通过土壤添加 Pb 和叶面喷施 Pb 溶液的方式研究了 Pb 污染对小麦(Triticum aestivum L.)地上部分和籽粒干质量的影响,并对 Pb 污染条件下小麦体内 Pb 的分布和积累规律以及 Pb 污染浓度与籽粒 Pb 含量的相关性、叶片Pb 含量与籽粒 Pb 含量的相关性进行了分析。 结果表明:土壤中 Pb 添加量为 2 000 mg· kg^-1时,小麦地上部分和籽粒的干质量分别较对照下降了 15. 5% 和 13. 3% ,差异显著( P<0. 05);叶面喷施 100 mg· L^-1 Pb 溶液,小麦地上部分和籽粒干质量分别较对照下降了 10. 3% 和 15. 5% ,差异显著(P<0. 05)。 在土壤和叶面 Pb 污染条件下,小麦各器官的 Pb 含量均随 Pb 污染浓度的提高而增大;在土壤 Pb 污染条件下,小麦根中的 Pb 含量远高于其他器官,籽粒中的 Pb 含量最低;在叶面 Pb 污染条件下,小麦叶片中的 Pb 含量远高于其他器官,籽粒和根中的 Pb 含量较低。回归分析结果表明,小麦籽粒中的 Pb 含量与 Pb 污染浓度呈极显著正相关(P<0. 001),籽粒中的 Pb 含量与土壤 Pb总含量和叶面 Pb 污染浓度的曲线方程分别为: y = 0. 269+0. 001 05x+2. 736×10^-7 x² -1. 707×10^-10 x³和 y = 0. 465+0. 013x-1. 1×10^-5 x² +3. 96×10^-9 x³ ; 土壤中总的Pb毒性临界值为 209. 3 mg· kg^-1 ,叶面Pb的毒性临界值为 2. 6mg· L^-1 ; 在土壤和叶面 Pb 污染条件下,小麦籽粒中的 Pb 含量与叶片 Pb 含量间呈极显著的正相关( P<0. 01),回归方程分别为:y = 0. 120 1x+0. 076 和 y = 0. 001 6x+ 0. 601 1,据此,在土壤和大气 Pb 污染条件下,可通过测定小麦叶片的 Pb 含量预测小麦籽粒中的 Pb 含量。

Effect of Pb pollution on dry weights of above-ground part and grain of wheat ( Triticum aestivum L.) was studied by adding Pb in soil or spraying Pb solution on leaf surface. Also, the distribution and accumulation rules of Pb in wheat, the correlation between Pb pollution concentration and Pb content in grain, and the correlation of Pb content between leaf and grain were analyzed. The results show that the dry weights of above-ground part and grain of wheat growing in soil added 2 000 mg· kg^-1 Pb decrease by 15. 5% and 13. 3% respectively, and those of wheat with sprayed 100 mg· L^-1 Pb on leaf surface decrease by 10. 3% and 15. 5% respectively, and all having significant difference compared with the control (P<0. 05). Under Pb pollution in soil or on leaf surface, Pb contents in different organs of wheat all increase with Pb concentration rising. Under Pb pollution in soil, Pb content in root is much higher than that in other organs, and that in grain is the lowest. Under Pb pollution on leaf surface, Pb content in leaf is much higher than that in other organs, and that in grain and root both are lower. The results of regression analysis reveal that there are extremely significantly positive correlations between Pb content in wheat grain and Pb pollution concentration (P<0. 001). And the regression equations of Pb content in wheat grain with Pb concentration in soil or on leaf surface are y = 0. 269+0. 001 05x +2. 736×10^-7x² -1. 707×10^-10 x³ or y = 0. 465 +0. 013x -1. 1 ×10^-5 x² + 3. 96 ×10^-9 x³, respectively. The toxicity critical value of Pb in soil is 209. 3 mg· kg-1 and that on leaf surface is 2. 6 mg· L^-1. There is extremely significantly positive correlation of Pb content between grain and leaf of wheat ( P < 0. 01 ) under Pb pollution in soil or on leaf surface, and regression equations are y = 0. 120 1x+0. 076 or y = 0. 001 6x+ 0. 601 1, respectively. Thus, Pb content in wheat grain can be predicted by measuring Pb content in leaf under Pb pollution in soil or on leaf surface.