【作者】 戚建华；

【导师】 梁宗锁； 梁银丽；

【作者基本信息】 西北农林科技大学 ， 植物学， 2004， 硕士

【摘要】 黄瓜(Cucumis statirus L)是设施蔬菜生产中主要的栽培种类,但由于有限的耕地面积与市场周年需求的矛盾，导致黄瓜连作现象普遍，连作障碍严重，化感作用是其中重要的原因之一。目前设施黄瓜的栽培多是以黑籽南瓜嫁接苗为主，对于嫁接黄瓜连作障碍的系统研究未见报道。本项研究采用盆栽试验以不同连作年限的土壤为基质比较系统地研究了连作年限对嫁接黄瓜的生长、产量和土壤微生物的影响；采用水培和XAD-4树脂吸附法分别收集嫁接黄瓜和砧木南瓜的根系分泌物并以黄瓜、南瓜为受体进行生物活性测定，并对嫁接黄瓜及其砧木南瓜根系分泌物化感作用的生理机制进行了初步探索。对设施蔬菜的合理生产，改进和调整设施黄瓜生产现有的不利栽培措施具有指导意义。通过研究得出如下结论：在连作6~8年黄瓜的土壤上生长的嫁接黄瓜幼苗中，所测定的生长指标与正茬黄瓜相比差异不显著。而连作6~8年土壤上生长的黄瓜植株，到了生长后期，无论在株高，叶片数，茎粗，根数，根粗，光合叶面积都明显不如1~4年连作和正茬的嫁接黄瓜植株。在整个生长季节，从嫁接黄瓜的耗水量、生物积累量、经济产量、光合速率和叶绿素含量的研究中证明：连作6~8年黄瓜明显低于正茬的嫁接黄瓜植株。在初步研究了连作条件下嫁接黄瓜保护酶的影响中，无论超氧化物歧化酶，还是过氧化物酶和过氧化氢酶，尽管在不同生育期表现不同，但在连作6年以后（或更早）活性显著降低。以上结果证明在6~8年连作的嫁接黄瓜中存在着生理障碍现象。嫁接黄瓜不同连作年限的土壤呼吸强度随着连作年限的增加而降低，因而土壤中微生物的总量和活性随着连作年限的增加而降低。土壤中微生物类群也随着连作年限的增加而发生了很大的变化，细菌和真菌随着连作年限的增加而增加，放线菌随着连作年限的增加而减少，造成黄瓜抗性的降低。南瓜和嫁接黄瓜根系分泌物对黄瓜发芽率，胚根胚轴的伸长均具有明显的抑制作用，这种抑制效果与浓度呈正相关；对南瓜发芽率及其胚根胚轴伸长的抑制也达到显著水平，这种抑制效果与浓度同样呈正相关。表明黄瓜经过黑籽南瓜嫁接以后，在重茬种植情况下依然存在化感作用的影响。在对其生理生化特性的研究中发现，根系分泌物显著的促进黄瓜和南瓜体内吲哚乙酸氧化酶的活性，从而降低其体内吲哚乙酸的水平，抑制其生长发育；根系分泌物还显著抑制受体淀粉酶的活性，这种抑制性随浓度升高而增加，通过影响黄瓜和南瓜体内的能量转化来影响其正常生长。说明南瓜不仅具有自毒作用，而且对黄瓜也有抑制性化感作用；嫁接黄瓜对黄瓜和南瓜都有抑制性化感作用。因而，经过黑籽南瓜嫁接以后的黄瓜，化感作用仍然是其连作障碍中的主要因子之一。更多还原

【Abstract】 Cucumber (Cucumis statirus L.) is the favorable vegetable for Chinese and has become the main variety of greenhouse vegetables. However, the contradiction between limited land and market supply all yearlong resulted in the fact that continuous cropping obstacles become common and serious more and more. Allelopathy is one of the most important factors of continuous cropping obstacles. At present, cucumber is cultivated in greenhouse generally by grafted with squash as rootstock. But systematic research concerning continuous mono-cropping grafted cucumber obstacle isn’t reported. This paper systematically studied the effect of continuous cropping soil on grafted cucumber in aspect of its growth, yield and edaphon in pot experiments. Further more, root exudates of squash and grafted cucumber were collected by solution cultivate and adsorption of XAD-4 resins, and bioassay of the root exudates was did with cucumber and squash as receptors, studied allelopathy of grafted cucumber and squash root exudates on cucumber and squash , physiobiochemistry as well as. It is significant to production of greenhouse vegetable in reason, improving and adjusting existing disadvantageous cultivated measures of protected cucumber. The main results are as follows:In the seedling period, long-term continuous mono-cropping grafted cucumber isn’t worse than no-replanting grafted cucumber in height of plant, number of the leaves, diameter of stem, number of the roots, diameter of the root and the area of the leaves. However, in the late stage of growth, long-term continuous mono-cropping grafted cucumber is significantly worse than short-term continuous mono-cropping and no-replanting grafted cucumber in these aspects, and in water use, biomass, economic yield , photosynthesis and the content of chlorophyll gained similar result. In the research about the effect of continuous cropping on protective enzyme of grafted cucumber, though superoxide dismutase, peroxydase and catalase have different representation, after continuous mono-cropping for 6 years or more earlier, their activity significantly decrease. So long-term continuous mono-cropping soil lead to continuous cropping obstacle of grafted cucumber, short-term continuous mono-cropping soil don’t bring this result.The respiratory rate of continuous mono-cropping soil of grafted cucumber decreased with increase of the number of years. So this show the total and activity of microbe in soil decreased with increase of the number of years. The species of microbe in soil also have changed with increase of the number of years, and bacteria and fuggi increased with increase of the number of years, but actino myces decreased with increase of the number of years. So worked resistance decrease of grafted cucumber.Grafted cucumber and squash root exudates have the inhibitory effect of germination of cucumber, elongation of root and hypocotyls, and have the same effect on squash. This effect have a direct correlation with the concentration of root exudates. and found root exudates have the promotable effect on the activity of IAAoxidase of cucumber and squash, .So explaining it can reduce the IAA of them, accordingly restrain the growth of them. And root exudates restrain the activity of amylase of cucumber and squash. This inhibitory effect also <WP=7>have a direct correlation with the concentration of secretion of grafted cucumber root.更多还原