土壤盐分离子对乌鲁木齐小白菜Pb含量的影响研究

为研究土壤中盐分离子对小白菜Pb含量的影响，采取正交试验L₁₆ 4⁵和盆栽试验方法，分析了5种阳离子（Ca²⁺、Mg²⁺、K⁺、Na⁺、Pb²⁺）和3种阴离子（SO₄^2-、Cl^-、NO₃^-）对小白菜地上部和根系中Pb含量的影响。结果表明，试验条件下小白菜地上部Pb含量为0.215~0.930 mg·kg^-1，根系中Pb含量为1.648~24.33 mg·kg^-1，可食用部分超标率达81.3%。土壤盐分离子对小白菜地上部Pb含量影响顺序为： Ca²⁺ > Mg²⁺ > Na⁺ > Pb²⁺ > K⁺。根据相关性分析，土壤中Ca²⁺与小白菜地上部Pb含量呈显著负相关（r=-0.540 3，P<0.05），Na⁺和Pb²⁺呈正相关但不显著。Mg²⁺和K⁺呈负相关，也不显著。Cl^-和NO₃^-与小白菜地上部Pb含量呈显著负相关（r=-0.540，P<0.05），SO₄^2-呈正相关，但不显著。对小白菜根系Pb含量影响顺序为： Pb²⁺ > K⁺ > Na⁺ > Ca²⁺ > Mg²⁺，土壤中Pb²⁺对小白菜根系Pb的含量呈显著正相关（r=0.483，P<0.05），Ca²⁺、Mg²⁺、K⁺、Na⁺、SO₄^2-、Cl^-和NO₃^-相关性不显著。乌鲁木齐土壤中固有的盐分离子对小白菜可食用部分Pb的吸收没有抑制作用。

Effect of Salt Ions in Soil on Pb Content of Chinese Cabbage (Brassica campestris L. ssp.)in Urumqi, China

In order to study the effect of soil salt ions on Pb content in Chinese cabbage(Brassica campestris L. ssp.), the methods of orthogonal experiment L₁₆ 4⁵ and pot experiment were adopted, and five cations (Ca²⁺, Mg²⁺, K⁺, Na⁺, Pb²⁺)and three anions (SO₄^2-, Cl^-, NO₃^-)in the soil on Pb content in the aboveground part and root of Chinese cabbage were analyzed. The results showed that the Pb content was 0.215~0.930 mg· kg^-1 in the aboveground part, 1.648~24.33 mg·kg^-1 in the root, and 81.3% in the edible part exceeded the limit. The impact of those factors on Pb content in the aboveground part of Chinese cabbage was:Ca²⁺ > Mg²⁺ > Na⁺ > Pb²⁺ > K⁺. According to correlation analysis, Ca²⁺ in soil had a significantly negative correlation with Pb content in the aboveground part of Chinese cabbage(r=-0.540 3, P<0.05), Na⁺ and Pb²⁺ were positively correlated to an insignificant difference; Mg²⁺ and K⁺ were negatively correlated but not significant either. Cl^- and NO₃^- in soil had a significantly negative correlation with Pb content in the aboveground part (r=-0.540 3, P<0.05), and with SO₄^2- insignificantly and positively correlated. The impact of those factors on Pb content in the root of Chinese cabbage was:Pb²⁺ > K⁺ > Na⁺ > Ca²⁺ > Mg²⁺; Pb²⁺ in soil had a significantly positive correlation with Pb in the root of Chinese cabbage, while Ca²⁺, Mg²⁺, Na⁺, K⁺, SO₄^2-, Cl^- and NO₃^-, showing an insignificantly correlation. The salt ions inherent in the soil in Urumqi caused no inhibition on Pb absorption in the edible part of Chinese cabbage.