| In the study, the methods of split-root apparatus, stable isotope tracer and drought simulated by polyethylene glycol (PEG-6000) were used to investigate the difference in hydraulic lift (HL) and drought-resistance of the three species seedlings of Caragana Fabr., including Caragana microphylla, Caragana intermedia and Caragana korshinskii.The main results are as follows:1. HL-activity was confirmed in C. intermedia and C. microphylla seedlings. But not confirmed in C. korshinskii seedlings, maybe because it's showed stronger drought-tolerance than the other species: had the highest bound water, the lowest free water and the biggest ratio of bound water to free water, lower water-loss ratio, strong capacity for water-conservation and anti-dehydration, the specific reasons need to determine by further researching.2. According to the analytical results of gray relating degree and subordinate function evaluation, drought-resistant adaptability of the three species seedlings of Caragana Fabr. were as follows: C. korshinskii > C. intermedia > C. microphylla, was similar with their natural habitats. The C. korshinskii seedlings showed stronger drought-tolerance than the other species, because it had a higher ratio of root to shoot, a slowly decreased Relative water content (RWC), a quickly increased natural water-saturated deficit (NWSD), a slower but higher accumulation of free proline content. The plant species maintained higher level of protective enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT); lower content of malondialdehyde (MDA) and lower degree of lipid peroxidation than the other two species seedlings after drought-stress treatment.3. Based on the analysis on relevance of drought-resistant adaptability to seedling growth and absorption of water by roots. This research suggests that in the same conditions, the HL of the three species seedlings of Caragana Fabr. had significant negative correlation with its drought-resistant adaptability. |
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