摘要
用离体干燥的方法,对生长于不同氮素营养水平下的小麦叶片进行快速水分胁迫处理后,研究了氮素营养水平对小麦光合作用的影响。结果表明:快速水分胁迫下,小麦叶片水势(Ψw)、净光合率(Pn)和气孔导度(Gs)的下降幅度是高氮营养(HN)的明显大于低氮营养(LN)的。随水分胁迫程度的增大,高氮营养对小麦叶片净光合率由促进转为抑制;水分胁迫期间,叶片细胞间隙CO_2浓度是HN低于LN,光合气孔限制则相反。而叶肉CO_2导度和叶肉光合活性仍是HN大于LN。
Effects of nitrogen (N) nutrition level on photosynthesis of wheat were studied using method of quick drying of detached leaves, under rapid water stress. The results showed that in the case, leaf water potential (Ψ_w). net photosynthetic rate (Pn) and stomatal conductance (Gs) of high N (HN) leaves decreased more quickly than that of low N (LN) leaves. There- fore, the difference of Pn between HN and LN leaves became less and less with increasing water stress. Under severe water stress, the Pn of HN leaves were lower than that of LN leaves. The intercellular concentration of CO_2 (Ci) of HN leaves were lower than that of LN leaves, and the value of stomatal limitation of photosynthesis (Ls) of HN leaves were higher during rapid water stress. However, the mesophllous conductance of CO_2 (Gm) and photosynthetic activity of mesophyll of HN leaves were still higher than that of LN leaves.
关键词
小麦
光合作用
氮素营养
水分胁迫
Rapid water stress
Nitrogen nutrition
Photosynthesis
Wheat
