干旱对鸭茅光合特性及叶绿体超微结构的影响

Effects of Drought on the Photosynthetic Characteristics and Chloroplast Ultrastructure of Dactylis glomerata L.

室内盆栽控水条件下,对苗期4份鸭茅种质光合生理特性和叶绿体的超微结构进行了研究。结果表明,供试材料的净光合速率、蒸腾作用日变化均为"双峰"曲线,有明显的光合"午休"现象。随着水分胁迫程度的加强,4份鸭茅种质的净光合速率、蒸腾速率、气孔导度及叶绿素含量均有较大幅度的降低,供试材料ZXY04P-201下降的速度慢、幅度小,而ZXY04 P-239下降速度快、幅度大。电镜超微结构观察显示:叶绿体超微结构受损,片层数减少,基粒片层解体。同时研究表明,轻度水分胁迫下,气孔限制是4份鸭茅光合作用降低的主要因素,中度及重度胁迫下净光合速率降低主要是非气孔限制起着主要作用。

The photosynthetic physiological characteristics of Dactylis glomerata L. were measured under water stress. And the results showed ： the net photosynthetic rate and transpiration rate of all four Dactylis glorrterata L. showed two peaks on the curves of diurnal changes, and all witnessed obvious phenomena in midday depression of the two aforementioned rate. With aggravation of water stress, the net photosynthetic rate, transpiration rate, stomatal conductance and chlorophyll decreased dramatically, compared with ZXY04P-239, the net photosynthetic rate, transPiration rate, stomatal conductance and chlorophyll in the leaves of ZXY04P-201 decreased slowly. Chloroplast lamellar structure disordered, and lamella number decreased. Meanwhile, the result also showed that, stomatal restriction was the main factor of the net photosynthetic rate＇s decrease in the leaves of 4 Dactylis glomerata L. when stress in slight water stress and the non-stomatal restriction was the main factor of the net photosynthetic rate in the leaves of 4 Dactylis glomerata L. when stressed in medium water stress and serious water stress.