单一重金属污染对水稻叶片光合特性的影响

以杂交稻协优818为材料，研究了Cu^2＋、Hg^2＋、Cd^2＋ 3种重金属离子对水稻叶片光合特性的影响。试验结果表明：（1）Cu^2＋在低浓度时BI起叶片叶绿素含量降低。而Hg^2＋、Cd^2＋在低浓度时。则导致叶绿素含量增加：高浓度时，3种重金属均BI起叶绿素含量降低。同时，低浓度时3种重金属离子均导致叶绿素a／b值升高：高浓度时则均引起叶绿素a／b值下降。（2）Cu^2＋、Hg^2＋、Cd^2＋对水稻叶片叶绿素的吸收光谱均无明显影响，在活体条件下并未发生卟啉环中Mg^2＋的置换。（3）Cu^2＋、Hg^2＋、Cd^2＋均引起叶片希尔反应活力降低，即重金属污染明显影响光合作用。

Effects of Individual Heavy Metals on Photosynthetic Characteristics in Rice Leaves

Effects of individual three heavy metal ions (Cu~(2+), Hg~(2+) and Cd~(2+)) on the photosynthetic characteristics in leaves of hybrid rice Xieyou 818 were studied. The results suggested that: (1) under lower concentration, Cu~(2+) ion constituent led the content of chlorophyll in the leaves to decrease, but Hg~(2+) or Cd~(2+) did on the contrary; meanwhile under higher concentration, any of those three heavy metal ions led the content of chlorophyll to decrease; the ratio of chlorophyll a to chlorophyll b rose under lower concentration of any of those three heavy metal ions whilst decreasing under higher concentration; (2) any of those three heavy metal ions had little effect on the absorbing spectrum of chlorophyll, and no displacement of Mg~(2+) in the porphyrin ring took place in vivo; (3) any of those three heavy metal ions gave rise to a descent of the activities of Hill reaction in the rice leaves, i.e., heavy metals affected photosynthesis significantly.