异子蓬二型性种子的种皮结构及离子含量差异

异子蓬(Borszczowia aralocaspica)是中亚荒漠区系特有的一年生盐生植物,其种子具有二型性。通过检测异子蓬二型性种子中的生理生化物质以及观察种皮的结构,比较异子蓬二型性种子中营养物质、养分全量以及种皮结构的差异,结果表明:(1)异子蓬的棕色种子只有一层薄种皮,而黑色种子不但具有一层薄的内种皮还有一层坚硬致密的外种皮;(2)棕色种子的质量大、质量频数分布较为集中,并且吸水迅速,在吸水率较低时就能够大量萌发;(3)棕色种子的可溶性糖、可溶性蛋白质、全氮、全磷以及K+、Na+、K+/Na+和Mg2+/Na+都显著高于黑色种子。说明在繁殖子代、产生二型性种子时,异子蓬对棕色种子和黑色种子之间的繁殖投入存在着巨大的差异,这可能是导致异子蓬二型性种子产生差异性萌发机制的重要原因。

Differences of Seed Coat Structure and Ions Content between Dimorphic Seeds of Borszczowia aralocaspica

Borszczowia aralocaspica,an annual halophyte,is an endemic species in the Central Asian deserts,whose dimorphic seeds are differed in color(black and brown),shape and size.The present study was to compare the differences in the physiology and biochemistry materials and seed coat structures of dimorphic seeds of B.aralocaspica,and reveal the effect of reproductive allocation on the ecological adaption mechanism of dimorphic seeds.The seeds were collected in natural populations from Fukang county in Xinjiang.A total of 1000 grains of dimorphic seeds of B.aralocaspica were respectively selected and weighted for black and brown seeds.The seed coat structures were observed by scanning electron micrographs(SEM).The soluble sugar,soluble protein and nutrient element of dimorphic seeds were also tested.Black seeds had two layers of seed coat compared to single layer in brown seeds.The structures of both seeds were found to be totally different.Brown seeds are bigger than black ones,and the weight distribution was mostly focused on 2.1 to 3mg.The contents of soluble sugar,soluble protein,total nitrogen,total phosphorus,K+,Na+,K+/Na+ and Mg2+/Na+ in brown seeds were significantly higher than those in black seeds.In the process of reproduction,the resource allocations of the maternal plant to brown seeds and black seeds are different,which leads to the distinct differences in dormancy and germination mechanism.This will help it to adapt to the unstable desert environment,and to maintain the stability of the B.aralocaspica population.