钒胁迫对水稻幼苗生理生化和富集特性的影响

水稻（Oryza.sativa L.）是我国最重要的粮食作物之一，水稻产量占粮食总产量的一半以上，一旦水稻受到重金属污染，将会影响水稻植株的正常生长和生理特性。目前关于钒胁迫对水稻植株生理特性指标的影响方面报道较少。通过水培实验，研究了不同钒（V）质量浓度（0、4、8、12、16、20 mg·L-1）对水稻幼苗（Oryza.sativa L）生理生化和富集特性的影响。结果表明：随着V胁迫浓度的增加，叶绿素含量、可溶性蛋白含量、过氧化氢酶（CAT）活性、过氧化物酶（POD）活性、超氧化物歧化酶（SOD）等均呈现先上升、后下降的变化趋势。当ρ（V）≤12 mg·L-1，与对照相比较，叶绿素含量、可溶性蛋白含量和酶活性增大了135.3%、104.2%、77.8%（CAT）、84.5%（POD）和273.2%（SOD）；当ρ（V）〉12 mg·L-1，则分别降低37.2%、39.4%、41.1%、24.1%和24.5%。随着 V 胁迫浓度的增加，丙二醛（MDA）含量和细胞膜透性逐渐增大，与对照相比，分别增加了38.5%~289.3%、21.2%~303.2%，根系活力下降了10.9%~82.2%。可见，低ρ（V）（≤12 mg·L-1）对水稻幼苗的生长有一定的刺激作用，水稻幼苗自身保护酶表现出较强的自我调节能力；高ρ（V）（〉12 mg·L-1）明显抑制叶绿素和蛋白合成、抗氧化酶活性和根系活力，伤害了细胞质膜系统，影响水稻幼苗的生长发育。不同V浓度胁迫下，水稻幼苗累积的V含量为：根〉茎叶。随着V胁迫浓度增加，水稻幼苗各器官V含量增大，其中根部增幅远大于茎叶，当ρ（V）从5 mg·L-1增加到40 mg·L-1，与对照相比较，根部增加了0.98~25.3倍，茎叶部增加了0.26~4.74倍。生物富集系数（BF）先增加后降低，最大值为2.8408；迁移系数（TF）下降，最低值为0.1170，说明水稻对V有较强的富集能力，但迁移能力较低，积累的V主要富集在根部，可减轻V对地上部植物的危害。

Effects of Vanadium Stress on Physiological,Biochemical Characteristics and Enrichment Characteristics of Rice Seedlings

Rice （Oryza.sativa L.） is one of the most important food crop in our country, and the rice yield accounts for more than half of the total grain output. Once the rice is contaminated by heavy metals, its normal growth and physiological characteristics will be affected.There were little reports about effects of vanadium stress on physiological characteristics of rice plants. In the present work, the effects of different vanadium （V） concentrations （0, 4, 8, 12, 16, 20 mg·L-1） on the physiological and biochemical characteristics, and enrichment characteristics of rice seedlings （Oryza.sativa L） wereinvestigated by hydroponics. The results showed that the contents of chlorophyll and soluble protein, catalase activity （CAT）, peroxidase activity （POD）, superoxide dismutase activity （SOD） firstly increased, and then decreased with increase of V press level. When V concentration was less than 12 mg·L-1, the activities of CAT, POD and SOD, increased by 77.8%、84.5% and 273.2%, the contents of chlorophyll and soluble protein increased by 135.3%、104.2% respectively, compared with the control, while they decreased by 37.2%、39.4%、41.1%、24.1% and 24.5% respectively, when V concentration was higher than 12 mg·L-1. With increase of V press level, MDA content, and cell membrane permeability increased by 38.5%~289.3% and 21.2%~303.2%, and root activity decreased by 10.9%~82.2% respectively, compared with the control. The growth of rice seedlings was stimulated, and self-protective enzymes in rice seedlings showed stronger self-regulation when V stress level was less than 12 mg ·L-1, while the synthesis of chlorophyll and protein, antioxidant enzyme activity and root activity were suppressed, the cell membrane system was hurt, and growth of rice seedlings was impeded significantly when V stress level was higher than 12 mg·L-1. The experimental results showed that the concentrations of V in different organs of rice seedlings were in sequence as follows： root 〉 stem and leave.With V level