4种荒漠植物种子出苗和幼苗生长对沙埋深度的响应

通过室内试验测定了黑果枸杞、沙冬青、沙蒿、霸王4种荒漠植物的种子生理特征以及沙埋深度（0、1、2、3、4、5 cm）对4种荒漠植物种子出苗及幼苗生长的影响。结果表明，体积较大的沙冬青和霸王种子萌发率与其重量、含水量、形状及活性间存在正相关关系；体积较小的黑果枸杞、沙蒿萌发率与种子重量、含水量、形状之间为正相关关系，与种子活性负相关。随着沙埋深度增加，4种植物种子出苗率下降、首次出苗时间延迟，茎高、绝对株高和根长及根冠比总体呈先增大后减小的趋势；幼苗生长方面，黑果枸杞和沙蒿分别适宜于1～2、0～1 cm的浅层沙埋，均在沙埋深度5 cm时种子几乎不萌发；沙冬青、霸王则适宜于3～4 cm较深层沙埋，在沙埋0 cm时均不萌发。此外，在荒漠区采用这4种植物进行植被恢复时，除考虑种子自身性状外，还应充分考虑当地的沙埋、降雨等条件，以提高出苗率、增大幼苗定植率。

Response of Seed Emergence and Seedling Growth of Four Desert Plant Species on Sand Burial Depth

The seed physiological characteristics and the effects of sand burial depth(0,1,2,3,4,5 cm)on seedling emergence and growth of four desert plant species(Lycium ruthenicum,Ammopiptanthus mongolicus,Artemisia desertorum,and Sarcozygium xanthoxylon)were determined by laboratory experiments.It was found that for the plant species with large seed volume,such as A.mongolicus and S.xanthoxylon,there existed positive correlations between the germination rates and seed physiological characteristics(such as the weight,water content,shape,and seed vigor).For the plant species with small seed volume,such as L.ruthenicum and A.desertorum,the correlations between germination rate and seed weight,water content and shape were positive,while the correlation between the germination rate and seed vigor was negative.With the increase of sand burial depth,the seedling emergence rate decreased and the first seedling emergence time was delayed for all four plant species.In terms of seedling growth,the L.ruthenicum and A.desertorum were suitable for shallow sand burial of 1-2 cm and 0-1 cm respectively,the seeds hardly germinated when they were buried at 5 cm in depth;while A.mongolicus and S.xanthoxylon were suitable for deep sand burial of 3-4 cm.Seeds did not germinate when they were buried at the depth of 0 cm.In order to increase the emergence rate and the seedling planting rate,the seed characteristics should be considered and the local conditions such as sand burial and rainfall also should be taken into full consideration when using these four plant species for vegetation restoration in desert areas.