3种藜科植物叶特性因子对土壤养分、水分及种群密度的响应

 以科尔沁沙地3种主要的藜科植物为实验材料，通过控制土壤养分、土壤水分以及种群密度,研究植物比叶面积（SLA）和叶干物质含量（LDMC）对土壤养分、土壤水分和种群密度及三者交互作用的响应。结果表明：养分和水分对这3种植物的SLA和LDMC的影响均为显著，其中养分为最大的变异源。3种藜科植物的SLA和LDMC对密度处理响应均为不显著。交互作用对3种藜科植物SLA和LDMC的影响则要弱于单因素（密度、水分）处理；养分的增加导致沙蓬、大果虫实的SLA增大，LDMC减小;水分对SLA、LDMC的影响和养分相似；尖头叶藜的响应方式与沙蓬、大果虫实相异，随养分的增加其SLA有减小的趋势，LDMC反而有增大的趋势; 土壤养分、水分的改变对尖头叶藜SLA和LDMC的影响较弱。

Respondence of Leaf Traits of Three Chenopodiaceae Plants to Soil Nutrients,Water Content and Plant Density

Specific leaf area (SLA, leaf area per unit dry mass) and Leaf dry matter content (LDMC, the ratio of leaf dry mass to fresh mass) are very important leaf traits. Both SLA and LDMC reflect a fundamental trade-off in plant functioning between a rapid production of biomass (high SLA, low LDMC species) and an efficient conservation of nutrients (low SLA, high LDMC species). In this study, the SLA and LDMC of three dominant Chenopodiaceae plants in Horqin sandy land was compared under different soil nutrients, soil water content and plant density. The results showed that soil nutrients and soil water content have predominant effects on SLA and LDMC of the three Chenopodiaceae plants, in which soil nutrients is the highest variation coefficient. But we didn't found plant density change the SLA and LDMC of the three plants obviously. The effect of interactions of soil nutrients, soil water content and plant density on SLA and LDMC is relatively insignificant, only nutrient-by-water interaction affect the SLA or LDMC of all three plants significantly. Nutrients supply increased SLA but reduced LDMC of Agriophyllum squarrosum and Chenopodium macrocarpum. Whereas, Chenopodium acuminatum has opposite response mode to nutrients supply, showing decreased SLA vs increased LDMC. The effects of soil nutrient and soil water content upon Chenopodium acuminatum were weaker than on the other two.