两种委陵菜对干旱胁迫的光合生理响应

采用自然失水胁迫方法,利用电镜制片和气体交换技术,研究了白叶委陵菜(Potentilla leucophylla)和轮叶委陵菜(P.verticillaris)的超微结构和光合生理因子对干旱胁迫的响应。结果表明,在轻度干旱胁迫下两种委陵菜叶片超微结构受损较轻;叶片气孔导度(Gs)明显下降,净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)和水分利用效率(WUE)也都有所下降,气孔限制是造成光合下降的主要原因;在中度和重度胁迫条件下,两种委陵菜叶片超微结构受损严重;同时Pn进一步降低,Tr、Gs和WUE下降较快,Ci缓慢上升,但始终低于对照水平,此时非气孔限制起着主要作用。对比干旱胁迫下两种委陵菜的结构和光合生理变化发现,两种委陵菜都具有一定的抗旱性,轮叶委陵菜抗旱能力略强于白叶委陵菜。

Photosynthetic physiology responses of two Potentilla species under drought stress

The ultra-structure and photosynthetic physiology of Potentilla leucophylla and P.verticillaris under different dehydrate stresses were studied with electron microscopy. Under light dehydrate stress, the ultra-structure of two P.species had minor damage. The photosynthetic indices including stomatal conductance (Gs), net photosynthetic rate(Pn), transpiration rate(Tr), intercellular CO2 concentration(Ci) and water use efficiency (WUE) also decreased, especially Gs decreased significantly which showed that stomatal limited photosynthesis. Under moderate and severe dehydrate stresses, the ultra-structure of two P.species had serious damage; simultaneously. The photosynthetic indices had different performance. Pn decreased further, Tr,Gs and WUE decreased rapidly and Ci increased slowly. Non-stomatal limitation played a major role in this progress. Both Potentilla species have drought resistance based on the the structural and physiological indices although P.verticillaris had slightly stronger drought tolerance than P.leucophylla.