Effects of Root Exudates of Wheat Stressed by Cd on the Germination of Crop Seeds

摘要

Plant allelopathy issue is very important to farming but it is always neglected. Effects of root exudates of wheat stressed by Cd on the germination of crop seeds (grain sorghum seed and maize seed) were investigated in this paper. Wheat was grown in nutrient solutions with different concentration of Cd in water and sand culture. Solution of root exudates were collected. The germination rate of grain sorghum seed and maize seed planted in the collected wheat root exudates were investigated. The germination rates of crop seeds planted in solution of root exudates were lower than control. The germination rates of crop seeds were decreased by root exudates solution. The germination rate was the lowest when the seeds were planted in solution of root exudates collected from wheat grown in nutrient solution with 5 mg/L concentration of Cd in water culture and 0.5 mg/L concentration of Cd in sand culture. When the concentration of Cd in water culture was lower than 5 mg/L, the inhibit of solution of root exudates was decrescendo; while the concentration of Cd was higher than 5 mg/L it was reverse. In sand culture when the concentration of Cd was lower than 0.5 mg/L, inhibit of solution of root exudates was decrescendo; while the concentration of Cd was between 0.5 and 15 mg/L it is reverse. The germination rate of crop seeds in solution of root exudates with water-culture were more than those in solution of root exudates with sand-culture when the concentration of Cd was 50 mg/L. On the contrary, the concentration of Cd was 0, 0.5, 5, 15 mg/L it was reverse. The results showed that solution of root exudates inhibited the germination of crop seeds to some extend. Its detailed mechanism is referring to allelopathy issue and worthy to be studied further. This paper primarily provides some new information on appropriately culturing in areas polluted by Cd.