【作者】 朱振家；

【导师】 陈年来；

【作者基本信息】 甘肃农业大学 ， 蔬菜学， 2007， 硕士

【摘要】 本研究以黄河蜜甜瓜为实验材料,研究了五种化学诱导物对甜瓜抗白粉病的诱导作用;以卡拉克赛、黄河蜜和Tam Dew三个抗性水平不同的甜瓜为试材,研究了品种的基础抗性对诱导效果的影响;以幼苗期、伸蔓期和幼果期三个生育期的黄河蜜甜瓜为试材,研究了诱导时期对诱导效果的影响。结果如下:1.苯并噻重氮（BTH）、水杨酸（SA）、草酸（OAA）、硅酸钠（Na₂SiO₃）均能显著诱导甜瓜对白粉病的抗性。各种诱导剂的最适诱导浓度分别为BTH 0.25mmol/L、SA 1.0 mmoL/L、OAA 30 mmoL/L、Na₂SiO₃ 10 mmoL/L,适宜浓度下的诱导效果分别为:67.4%、49.9%、43.4%和34.9%。在供试浓度范围内,磷酸氢二钾（K₂HPO₄）对甜瓜抗白粉病的诱导作用不显著。2.经五种化学诱导物处理的甜瓜幼苗接种白粉菌后PAL活性快速增加,增长幅度均显著大于只接种植株;BTH、SA、OAA和Na₂SiO₃处理后GLU活性变化与PAL相似,而K₂HPO₄处理对GLU活性的改变与只接种植株中的基本一致;白粉菌侵染后甜瓜幼苗PPO活性升高,但五种诱导剂处理并不能促进其增加。除用SA和K₂HPO₄处理外,CHI活性在诱导剂处理和白粉菌接种后均无明显变化。3. BTH诱导甜瓜抗白粉病的效果与三个品种的基础抗性正相关,对抗病品种的诱导效果高于中抗和感病品种,抗病品种叶片中β-1,3-葡聚糖酶（GLU）和苯丙氨酸解氨酶（PAL）活性增长幅度也较中抗和感病品种大。BTH处理3天后接种白粉菌,三个抗性水平不同的甜瓜叶片中GLU、PAL和多酚氧化酶（PPO）活性均较只接种病原菌的植株显著上升。叶片超微结构观察显示:接种白粉菌后,三个抗性水平的甜瓜寄主细胞中叶绿体、线粒体等细胞器都受到不同程度的损伤,大量的乳突结构存在于寄主细胞中,高抗品种中乳突结构多呈半圆球型,中抗和感病品种中多呈圆筒型,并且前者乳突数量较后两者明显增多。4. BTH对幼苗期和伸蔓期甜瓜植株的诱导效果显著高于幼果期甜瓜植株。而伸蔓期和幼苗期植株之间病情指数差异不显著;BTH处理后,幼苗期甜瓜叶片中的GLU活性在接种后增幅最大,伸蔓期次之,幼果期的最小;无论是诱导+接种的植株,还是只接种的植株,叶片中的PAL活性高峰都随着苗龄增大呈现出不断推迟的现象。更多还原

【Abstract】 The five chemicals, induction effect on resistance to powdery mildew of melon were systemically compared in melon leaves which planted on greenhouse. Effects of BTH spaying on induced resistance to powdery mildew （Erysiphe cucurbitacearum） of melon were studied on three melon cultivars with different resistance levels. Effects of BTH spaying on induced resistance to powdery mildew （Erysiphe cucurbitacearum） were studied at three stages of melon plants treated with BTH and then inoculated with Erysiphe cucurbitacearum.1. The results showed that BTH、SA、OAA and Na₂SiO₃ have significant induction effects. The best concentration on induced resistance of them is 0.25 mmoL/L ,1.0 mmoL/L,30 mmoL/L and 10 mmoL/L respectively, and induction effect is 72.4%、49.9%、43.4% and 34.9% respectively, whereas the induction effect of K₂HPO₄ is not significantly.2.The changes in activities of phenylalanine chitinase（CHI） ,1,3-β-glucanase（GLU）, phenylalanine ammonialyase（PAL） and polyphenoloxidase（PPO） in melon leaves treated with five chemical elicitors and inoculated with powdery mildew were analyzed to explore the physiological and biochemical mechanisms of five chemical elicitors induced systemic acquired resistance （SAR）.No significant difference in the PPO activity was observed between five elicitors treated and untreated after inoculation with powdery mildew.However,the CHI activity in the leaves did not show any remarkable changes upon chemical elicitors treatment and inoculation with powdery mildew,except for the elicitors SA and K₂PO₄3. Positive correlations existed between the induction effect and the intrinsic resistance to powdery mildew of melon cultivars. The resistant cultivars showed higher induced resistance to powdery mildew and higher increase rate of leaf GLU and PAL activity than tolerant and susceptible cultivars. Leaf activities of GLU、PAL and PPO in melon plants treated with BTH and then inoculated with Erysiphe cucurbitacearum were higher than in plants only inoculated. Ultra-structure observation showed that papilla may be an active responsive structure of melon leaves to Erysiphe cucurbitacearum, the papilla structures in the disease resistant cultivar was hemispherical type but was cylinder type in the tolerant and susceptible cultivars.4. Melons in the tendril and young plant stages demonstrated higher induction effect than those at the young fruit stages.But induction effect is not significantly between melon in the tendril and young plant stages. The increase rate of GLU activity of melon leaves in the young plant stages is the biggest.and the activity climax of PAL is postponed with the increase of plant ages.更多还原