Developmental Selection within the Angiosperm Style: Using Gamete DNA to Visualize Interspecific Pollen Competition

摘要: Among flowering plants, females often have little control over the genetic relatedness of pollen deposited on stigmas. Thus, postpollination processes are primary importance for mate discrimination. The ability to screen and select among male gametes during tube growth within female tissues stigma, style, ovary is critical process choice reproductive isolation. However, direct evidence mechanistic/developmental associated with in plants sparse. We studied contribution postpollination, prefertilization isolation two wind-pollinated species birch (Betula) that commonly hybridize nature. exploited 3-fold difference ploidy level between these determine paternity individual tubes growing tissues. then tracked their developmental fate conspecific, heterospecific, mixed-species crosses. This design allowed a comparison responsible both single-species pollinations. Our results important implications population outcome hybridization dynamics natural populations. Paternity analysis progeny from pollinations revealed conspecific sired more than 98% seedlings. Biased siring success was not result differential embryo abortion. detected strong, early barriers such as incompatibility, slower growth, delayed generative cell mitosis. Conspecific fertilization precedence mediated by favorable or unfavorable male-female interactions, but there no antagonistic male-male interactions.