The Analysis And Appraising On The Drought Resistance Of Nine Tree Species

This paper studied systematically on the drought-resistance of different tree species from morphological characteristics, anatomical structure of leaves, water holding ability, and the membrane super oxidation, protection enzyme system anti-oxidation capability, and photosynthesis character under water stress. The intrinsic relationship of drought-resistance indexes was analyzed by factor analysis. The drought-resistance ability of these nine tree species was evaluated comprehensively by clustering analysis method and statistics of subordinate function. The main result were as follow: 1. Using morphological characteristics, root-shoot ratio, anatomical structure of leaves, leaf water holding and WSD analyzed the water holding ability of 11 tree species. The result showed that Laburnum alpinum, Caragana Korshinkii , Poncirus trifoliata , Elaeagnusangustifolia , Sophora japonica had stranger water holding ability; Amorpha fruticosa, Robinia pseudoacacia L., Toona sinensis, Eucommia ulmoides , were in the middle level and P.thunbergiana, Albizziajulibrissin had a poor ability. 2. The response of the electrolyte leakage, the activation of SOD and POD,and the content of MDA and Pro etc., in 11 tree species to water stress at rhizosphere was investigated with one-year-old seedlings. With water stress degree aggravating, the varieties of different tree species are in the same trend: the activation of SOD raised first then decreased, the activation of POD decreased slowly, and the content of MDA raised gradually, the electrolyte leakage increased gradually, and the content of Pro raised gradually. 3. The response of main photosynthesis and transpiration indexes of nine tree species to water stress at rhizosphere were investigated with one-year-old seedlings. The physiological indexes were significantly affected by water stress. Each species was showed different photosynthesis and transpiration response to water stress .The response index of different species represented its resistant capability to water stress .The index analysis of 9 tree species by comparison and statistics of subordinate function showed that Laburnum alpinum, Amorpha fruticosa, Toona sinensis, Chaenomelesspeciosa had stranger drought-resistance; Elaeagnusangustifolia, Eucommia ulmoides, Caragana Korshinkii, Sophora japonica were in the middle level and P.thunbergiana, Albizziajulibrissin had a poor resistance. 4. The study was to determine inherent rules of physiological and biochemical indexes by factor analysis. The ten indexes could be divided into four common factors. F1 reacted dominantly on POD, MDA, electrolyte leakage, WSD, and Tr, which reflected the drought-resistance ability; drought-tolerance ability F2 reacted primarily on SOD and Pro, which reflected the drought-tolerance ability. In F3, only Gs had bigger load, which indicated that the relationship between Gs and the other parameters was small. F4 reacted primarily on Pn and WUE, which reflected the productivity during drought stress. 5. The nine tree species was divided into four groups by clustering analysis method: Toona sinensis, Eucommia ulmoide, Sophora japonica, and Laburnum alpinum are in group one; Albizziajulibrissin, and P.thunbergiana are in group two; Elaeagnusangustifolia, and Amorpha fruticosa are in group three; Caragana Korshinkii was in group four only. The drought resistance ability of nine tree species was evaluated comprehensively. The main results were as follow: Laburnum alpinum, Caragana Korshinki, and Elaeagnusangustifolia had stronger drought-resistance ability; Toona sinensis, Sophora japonica, Amorpha fruticosa, Eucommia ulmoides, were in the middle level; and P.thunbergiana, Albizziajulibrissin had a poor resistance.