砷对冬小麦根系生长和养分吸收的影响

目的]研究砷对冬小麦根系生长和养分吸收的影响,揭示砷对小麦根系的毒害作用与机理。方法]采用水培试验,设定砷浓度分别为0、5、10、15、20 mg/L,培养30 d,测定小麦根长、根体积和根系活力,分析根系中砷的累积量和养分元素含量。结果]小麦根系能够累积较高浓度的砷,根系砷含量最高达4 506.11 mg/kg。砷显著抑制了小麦根系总吸收面积、活跃吸收面积、根长、根体积,降低了根系的生物量。溶液砷浓度为5～10 mg/L时,小麦根系中P、K、Mg和Mn、Cu、Zn的含量有增加的趋势;溶液砷浓度为15～20 mg/L时,小麦根系P、Mn、Zn的含量与对照相比均降低。小麦根系N的含量受溶液砷浓度影响不显著,砷显著降低了小麦根系Fe的含量。结论]砷的毒害作用主要体现在抑制小麦根系生长,降低根系活力及生物量;砷对小麦根系中N、K、Ca和Mg等的含量影响较小,对Fe、Mn、Cu和Zn等微量元素含量影响较大;15～20 mg/L砷处理时,砷与P的竞争作用明显,抑制小麦根系对磷的吸收。

Effect of As on the Concentration of Nutrient Elements and Root Growth of Winter Wheat ( Triticum aestivum L.)

Objective] The study aimed to research the effects of arsenic on the growth and macro-micronutrient concentration in the root of winter wheat(Triticum aestivum L.) and reveal the toxic action and mechanism of arsenic to wheat root.Method] A pot experiment was carried out in the hydroponic culture.The solution arsenic concentrations were 0,5,10,15 and 20 mg/L,respectively.After 30 days,the wheat root activity,root length,root volume and root nutrient elements concentration were investigated.Result] The results indicated that wheat root accumulated high arsenic with maximum concentration was 4 506.11 mg/kg.Arsenic decreased root total absorption area,root activity absorption area,root length and volume significantly.It assumed that arsenic was toxic to wheat root badly.The concentration of P,K,Mg,Ca,Mn,Cu and Zn in root increased when solution arsenic was 5-10 mg/L,but decreased with solution arsenic 15-20 mg/L.As did not affect N concentration significantly compared with the control but decreased the concentration of Fe in the wheat root significantly.Conclusion] Arsenic was toxic to wheat and decreased root length,root volume,root activity and root biomass significantly.Arsenic affected root micro-elements concentration significantly.The P,K and Fe in wheat root were sensitive elements to arsenic stress,more researches should be carried out to identify relationship between these elements and arsenic.