An unusual heteromorphic incompatibility system

1984 ◽  
Vol 68-68 (1-2) ◽  
pp. 139-144 ◽  
Author(s):  
O. Schou ◽  
M. Philipp
Keyword(s):  
Incompatibility System ◽  
Heteromorphic Incompatibility

Heteromorphic incompatibility system under disruptive selection

1975 ◽  
Vol 188 (1092) ◽  
pp. 247-256 ◽  
Keyword(s):  
Pollen Grains ◽  
Single Type ◽  
Disruptive Selection ◽  
Intermediate Point ◽  
Widespread Distribution ◽  
Population Selection ◽  
Incompatibility System ◽  
Type Population ◽  
Heteromorphic Incompatibility ◽  
Selection Of

Forty populations of Pemphis acidula sampled from Africa to Taiwan have been analysed for heterostylic incompatibility. All populations except one are distylic. The exceptional population comes from southern Madagascar. It consists of 100% long homostyled plants that are self-compatible. A semi-homostyle which is self-incompatible in some and self-compatible in others is found in nine populations at 10% frequency. Measurements of anthers, styles and pollen grains reveal that all the distylic populations are similar. Both the long- and short-styled plants have two levels of anthers with two sizes of pollen grains. In a more extreme form this is a feature usually found only in tristylic species. If distylic Pemphis has been derived from tristyly by the loss of the ‘mid’ type, then the end point of selection would be equal anthers and pollen within each type. The widespread distribution of the forty populations and their similarity indicate that this final equilibrium is unattainable. The explanation of this paradox comes from the homostyle population. The two rows of anthers are at equal heights and the two classes of pollen grains are equal in size. Thus in a self-compatible, single type population, selection has gone to completion. In the distylic populations the selection within the two types, for equality of anthers and pollen grains, is in opposite directions in each type. The 'mid’ anthers have to be raised in the short-styled and lowered in the long-styled plants. Similarly the selection of ‘mid’ pollen is in opposite directions. This disruptive selection keeps the equilibrium at an intermediate point.

Pollen flow in distylous populations of Amsinckia (Boraginaceae)

1976 ◽  
Vol 54 (22) ◽  
pp. 2530-2535 ◽  
Author(s):  
Fred R. Ganders
Keyword(s):  
Pollen Flow ◽  
Progeny Testing ◽  
Self Incompatibility ◽  
Disassortative Mating ◽  
Pollen Loads ◽  
Self Pollination ◽  
Incompatibility System ◽  
Total Pollen

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.

The formation of the tryphine coating the pollen grains of Raphanus , and its properties relating to the self-incompatibility system

1973 ◽  
Vol 184 (1075) ◽  
pp. 149-165 ◽  
Keyword(s):  
Granular Material ◽  
Pollen Grains ◽  
The Self ◽  
Self Incompatibility ◽  
Pollen Maturation ◽  
Incompatible Pollen ◽  
Incompatibility System ◽  
Two Stages ◽  
Stimulation Of ◽  
Incompatible Pollen Tube

The tryphine that coats the pollen grains of Raphanus is tapetally synthesized and is composed of a fibro-granular and a lipidic component. The fibro-granular material is proteinaceous and is secreted by cisternae of the endoplasmic reticulum. The lipidic component is derived, mainly, from degraded elaioplasts. The fibro-granular material is applied to the pollen exine first, followed by the lipidic mass. The tryphine condenses during the final stages of pollen maturation and dries down to form a thick, highly viscous coating. The major part of the condensation appears to result from dehydration. The tryphine, extracted from the pollen by a centrifugal method and mounted in a membrane, appears to be capable of penetrating the outer layers of a stigma of the same species and, if the pollen from which it was derived is incompatible with respect to the stigma, the stimulation of the production of the callosic reaction body in a manner similar to an incompatible pollen tube. It is proposed that, in Raphanus , substances responsible for the initiation of at least two stages in the self-incompatibility system are held in the tryphine.

scholarly journals Expression of Brassica napus GLO1 is sufficient to breakdown artificial self-incompatibility in Arabidopsis thaliana

