Study On Drought Resistance Of Four Plants In The Qilian Mountain Nature Reserve To Tianzhu

Using four species (Bupleurum scorzonerifolium Willd. , Gentiana straminea Maxim.,Adenophora paniculata Nannf.and Tussilago farfara Linn.) Qilian Mountain Nature Reserve at Tianzhu as experiment materials and under man-made simulated drought conditions, this paper mainly measured some water indexes and biochemical indexes under 20% PEG.. We expected to discover difference of drought-resistance mechanism and to comprehensive evalue the drought resistance of four species. The results were:1. Leaf water content and relative water content was gradually decreased with the continuation of water stress time. During the water stress, leaf water content and relative water content of B.scorzonerifolium Willd. and Gentiana straminea Maxim. were higher than Adenophora paniculata Nannf. and Tussilago farfara Linn.. The changes of leaf water content and relative water content in Adenophora paniculata Nannf. and Tussilago farfara Linn. were also higher than in B.scorzonerifolium Willd. and Gentiana straminea Maxim.. But water saturation deficiencies of four species had a trend of increase with the continuation of water stress time.2. Water stress made water potential in four species decreasing, but the changes of water potential in different species were different. The increasing in B. scorzonerifolium Willd. were higher than in Gentiana straminea Maxim.,Adenophora paniculata Nannf. and Tussilago farfara Linn.. The trend of water losing rate in 24 hours showed that Tussilago farfara Linn.> B. scorzonerifolium Willd.> Gentiana straminea Maxim.> Adenophora paniculata Nannf..3. The performance on protective enzyme activity and cell membrane structure were various in different of water stress time. Activity of SOD of four species was ascended slowly; with the strength of water stress time the activity of SOD ascended sharply. When the water stress time continuation more the activity of SOD was descended. The changes of activity of POD in four species were increased firstly. The increase of activity POD in Gentiana straminea Maxim. was the largest. The electrolyte leakages of four species were increasing with the inchance of water stress, Tussilago farfara Linn. and B. scorzonerifolium Willd. were higher harmed to membrane system than others. 4. Proline content and soluble sugar content of four species were increased with the continuation of water stress time, B. scorzonerifolium Willd. and Gentiana straminea Maxim. were higher than Adenophora paniculata Nannf. and Tussilago farfara Linn..5. The results showed that the ability of drought resistance of four species were: B. scorzonerifolium Willd.> Gentiana straminea Maxim. > Adenophora paniculata Nannf.> Tussilago farfara Linn..