沙埋对无芒雀麦种子萌发和幼苗生长的影响

研究了沙埋对浑善达克沙地植物群落中多年生禾草无芒雀麦种子萌发、出苗和幼苗生长的影响.结果表明:无芒雀麦种子能在深度≤12cm的沙埋中萌发,≤8cm的沙埋中出苗.在此范围内,随着沙埋深度的增加,无芒雀麦种子的萌发率和出苗率逐渐降低.沙埋深度在植株高度的33%时,无芒雀麦1周龄和2周龄幼苗均全部存活,且总生物量≥对照(未沙埋幼苗);当沙埋深度增至植株高度的66%时,1周龄和2周龄幼苗的存活率分别降至70%和25%,生长也受到抑制;而遭受全部沙埋时,1周龄和2周龄幼苗均不能存活.遭受沙埋后,无芒雀麦幼苗分配较多的生物量用于地上部分的生长,其生物量分配模式改变可能是无芒雀麦幼苗对沙埋环境的重要适应对策.

Effects of sand burying on caryopsis germination and seedling growth of Bromus inermis Leyss

This paper studied the effects of different depth sand burying on the caryopsis germination,seedling emergence and growth of Bromus inermis Leyss.,a perennial gramineous grass dominated on Othidag sandy land.The results showed that the maximum burying depth for B.inermis caryopsis germination and seedling emergence was 12 cm and 8 cm,respectively.Below the thresholds,the percentages of caryopsis germination and seedling emergence decreased with increasing depth of sand burying.All the 1-and 2-week-old seedlings of B.inermis could survive when the sand burying depth was up to 33% of their height,and their biomass was no less than the unburied seedlings.When the burying depth increased to 66% of their height,70% of 1-week-old seedlings and 25% of 2-week-old seedlings could survive,but their growth was impaired.No seedlings could survive when they were wholly buried in sand.When buried by sand,the seedlings allocated more biomass for the development of their aboveground part,which might be an important adaptation strategy of B.inermis to sand burying.