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.

Cytochemical and ultrastructural differences between intraspecific compatible and incompatible pollinations in Raphanus

1973 ◽  
Vol 183 (1070) ◽  
pp. 21-38 ◽  
Keyword(s):  
Pollen Tube ◽  
The Self ◽  
Self Incompatibility ◽  
Second Stage ◽  
Incompatible Pollen ◽  
Large Numbers ◽  
Third Stage ◽  
Incompatibility System ◽  
Three Stages ◽  
Two Stages

Examination of the behaviour of pollen on the style of Raphanus , following compatible and incompatible intraspecific pollinations, has revealed the self-incompatibility system in this species to be composed of at least three stages. The first, on which no information has been obtained in this study, involves the germination of the grain. The second stage concerns the ability of the pollen tube to penetrate the cuticle of the stigmatic papilla. It is possible that cutinase is deficient in incompatible pollen tubes but, in most instances, the outer layers of the stigmatic wall are penetrated. The third stage involves the interaction of substances secreted by the pollen tube with products of the stigmatic cytoplasm. The interaction is swiftly followed by the deposition, in the stigma, of a layered callosic body. This is formed immediately under the point of penetration and takes about 6 h to develop fully. Development of the pollen tube ceases as the first layers of callose are laid down. It is possible that the substances in the pollen responsible for the initiation of the second two stages are held in the tapetally synthesized tryphine, thus accounting for the sporophytic control of pollen compatibility in this species. The mature stigma contains large numbers of crystalline protein bodies, but it is not known whether they play any role in the self-incompatibility system.

scholarly journals Two Self-Incompatibility Sites Occur Simultaneously in the Same Acianthera Species (Orchidaceae, Pleurothallidinae)

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1758
Author(s):  
Mariana Oliveira Duarte ◽  
Denise Maria Trombert Oliveira ◽  
Eduardo Leite Borba
Keyword(s):  
Pollen Tubes ◽  
The Self ◽  
Main Reaction ◽  
Reaction Site ◽  
Self Incompatibility ◽  
Incompatible Pollen ◽  
Plant Groups ◽  
Transmission Electron ◽  
Incompatibility System ◽  
Cytological Characteristics

In most species of Pleurothallidinae, the self-incompatibility site occurs in the stylar canal inside the column, which is typical of gametophytic self-incompatibility (GSI). However, in some species of Acianthera, incompatible pollen tubes with anomalous morphology reach the ovary, as those are obstructed in the column. We investigated if a distinct self-incompatibility (SI) system is acting on the ovary of A. johannensis, which is a species with partial self-incompatibility, contrasting with a full SI species, A. fabiobarrosii. We analyzed the morphology and development of pollen tubes in the column, ovary, and fruit using light, epifluorescence, and transmission electron microscopy. Our results show that the main reaction site in A. johannensis is in the stylar canal inside the column, which was also recorded in A. fabiobarrosii. Morphological and cytological characteristics of the pollen tubes with obstructed growth in the column indicated a process of programmed cell death in these tubes, showing a possible GSI reaction. In addition, partially self-incompatible individuals of A. johannensis exhibit a second SI site in the ovary. We suggest that this self-incompatibility site in the ovary is only an extension of GSI that acts in the column, differing from the typical late-acting self-incompatibility system recorded in other plant groups.

scholarly journals Controlling for genetic identity of varieties, pollen contamination and stigma receptivity is essential to characterize the self-incompatibility system ofOlea europaeaL.

2017 ◽  
Vol 10 (9) ◽  
pp. 860-866 ◽  
Author(s):  
Pierre Saumitou-Laprade ◽  
Philippe Vernet ◽  
Xavier Vekemans ◽  
Vincent Castric ◽  
Gianni Barcaccia ◽  
...  
Keyword(s):  
The Self ◽  
Genetic Identity ◽  
Self Incompatibility ◽  
Stigma Receptivity ◽  
Pollen Contamination ◽  
Incompatibility System

The effect of pollination intensity and incompatible pollen on seed set in Turnera ulmifolia (Turneraceae)

1984 ◽  
Vol 62 (6) ◽  
pp. 1298-1303 ◽  
Author(s):  
Joel S. Shore ◽  
Spencer C. H. Barrett
Keyword(s):  
Regression Analysis ◽  
Seed Set ◽  
Pollen Grains ◽  
The Self ◽  
Time Intervals ◽  
Pollination Experiments ◽  
Controlled Pollination ◽  
Incompatible Pollen ◽  
Turnera Ulmifolia ◽  
Compatible Pollen

Controlled pollination experiments were performed on the self-incompatible distylous herb Turnera ulmifolia L. to investigate the effects of pollination intensity and large amounts of incompatible pollen on seed set. In the first experiment, known numbers of compatible pollen grains ranging from 1 to 100 were applied to stigmas of the floral morphs. In both morphs, increasing amounts of pollen generally resulted in increased levels of seed set, although considerable variance was observed at all pollination intensities. Approximately two to seven pollen grains are required to produce a single seed and more than 95 grains are required to achieve maximum seed set in T. ulmifolia. Regression analysis of the seed set data failed to detect a difference in the response of the floral morphs to pollination intensity. In the second experiment, known proportions of compatible and incompatible pollen were applied to stigmas at various time intervals. Most treatments involving mixtures of compatible and incompatible pollen had no significant effect on seed set when compared with the controls. Clogging was only observed in the long-styled morph when one anther of compatible pollen was applied to stigmas 1.5 and 3.0 h after pollination with five anthers of incompatible pollen. The clogging of stigmas by incompatible pollen seems unlikely to have played a major role in the evolution and maintenance of distyly in Turnera ulmifolia.

