大蒜素对番茄叶霉菌不同生理小种的抑制作用

Inhibition of Allicin on Different Races of Tomato Leaf Mold

研究大蒜素对番茄生产上叶霉菌主流生理小种1.2.3.4以及2014年新发现生理小种2.5、2.4.5和1.2.3.4.9的抑制作用,为开发安全、高效的植物源农药奠定基础。首先制备大蒜素抽提母液,采用定硫法对其中的大蒜素进行定量测定,发现当溶液中滴加4 m L浓硝酸、溶液p H值为2.0时能够更为准确地测得大蒜素的含量,试验测得大蒜素含量为0.52%。在此基础上,进行了大蒜素对4个叶霉菌生理小种菌丝生长、孢子萌发的抑制试验,离体叶片上的病害预防试验以及苗期药效试验。结果表明,当大蒜素剂量>25μL/m L时,其对叶霉菌生理小种菌丝生长的抑制活性较高,其中对1.2.3.4的抑制率最高,对1.2.3.4.9的抑制率最低,对其他2个生理小种的抑制率差异不显著。当大蒜素剂量<7.5μL/m L时,其对4个生理小种孢子萌发的抑制效应存在差异,其中对1.2.3.4.9的孢子萌发抑制率最低,对1.2.3.4的孢子萌发抑制率最高。当大蒜素剂量为125μL/m L时,其对叶霉菌4个生理小种在离体叶片上的预防效果均超过95%。苗期药效试验表明,在相等剂量下,大蒜素对叶霉菌的防治效果高于多菌灵和甲基托布津,说明大蒜素是一种可以替代化学药剂防治叶霉病的有效抑菌物质。

This experiment studied the inhibition effect of allicin on the leaf mold mainstream physiological race in tomato production（ 1. 2. 3. 4）,and the newly discovered physiological races in 2014（ 2. 5,2. 4. 5 and 1. 2. 3. 4. 9）,to lay a foundation for the development of safe,effective botanical pesticides. At first,allicin extract was prepared and the allicin content was quantitatively determinated using sulphur test method. The result showed that when 4 m L of concentrated nitric acid was dropped and p H was 2. 0,the content of allicin could be measured more accurately. In this study the allicin content was 0. 52%. Based on this,we studied the inhibition effect on mycelial growth and spore germination,preventive effect on isolate leaves and control efficacy at seedling stage of allicin with the four races as control targets. The results showed that when the concentration of allicin was more than 25 μL / m L,its inhibition effect on mycelial growth was higher. The highest mycelium inhibition rate was determined on race 1. 2. 3. 4,the lowest mycelium inhibition rate was on race 1. 2. 3. 4. 9,and the inhibition rate between the other two physiological races had no significant difference. When the allicin concentration was less than 7. 5 μL / m L,its inhibition effects on spore germination showed difference among the four races,with the highest spore germination inhibition rate on race 1. 2. 3. 4,and the lowest spore germination inhibition rate on race 1. 2. 3. 4. 9.When the concentration of allicin was 125 μL / m L,the preventive effects on the four races on isolate leaves were all more than 95%. Seedling efficacy trials showed that under the condition of equal concentration,the control efficacy of allicin was better than carbendazim and thiophanate-methyl on tomato leaf mold,indicating that allicin is an effective antimicrobial substance,and it can substitute for chemicals to control tomato leaf mold.