池杉幼苗对不同土壤水分水平的光合生理响应

Photosynthetic Physio-response of Taxodium ascendens Seedlings to Different Soil Water Gradients

为模拟三峡库区消落带土壤水分变化特征,作者设置了常规生长水分条件(CK)、轻度干旱水分胁迫(T1)、土壤水饱和(T1)以及水淹(T3)4个不同处理组,研究池杉当年实生幼苗在三峡库区消落带水位变化条件下的光合生理生态响应机理和适应对策。研究结果表明,不同水分处理均显著影响池杉幼苗光合色素、叶片气体交换以及表观资源利用效率。池杉幼苗不仅具有耐水湿的特点,还具有一定程度的耐旱性。在消落带防护林体系建设中,池杉适宜栽植于土壤饱和水或渍水的环境中;在干旱环境条件下应注意浇水抗旱,使池杉保持正常的净光合速率。

Upon simulation of soil water change of hydro-fluctuation belt in Three Gorges Reservoir Area, four different kinds of water treatment were applied to study the photosynthetic eco-physiological characteristics of Taxodium ascendens seedlings under the environment of hydro-fluctuation belt. Four kinds of water treatment were normal growth water condition （ CK）, light drought stress （ T1 ）, soil water saturation （ T2 ） and soil submersion （ T3 ）. The results showed that different water treatments could effectively influence the content of photosynthetic pigment, leaf gas exchange and apparent resources use efficiency of Taxodium ascendens seedlings. It was also demonstrated that the Taxodium ascendens seedlings could not only tolerate water submersion and wet condition but also endure a certain degree of drought. To establish protection forest system of hydro-fluctuation belt in Three Gorges Reservoir Area, the species Taxodium ascendens was suitable to be planted in conditions of root submersion or saturation soil water. In case planted in drought soil condition, this tree species should be watered appropriately in order to keep its normal net photosynthetic rate.