等渗盐分与水分胁迫对三角叶滨藜和玉米光合作用的影响

以溶液培养的三角叶滨藜(Atriplex triangularis)和玉米(Zeamays)为材料,测定了等渗的盐分和水分胁迫对2种植物光合作用的短期影响。结果表明:等渗的水分和盐分胁迫均会造成三角叶滨藜和玉米净光合速率(Pn)的降低,而且随着胁迫程度的增强,水分胁迫引起Pn下降的幅度要明显高于等渗的盐分胁迫;在较低渗透胁迫强度下,2种胁迫导致光合速率下降的主要原因是气孔限制;但在环境溶液渗透势为-1.0MPa时,水分胁迫对光合作用的影响逐渐转化成非气孔限制,而盐胁迫仍然是气孔限制起主要作用;由此可见,等渗透势的水分胁迫对2种植物光合系统的影响要明显大于盐分胁迫。

Effects of isotonic NaCl and mannitol stress on the photosynthesis of Atriplex triangularis and Zea mays

A hydroponic experiment was conducted to study the short-term effects of isotonic NaCl and mannitol stress on the photosynthesis of arrow-leaf saltbush (Atriplex triangularis) and maize (Zea mays). Both the NaCl and the mannitol stress decreased the net photosynthetic rate (Pn) of A. triangularis and Z. mays. With the increase of the stress, the mannitol-induced decrement of Pn was much greater than the NaCl-induced one. Under the mild stress of NaCl or mannitol, the decline of Pn was mainly due to stomata ...