Study On Drought Resistance Of Picea Mongolica In Drought Desert Area

Picea Mongolia belong to the Pinaceae, Picea evergreen trees, was one of Chinese endemic species, cold resistant and drought tolerant, barren, and growth in the sand, was one of good tree species in protection forest construction and windbreak and sand-fixation in our country northwest arid desert, so it was ital significance to study ecological adaptability of Picea Mongolia. In this paper, eight years Picea Mongolia as experimental material in the drought desert Minqin desert control station, set different soil moisture gradient under natural conditions, through studying photosynthetic characteristics, fluorescence characteristics, biochemical index and the changes of chlorophyll under drought condition, in order to further clarify Picea Mongolia of drought resistance. The main results were summarized as follows:1 With the loss of the soil water content, Water content of leaves of picea mongolica and relative water content gradually decreased, The change of water saturation deficit showed a trend of rising. Water content of leaves was significantly different between different soil moisture content(p<0.05), the relative water content was not significant difference(p > 0.05).the correlation between leaf water content and soil water content was significant(R=0.864), The regression equation was Y=60.33X+50.56. The change of water saturation deficit showed a trend of rising. Leaf water content decrease with dehydration time, dehydration in the early fall, after the drop flattens out, the overall trend of spruce sand filtration process stage can be summarized as the downhill period and slow down period.2 With the degree of drought stress increasing, picea mongolica the net photosynthetic rate, stomatal conductance, intercellular co2 concentration and the transpiration rate decreases, when the soil moisture content is 17%, the largest net photosynthetic rate. stomatal conductance and intercellular co2 concentration fall at the same time, showed that picea mongolica leaves net photosynthetic rate of decline is mainly restricted by stomatal factors.3 Drought stress have a significant impact on Picea mongolia chlorophyllfluorescence parameters, the largest PSII photochemical efficiency(Fv/Fm), the actual photochemical efficiency(ΦPSⅡ), apparent photosynthetic electron transport rate(ETR) sensitive response to drought stress, can be used as a reference index for sand spruce drought-resistant ability evaluation.4 The chlorophyll a and chlorophyll b, total chlorophyll, with the dry degree increasing presents a trend of gradual decline; With the loss of the soil moisture content, soluble protein, soluble sugar content of Picea mongolia leaves significantly(p<0.05) increased, the effect of drought stress on leaves, proline content was significant(p<0.05), and present the trend of increased after decreased.5 In the process of drought stress, the malondialdehyde content of Picea mongolia leaves increased, soil water content was 11% maximum, increased 38.5% than the soil water content 19%.