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

Abstract

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.