氯酸钾对花生生长的毒害效应

 氯酸盐是一类毒性强的氧化剂，曾被作为非选择性除草剂和脱叶剂大量施用，近年来，氯酸钾作为产期调控剂也在龙眼(Dimocarpus longan)反季节生产中大量应用。然而， 氯酸根离子强氧化性对生物体有明显的毒害效应，其残留及次生污染物对水体和土壤环境也存在较强的污染效应。龙眼园通常间种花生(Arachis hypogaea)，该文实验研究了氯酸钾和氯化钠对花生生长的毒害效应。结果表明，当浸种溶液的KClO3浓度高于50 mg?L－1时，花生种子的发芽率和胚根长度大大降低，幼芽的电解质渗漏率和过氧化氢酶活性显著升高；当土壤中KClO3浓度高于50 mg?kg－1时，会使花生幼苗叶片质膜透性增大，而硝酸还原酶活性 、叶绿素含量和根系活力显著降低，氯酸钾的毒害效应远远超过氯化钠的盐害效应，高于50 mg?kg－1的KClO3还能使花生荚果期植株的光合速率、蒸腾速率、叶绿素含量、 根系活力、 生物量合成和根瘤菌的数量显著降低。结论是，土壤中的KClO3浓度高于50 mg?kg－1时，即会显著影响花生植株的正常生长。

TOXIC EFFECTS OF POTASSIUM CHLORATE ON PEANUT GROWTH

Chlorates are a group of oxidizers with strong toxic effects that can cause significant damage to plants. However, chlorates have been used as a non_selective herbicide, defoliant and desiccant. It was found that potassium chlorate can induce flowering in longan (Dimocarpus longan). It has been widely used in longan orchards in recent years, especially in north Thailand and south China, but research has shown that potassium chlorate is toxic to organisms. It can also contaminate soil and water. The aim of this study was to determine the effects of potassium chlorate stress on the growth and physiological response of peanut (Arachis hypogaea). The main method used to induce flower initiation in longan for off_season production is the application of potassium chlorate under the tree canopy. Most research efforts have been devoted to determining the optimum time and amount of application. Little is known about the phytotoxic effects of potassium chlorate on peanut plants, which usually is planted within longan orchards. In this paper, the effects of potassium chlorate on the growth of peanut plants were studied. Usin g the soil culture method, six potassium chlorate treatments were used to assess its effects on seed germination, chlorophyll content, levels of electrolytic leakage (EL), membrane permeability (MP), and activities of nitrate reductase (NR) and catalase (CAT) in peanut seedling leaves, as well as the biomass and number of Rhizobium, and the transpiration and photosynthetic rates in mature peanut plants. The results showed that: when the concentration of potassium chlorate was higher than 50 mg?L-1, the germination rates of peanut seeds and root lengths were greatly reduced, while the amount of electrolytic leakage and the activity of CAT were increased significantly. When the concentration of potassium chlorate was higher than 50 mg?kg-1 in soil, its phytotoxic effects resulted in a significant increase in MP in seedling leaves, and a decrease in NR, chlorophyll, biomass and the number of Rhizobium, and a reduction in transpiration and photosyn thesis. It can be concluded that soil concentrations of potassium chlorate higher than 50 mg?kg-1 would have a significantly negative effect on the growth of peanut plants.