【作者】 黄彩红；

【导师】 于广建；

【作者基本信息】 东北农业大学 ， 蔬菜学， 2002， 硕士

【摘要】 随着社会经济的发展及人民生活水平的提高，设施蔬菜已经成为农业中最有活力的新产业之一。黄瓜(cucumis．Sativas L．)是中国人民喜爱的蔬菜之一，是设施蔬菜生产中的主要栽培种类。随着栽培面积的递增，连作障碍十分严重。自毒作用是连作障碍的重要原因之一，对其致毒机制的研究具有重要的理论和实践意义。本试验将与黄瓜自毒物质的主要成分相一致的两种酚酸(对羟基苯甲酸和苯丙烯酸)作为外加处理物质，设置不同浓度水平，同时在土壤栽培和基质栽培两种方式下模拟连作逆境胁迫，通过系统研究酚酸对黄瓜种子萌发、根系细胞膜保护系统及植株生长的影响，探讨其对黄瓜的致毒作用规律及对膜保护系统的可能伤害机制，为制定减轻或避免黄瓜连作障碍的对策提供科学依据。试验得出如下结论： 1．酚酸类物质能够抑制黄瓜种子的萌发，对羟基苯甲酸在150uM的浓度下明显抑制黄瓜种子萌发的发芽势、发芽率及发芽指数，其中发芽势对酚酸的反应最敏感。 2．外源酚酸通过降低保护酶活性及其清除自由基的能力，使植株体内自由基大量剩余，膜脂过氧化水平上升，电解质大量外渗。这种影响的外在表现是植株生长受抑，光合色素含量降低，光合作用和呼吸作用强度下降，干物质积累减少，可溶性糖含量升高及根系活力下降。 3．外源酚酸对黄瓜的作用及其强度因不同栽培条件、不同处理时间及所用酚酸的种类和浓度密切相关。苯丙烯酸的生物毒性大于对羟基苯甲酸。低浓度酚酸短时间处理可刺激大田土培幼苗生长，对基质栽培和连作土培幼苗的毒害作用不明显；高浓度处理毒害作用明显，随处理浓度增大及处理时间延长，抑制强度加大。 4．在所有指标中，植株的株高、叶面积、全株干重、相对电导率、SOD活性、MDA含量变化规律相对稳定，而且对酚酸反应的敏感性较强，因而可用作评价蔬菜化感作用效应的合理指标。更多还原

【Abstract】 With the development of social economy and the increase of people’s living standards, vegetables cultured under structure have become one of ihe most active industries in agriculture. Cucumber (Cucumis sativus L.) is the favorable green stuff for Chinese and has become the main variety of structure vegetables, its yield and quality have been limited by continuous cropping obstacles more and more while its culture area enlarges year by year. Auto-toxic effect is one of the important factors of continuous cropping obstacles. The study on toxic mechanism of these toxins has important significance both theoretically and practically.Exogenous p-hydroxy benzoic acid and cinnamic acid, which are consistent with the ingredients of auto-toxic substance exudated by cucumber’s roots, were applied as treatment phenolic acids in our test. Different levels of concentrations were involved to analogue the stress of continuous cropping under substrate culture and soil culture. We had researched systematically the effects of phenolic acids on germination of cucumber seed, membrane protective system of the roots and growth of cucumber seedlings, so as to discuss the laws of toxic action and the injury mechanism of auto-toxic substance to cucumber meanwhile try to supply the scientific bases for the alleviation or elimination of cucumber continuous cropping obstacles. The main results are as follows:First, phenolic acids can inhibited seed germination of cucumber. The germination force, germination percentage and germination index were inhibited obviously over 100uM concentration of p-hydroxy benzoic. The germination force was the most sensitive one to the action of phenolic acids among the three indicators.Second,through decreasing the activity of protective enzymes and their ability of cleaning free radical, exogenous phenolic acids made lots of free radical remain in plant so that induced membrane lipkd peroxidization. Electrolytic leakage became heavier. Content of soluble sugar increased. The external manifestation of this influences were that plant growth was inhibited, content of photosynthetic pigments decreased, so did the intensity of photosynthesis and respiration, content of dry mass and root activity.Third, The toxic degree of phenolic acids to cucumber were related closely to phenolic acids’ concentration and variety, treatment time, culture ways and so on. Cinnamic acid had more greater action intensity than p-hydroxy benzoic acid. Phenolic acids under low concentrations could stimulate the growth of seedlings cultured by field soil and showed no significant effect on seedlings cultured by substrate and continuous cropping soil, while the higher concentrations (>100uM or 200mg.kg-1) could inhibit growth of all seedlings significantly and its intensity became stronger with increase of treatment concentrations and extending of treatment time.Finally, the changes of plant height, leaf area, dry weight, relative conductivity rate, SOD activity, MDA content were stable relatively, their sensitivity to phenolic acids were greater than other indicators. So they can be used as reasonable indicators to appraise allelopathic effect of vegetables.更多还原