scholarly journals Cordia subcordata (Boraginaceae), a distylous species on oceanic coral islands, is self-compatible and pollinated by a passerine bird

2020 ◽  
Vol 153 (3) ◽  
pp. 361-372
Author(s):  
Xiangping Wang ◽  
Meihong Wen ◽  
Mingsong Wu ◽  
Dianxiang Zhang

Background and aims – Distyly is usually rare on oceanic islands, which is probably due to the difficulty for distylous plants to colonize those islands. However, Cordia subcordata was observed to be distylous with short- and long-styled morphs on the Xisha Islands in the South China Sea. To characterize the reproduction system of Cordia subcordata and to understand how this distylous species maintains itself on these islands, we studied its reproductive and pollination biology.Methods – Seed set and pollen tube growth under manipulated intermorph, intramorph, and self-pollination were examined to investigate self-incompatibility in the species. The number of pollen grains deposited on the stigmas after a single pollinator visit were counted to investigate the pollination efficiency of different visitors. Key results – Our study indicated that Cordia subcordata shows reciprocal herkogamy as is typical in distylous species. Pollen tubes could reach the base of the style and move into the ovules under all the manipulated pollination treatments in both morphs. Seed set resulting from four hand-pollination experiments did not show any differences between both morphs, suggesting that Cordia subcordata lacks heterostylous self-incompatibility. The most frequent flower visitors, Zosterops japonicus and Apis cerana, were observed foraging on the large volumes of nectar and pollen grains, respectively, with Zosterops japonicus being the most effective pollinator, depositing large number of pollen grains on the stigmas during their visits.Conclusions – Our findings show that Cordia subcordata established itself and persists in the archipelago by producing fruits through a combination of self-compatibility and pollination by the most common passerine bird on the oceanic islands.

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fan Wang ◽  
Feng-Jiao Zhang ◽  
Fa-Di Chen ◽  
Wei-Min Fang ◽  
Nian-Jun Teng

There has been a heated argument over self-incompatibilityof chrysanthemum (Chrysanthemum morifolium) among chrysanthemum breeders. In order to solve the argument, we investigated pistil receptivity, seed set, and compatible index of 24 chrysanthemum cultivars. It was found that the 24 cultivars averagely had 3.7–36.3 pollen grains germinating on stigmas at 24 hours after self-pollination through the fluorescence microscope using aniline blue staining method. However, only 10 of them produced self-pollinated seeds, and their seed sets and compatible indexes were 0.03–56.50% and 0.04–87.50, respectively. The cultivar “Q10-33-1” had the highest seed set (56.50%) and compatible index (87.50), but ten of its progeny had a wide range of separation in seed set (0–37.23%) and compatible index (0–68.65). The results indicated that most of chrysanthemum cultivars were self-incompatible, while a small proportion of cultivars were self-compatible. In addition, there is a comprehensive separation of self-incompatibility among progeny from the same self-pollinated self-compatible chrysanthemum cultivar. Therefore, it is better to emasculate inflorescences during chrysanthemum hybridization breeding when no information concerning its self-incompatibility characteristics is available. However, if it is self-incompatible and propagated by vegetative methods, it is unnecessary to carry out emasculation when it is used as a female plant during hybridization breeding.


1993 ◽  
Vol 41 (1) ◽  
pp. 35 ◽  
Author(s):  
M Ramsey ◽  
N Prakash ◽  
S Cairns

