不同季节龙葵叶面微生物与叶片冻害的关系

为了探明植物叶面微生物与叶片冻害的关系 ,于不同季节 (冬季和夏季 )对龙葵叶片进行无菌水清洗和不清洗处理 ,将叶片置于 - 17℃冰箱中冷冻不同时间 ,观察叶片冻害情况 ,并对叶面微生物作了分离、鉴定 .结果表明 ,冬季冷冻 1m in可见叶片的冻斑 ,其平均直径为 (2 .6 0± 0 .2 4) m m ,水清洗组叶片冻斑比未清洗组冻斑减少71% ;夏季冷冻 1m in未见冻斑 ,冷冻 5 min叶片出现冻斑 ,其平均直径为 (1.80± 0 .17) mm ,水清洗组叶片冻斑较未清洗组减少 76 .7% .随着冷冻时间的延长 ,叶片冻害加重 ,冬季 1h,夏季 1.5 h,未清洗组叶片全部冻坏 .相应水清洗组叶片全部冻坏时间为 1.5 ,2 h.嫩叶对照组叶片 ,冬季冷冻 1min,冻坏面积达 80 % ,冷冻 30 min叶片全部冻坏 ;夏季冷冻 5 m in,冻坏面积达 72 % ,冷冻 40 m in叶片全部冻坏 .从龙葵叶片上分离出 5类叶面微生物 ,分别是 G+球菌 ,G+杆菌 (2类 ) ,G-杆菌 ,放线菌 ,其中数量最多的是 G+球菌

Relationship between Phyllospheric Microoganisms and Freeze Injury to Leaves of Solanum nigrum in Different Seasons

In order to study the relationship between phyllospheric microoganisms and freeze injury to leaves of plant, leaves of Solanum nigrum were washed with sterile water in summer and winter,while the control was not.These leaves were frozen at -17 ℃ in refrigerator for different periods of time.The freeze injury to leaves was observed and phyllospheric microoganisms were isolated and identified. The results show that the frozen spots with average diameter of (2.60±0.24) mm is found on leaves after frozen for 1 min in winter;the number of frozen spots of washed group reduce by 71% compared with the control;the frozen spots don't appear after frozen for 1 min in summer; and the number of frozen spots with average diameter of (1.80±0.17) mm reduced by 76.7% compared with the control.The longer the time was , the worse the freeze injury is.Leaves of the control are all injured after frozen for 1 h in winter and 1.5 h in summer, while washed leaves are all injured after frozen for 1.5 h in winter and 2 h in summer. When young leaves are frozen, the freeze injury covers 72% of the whole area after frozen for 5 min in summer and 80% after frozen for 1 min in winter. All leaves are injured after frozen for 30 min in winter and 40 min in summer. 5 kinds of phyllospheric microoganisms are isolated:coccus G+,bacillus G+(2 kinds),bacillus G－,actinomycetes.The bacteria with the largest number are staphylococci albus.