Protogyny, Self-Incompatibility and Pollination in Anthocercis gracilis (Solanaceae)

1995 ◽  
Vol 43 (5) ◽  
pp. 451 ◽  
Author(s):  
HM Stace

The pollination biology of A. gracilis was examined in glasshouse plants and natural populations. The species is both protogynous and pre-zygotically self-sterile (self-incompatible). Protogyny prevents autopollination (autogamous self-pollination), and self-incompatibility avoids geitonogamous self-fertilisation. This sequence is essential because prior selfing blocks the style with pollen tubes and prevents subsequent outcrossing. Flowers have no discernible daytime odour, the pollen is clumped and not easily shaken from opened anthers, and daytime insect visitors are rarely observed in the field. However in long-established populations, mast plants carry one or a few capsules during winter-spring and seeds per capsule are generally high. Reproduction of natural populations involves reliable pollinators of unknown identity, possibly small flies, bees or moths lured by a tiny amount of sucrose-rich nectar secreted by the hypogynous disc. It is not anomalous that A. gracilis has two devices for preventing self-fertilisation, protogyny and strong self-incompatibility, as both are functional aspects of the same outcrossing system. This is the first report of self-incompatibility in the Anthocercideae which is an old and apparently basal lineage in the Solanaceae.

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 432
Author(s):  
Yaling Chen ◽  
Benchang Hu ◽  
Fantao Zhang ◽  
Xiangdong Luo ◽  
Jiankun Xie

Dendrobium officinale is a rare and traditional medicinal plant with high pharmacological and nutritional value. The self-incompatibility mechanism of D. officinale reproductive isolation was formed in the long-term evolution process, but intraspecific hybridization of different germplasm resources leads to a large gap in the yield, quality, and medicinal value of D. officinale. To investigate the biological mechanism of self-incompatibility in D. officinale, cytological observation and the transcriptome analysis was carried out on the samples of self-pollination and cross-pollination in D. officinale. Results for self-pollination showed that the pollen tubes could grow in the style at 2 h, but most of pollen tubes stopped growing at 4 h, while a large number of cross-pollinated pollen tubes grew along the placental space to the base of ovary, indicating that the self-incompatibility of D. officinale may be gametophyte self-incompatibility. A total of 63.41 G basesum of D. officinale style samples from non-pollinated, self-pollination, and cross-pollination by RNA-seq were obtained, and a total of 1944, 1758, and 475 differentially expressed genes (DEGs) in the comparison of CK (non-pollinated) vs. HF (cross-pollination sample), CK vs. SF (self-pollination sample) and SF vs. HF were identified, respectively. Forty-one candidate genes related to self-incompatibility were found by function annotation of DEGs, including 6 Ca2+ signal genes, 4 armed repeat containing (ARC) related genes, 11 S-locus receptor kinase (SRK) related genes, 2 Exo70 family genes, 9 ubiquitin related genes, 1 fatty acid related gene, 6 amino acid-related genes, 1 pollen-specific leucine-rich repeat extensin-like protein (LRX) related gene and 1 lectin receptor-like kinases (RLKs) related gene, showed that self-incompatibility mechanism of D. officinale involves the interaction of multiple genes and pathways. The results can provide a basis for the study of the self-incompatibility mechanism of D. officinale, and provide ideas for the preservation and utilization of high-quality resources of D. officinale.


HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 917-920 ◽  
Author(s):  
Shao-Ling Zhang ◽  
Shin Hiratsuka

Cultivars of the Japanese pear [Pyrus pyrifolia (Burm.) Nakai] have variable degrees of self-incompatibility (SI) and can be classified into at least three groups: strong, intermediate, or weak SI; as shown by the extent of self-pollen tube growth in the style, and the percentage of fruit set following self-pollination. Following self-pollination, the elongation of pollen tubes in the detached styles of `Kosui' and `Kikusui' became increasingly suppressed from 4 days before anthesis (–4 DAA) to 2 days after anthesis (2 DAA). Tube growth of `Kosui' was more suppressed than that of `Kikusui' during this period. In `Osa-Nijisseiki', however, the rate of tube growth did not vary with stage of stylar development, from –8 to 2 DAA. Pollen tubes elongated much better after cross-pollination than after self-pollination at all stages tested, and the extent of the elongation increased as the styles matured. The concentration of total S-protein (sum of two S-proteins per buffer-soluble protein) increased with stylar development, but the rate of increase varied with the cultivar. The rate was significantly greater in the strongly self-incompatible `Kosui' than in the moderately self-incompatible `Kikusui', and was slowest in the weakly self-incompatible `Osa-Nijisseiki' at all developmental stages. During stylar maturation, the concentration of S4-protein, which is common in all cultivars, was highest in `Kosui', followed by `Kikusui' and `Osa-Nijisseiki'. Thus, the cultivar differences in SI expression in the Japanese pear are determined about –4 DAA and appear to be regulated, in part, by the concentration of S-proteins produced in the style.