The breeding systems of disjunct tableland and coastal populations of Christmas bells were determined using hand-pollination experiments. In both populations, 90% or more of self-pollinated plants produced seeds. Tableland plants were significantly more self-fertile than coastal plants (ratio of self seed set to cross seed set: tableland, 0.55 ± 0.03; coast, 0.08 ± 0.02). Significant variation among plants for self-fertility was found in both populations. Autofertility was 1.6% or less in both populations indicating that pollen vectors are necessary for seed set. Seed set by agamospermy in both populations was less than 0.1%. Percentage seed abortion was greater in self-pollinated plants than cross-pollinated plants in both populations. In both self- and cross-pollinated plants, seed abortion was twice as great in the coastal population than in the tableland population. No evidence was found for stigmatic or stylar self-incompatibility. Self and cross pollen adhered to and germinated equally well on stigmas in both populations (72 - 77% germination). Similarly, there were no differences between pollination treatments or populations in the percentage of ovules penetrated by pollen tubes (82 - 89% penetration). When self-pollination preceded cross-pollination by 24 h or longer seed set was significantly reduced compared to flowers that were cross-pollinated only, suggesting ovules were pre-empted by self pollen tubes. Collectively these results strongly suggest that self seed set was reduced by a mechanism operating at the ovule level, such as early-acting inbreeding depression due to recessive seed-aborting genes, although incomplete late-acting self-incompatibility cannot be ruled out. For coastal plants, this ovular mechanism largely prevents selfing, indicating plants were predominantly outcrossing although most produced some self seed. For tableland plants, substantial seed set by selfing may occur under natural conditions.


HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1280-1282 ◽  
Author(s):  
Doron Schneider ◽  
Raphael A. Stern ◽  
Martin Goldway

Apple (Malus domestica) has a gametophytic self-incompatibility (GSI) system. Consequently, fertilization is achieved by cross-pollination with a compatible pollinator. Compatibility is governed by a multiallelic S locus. Cultivars are fully compatible when both of their S-loci differ and are semi compatible when one locus is identical and the other differs. In a previous study we found that the fruit set and yield of the apple cultivar `Topred' was reduced when it was pollinated by a semi compatible cultivar. To examine if this occurrence is a general feature in apples grown under suboptimal conditions, three additional cultivars, `Golden Delicious', `Granny Smith' and `Royal Gala', were studied as pollen recipients of semi and fully compatible pollinators. Based on PCR analysis of the S-RNase allele, it was determined that the pollination rate of the semi compatible was significantly lower than that of the fully compatible pollinator in all cases. This was reflected by the lower fruit set and seed set of `Golden Delicious' and `Royal Gala', but not of `Granny Smith'. In hand pollination experiments, where pollen was in excess, no difference was found between the semi and fully compatible pollinators in all three cases. These results indicate that the low yield, conferred by semi compatible pollinators, is due to insufficient cross-pollination (and not to cultivar characteristics). Thus, low yields due to semi compatibility may be avoided by appropriate honeybee management that will increase pollination. Still, under suboptimal conditions, for growth and pollination, full compatibility is preferable.


1971 ◽  
Vol 77 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Gillian Toynbee-Clarke

SummaryPollination treatments were carried out on highly inbred lines of winter beans over a period of four years.Tripping produced an inferior seed-set compared with all treatments involving emasculation and hand pollination with either cross or self-pollen. It is suggested that with highly inbred lines the stigmatic surface requires some form of scarification to improve the seed-set. Most lines showed no preference for cross or self-pollen, and there was no evidence of self-incompatibility. Bud and mature flower pollination gave an improved seed-set over tripping in all lines.One inbred line gave a high seed-set in all pollination treatments. Results from another line were consistent with a short period of ovule receptiveness.Using data obtained from three experiments, two self-pollination treatments were used to screen breeding lines for their suitability as components of synthetic varieties. Significant differences in seed-set were found between the lines.


2002 ◽  
Vol 80 (4) ◽  
pp. 340-348 ◽  
Author(s):  
Thierry Pailler ◽  
Benjamin Warren ◽  
Jean-Noël Labat

A particularly interesting aspect of the study of organisms in insular environments is plant reproduction and the interaction of plants with their pollinators. Differences in composition between the fauna and flora of continental and island populations, combined with their geographical isolation, have frequently driven rapid evolution in colonizing populations. In particular, floral traits and compatibility systems tend to favour autogamy in response to a paucity of pollinators in the environment. In this context we investigate the origins of the reproductive biology of Aloe mayottensis Berger, a lily endemic to the island of Mayotte. We show that this species is pollinated by the island's endemic sunbird species, and has floral traits and a reproduction system that favour allogamy. Our results show that A. mayottensis is a protandrous and partially self-compatible species. Analysis of stigmatic pollen load shows that stigma received a mean of 56 crossed pollen grains and 62.2 selfed pollen grains per stigma. Study of visitation rates of plants and flowers by the sunbird showed that there is daily variation in the activity of this pollinator, and that males are more active than females.Key words: Aloe mayottensis, floral biology, Lomatophyllum, Nectarinia, bird pollinization, sunbirds, Oceanic islands, Mayotte.


