水分变化对荒漠植物红砂和珍珠猪毛菜细根性状的影响

Effects of Moisture Change on Fine Root Characteristics of Desert Plants Reaumuria soongorica and Salsola passerina

本研究在我国西北干旱区沿生物地理梯度,量化了红砂(Reaumuria soongorica)和珍珠猪毛菜(Salsola passerina)细根性状的变异,并分析了细根性状与环境因子的关系。结果表明:随着水分减少(从武威到酒泉),红砂平均直径(Average diameter,AD)逐渐增大,比根长(Specific root length,SRL)、比根面积(Specific root area,SRA)逐渐减小,根氮含量(Root nitrogen content,RNC)降低;而珍珠猪毛菜得到相反的结果。红砂和珍珠猪毛菜部分性状间均存在显著或极显著的相关关系;年均降水量(Average precipitation,AP)、土壤磷含量(Soil phosphorus content,SP)与红砂的比根长、比根面积、根氮含量正相关,与平均直径负相关,而珍珠猪毛菜的结果与红砂相反。综上,随水分的变化,红砂趋向保守策略,珍珠猪毛菜趋向获取策略;年均降水量、土壤磷含量是影响两物种细根性状的主要环境因子,两种植物均会通过性状间的权衡或协同使自身在荒漠复杂多变的生境中存活和生长。

In this study,the fine root characteristics of Reaumuria soongorica and Salsola passerina were quantified along the biogeographic gradient in the arid region of Northwest China,and the relationship between fine root characteristics and environmental factors was analyzed.The results showed that with the decrease of moisture content(from Wuwei to Jiuquan),the average diameter(AD)of Reaumuria soongorica increased gradually,the specific root length(SRL)and specific root area(SRA)decreased gradually,and the root nitrogen content(RNC)decreased.The opposite results were obtained for Salsola passerina.There were significant correlations between some characteristics of Reaumuria soongorica and Salsola passerina.The average annual precipitation(AP)and soil phosphorus content(SP)were positively correlated with the specific root length,specific root area and root nitrogen content of Reaumuria soongorica,and negatively correlated with the average diameter,while the results of Salsola passerine were opposite to those of Reaumuria soongorica.In summary,with the change of moisture content,Reaumuria soongorica tended to be conservative strategy,and Salsola passerina tended to be acquisition strategy;the average annual precipitation and soil phosphorus content were the main environmental factors affecting the fine root characteristics of the two species.Both plants could survive and grow in the complex and changeable habitats of the desert through the trade-off or synergy between characteristics.