1990 ◽  
Vol 41 (6) ◽  
pp. 1101 ◽  
Author(s):  
TA Heard ◽  
V Vithanage ◽  
EK Chacko

Aspects of the pollination biology of cashew Anacardium occidentale L. (Anacardiaceae) were investigated at a site of potential commercial production. A mean of 442.9 flowers were produced per panicle of which 32.1 (7.3%) were hermaphrodite, the remainder being male. Mean initial fruit set was 5.0 per panicle, representing a percentage fruit set of 15.5%. The absence of either male or hermaphrodite flowers at any particular stage of flowering did not limit fruit set. Diversity of insect flower visitors, attracted by nectar rewards, was great, but only a few species were common. Three species of potentially efficient pollinators were tested for their pollinator efficiency which was found to be high for honey bees, Apis mellifera, and a native fly, Ligyra sp. Only 25% of flowers were pollinated in 1987, but this increased to 98% owing to a corresponding increase in the natural populations of insect visitors. Wind and night flying insects played no role in pollination. Although 98% of flowers were pollinated, initial fruit set averaged only 15.5%. This suggests that factors other than pollination limit fruit set. However, pollination is important and the insect pollinators will need protection from insecticide applications and destruction of breeding sites.


Biologia ◽  
2012 ◽  
Vol 67 (2) ◽  
Author(s):  
Xuan Chen ◽  
Shan Hao ◽  
Li Wang ◽  
Wanping Fang ◽  
Yuhua Wang ◽  
...  

AbstractThe self-incompatibility of tea plant (Camellia sinensis (L.) O. Kuntze) was studied with the methods of aniline blue fluorescence assay and paraffin sections. The characteristics of pollen tube elongation after hand pollination was analyzed in 4 tea cultivars, including ‘Keemenzhong’, ‘Longjing-changye’, ‘Fuding-dabaicha’ and ‘Yabukita’, under self-pollination and cross-pollination, respectively. Although there were some difference among cultivars, pollen tubes elongated through the style and reach the ovary successfully at 48 h after pollination for both cross- and self-pollen tubes in all the four cultivars of tea. Pollen tubes entered into the ovule micropyles, however, only for cross-pollination, but not for self-pollination. Pollen tubes of selfing plants, failed in fertilizing, seemed have some difficulties to enter the ovule. All of which indicated that the self-incompatibility of tea plant is a late-acting self-incompatibility system (LSI) or an ovarian sterility (OS), in which the self incompatibility was due to none self pollen tube penetrating into the ovule and no fertilization.


HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 312-315 ◽  
Author(s):  
Sandra M. Reed

The objectives of this study were to evaluate self-incompatibility in Hydrangea paniculata Sieb. and H. quercifolia Bartr. and to determine optimum time for pollination of these two species. Flowers from three genotypes of each species were collected 1, 2, 4, 8, 24, 48, and 72 hours after cross- and self-pollination, stained with aniline blue and observed using a fluorescence microscope. In both species, pollen germination was observed on stigmas of over half of the flowers collected 4 to 72 hours after cross- or self-pollination. Differences in pollen tube length between cross- and self-pollinated flowers were noted from 8 to 72 hours after pollination in H. paniculata and from 24 to 72 hours after pollination in H. quercifolia. By 72 hours after pollination, most self-pollen tubes had only penetrated the top third of the style but cross-pollen tubes had grown to the base of the style and entered 40% to 60% of the ovules. Stigmas of H. paniculata were receptive to pollen from anthesis to 5 days after anthesis, while stigmas of H. quercifolia were receptive from 1 to 5 days after anthesis. This study provides evidence of a gametophytic self-incompatibility system in H. paniculata and H. quercifolia. Occasional self-seed set previously observed in these species was theorized to have been due to pseudo-self compatibility.


