Joseph Trapp E, Hendrix Stephen D
Department of Botany and Program in Evolutionary Ecology and Behavior, University of Iowa, 52242, Iowa City, IA, USA.
Oecologia. 1988 Mar;75(2):285-290. doi: 10.1007/BF00378611.
The forest annual, Amphicarpaea bracteata L. can reproduce via aerial chasmogamous, aerial cleistogamous, and subterranean cleistogamous flowers. Both plant size and light intensity influenced the utilization of the three modes of reproduction. chasmogamous and aerial cleistogamous flower number and the ratio of chasmogamous flowers to the total number of aerial flowers increased with plant size. The latter demonstrated a shift to xenogamy and outbreeding in larger plants. Light intensity indirectly influenced reproductive modes through its infuence on plant size. Seed set by both types of aerial flowers was low and unrelated to plant size. Subterranean seed number and the total dry weight of subterranean seeds per plant increased with size. The subterranean seeds of Amphicarpaea bracteata are thirty-four times larger than the aerial seeds (fresh weight). Under field conditions, subterranean seeds had greater germination after one year than acrial seeds. The plants arising from subterranean seeds were significantly larger and more fecund than those from aerial seeds. Seeds produced by aerial cleistogamous, hand selfpollinated chasmogamous, and naturally pollinated chasmogamous flowers had equivalent germination rates and produced plants of equal size and fecundity. This suggests that the outbred progeny from chasmogamous flowers have no advantage over the inbred progeny from aerial cleistogamous flowers.
一年生植物两型豆（Amphicarpaea bracteata L.）可以通过地上开花受精花、地上闭花受精花和地下闭花受精花进行繁殖。植株大小和光照强度都会影响这三种繁殖方式的利用情况。开花受精花和地上闭花受精花的数量以及开花受精花与地上花总数的比例随植株大小增加。这表明较大植株会向异花授粉和远交转变。光照强度通过对植株大小的影响间接影响繁殖方式。两种地上花的结实率都很低，且与植株大小无关。地下种子数量和单株地下种子的总干重随植株大小增加。两型豆的地下种子比地上种子大34倍（鲜重）。在田间条件下，地下种子一年后的发芽率高于地上种子。由地下种子发育而来的植株比由地上种子发育而来的植株明显更大且繁殖力更强。由地上闭花受精花、人工自花授粉的开花受精花和自然授粉的开花受精花产生的种子具有相同的发芽率，且发育出的植株大小和繁殖力相当。这表明开花受精花的远交后代并不比地上闭花受精花的近交后代有优势。
