pollen dehiscence occurred 1–2 h before anthesis. Pollen remained viable throughout the day with maximum germination (96.15%) coinciding anthesis time. Whereas, maximum pollen tube length (0.54 ± 0.10) was observed during 1000 h. Stigma remained receptive for 8 h after anthesis, the maximum receptivity was noticed 2 h after anthesis (82% of pollen germination) and it was coinciding the time where maximum pollen tube length recorded. The style was longer than stamens, indicating that the flower appeared to be adapted for cross-pollination. There were 13 flower visitors recorded, of which Megachile species were more abundant compared to Apis, Xylocopa species and, other flower visitors. The pollinator exclusion experiment was conducted to assess the role of flower visitors on pollination and fruit set. No pod set was noticed in the absence of insect pollinators. Whereas, in an open-pollinated condition, pod set ranged between 15 to 18%. [ABSTRACT FROM AUTHOR]

In angiosperms, the process of pollination relies on species-specific interaction and signaling between the male (pollen) and female (pistil) counterparts where the interplay between several pollen and stigma proteins decides the fate of the pollen. In Brassicaceae, the dry stigmatic papillary cells control pollen germination by releasing resources only to compatible pollen thereby allowing pollen to hydrate and germinate. Despite the identification of a number of stigmatic proteins that facilitate pollination responses, the signaling mechanisms that regulate functions of these proteins have remained unknown. Here, we show that, in Arabidopsis , an extremely functionally redundant mitogen-activated protein kinase (MAPK) cascade is required for maintaining stigma receptivity to accept compatible pollen. Our genetic analyses demonstrate that in stigmas, five MAPK kinases (MKKs), MKK1/2/3/7/9 are required to transmit upstream signals to two MPKs, MPK3/4, to mediate compatible pollination. Compromised functions of these five MKKs in the quintuple mutant (mkk1/2/3RNAi/mkk7/9) phenocopied pollination defects observed in the mpk4RNAi/mpk3 double mutant. We further show that this MAPK nexus converges on Exo70A1, a previously identified stigma receptivity factor essential for pollination. Given that pollination is the crucial initial step during plant reproduction, understanding the mechanisms that govern successful pollination could lead to development of strategies to improve crop yield. Stigma receptivity is crucial for successful pollination to occur. Here, we show that, in Arabidopsis , a functionally redundant MAPK network involving five MKKs and two MPKs, converges on the stigmatic receptivity factor, Exo70A1, to mediate priming of the stigmatic papillary cells for pollen acceptance. [ABSTRACT FROM AUTHOR]

Mate choice in plants is poorly understood, in particular its indirect genetic benefits, but also the direct benefits of avoiding harmful matings. In the herb Collinsia heterophylla, delayed stigma receptivity has been suggested to enhance pollen competition, potentially functioning as a female mate choice trait. Previous studies show that this trait can mitigate the cost of early fertilization caused by pollen, thus providing a direct benefit. We performed two‐donor pollinations during successive floral stages to assess how this stigma receptivity trait and two pollen traits known to affect siring success influence indirect benefits in terms of offspring performance. We also investigated differential resource allocation by studying the influence of sibling performance in the same capsule. Offspring performance in terms of flower number was mainly affected by parental identities and differential resource allocation. Offspring seed production showed some influence of resource allocation, but was also affected by pollen donor identity and varied positively with late stigma receptivity. However, the effect of late stigma receptivity on offspring seed production was weakened in matings with pollen that advanced stigma receptivity. In conclusion, delayed stigma receptivity may be selected through both direct and indirect fitness effects in C. heterophylla, where pollen‐based delay on stigma receptivity might act as a cue for mate choice. However, selection may also be counteracted by antagonistic selection on pollen to advance stigma receptivity. Our results highlight the challenges of studying indirect genetic benefits and other factors that influence mate choice in plants. [ABSTRACT FROM AUTHOR]

Guangxi is one of the distribution centers of Primulina of the world. There are many endemic species. For the purpose of introdution and cultivation, germplasm presrvation and hybridization breeding, this study focused on the flow, ering phenological period, flowering habit, ovary development, pollen activity and other flowering biological characteris, tics of eight Primulina species endemic to Guangxi, including Primulina linearifolia, P. ophiopogoide, P. spinulosa, P. macrorhiza, P. linearicalyx, P. leprosa, P. guizhongensis and P. baishouensis. The results were as follows: (1) There were significant differences between in the wild and the artifical conditions in the flowering period, single bud blooming amount and single flower opening duration of these eight endemic species in Guangxi. In artificial conditions, the amount of flowering per plant and the duration of flower blooming were better than those of wild plants. (2) The duration of single flowering period of different species was 3-14 d. The stamens stopped growth in bud stage. The maturities of pistils and stamens were inconsistent, the stamens matured earlier than the pistils. (3) The pollen vitality was increasing from half-open to fully,open stage, which could reach more than 90% in fully,open stage. (4) The stigma was most compatible in the fully-opend stage of the corolla. At corolla completely open stage, the stigma receptivity rised to the highest level. (5) Self pollination was sterile, cross pollination was fertile. The seed germination rate of crossing seeds was more than 80%. This study provides data to support the multiplication of rare species and germplasm resources preservation, and also provides solutions for hybridization breeding in Primulina. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)