SA对温室甜瓜白粉病预防效果的影响

Effect of SA on prevention of powdery mildew in the greenhouse muskmelon

新疆甜瓜在生长期受到各种病害特别是白粉病的影响,而传统的农药防治不但污染环境,而且影响人畜安全。植物抗性诱导剂SA(水杨酸)是一类新型的生物农药,可激发植物免疫系统,达到防病的目的。采用不同浓度SA溶液在甜瓜植株开花前1周、雄花开花后10 d、采收前10 d进行处理,在处理后3、6、9 d取新鲜的叶片测定其PAL、PPO和POD活性,处理后6 d调查病情指数,待果实成熟采收后测定产量、单瓜质量、可溶性固形物含量、果肉硬度及维生素C含量。结果表明,不同浓度SA处理均增强了PAL、PPO和POD活性,以100μg·m L^(-1)SA处理效果最好,随着处理时间的延长,POD和PPO活性均呈现了先升高后降低的趋势,而PAL活性则呈现出了逐渐降低的趋势。通过差异显著性分析,POD活性在处理后6 d时差异达到显著水平,PPO和PAL活性在处理后3 d时达到显著水平。通过采收后测定产量、单瓜质量、可溶性固形物含量、果肉硬度及维生素C含量,100μg·m L^(-1)SA处理能有效减少白粉病对哈密瓜产量和品质的影响。

The growth of muskmelon in Xinjiang was influenced by kinds of diseases, especially powdery mildew. Considering the negative effects of the traditional insecticide on the environment, health of people and livestock, a new type biologi- cal pesticide （SA） , which is a plant resistance inducer can stimulate plant defense system to achieve the effects of dis- ease prevention. Different concentrations SA were used to treat the different stages （a week before flowering, 10 days after male flower blossoming, and 10 days before harvest） in muskmelon plants. Changes of enzyme activity of PAL, PPO and POD of muskmelon leaves that were treated for 3 days, 6 days and 9 days were determined, disease indexes after treated for 6 days were investigated, yield, fruit weight, soluble solids content, fruit hardness and Vitamin C content were measured after harvest. The results showed that the activity of PAL, PPO and POD were enhanced by SA, the effect of 100 μg·mL-1 SA was the best, with the increase of the treatment time, the activity of PPO and POD decreased firstly and increased subsequently, the activity of PAL exhibited a gradually decreasing process. The differences analysis had shown that the activity of POD reached significant level after treated for 6 days, and the activity of PAL and PPO reached significant level after treated for 3 days. According to the analysis of yield, fruit weight, soluble solids content, fruit hardness and Vitamin C content after harvest, the influences of powdery mildew upon the yield and quality of muskmelon were reduced effectively by 100 μg-mL-1SA.