Study On The Effects Of Weak Light On Cucumber Growth

Weak light is one of the important environmental characteristic in the protected cultivation, and the shortage of light is greatly influencing the yield and the quality of the vegetable products. Cucumber, as a world wide important vegetable, is mostly planting in the protected cultivation. Cucumber enjoy light, but can bear weak light comparatively. On the topic of cucumber growth, most researchers focused on common functions of low temperature and weak light on cucumber growth, or effects of weak light in short-time on cucumber growth in the past, but there was fewer studies about weak light'effects in the whole life of cucumber growth. In protected cultivation, cucumber mostly or even wholly lives in weak light of its growth time, so it's necessary to study the cucumber reactions when it is whole life placed in weak light during its whole life time, which not only perfects the reseach system of weak light on cucumber, but also provides more instructional measures of better cultivation and better useing of weak light on cucumber produce.In order to that, Two cucumber varieties were selected in the experimentation to study the change of plant height, stem diameter, leaf area, leaves number, plant expension, malondialdehyde, catalase, peroxidase, superoxide dismutase and chlorophyll index under four different illumination intensities. Based on the results, a lowest illumination intensity under which cucumber lives with minimum injury could be found and cucumber growth characteristics could be given when it was placed under weak light intensity in its whole growth time. Results are as follows:With the dying down of illumination, the growth of plant height, stem diameter, leaf area, leaves number, plant expension of cucumber reduced, even restrained when the illumination was badly weak. But under the intensity of natural light over 35%, cucumber was less injured. By contrast, when the intensity was lower than 35% of nature light such as 15% of nature light, the growth of cucumber lagged. Shore-time weak light had not obvious influenced on the growth of plant, and about a week later, with the extension of time, the restraining effect became more and more clearly. It showed that weak light does not have huge injury on growing plant under short time...