外源Mo降低As(Ⅲ)和As(Ⅴ)对水稻的毒性及As的积累

通过溶液培养试验,研究外源添加Mo对2种价态砷(As(Ⅲ)和As(Ⅴ))胁迫下水稻吸收积累Mo和As的影响。结果表明,这2种价态的As对水稻生长均有抑制作用,As(Ⅲ)比As(Ⅴ)对水稻毒害更明显,添加Mo可缓解As对水稻的毒害。As添加可影响水稻根系和茎叶对Mo的吸收积累,但是不同价态As对Mo积累量的影响不一致。同时,Mo的添加也可以显著地降低水稻根系和茎叶对2个价态As的吸收积累。在100μmol·L~(-1)As(Ⅲ)处理下,添加0.1和0.5 mg·L~(-1)的Mo可导致水稻根系As积累量分别比对照处理降低38.8%和52.8%,茎叶As积累量分别降低5.1%和10.6%;当As(V)浓度为100μmol·L~(-1)时,添加0.1和0.5 mg·L~(-1)的Mo可导致水稻根系As积累量分别比对照处理降低15.4%和62.4%,茎叶As积累量分别降低11.9%和23.7%。Mo的添加还能显著地降低2种价态As在水稻根系和茎叶中的富集系数。因此,通过施用适量的Mo肥可以用来防治农田As污染,降低As对人体健康的危害。

Molybdenum Reduced the Toxicity and Accumulation of As (Ⅲ) and As (Ⅴ) in Rice Seedling

Plant nutrition may influence the uptake of heavy metals and some essential elements.Inorganic molybdenum (Mo) is an essential micronutrient element for plant survival.Control of Mo content in tissues is of major importance for normal plant growth and development.Effects of different Mo concentrations on uptake and accumulation of Mo and As by rice seedlings under As(Ⅲ) and As(Ⅴ) stress were studied.The results showed that both As(Ⅲ) and As(Ⅴ) could significantly inhibit rice growth,and As(Ⅲ) was more toxic than As(Ⅴ).Addition of exogenous Mo could alleviate the toxic effect of As.The uptake and accumulation of As in rice shoot and root were decreased by Mo addition.At the As(Ⅲ) concentration of 100 μmol·L-1,addition of 0.1 and 0.5 mg·L-1 Mo decreased As accumulation by 38.8％ and 52.8％ in rice root,by 5.1％ and 10.6％ in rice shoot,respectively,compared with the control.At the As(Ⅴ) concentration of 100 μmol·L-1,addition of 0.1 and 0.5 mg·L-1 Mo decreased As accumulation by 15.4％ and 62.4％ in rice root,by 11.9％ and 23.7％ in rice shoot,respectively,compared with the control.Bio-accumulation factor of As were also influenced by Mo addition.The results indicated that application of appropriate Mo can prevent As contamination in farmland,and decrease the harmful effect of As on human health.