沙埋对河西走廊4种旱生植物种子萌发和幼苗生长的影响

Effect of Sand Burial on Seed Germination and Seedling Growth of Four Xeromorphic Species in the Hexi Corridor

测定了驼蹄瓣(Zygophyllum fabago)、骆驼蒿(Peganum nigellastrum)、唐古特白刺(Nitraria tangutorum)和黒果枸杞(Lycium ruthenicum)等4种旱生植物种子重量、形状、萌发及活性,试验了沙埋深度(0、1、2、3、4、5cm)对种子萌发、幼苗出土和生长的影响。结果表明:4种植物的种子扩散时为中度休眠;种子活性与重量、形状之间为显著负相关关系(p<0.05);种子初次萌发率与重量之间为不显著负相关关系;大而不规则种子有较低的活性,小种子扩散时有较高萌发率。随沙埋深度的增加,4种植物种子出苗率下降,首次出苗时间推迟,茎高、绝对株高和根长呈现先上升后下降的趋势,地下和地上生物量比值呈先上升后下降或随埋深增加而下降。幼苗出土和生长的最佳沙埋深度是:驼蹄瓣1~3cm,骆驼蒿0~1cm,唐古特白刺0~2cm,黑果枸杞1~2cm。在植被恢复过程中应考虑破除种子休眠的方法以及浅层沙埋等条件,以提高出苗率、增大幼苗定植率。

Seed traits including germination,seed vigor,seed mass and shape of 4 xeromorphic species(Zygophyllum fabago,Peganum nigellastrum,Nitraria tangutorum and Lycium ruthenicum)were detected,and then seedling emergence and growth incubated at room temperature(20℃)following sand burial 0,1,2,3,4and 5 cm was studied.The results showed that matured seeds of four species have medium dormancy,and there were significantly negative correlation between seed vigor and seed mass,and shape(p<0.05),an insignificantly negative correlation between germination and seed mass,exhibiting the large and irregular seeds had lower vigor,and that small seed had high probability of vigor and germination.With increasing of burial depth,the probability of seedlings emergence decreased,days to first emergence delayed,and the height of stem,absolutely height of plant and root length increased firstly,then decreased;the crown-root ratio increased with increasing of sand burial depth.It indicates that the optimum depths of sand burial for seedling emergence and growth for Z.fabago is 1-3 cm,P.nigellastrum0-1 cm,N.tangutorum0-2 cm and L.ruthenicum1-2 cm.The method of breaking seed dormancy and the depth of sand burial should be considered during vegetation recovery to improve emergence and growth of seedling,further benefit to establishment of species.