|
Locust (Robinia persudoscacia) is important afforestation tree species in north China, is widely used in soil and water conservation, windbreak and sand, soil improvement, and \Western Shelterbelt in the windy, arid, cold regions Mizobe, flood, Sand Valley Strip vigorously to create Robinia pseudoacacia, often due to excessive water loss, resulting in water metabolism imbalance, causing the tip dry. In order to play the role of soil and water conservation locust, Green arid land, this article by potted simulation experiments on the growth of locust under drought conditions, physiological system, and made some valuable conclusions. The potted plant drought resistance for trial locust clones (Anhui, Lu a, Lu-78, Lu 59), mainly under drought locust clones net photosynthetic rate (Pn), transpiration rate (Tr), diurnal variation of water use efficiency (WUE) as well as changes in chlorophyll content, Pn diurnal variation of \The sub>, and 59Pn were decreased slowly drought for 20 days decreased Pn. Water supply good condition L 78 and W 1 time of maximum transpiration rate and photosynthetic lunch break, 59 and L 1 Tr variations do not large. 10 days of drought overall Tr decline, but the fluctuation is relatively large, arid 20 days locust seedlings the Tr continue to reduce the maximum value is less than 3mmolm -2 s -1 . Good case of the water supply, L 78 and 59 relatively high WUE drought of 10 days and 20 days L 1 relatively high WUE drought 10 days and 20 days WUE was significantly higher, a range of drought can increase the WUE. L 1 the Drought 20 days WUE than 10 days decreased slightly. Locust clones chlorophyll content first and then decreased with the drought intensified drought 10 days chlorophyll chlorophyll decomposition caused by drought stress are sensitive to drought, severe drought leaf water loss per unit mass of elevated chlorophyll content. Anhui and a and Lu a pot experiment under drought conditions increased nitrogen fertilizer phosphate fertilizer after photosynthetic fluorescence parameters, tests showed that the photosynthetic characteristics, LSP, LCP significant factors affecting mainly water and nitrogen and phosphorus interaction Nitrogen phosphate fertilizer improve the the locust leaves LSP. L 1 LSP is higher than W 1 . Water stress inhibited height growth, nitrogen supply to mitigate this inhibition. Phosphorus impact on height growth was not significant. The Water Stress reducing the Fo, Fv did not change significantly. Water stress reduced Fv / Fm. Additions of fertilizer can slow Fo, Fv, Fv / Fm reduce to some extent, which is fertilization can slow down the destruction of water stress on PS II reaction center. 3 different moisture gradient under Robinia pseudoacacia clones Adding Nitrogen, Phosphorus on locust clones photosynthetic characteristics and chlorophyll fluorescence parameters, growth, and plant nutrient elements. Of Pn by water stress significantly, different water stress Pn turn: mild drought gt; moderate drought gt; severe drought, nitrogen rate significantly affect Pn right amount of nitrogen fertilizer can improve Pn. Moderate and severe water stress under the locust leaf WUE is higher than that under mild water stress, drought stress can increase the appropriate plant WUE. Nitrogen fertilization can increase the moisture content of the locust roots, stems and leaves under moderate water stress, severe water stress, this improvement is not obvious. Nitrogen and Water a significant impact on the increase of the height and diameter. Proline content increased with the prolonged drought time significantly increasing N also increased proline content. Mild water stress, low leaf water potential, with the stress aggravated higher leaf water potential, Adding nitrogen fertilizer to some extent, improve the leaf water potential. Appropriate water stress are conducive to root nitrogen accumulation the different moisture gradient root nitrogen content as follows: moderate drought gt; the severe drought gt; mild drought. Nitrogen fertilization promote to stem calcium accumulation, leaf calcium content with the nitrogen rate increases.
|