白蜡容器苗和裸根苗对盐分胁迫的生长响应

Growth Responses of White Wax(Fraxinus chinensis Roxb) Container Seedlings and Bareroot Seedlings to Salt stress

以白蜡为试材,研究了白蜡容器苗和裸根苗在不同盐分梯度(0.1%、0.2%、0.3%、0.4%和0.5%)土壤中的生长及干物质积累特征。结果表明:当土壤盐分在0.2%~0.4%时,白蜡容器苗的地径和株高显著高于裸根苗。当土壤盐分增加至0.5%,白蜡的株高和地径继续下降,容器苗和裸根苗之间差异不显著。无论是容器苗还是裸根苗,随着盐分的增加,<2 mm的根系比例逐渐降低,而>5 mm根系所占比例逐渐增加,但容器苗细根鲜质量显著大于裸根苗。随着土壤盐分的逐渐增加,白蜡容器苗的根系含水量呈二次多项式形式下降(R^2=0.978),盐分质量分数较低时下降较平缓。而白蜡裸根苗含水量呈直线下降(R^2=0.927 9),根系含水量下降始终比较迅速。土壤盐分的增加降低了白蜡干物质的最大积累速率。在0.1%、0.3%和0.5%的3种盐分土壤中,同白蜡裸根苗相比,容器苗干物质最大积累速率分别提高了17.01%、39.63%和5.64%。以上分析可知,容器苗可一定程度上增加苗木对盐分的缓冲性能,无论是在盐渍化土壤还是普通土壤中,白蜡容器苗干物质积累速率均不同程度地优于裸根苗。

For the difference between container seedlings and bareroot seedlings under salt stress conditions,we studied the growth difference between container seedlings and bareroot seedlings of Fraxinus chinensis Roxb under different salt stress conditions（ 0.1%,0.2%,0.3%,0.4% and 0.5%）. The height and diameter of F. chinensis container seedlings were significantly higher than those of bareroot seedlings,when the soil salinity was in 0.2%-0.4%. The height and diameter of F.chinensis were decreasing when soil salinity was 0.5%,and there was no significantly difference between container seedlings and bareroot seedlings. Whether it was container seedlings or bareroot seedlings,the root proportion of less than 2 mm was decreasing. However,the root of more than 5 mm was increasing. In spite of the soil salinity,the fresh root weight of container seedlings was significantly higher than that of the bareroot seedlings. The root water content of F. chinensis container seedlings was decreasing along with the increasing soil salinity,and could be well described by quadratic polynomial（ R^2= 0.978）,indicating a gentle decrease in the lower soil salinity. However,the root water content of bareroot seedlings was linear decrease（ R^2= 0.927 9）,indicative of the fast decreasing along with the soil salinity. The increasing soil salinity decreased the maximum increase rate of F. chinensis. Compared with bareroot seedlings,the maximum increase rate of container seedlings was increased by 17.01%,39.63% and 5.64%,respectively,in 0.1%,0.3% and 0.5% soil salinity. In general,container seedlings could increase cushioning capacity to some extent. Under normal and saline soil,the dry matter accumulation rate of container seedlings was higher than that of bareroot seedlings.