高温灭菌酸性红壤可能诱发其对烟草幼苗的锰毒害

Autoclave Sterilization of Acid Red Soil May Induce Mn Toxicity in Tobacco Seedlings

以存在烟草连作障碍的两种土壤(红壤和水稻土)为材料,研究高温灭菌对幼苗期烟草鲜干质量、农艺性状和土壤理化性状的影响.结果显示:(1)酸性红壤土高温灭菌后,烟草植株干质量、株高、茎粗和叶面积,均显著低于不灭菌处理;然而,碱性水稻土高温灭菌后,上述参数值则恰恰相反.(2)高温灭菌,显著降低了红壤土Eh值,可能是导致土壤二价锰质量分数超过了烟株锰毒害临界值的因素之一,但高温灭菌对水稻土pH值和Eh值影响均无统计学意义.据此,在进行土壤生物学障碍机理研究时,应该考虑高温灭菌诱发酸性红壤锰毒,抑制烟株生长,从而影响对试验结果的客观评价.

An experiment was carried out on red soil(acid) and paddy soil(alkaline), on which continuous cropping obstacles occurred, to study the impact of autoclave sterilization on leaf fresh/dry weight and agronomic traits of tobacco plants at the seedling stage and on soil physicochemical properties. The results showed that autoclave sterilization significantly decreased the dry weight, plant height, stem diameter and leaf area of the tobacco seedlings on the acid red soil and the opposite was true for the plants on the alkaline paddy soil. Autoclave sterilization significantly decreased soil Eh for red soil, which may be one of the factors responsible for the results that soil divalent manganese content exceeded the tobacco Mn toxicity threshold on red soil. However, no significant difference was observed in soil pH and Eh between autoclave sterilization and non-sterilization for paddy soil. Therefore, in researches of the mechanism for soil biological barriers it should be taken into consideration that autoclave sterilization may induce Mn toxicity in acid red soil and thus inhibit tobacco growth, so that the evaluation of the experiment results is objective and reliable.