| In the research of tea plant drought-resistance much progress has been made in our country, while it's less compared with that of other economic plants. A few problems exist. For instance, many scholars have chosen several single indexes when studying changes of physiological and biochemical indexes in tea plant under drought stress. Seldom appeir systemic researches on physiological and biochemical indexes. Up to now, there are ID available indexes accepted to valuate the capability of drought-resistance of different tea cultivars. So it is not enough precise and scientific to estimate whether a tea cultivar is a high drought-resistance one or not.In this paper, the 2-year seedlings of 3 tea cultivars that are widespread cultivated hi oar country are chosen for the experimental materials: Fudingdabai tea, Meizhan and Mengshan 131. And they have undergone drought stress by being controlled the irrigating water capacity in the drought shed. With the drought stress going on, changes of soil water content, letf water content and activity of catelase(CAT), superoxide dismutase(SOD), peroxidase(POD), polyphenol oxidase(PPO) in NO.2 leaf and NO.3 leaf under the bud are measured respectively; and also the changes of relative electronic conductivity and content of proline(Pr , melondiadehyde(MDA), chlorophyll and soluble sugar in NO.2 leaf and NO.3 leaf under the bud are measured. Then the variance analysis, correlation analysis and fuzzy function analysis are carried out according to the data acquired. Experimental results obtained are as follows: 1. Under drought stress, the soil water content of 15 drought 15th drought day of 3experimental tea cultivars decrease 56.0%-63.2% compared with the check(CK) which irrigated every day. The average soil water content is 6.84% when the controlled drought stress is over. Compared with the CK, the average leaf water content decreases 16.0% in NO.2 leaf under the bud, while 17.6% in NO.3 leaf under the bud. Both the decreases are significantly different (p<0.05).2.The changes of activity of CAT have a trend of first increase and following decrease. The activity of CAT increases at the beginning of controlled drought stress, reaches maximum on 6th drought days; and then decreases gradually. And the activity of 15th drought days is lower than that of CK and the initial value. Both the activity of CAT in NO.2 leaf and NO.3 leaf under the bud are significantly different among 3 experimental tea cultivars (p<0.05).3. The trend of changes of SOD in tea plant under drought stress is similar with that of CAT. The activity of SOD increases very slowly in the first 6 drought days and rapidly reaches maximum till the 9th drought days, and then decreases. The values of the 15th drought days are larger than that of CK and the initial ones. The changes of activity of SOD either in NO.2 leaf or NO.3 leaf under the bud are significantly different among 3 experimental tea cultivars (p<0.05).4. The trend of changes of POD is also alike to that of CAT. With the drought stress going on, the activity of POD increases readily, reaches maximum on the 6* drought days, and then decreases gradually. The values of the 15th are still larger than those of CK and the initial drought days. The correlation coefficient between the activity of POD and the relative electronic conductivity is significantly different (p<0.05).5. The activity of PPO in 3 experimental tea cultivars under drought stress turns down step by step. And the changes of activity of PPO neither in NO.2 leaf or NO.3 leaf under the bud are significantly different among 3 experimental tea cultivars (p<0.05).6. The relative electronic conductivity in NO.2 leaf and NO.3 leaf under the bud are both increases gradually. The changes of it among 3 experimental tea cultivars are significantly different (p<0.05).7. The content of MDA in Meizhan during the drought stress increases most gently. Compared with CK, contents of MDA on the 3rd, 6th, 9th, 12th and 15th drought days increase respectively 15.0%, 40.5%, 78.2%, 112.2% an... |
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