狭果鹤虱幼苗营养生长和生物量分配对凝结水梯度的响应

以新疆艾比湖湿地国家级自然保护区荒漠短命植物狭果鹤虱为研究对象,研究少凝结水、自然凝结水和倍增凝结水3个梯度下狭果鹤虱幼苗形态、生理响应对策及单株植物的干物质分配格局.结果表明: 随凝结水量增加,狭果鹤虱幼苗与叶片吸收水分有关的性状叶绿素相对含量、叶片水势、株高、冠幅、茎质量和叶质比均显著增高,而与根吸收和运输水分有关的性状主茎径、根长和根径无显著变化;株高和叶绿素相对含量对凝结水量的响应最迅速;不同凝结水梯度下,狭果鹤虱幼苗对茎的生物量投入比例无显著差异,但随幼苗生长,3个梯度植物的根质比均逐渐下降,少凝结水处理植株降幅相对较小.狭果鹤虱幼苗主要通过改变地上部分性状响应凝结水量的变化,叶片光合潜力和干物质比重随凝结水量增加而显著增加.

Response of vegetative growth and biomass allocation of Lappula semiglabra seedlings to dew gradient.

Three dew amount gradients,i.e., few amount of dew (W₀), natural amount of dew (W₁) and the doubled amount of natural dew (W₂) were set to study the response strategies of the morphology, physiology and the dry matter allocation of Lappula semiglabra seedlings on dew amount in Ebinur Lake Wetland National Nature Reserve in Xinjiang, China. The results showed that plant traits in connection with absorbing water by plant leaves, involving in relative content of chlorophyll, leaf water potential, plant height, crown breadth, stem mass and leaf mass ratio increased significantly with the amount of dew. On the contrary, the main stem diameter, root length and root diameter which associated with water absorption and transportation by root had no significant change with the amount of dew. Plant height and the relative content of chlorophyll were the most obvious traits in response to dew amount among all leaf absorption water traits. The proportion of stem biomass had no significant difference along the dew amount gradient. However, the root mass ratio declined gradually along the growth of seedlings, and seedlings in W₀ had the smallest decline rather than W₁ and W₂. In conclusion, L. semiglabra seedlings changed aboveground traits in response to the change of dew amount. Specifically, it increased its photosynthetic capacity and ratio of leaf dry matter to adapt to the variation on dew amount.