Self-Incompatibility-Induced Programmed Cell Death in Field Poppy Pollen Involves Dramatic Acidification of the Incompatible Pollen Tube Cytosol

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.

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Ultrastructural Aspects of the Self-Incompatibility Mechanism in Lycopersicum Peruvianum Mill

Journal of Cell Science ◽

10.1242/jcs.12.2.403 ◽

1973 ◽

Vol 12 (2) ◽

pp. 403-419 ◽

Cited By ~ 1

Author(s):

D. DE NETTANCOURT ◽

M. DEVREUX ◽

A. BOZZINI ◽

M. CRESTI ◽

E. PACINI ◽

...

Keyword(s):

Pollen Tube ◽

Tube Wall ◽

Degradation Mechanism ◽

Embryo Sac ◽

Pollen Tubes ◽

Self Incompatibility ◽

Weak Reaction ◽

General Hypothesis ◽

Incompatible Pollen ◽

Compatible Pollen

The experimental results obtained show that the tip of the incompatible pollen tube bursts open after the outer-wall has considerably expanded in the intercellular spaces of the conducting tissue and the inner-wall has disappeared and numerous particles have accumulated in the tube cytoplasm. These particles, which measure approximately 0.2 µm in diameter and give a weak reaction to the test of Thiéry, differ in many respects from the vesicles normally present in compatible pollen tubes growing through the style; they appear to resemble, in some cases, the spheres which are discharged by the compatible pollen tubes after they have reached the embryo-sac. It is considered that these observations support the current belief that the tube wall is the site of action for the incompatibility proteins and suggest that self-incompatibility is not a passive process resulting from lack of growth stimulation but an active event which leads to the destruction of the incompatible pollen tubes. The degradation mechanism involved appears similar to the one which enables the compatible pollen tube to release its contents in the degenerated synergid and presents some analogies with the lytic process taking place in virus-infected cells. The general hypothesis is presented that the particles observed in the cytoplasm of self-incompatible pollen tubes consist of a mixture of incompatibility proteins and of basic constituents of the tube wall.

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Erratum to: Programmed-cell-death hallmarks in incompatible pollen and papillar stigma cells of Olea europaea L. under free pollination

Plant Cell Reports ◽

10.1007/s00299-010-0858-0 ◽

2010 ◽

Vol 29 (6) ◽

pp. 573-573 ◽

Cited By ~ 17

Author(s):

Irene Serrano ◽

Salvatore Pelliccione ◽

Adela Olmedilla

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Olea Europaea ◽

Olea Europaea L ◽

Incompatible Pollen ◽

Olea Europaéa

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Pollen tube reuses intracellular components of nucellar cells undergoing programmed cell death in Pinus densiflora

PROTOPLASMA ◽

10.1007/s00709-010-0176-y ◽

2010 ◽

Vol 248 (2) ◽

pp. 339-351 ◽

Cited By ~ 9

Author(s):

Rie Hiratsuka ◽

Osamu Terasaka

Keyword(s):

Cell Death ◽

Programmed Cell Death ◽

Pollen Tube ◽

Pinus Densiflora

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

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1973.0002 ◽

1973 ◽

Vol 183 (1070) ◽

pp. 21-38 ◽

Cited By ~ 100

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.

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