Effects Of Root Zone Temperature On Growth And Physiological Function Of Pepper In Greenhouse

In recent years, progress has been made in the study of greenhouse control with the rapid development of Chinese facility agriculture, humans mainly studied about air temperature, but little research on the soil temperature. In this study, pepper in greenhouse as research object, with Changjin, Xunchi37-74 and Yunchi37-82 were treated, we studied root zone temperature on effects of growth and development, photosynthetic characteristics, physiological index, mineral nutrition, endogenous hormones and yield in the greenhouse. This experiment included seedling and adult plant. Seedling experiment were three treatments, it were optimum temperature, suboptimal temperature and low temperature. Adult plant experiments were height, medium and low temperature. We reached the following conclusions by the experiment:1. The seedling experiment result showed, with the root zone temperature decreased, it inhibited pepper seedling growth characteristics, at the same time,it decresed dry matter cumulant, first production, Pn, E, SPAD. Above-ground water content, root-shoot ratio, root activity, MDA, EC, SAR were showed increasing trend. Stomatal limitation was the main reason of lower photosynthetic rate. With the extension of treatment time. SOD,POD and CAT were rised first and fell later in the low temperature treatment. Pro and soluble suger were increased; N and P contents of above-ground; N, P and K cumulants of above-ground; P and K cumulants of under-ground were decreased. N content, P content and N cumulant of under-ground, K content were rised. On the whole, distribution ratio of mineral elements in the under-ground were increased, but in the above-ground were decreased.2. pepper plant adult experiment result showed, With the root zone temperature increased, growth characteristics were significant increased, root-shoot ratio was significant decreased, root activity was manifested as rises. First and second yield, total yield under the height and medium temperature treatment were higher than low temperature. Pn and E were significant rised, above-ground N, N, P, K contents of under-ground were decreased; above-ground P, K contents manifested as rises first and fall later. Above and under-ground N, P, K cumulants were increased; N, P, K distribution rate of under-ground were increased, above-ground distribution rate were decreased. MDA and EC contents were significantly decreased, SOD, POD, and CAT contents were significantly increased.3. There were a negative correlations among the root-shoot ratio, under-ground water content, plant diameter, root volume and soil accumulated temperature, there were positive correlations between the other growth indexes and soil accumulated temperature. There were a negative correlations among the N, P, K contents in the above, under-ground, there were a positive correlations among the soil accumulated temperture and N, P, K cumulants in adult experiment. Correlation coefficient range were 0.960-0.988.4. GA, IAA in the height temperature treatment was lower than low temperature. With the root zone temperature increased, ABA, ZR, ABA/IAA, ABA/GA manifested as fall first and rises later.