Studies On The Drought Resistance Of Three Prunus Armeniaca Cultivars

The physiological mechanism of drought-resistance in four-year Prunus armeniaca cultivars was studied, with cultivar'Katy', cultivar'Hongfeng'and'Lanzhou'as materials and under field controlling soil water environments, some mainly Biological Indices were measured in different drought stress of three cultivars, this paper mainly measure some water indexes and biochemical indexes of three cultivars in different soil water, We expected to discover difference of drought-resistance mechanism and to comprehensive evalue the droughte resistance of three cultivars. The main results are as follows:The tissue water content ,relative water content and the rate of bound water content to free water in leaves of'Katy'was obviously higher than'Lanzhou', and'Lanzhou'higher than'Hongfeng'. The water saturation deficiency of'Katy'was obviously lower than'Lanzhou', and'Lanzhou'lower than'Hongfeng'. With the drought-resistance of 30th day, transpiration rate of'Katy'is lower than'Lanzhou', and'Lanzhou'lower than'Hongfeng'. The photosynthetic rate and water use efficiency of'Katy'was obviously higher than'Lanzhou', and'Lanzhou'higher than'Hongfeng'. The results of this research showed that the peak of net photosynthesis rate of'Katy'comes earlier than'Lanzhou'in the morning, they all decreased at noon, showing the presence of midday depression of photosynthesis. The peak of net photosynthesis rate of Hongfeng comes earlier than'Katy'and'Lanzhou'in the morning,but have no obviously midday depression of photosynthesis. By analyzing results and comprehensive appraisal of all indices, the ability of drought tolerance was arranged from strong to weak as following:'Katy','Lanzhou'and'Hongfeng'.'Katy'with high photosynthetic rate and high water use efficiency, but transpiration rate is lower.During the stressed period, the activity of SOD and CAT increased firstly, reached the climax on the 20th day after stressed, then decreased. The activity of SOD and CAT of'Katy'were higher than that of'Lanzhou'and'Hongfeng'., and'Lanzhou'higher than'Hongfeng'. With the activity to SOD and CAT in leaves of'Katy'was obviously higher than'Lanzho'u, and'Lanzhou'higher than 'Hongfeng'.The proline content was increased in stressed course, reached the climax on the 40th day. The increasing rate of proline of'Katy'was higher than that of'Lanzhou', and'Lanzhou'higher than of'Hongfeng'. The content of MDA with'Lanzhou'and'Katy'increased firstly, reached the climax, then decreased.The content of MDA with Hongfeng. enhanced with the deeper of stressed. With content of MDA of'Katy'was obviously higher than'Lanzhou', and'Lanzhou'higher than'Hongfeng', the degree of velum damage of'Hongfeng'was deeper than'Lanzhou'and'Katy'in prophase of stressed.'Katy'is lower then'Lanzhou'. The content of of three spaces increased firstly, reached the climax, then decreased. The content of superoxide anion radical (O2-·) of'Katy'was obviously higher than'Lanzhou', and'Lanzhou'higher than'Hongfeng'.It is considered that the mechanism of drought resistance of three cultivars is similar, and they all having strong drought resistance ability, by analyzing results of main component analysis and comprehensive appraisal of all indices. By comprehensived appraisal of all indices, the results show that the ability of drought resistance of three cultivars is:'Katy'>'Lanzhou'>'Hongfeng'.