DataSheet_1_Preventing self-fertilization: Insights from Ziziphus species.pdf

The fitness of self-progeny individuals is inferior to that of their outcrossed counterparts, resulting in a reduction in a plant population’s ability to survive and reproduce. To prevent self‐fertilization, angiosperms with hermaphrodite flowers may exploit a variety of mechanisms, including synchronous dichogamy and self-incompatibility. Synchronous dichogamy involves two flowering morphs, with strict within-morph synchronization, thereby preventing not only autogamy and geitonogamy but also intra-morph mating. Self-fertilization is also prevented by self-incompatibility, a genetic mechanism that allows the identification and rejection of “self” pollen, thereby preventing both autogamy and geitonogamy. Here, I seek to provide a perspective of flowering in Ziziphus species exhibiting both synchronous (i.e., “Early” morph flowers open in the morning and “Late” morph flowers open in the afternoon) protandrous dichogamy (i.e., pollen dispersal before the stigma becomes receptive) and self-incompatibility.

自交后代个体（self-progeny individuals）的适合度劣于异交对应个体（outcrossed counterparts），进而降低植物种群的存活与繁殖能力。为防止自交受精，具有两性花的被子植物可利用多种调控机制，包括同步雌雄异熟（synchronous dichogamy）与自交不亲和性（self-incompatibility）。同步雌雄异熟包含两种开花形态型，且具有严格的同形态内同步性，由此不仅可阻断自花授粉（autogamy）与同株异花授粉（geitonogamy），还能避免同形态内交配。自交不亲和性同样是阻止自交受精的遗传机制，该机制可识别并排斥"自身"花粉，从而阻断自花授粉与同株异花授粉。本文旨在针对同时兼具同步雄性先熟雌雄异熟（protandrous dichogamy，即花粉在柱头可授前散发）与自交不亲和性的枣属（Ziziphus）植物的开花特性提出见解，这类物种存在两种开花形态型："早花"形态型的花朵于清晨开放，"晚花"形态型的花朵于午后开放。