钼污染对冬小麦光合作用特性及产量的影响

采用土壤培养试验研究了不同钼水平对冬小麦光合作用特性及产量的影响。结果表明:适量施钼(0.15 mg·kg~(-1))能够增加缺钼土壤上冬小麦的叶绿素含量、净光合速率(P_n)和产量;0.15~2000 mg·kg~(-1)条件下,随钼水平的提高,冬小麦叶绿素含量、净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)和产量呈下降趋势;随着P_n下降,胞间CO_2浓度(C_i)和Gs呈下降趋势,推测气孔限制是导致P_n下降的主要因素;叶绿素a/b值呈上升趋势,表明叶绿素a向叶绿素b的转化受阻,从而抑制光合作用。极端钼污染条件下(3000~4000 mg·kg~(-1))冬小麦不能完成其生命周期。

Effects of Mo pollution on photosynthesis characteristics and yields of winter wheat

A pot culture experiment was conducted to investigate the effects of different levels of Mo on photosynthesis characteristics and yields of winter wheat. Results showed that appropriate Mo application(0.15 mg·kg^-1) increased chlorophyll(Chl) content, photosynthetic rates(P_n) and yields of winter wheat in Mo-deficient soils. The chlorophyll content, photosynthetic rates(P_n), transpiration rates(T_r), stomatal conductance(G_s) and yields of winter wheat were decreased by Mo at 0.15~2000 mg·kg^-1. The decline in P_n along with C_i and G_s decreases indicated that stomatal limitation was the main factor for P_n decreases. The Chla/b decreased with increases in Mo pollution levels, indicating that the transformation from Chla to Chlb was blocked under Mo pollution conditions. The life cycle of winter wheat was not completed when Mo levels were higher than 3000~4000 mg·kg^-1.