2020 ◽  
Author(s):  
Patrick Kenney ◽  
Subramanian Sankaranarayanan ◽  
Michael Balogh ◽  
Emily Indriolo
Keyword(s):  
Arabidopsis Thaliana ◽  
Brassica Napus ◽  
Specific Interaction ◽  
Peptide Ligand ◽  
Self Incompatibility ◽  
Stigma Surface ◽  
Compatibility Factor ◽  
Incompatibility System ◽  
Allele Specific ◽  
Armadillo Repeat

AbstractMembers of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including Glyoxalase I (GLO1) which is necessary for successful pollination. Suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCRb, AlSRKb and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility response in A. thaliana stigmas, suggesting that GLO1 functions as an inter-species compatibility factor. Therefore, GLO1 has an indisputable role as a compatibility factor in the stigma in regulating pollen attachment and pollen tube growth. Lastly, this study demonstrates the usefulness of an artificial self-incompatibility system in A. thaliana for interspecific self-incompatibility studies.

scholarly journals Inferences on specificity recognition at the Malus×domestica gametophytic self-incompatibility system

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Maria I. Pratas ◽  
Bruno Aguiar ◽  
Jorge Vieira ◽  
Vanessa Nunes ◽  
Vanessa Teixeira ◽  
...  
Keyword(s):  
Malus Domestica ◽  
Self Incompatibility ◽  
Incompatibility System

Breeding System, Karyotype and Variation Within and Between Populations of Rutidosis leptorrhynchoides F Muell (Asteraceae, Inuleae)

1991 ◽  
Vol 39 (1) ◽  
pp. 85 ◽  
Author(s):  
P Leeton ◽  
YJ Fripp
Keyword(s):  
Chromosome Number ◽  
Breeding System ◽  
Geographic Distance ◽  
Endangered Plant ◽  
Allozyme Analysis ◽  
Self Incompatibility ◽  
Eastern Australia ◽  
Incompatibility System ◽  
Leaf Dimensions ◽  
Allozyme Loci

The endangered plant species, Rutidosis leptorrhynchoides (button wrinklewort), is now known from only a few populations in each of two regions separated by approximately 500 km in south-eastern Australia. Plants were examined from several populations from each region. No differences in chromosome number or morphology were observed among plants or populations. All counts were diploid, 2n = 26. Viable progeny were obtained following self-pollination and allozyme analysis indicated that these progeny were the result of selfing and not agamospermy. This species is not an obligate outcrosser and does not have a classical pre-zygotic self-incompatibility system. However, outcross pollen may have an advantage over self pollen and this species may thus be preferentially outcrossing. The pollen: ovule ratios (mean 3186 ± 48.5) were consistent with this hypothesis. Allele frequencies at allozyme loci diferred little between populations, with an estimated 97% of the variation within populations. There was no correlation between genetic distance and geographic distance. In contrast, for the leaf dimensions of plants germinated and raised together in a glasshouse there were differences between plants from the two regions. It is recommended that populations from both regions should be conserved.

The Breeding Systems of Stylidium graminifolium and Stylidium productum (Stylidiaceae)

1990 ◽  
Vol 38 (2) ◽  
pp. 217 ◽  
Author(s):  
AJ Willis ◽  
JE Ash
Keyword(s):  
Breeding System ◽  
Seed Set ◽  
Breeding Systems ◽  
The South ◽  
Pollination Experiments ◽  
Australian Species ◽  
South West ◽  
Self Pollination ◽  
Incompatibility System ◽  
Close Relationship

The breeding systems of Stylidiurn grarninifolium and S. producturn (= S. grarninifoliurn var. caulescens) were studied by observing the phenology of individual flowers and inflorescences, and relating the data to a series of pollination experiments within and between the species. Inter-specific pollinations yielded similar levels of seed-set to crosses within the species indicating a close relationship between the taxa. Self-pollination of either species is uncommon; however, when it occurs, the majority of selfed ovules are aborted post-zygotically, probably by a system of recessive lethals, as there is no indication of an incompatibility system. It is concluded that the breeding systems of S. grarninifoliurn and S. productum, two of the few eastern Australian species, are similar to those of many Stylidiurn species from the south-west, casting doubt upon hypotheses that the breeding system has led to high rates of speciation in the south-west.

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