紫花地丁近交衰退的遗传效应和花型效应研究

Evaluating the genetic and floral type effects on inbreeding depression in dimorphic cleistogamous plant Viola philippica Cav.

以二型闭花受精植物紫花地丁(Viola philippica Cav.)为实验材料,将人工授粉获取的开放花异交后代、开放花自交后代、闭锁花后代3种类型种子,分别进行单独种植和两两竞争种植实验,通过对比3种类型种子的大小和萌发率,以及营养生长阶段的植株高度、最大叶叶片长度和宽度、叶片数,分析不同类型后代的适合度差异.结果显示,开放花异交后代的适合度最大,开放花自交后代次之,闭锁花后代最小.这表明遗传效应和花型效应对适合度均会造成影响,其中遗传效应起主导作用.

Avoidance of inbreeding depression is thought to be an important selection force for maintenance of chasmogamous flowers in dimorphic cleistogamous plants.Inbreeding depression may be caused by genetic(outcrossing and selfing)and floral type(chasmogamous and cleistogamous)effects in cleistogamous plants.This study aims to distinguish genetic effects on inbreeding depression from floral type effects by comparing the performance in growth between offspring of cleistogamous flowers,selfed and outcrossed offspring of chasmogamous flowers in perennial herb Viola philippica Cav.The fitness,in terms of seed size,germination rate,plant height,number of leaves,were estimated.Data showed that the fitness of outcrossed offspring from chasmogamous flowers was the highest,followed by selfed offspring from chasmogamous flowers,and the offspring from cleistogamous flowers was the smallest.These data suggest that both genetic and floral type effects contribute to inbreeding depression in offspring from cleistogamous flowers in dimorphic cleistogamous plants,and genetic effects play a major role.