熏蒸灭菌对连作马铃薯生长发育及土壤微生物的影响

采用土壤熏蒸灭菌的方法,分析了连作土壤灭菌对盆栽马铃薯生长发育及根际土壤微生物功能多样性的影响.结果表明：土壤熏蒸灭菌对马铃薯主要光合特征参数影响规律较复杂,连作时间长短对叶片光合能力有显著影响;连作土壤熏蒸灭菌后,马铃薯具有较低的光合强度、蒸腾速率、气孔导度和较高的胞间CO2浓度.熏蒸土壤马铃薯光合作用的影响是由非气孔限制引起,水分因子可能是影响马铃薯叶片气孔导度下降的主要原因.连作提高了植物超氧化物歧化酶（SOD）活性,降低了马铃薯叶片抗坏血酸过氧化物酶（POD）活性.熏蒸灭菌在一定程度上缓解了不利马铃薯生长的环境因素,但马铃薯连作栽培障碍引起的过氧化反应没有完全消除.连作5年、10年土壤熏蒸灭菌提高了Biolog Eco板平均颜色变化率（AWCD）;与未灭菌相比,培养96h时AWCD分别提高30.9%～41.6%和2.7%～12.8%.连作土壤微生物对单一碳源底物利用能力一直较高,土壤微生物群落利用碳源的功能多样性也较高,但持续连作土壤微生物对碳源利用有趋于微生物功能多样性单一的趋势.

Effects of fumigation sterilization to potato growth and soil microorganism of the continuous cropping soils

In order to study the effect of sterilized soil on the potato growth and soil microorganism community function diversity.The experiment was carried out by potted culture with sterilized potato continuous cropping soil,which were seperately sampled from the fields from potato normal rotation and different continuous cropping period. The result showed that the characteristics of photosynthetic parameters were complicated under the condition of sterilized continuous cropping soil.The photosynthetic characteristics may be affected by nonstomatal limitation and the stomata conductance were decreased owning to the absence of soil water content,which may be the main influential factor.The activities of superoxide dismutase(SOD) in the potato leaves were increased under the continuous cropping,but the activities of ascorbate peroxidase(POD) were obviously decreased when the continuous cropping soil were sterilized.The harmful soil environment factors to potato growth were changed.Soil microorganism function diversity in potato rhizosphere soils were also influenced by continuous cropping.The average color change rate(AWCD) of Biolog Ecoplate were significant increased in the five and ten years continuous cropping period when the soil were sterilized.Compared with no sterilized soil,the AWCD were separately increased 30.9%-41.6% and 2.7%-12.8%.There are still have more high carbon substrate utilization ability and soil microorganism carbon substrate using function diversity.But the diversity of soil microbial community function to carbon substrate utilization have the trendency of gradually decline under the condition of continuous cropping.