2021 ◽  
Vol 12 ◽  
Author(s):  
Han-Wen Xiao ◽  
Yan-Bo Huang ◽  
Yu-Hang Chang ◽  
Yun Chen ◽  
Richard J. Abbott ◽  
...  

Delayed autonomous selfing (DAS) provides reproductive assurance under conditions of pollinator and/or pollen-limitation. Few plant species have been investigated to determine if DAS is terminated when a flower is sufficiently pollinated by a pollen vector, thereby saving plant resources for other purposes. We examined this possibility in bumblebee-pollinated Salvia umbratica. We first showed that DAS resulting in high fruit set (100%) and seed set (>80%) per flower occurred in the absence of insect pollinators by means of style recurvature and was completed in 94% of flowers 72 h after they opened. In contrast, in flowers pollinated immediately after opening, DAS was prevented by corollas dropping away before styles recurve toward the upper thecae. We next showed that hand-pollination of flowers immediately after they opened resulted in high fruit set (100%) and seed set (>80%) when 5–10 pollen grains or more were deposited on their stigmas, whereas fruit set and seed set were reduced to 45.00 and 22.50%, respectively, when pollen loads were reduced to 1–3 pollen grains. Finally, we showed that on average single pollinator visits deposited 26 pollen grains on stigmas of flowers that had just opened, which is more than enough to ensure high fruit and seed set. Our results indicate that flower longevity is highly correlated with the pollinator environment and female fitness of S. umbratica, with extended flower longevity allowing DAS to occur being advantageous when pollinators are absent, while reduced floral longevity and prevention of DAS being favored when flowers are pollinated by pollinators. Thus, flower longevity in S. umbratica varies so as to optimize reproductive output and resource efforts, and is dependent on the availability and effectiveness of pollinators to pollinate flowers.


2006 ◽  
Vol 7 (3) ◽  
pp. 248-252 ◽  
Author(s):  
Kazuki Ariyoshi ◽  
Emily Magnaghi ◽  
Mark Frey
Keyword(s):  
Seed Set ◽  

1972 ◽  
Vol 52 (4) ◽  
pp. 569-574 ◽  
Author(s):  
K. C. YEUNG ◽  
E. N. LARTER

A study of the pollen production properties of three hexaploid triticale strains (Triticale hexaploide Lart.) showed that their anther length was significantly greater than that of wheat anthers (Triticum aestivum L. em Thell.) and the estimated number of pollen grains per anther ranged from 15,000 to 21,000. In comparison, a total of 8000 grains per anther was estimated for wheat, cult Manitou. Eighty-nine percent anther extrusion occurred in triticale cult Rosner, while Manitou averaged 70% anther extrusion. The period of anthesis of triticale varied according to strain but generally was of longer duration than in Manitou and thereby promoted outcrossing. Using a triticale strain carrying a dominant marker gene, 50% seed-set was obtained at a distance of 12 m leeward of the pollen source; however, a small percentage was still obtained at a distance of 30 m. It would appear from the limited number of triticales used in this study that a wide range of variability exists within this species in its pollen production and disseminating properties. With appropriate selection pressures, strains with an outbreeding habit could be developed for the purpose of hybrid seed production.


Heredity ◽  
1983 ◽  
Vol 50 (2) ◽  
pp. 169-177 ◽  
Author(s):  
C H Fearon ◽  
M D Hayward ◽  
M J Lawrence

1979 ◽  
Vol 21 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Nicholi Vorsa ◽  
E. T. Bingham

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.


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