| This experiment used the formula fertilization of Eucommia ulmoides seedlings test (14 treatments designed by N, P, K factors and 4 fertilizer levels), studied the changes in seedling height, diameter, chlorophyll, net photosynthetic rate, light response curve and other characteristics under different fertilization formula processings, determined the suitable fertilizer formula for Eucommia ulmoides growth.Eucommia ulmoides seedlings (JC009 JC119 JC144, JC159) were treated with four different concentration of NaCl (0,0.3%,0.6%,0.3%) to study their physiological responses to salt stress. Seedling growth condition was observed every 10 days, using the determination of relative conductivity(REC), the content of chlorophyll(Chl) and carotenoid content(Car), superoxide dismutase (SOD) activity and proline (Pro) content as indicators. The results could be used to explore the difference of salt resistance in 4 kinds of Eucommia ulmoides seedlings, and to select the varieties that had the most salt resistance. The main results were as follows:(1) All the different fertilizing treatments of Nitrogen, phosphorus, potassium had significant effects on the indexes of Eucommia ulmoides. In all the 14 treatments, the treatment 7 (N2P3K2:N 3.6g, P2O5 4.5g, K2O 2.4g) has the best effect, the treatment 6 (N2P2K2:N3.6g, P2O53g, K2O 2.4g) and the treatment 9(N2P2K1:N3.6g, P2O53g, K2O 1.2g) were the better, the treatment 2 (N0P2K2:N Og, P2O53g, K2O 2.4g),4 (N2P0K2:N 3.6g, P2O5 Og, K2O 2.4g),8 (N2P2K0:N 3.6g, P2O53g, K2O Og) and 11 (N3P2K2:N 6g, P2O53g,K2O 2.4g) were the poorest.(2) Nitrogen, phosphorus, potassium sort of effect on plant height was N> P> K; sort of effect on diameter was P> K> N; sort of effect on biomass was P> N> K; sort of effect on the root-shoot ratio was N> K> P; sort of effect on chlorophyll was P> K>N; sort of effect on carotenoids was P> K> N; sort of effect on the net photosynthetic rate was N> P> K; sort of effect on light response curve was N> P> K.(3) Leaf salt injury index is the most visibly performance of Eucommia ulmoides salt injury. Eucommia leaf salt injury showed response rate and the symptom that related to resistance under stress concentration and duration.(4) Chlorophyll is one of the important physiological index of plant salt resistance. The change of chlorophyll content showed four varieties of Eucommia ulmoides was slightly increased at the early stage of salt stress, while later significantly decreased in the middle and high salt stress concentrations.(5) The physiological and biochemical process of Eucommia ulmoides had common characteristics under salt stress.Membrane permeability, SOD activity and proline content increased with the increase of the concentration of NaCl and processing time.The increasing trend was not obvious under low salinity stress, while rose rapidly under medium and high salinity stress. Then the trend began to decline after rising to a certain degree.(6) To correlation analysis of the indicators of Eucommia ulmoides, there was a positive correlation between the salt injury index and the relative conductivity, SOD activity, a negative correlation between the salt injury index and chlorophyll content, carotenoid content, Pro content; there was a positive correlation between relative electrical conductivity and SOD activity, Pro content, a negative correlation between relative electrical conductivity and chlorophyll content, carotenoid content; there was a positive correlation between chlorophyll content and carotenoid content, Pro content,a negative correlation between chlorophyll content and SOD activity; there was a positive correlation between carotenoid content and SOD activity, there was a negative correlation between carotenoid content and Pro content; there was a positive correlation between SOD activity and Pro content.The relationship between each index closely, are adversely affected by salt stress.(7) The salt resistance of 4 kinds of Eucommia ulmoides were comprehensive evaluated with the method of subordinate function. The order was:JC009>JC159>JC144 >JC119. |
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