2003 ◽  
Vol 51 (2) ◽  
pp. 189 ◽  
Author(s):  
L. M. Pound ◽  
B. Patterson ◽  
M. A. B. Wallwork ◽  
B. M. Potts ◽  
M. Sedgley

This study investigated whether pollen competition favours cross- over self-pollination in Eucalyptus globulus Labill. ssp. globulus. Controlled pollinations with self-pollen, cross-pollen and a mixture of self- and cross-pollen were conducted on three partially self-incompatible trees. The paternity of individual seeds resulting from mixed pollination was determined by isozyme analysis. No evidence for pollen competition was found. Instead, seed paternity reflected the level of self-incompatibility of each tree as determined by separate self- and cross-pollinations. Furthermore, the number of seeds set per capsule following mixed pollination was significantly less than that following cross-pollination in the two least self-compatible trees. These results suggest that both self- and cross-pollen tubes reach ovules following mixed pollination and that a late-acting self-incompatibility mechanism operates to abort a certain proportion of self-penetrated ovules.


2021 ◽  
Author(s):  
Marta B Bianchi ◽  
Thomas R Meagher ◽  
Peter E Gibbs

Abstract Background and Aims Genetically controlled self-incompatibility (SI) mechanisms constrain selfing and thus have contributed to the evolutionary diversity of flowering plants. In homomorphic gametophytic SI (GSI) and homomorphic sporophytic SI (SSI), genetic control is usually by a single multi-allelic locus S. Both GSI and SSI prevent self pollen tubes reaching the ovary and so are pre-zygotic in action. In contrast, in taxa with late-acting self-incompatibility (LSI), rejection is often post-zygotic, since self-pollen tubes grow to the ovary where fertilization may occur prior to floral abscission. Alternatively, lack of self fruit set could be due to early-acting inbreeding depression (EID). The aim of our study was to investigate mechanisms underlying lack of selfed fruit set in Handroanthus heptaphyllus in order to assess the likelihood of LSI versus EID. Methods We employed four full sib diallels to study the genetic control of LSI in Handroanthus heptaphyllus using a precociously flowering variant. We also used fluorescence microscopy to study the incidence of ovule penetration by pollen tubes in pistils that abscised following pollination or initiated fruits. Key Results All diallels showed reciprocally cross-incompatible full-sibs (RCI), reciprocally cross compatible full-sibs (RCC), and non-reciprocally compatible full-sibs (NRC) in almost equal proportions. There was no significant difference between the incidence of ovule penetrations in abscised pistils following self- and cross-incompatible pollinations, but those in successful cross pollinations were around twofold greater. Conclusions A genetic model postulating a single S locus with four s alleles, one of which, in the maternal parent, is dominant to the other three, will produce RCI, RCC and NRC situations each at 33 %, consistent with our diallel results. We favour this simple genetic control over an early-acting inbreeding depression (EID) explanation since none of our pollinations, successful or unsuccessful, resulted in partial embryo development, as would be expected under a whole genome EID effect.


2013 ◽  
Vol 40 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
D. Milatović ◽  
D. Nikolić ◽  
B. Krška

Self-(in)compatibility was tested in 40 new apricot cultivars from European breeding programmes. Pollen-tube growth in pistils from laboratory pollinations was analysed using the fluorescence microscopy. Cultivars were considered self-compatible if at least one pollen tube reached the ovary in the majority of pistils. Cultivars were considered self- incompatible if the growth of pollen tubes in the style stopped along with formation of characteristic swellings. Of the examined cultivars, 18 were self-compatible and 22 were self-incompatible. Fluorescence microscopy provides a relatively rapid and reliable method to determine self-incompatibility in apricot cultivars.      


1976 ◽  
Vol 54 (22) ◽  
pp. 2530-2535 ◽  
Author(s):  
Fred R. Ganders

Stigmatic pollen loads were analyzed from naturally pollinated pin and thrum form flowers of Amsinckia douglasiana and A. vernicosa var. furcata. Pin stigmas captured more total pollen than thrum stigmas. Pins experienced either net self-pollination or random pollination. Thrum stigmas experienced significant disassortative pollination. Comparing pollen loads from intact and emasculated thrum flowers of A. douglasiana indicated that self-pollination and geitonogamy were relatively unimportant in the pollination of the thrum form. The level of disassortative pollination of A. vernicosa var. furcata does not appear to be high enough to account for the level of disassortative mating observed by progeny testing, suggesting that this species may possess an incomplete stylar self-incompatibility system such as has been reported in A. grandiflora.


1991 ◽  
pp. 271-283 ◽  
Author(s):  
J. E. Gray ◽  
B. A. McClure ◽  
I. Bonig ◽  
M. A. Anderson ◽  
A. E. Clarke

Sign in / Sign up

Export Citation Format

Share Document