Studies on heteromorphic self-incompatibility systems: the cytochemistry and ultrastructure of the tapetum of Primula obconica

1981 ◽  
Vol 50 (1) ◽  
pp. 419-431
Author(s):  
V.A. Stevens ◽  
B.G. Murray
Keyword(s):  
Tapetal Cell ◽  
Pollen Grains ◽  
Anther Wall ◽  
Cell Periphery ◽  
Self Incompatibility ◽  
Fibrous Layer ◽  
Ultrastructural Studies ◽  
Incompatibility System ◽  
Secretory Type ◽  
Main Components

This paper describes the cytochemistry and ultrastructure of the developing tapetum in Primula obconica, a plant with a heteromorphic, sporophytic self-incompatibility system. The tapetum is of the secretory type and cytochemical tests have shown that when it breaks down proteinaceous (esterase) and lipidic components are deposited on the developing pollen grains. Acid phosphatase, a marker of gametophytic enzyme activity, is confined to the cytoplasm and intine of the developing pollen. Ultrastructural studies show that prior to its dissolution the tapetum undergoes a number of changes. In the early stages of development the tapetum is rich in ribosomes and rough endoplasmic reticulum, but following the breakdown of the tapetal cell wall the main components of the cytoplasm are densely staining spherical bodies surrounded by ribosomes and orbicular bodies, which appear to be confined to the cell periphery. As the cells break down, rod-like fibrils can be seen amongst the degenerate organelles and within the bacular cavities of the pollen. On dehiscence the pollen has a lipidic coating in addition to the fibrillar material in the pollen wall and the remnants of the tapetum can be seen adhering to the fibrous layer of the anther wall. Thus the mature, binucleate pollen of P. obconica is demonstrated to carry wall materials of sporophytic origin.

Post-Zygotic Seed Abortion in Sexual Diploid × Apomictic Tetraploid Intraspecific Paspalum Crosses

1994 ◽  
Vol 42 (4) ◽  
pp. 449 ◽  
Author(s):  
GA Norrmann ◽  
OA Bovo ◽  
CL Quarin
Keyword(s):  
Pollen Tube ◽  
Success Rate ◽  
Pollen Tube Growth ◽  
Endosperm Development ◽  
Tube Growth ◽  
Seed Abortion ◽  
Self Incompatibility ◽  
Incompatible Pollen ◽  
Incompatibility System

In many species of Paspalum, diploid (2x) cytotypes are usually outbreeders due to a self incompatibility system, while tetraploid (4x) conspecific counterparts are pseudogamous self-fertile apomicts. Intraspecific crossability between 2x female and 4x male cytotypes was investigated using classical methods of crossing in P. almum, P. brunneum, P. rufum, P. intermedium and P. quadrifarium. Expected triploid BII hybrids were obtained in P. intermedium (crossability: 0.004%) and in P. brunneum (crossability: 0.015%). In P. rufum, only tetraploid BIII hybrids were achieved with a crossability of 0.025% Looking for a better performance, in vitro ovary rescue was attempted 5 days after pollination in intraspecific 2x × 4x crosses of P. almum, P. quadrifarium, P. intermedium and P. rufum. The method was useful to recover some triploid BII hybrids in P. almum (success rate: 0.49%) and in P. rufum (0.59%), but failed in P. intermedium and P. quadrifarium. Pollen tube growth was usually inhibited at the stigma or style levels after self-pollination in 2x plants, confirming that diploids are self-incompatible. Pollen of 4x cytotypes germinated and penetrated the pistils of diploid conspecific cytotypes. This indicated that no incompatibility system exists in these species to keep the 2x cytotypes from hybridising with 4x conspecific cytotypes as pollen donors. However, after pollination of 2x cytotypes with pollen of 4x counterparts, most ovules showed embryo and endosperm development, but a few days later, endosperms collapsed and embryos stopped their development. As a result of these processes, sexual self-incompatible 2x cytotypes of Paspalum species produced very few triploid hybrids when pollinated with pollen of their apomictic 4x counterparts. Thus, the low diploid-tetraploid crossability was due to the existence of a post-zygotic abortive system and not caused by pre-fertilisation barriers.

scholarly journals Plasticity in the self-incompatibility system of Solanum carolinense

2004 ◽  
Vol 19 (3) ◽  
pp. 127-135 ◽  
Author(s):  
STEVEN E. TRAVERS ◽  
JORGE MENA-ALI ◽  
ANDREW G. STEPHENSON
Keyword(s):  
The Self ◽  
Self Incompatibility ◽  
Solanum Carolinense ◽  
Incompatibility System
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