Pollen tube dynamics following half- and fully-compatible pollinations in self-compatible almond cultivars

In order to characterize the self-incompatibility system in Theobroma cacao, the levels of ethylene, indole-3-acetic acid (IAA), and abscisic acid (ABA) were determined after pollination with compatible and incompatible pollen and in unpollinated flowers. Pollen tube growth rates after incompatible and compatible pollinations were identical, and the majority of the pollen tubes reached the ovules between 12 and 20 hours after pollination. ABA levels rose in incompatibly pollinated flowers, and fell in compatibly pollinated flowers, prior to pollen tube—ovule contact. Ethylene evolution remained stable in compatibly pollinated flowers and rose in incompatibly pollinated flowers. IAA concentrations increased in compatibly pollinated flowers, and remained stable in incompatibly pollinated flowers after pollination and subsequent to pollen tube—ovule contact.

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Citrus pollen tube development in cross-compatible gynoecia, self-incompatible gynoecia, and in vitro

Canadian Journal of Botany ◽

10.1139/b88-344 ◽

1988 ◽

Vol 66 (12) ◽

pp. 2527-2532 ◽

Cited By ~ 9

Author(s):

Tracy L. Kahn ◽

Darleen A. DeMason

Keyword(s):

Pollen Tube ◽

Generative Cell ◽

Pollen Tubes ◽

Citrus Paradisi ◽

Incompatible Pollination ◽

Incompatible Cross ◽

Compatible Pollinations ◽

Compatible Pollen ◽

Incompatibility Reaction

The route of 'Orlando' tangelo (Citrus paradisi Macf. × C. reticulata Blanco) pollen tubes was traced and compared in self-incompatible pollinations and cross-compatible pollinations with 'Dancy' tangerine (C. reticulata Blanco). In both crosses, 'Orlando' pollen germinated in the stigmatic exudate and grew between the papillae on the stigma surface and inter-cellularly between the parenchymatous cells until reaching a stylar canal by 3 days. However, in the incompatible pollination, irregular deposition of callose occurred in the pollen tube walls as early as 1 day after pollination. By day 6, pollen tubes were in the upper portion of the ovary in the compatible pollination, whereas most pollen tubes from the incompatible pollination were still in the upper style. 'Orlando' pollen tube growth rate decreased substantially by day 3 in both the self-incompatible pollination and in vitro but increased rapidly after day 3 in the compatible combination. The generative cell divided between 1 and 3 days after pollination in the compatible cross. Generative cell division was observed by day 3 in only a few pollen tubes in the incompatible cross and in cultured tubes. Compatible pollen tubes grew slowly for the first 3 days after pollination, during which time generative cells divided and then grew rapidly until fertilization. In contrast, incompatible pollen tubes showed morphological features indicative of an incompatibility reaction by 1 day after pollination and grew slowly for a period of 6 days, and then ceased growth.

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A quantitative and structural comparison of Citrus pollen tube development in cross-compatible and self-incompatible gynoecia

Canadian Journal of Botany ◽

10.1139/b86-337 ◽

1986 ◽

Vol 64 (11) ◽

pp. 2548-2555 ◽

Cited By ~ 13

Author(s):

Tracy L. Kahn ◽

Darleen A. DeMason

Keyword(s):

Pollen Tube ◽

Pollen Tubes ◽

Citrus Paradisi ◽

Structural Comparison ◽

Stigma Surface ◽

Incompatible Pollination ◽

Compatible Cross ◽

Incompatible Cross ◽

Compatible Pollinations ◽

Compatible Pollen

Pollen tube development in Orlando tangelo (Citrus paradisi Macf. × C. reticulata Blanco.) was compared within and between cross-compatible pollinations of Orlando pollen on Dancy tangerine (C. reticulata Blanco.) stigmas and self-incompatible pollinations on Orlando tangelo stigmas. Orlando and Dancy gynoecia were morphologically similar but differed slightly in stigma, style, and ovary lengths. Orlando pollen tube development was studied 1, 3, 6, 9, and 12 days after both cross- and self-pollination to record the number of pollen tubes at each of five levels: stigma surface, upper style, lower style, ovary, and entrance into ovules. In the incompatible cross (self-pollinated Orlando), the stigma was the primary region of pollen tube arrest. In the compatible cross (Orlando pollen on Dancy), some pollen tubes penetrated ovules between 9 and 12 days after cross pollination; however, other pollen tubes were arrested in the stigma. Pollen tubes that successfully penetrated ovules in the compatible cross differed morphologically from pollen tubes arrested in both the compatible and incompatible situations. Successful compatible pollen tubes were straight with thin-walled tips and regularly spaced callose plugs behind the growing tips. Many pollen tube abnormalities associated with the self-incompatible pollination of Orlando were also present among arrested pollen tubes from the compatible cross.

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