著者

Daiki Matsumoto Ryohei Yamazaki Misato Kasai Satoshi Taira Ryutaro Tao

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-087, (Released:2023-07-19)

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Prunus fruit trees of the Rosaceae family exhibit S-RNase-based gametophytic self-incompatibility (GSI), which enables pistils to reject self-pollen by suppressing pollen tube elongation. In other plant species with S-RNase-based GSI, it has been shown that this suppression consists of two steps: first, slowing down of pollen tube elongation in the middle part of the style and second, complete arrest involving programmed cell death. To characterize the suppression pattern of incompatible pollen tubes in Prunus, we observed pollen tube elongation of ‘Satonishiki’ sweet cherry (Prunus avium) in ‘Satonishiki’ and ‘Rainier’ pistils on agar plates and ‘Satonishiki’ and ‘Rainier’ pollen tube growth in pistils on ‘Satonishiki’ cut branches. Incompatible selfed pollen tubes delayed penetration into the stigma in both experiments. Observation of pollen tubes in pistils on agar plates was difficult 24 h after pollination (HAP) due to wilting of the styles, while observing them on cut branches was possible up to 72 HAP. In the pistils on cut branches, ‘Satonishiki’ pollen tubes barely elongated in self pistils from 32 to 48 HAP when compatible ‘Rainier’ pollen tubes reached the base of a style, but resumed growth after 48 HAP and reached the base of the style. An RNase activity staining indicated that S-RNase was inactive 48 HAP. Finally, we observed pollen tube elongation in the style-grafted pistils on the cut branches. ‘Satonishiki’ pollen tube elongation was accelerated when the upper one-third of the self-pollinated styles was grafted onto compatible ‘Taishonishiki’ pistils. These results indicated that the suppression of incompatible pollen tube elongation in P. avium was consistently reversible. We discuss the suppression mechanism of incompatible pollen tube growth and the possibility of artificial control of Prunus self-incompatibility.

著者

Daiki Matsumoto Seita Shimizu Aoi Shimazaki Kohei Ito Satoshi Taira

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-385, (Released:2022-07-14)

被引用文献数

3

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Akebia trifoliata is cultivated locally in few areas of Japan. Artificial pollination is considered indispensable for stable fruit production, as Akebia spp. exhibit self-incompatibility (SI). However, little is known about the reproductive physiology required for effective artificial pollination. In this study, we investigated the effects of self-pollen contamination on the fruit set of ‘Fuji Murasaki’ (A. trifoliata), one of the main lines in Yamagata Prefecture, Japan. Both the self- and cross-pollen tubes reached the base of the ovary and penetrated the ovules at 10 days after pollination, indicating that A. trifoliata exhibits late-acting SI. Self-pollination one day before cross-pollination completely inhibited fruit set, while self-pollination one day after cross-pollination did not inhibit fruit set in both 2016 and 2020, indicating interference in cross-pollination by self-pollen contamination. Fruit set rates for artificial pollination using a 1:1 mix of self- and cross-pollen were significantly lower than those that used non-contaminated cross-pollen in both 2016 and 2019, but were comparable when using a 1:1 mix of lycopodium powder and cross-pollen. The seed number of fruit resulting from mixed pollination was not significantly lower than that of fruit resulting from cross-pollination. Interestingly, 1:1 mixed pollination of self- and cross-pollen sometimes yielded abnormal fruits with an apex that remained pale and did not soften. These results suggest that excessive self-pollen contamination in artificial pollination may not be desirable for A. trifoliata fruit production.