中文摘要：

以流动沙丘先锋植物沙蓬（Agriophyllum squarrosum）为研究对象,通过不同温度、光照、干旱胁迫和沙埋对沙蓬种子萌发和出苗影响的控制试验,以探索沙蓬种子萌发对风沙环境的适应性。结果表明,1）沙蓬种子具有休眠现象,在自然条件下发芽率仅18.3%,有利于适应沙漠恶劣和多变的环境条件;2）沙蓬种子萌发属于厌光型,光抑制了干沙层表面的种子萌发,从而保护了土壤种子库;3）沙蓬种子萌发的最适温度为25℃。4）在干旱胁迫环境下沙蓬种子发芽率〈2%,加入1 000mg·L-1外源GA3后,沙蓬种子在渗透势为-0.067 6 MPa时发芽率高达81.13%,GA3可以缓解干旱胁迫;5）1.5cm沙埋＋2 000mg·L-1 GA3处理沙蓬种子出苗率高达70%,过深或过浅均不利于沙蓬种子出苗。

英文摘要：

Agriophyllum squarrosum is a pioneer plant species that grow in mobile sand dune.In order to understand the adaptability of the seed germination to the windy and sandy environment,a controllable experiment was carried out to examine the influences of the relative factors to seed germination and seedling sprouting,such as light,temperature,drought stress and sand burial depths.The results showed that 1） dormancy occurred in A.quarrosum seeds,the seed germination rate in natural conditions only reached 18.3%,which however,was conducive to the adapt to the harsh desert and varying environmental conditions.2） The seed germination rate under dark condition was higher than that of light condition.Light inhibited the germination of the seeds that were in the dry and surface sand layer,which was favorable to the protection of the seed bank in the soil.3） The optimum temperature for seed germination was 25℃.4） Under the drought stress,the seed germination rate was below 2%.However,under osmotic potential of -0.067 6 MPa,the seed germination rate increased to 81.13% by adding 1 000 mg·L-1 exogenous GA3.GA3 could alleviate drought stress for seed germination.5） Seedling emergence rate was as high as 70% under the sand burial depth of 1.5 cm with GA3 concentration of 2 000 mg·L-1.Higher or lower than 1.5 cm would not favorable to the emergence.