空气湿度对灰霉菌侵染番茄叶片组织结构分析及抗氧化系统的影响

 空气湿度对番茄灰霉病的发生有显著性影响。为了探明空气湿度对灰霉菌侵染番茄叶片的过程与机理,本研究以‘金棚14-6’番茄为材料,观察分析了高空气相对湿度(80%~95%)和低空气相对湿度(65%~80%)对灰霉菌侵染番茄叶片表型变化、细胞学差异、形态结构变化、活性氧含量和抗氧化酶的影响。结果表明:高湿接种60 h大量芽管伸长出现在叶片下表皮细胞并分化菌丝,叶肉细胞间隙分布了大量的菌丝并伴随病斑出现,灰霉菌在60 h完成侵染;低湿接种108 h芽管伸长出现在叶片下表皮并分化菌丝,叶肉细胞间隙有少量菌丝分布,没有明显病斑出现。随着灰霉菌的侵染,低湿与高湿相比栅栏组织和海绵组织结构从整齐紧密变为排列疏松的时间滞后;高湿和低湿处理的叶片厚度、栅栏组织和海绵组织厚度均呈先上升后下降的变化趋势,侵染后期低湿处理的叶片组织结构厚度显著高于高湿。随着接菌时间延长,高湿和低湿的活性氧含量和抗氧化酶活性处于相对活跃的调整、适应的变化过程,大致呈先上升后下降趋势,而对照和接菌相比无显著差异,变化趋势维持在基本的振幅上。研究显示灰霉菌发生的环境条件:湿度80%~95%和侵染完成时间60 h,即控制高空气湿度的持续时间在60 h内。这为设施内番茄灰霉病的湿度调控防治提供了理论基础。

The influence of air humidity on the tissue structure and antioxidant system of tomato leaves infected by Botrytis cinerea

The air humidity has a significant impact on the occurrence of tomato gray mold. In order to explore the impact of air humidity on the process and mechanism of gray mold infecting tomato leaves, this study used the ‘Jin peng 14-6’ tomato as the material to observe and analyze the high (80%-95%) and low air relative humidity (65%-80%) on the phenotypic changes, cytological differences, morphological changes, active oxygen content and antioxidant enzymes of tomato leaves infected by Botrytis cinerea. The results showed that a large number of bud tubes elongated in the leaf epidermal cells and differentiated hyphae after 60 hours of high humi-dity inoculation, and a large number of hyphae were distributed in the mesophyll intercellular space accompanied by disease spots. Botrytis cinerea completes infection in 60 h. After 108 hours of low-humidity inoculation, the bud tube elongated and appeared in the epidermis of the leaves and differentiated into hyphae. There was a small number of hyphae in the mesophyll intercellular space, and no obvious lesions appeared. With the infestation of B. cinerea, compared with high humidity, the palisade tissue and sponge tissue structure changed from neat and compact to loosely arranged time lag; the leaf thickness, palisade tissue and sponge tissue thickness at low and high humidity increased initially, followed by a decreasing trend. The leaf tissue thickness after low humidity treatment at the later stage of infection was significantly higher than that of the high-humidity. With progression of the inoculation time, the active oxygen content and antioxidant enzyme activity in high humidity and low humidity were in a relatively active adjustment and adaptation process, which roughly increased at first and then decreased, while there was no significant difference between the control and the inoculation. The trend of change was maintained at the basic amplitude. The study concludes that the environmental conditions for the occurrence of gray mold include 80%-95% humidity and a 60 h time period for completion of infection. These findings provide a theoretical basis for the control and prevention of tomato gray mold, that is, duration of high air humidity should be regulated within 60 h.