三种一年生藜科沙生植物出苗对沙埋深度和水分条件的响应

 通过盆栽控制试验，研究了沙米、大果虫实和长穗虫实３种一年生沙生植物在４个模拟降水水平（Ａ、Ｂ、Ｃ 和Ｄ）和６种埋深水平（０，１０，２０，３０，４０和５０ｍｍ）的出苗情况。结果表明，３种植物种子均没有休眠现象。沙米和长穗虫实均在１０ｍｍ 埋深处的出苗率最大，而大果虫实在３０ｍｍ 埋深处的出苗率最大，沙米、大果虫实和长穗虫实，各降水处理的平均出苗率分别为５０．６３％，７７．２９％和７５．２１％。在沙土表面的种子，沙米萌发受强烈抑制，而其余２种植物在降水较多的Ａ、Ｂ和Ｄ 处理下萌发较多但成苗较少。这３种植物耐埋深的大小依次为：大果虫实＞沙米＞长穗虫实。降水量越大，其出苗率越高，沙米和大果虫实单次强降水下其种子出苗率大于等量的多次少量降水的积累，但是长穗虫实相反。这表明在干旱半干旱沙地，降水是调节季节性种子出苗最重要的决定因素，种子在沙土中的垂直分布决定了降水后种子萌发的比例并有助于维持土壤种子库。

Seedling emergence of three Chenopodiaceae annuals in response to different sand burial depths and irrigation regimes

The interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in 3 annuals(Agriophyllum squarrosum,Corispermum macrocarpum and C.elongatum) which commonly grow on sand dunes in the experimental region of Inner Mongolia were investigated.Seedling emergence was examined for seeds sown on the surface,or at depths of 10,20,30,40 and 50 mm in sand-filled pots.There were 4 different watering regimes in pots was: Treatments A(30 mm,initial irrigation),B(10 mm),C(10...