| In the green house, pot experiments were conducted to study the responses of Aloe vera growth to different concentration of NaCl(100 mmol ·L~-1, 200 mmol ·L~-1 and 400 mmol ·L~-1 ), and the effects of nitrogen level on growth and physiological characteristics of Aloe vera under 200 mmol ·L~-1 NaCl and sea salt of 8.3 g·L~-1 and 16.7 g·L~-1 stress.The results showed that:The dry weight and leaf chlorophyll content of Aloe vera appeared no difference between treatments of 100 mmol ·L~-1 NaCl stress and control(no NaCl stress), while both of them declined notably with increasing concentration of NaCl(200,400 mmol ·L~-1 NaCl).The root vigor of Aloe vera grown under 200 mmol ·L~-1 NaCl stress was higher than that of under other concentrations of NaCl stress and control; Leaf electrolytic leakage (EL) of Aloe vera under NaCl stress was higher than that of control, while increased with increasing concentration of NaCl. Under NaCl stress, K+, Na+ and Cl" contents increased with increasing concentration of NaCl, while opposite change in Ca2+content of Aloe vera was observed compared with other content of ions measured in the experiment. Na+ was mainly accumulated in the stem and roots. Na+ content was lower in the leaves compared with other parts of the plant; Cl" was mainly accumulated in the leaves and the content in the stem was higher than the roots. NaCl tolerance of Aloe vera might due to the lower value of Na+/K+ in leaves, and the stronger ability that K+ and Ca2+ was preferably transported to the shoots as compared with Na+.It had also showed that the application of NH4NO3 (3.75-18.75 mmol ·L~-1) increased the dry weight and root vigor of Aloe vera which was grown under NaCl stress, thus improved the NaCl tolerance of Aloe vera seedlings. Content of nitrogen, phosphorus, free amino acids,chlorophyll,soluble protein and total anthraquinone in leaves were increased obviously with increasing nitrogen level, and all of them was higher when the concentration of NH4NO3 was supplied as 11.25-15 mmol ·L~-1, while the excessive NH4NO3 application (18.75 mmol ·L~-1) led to the negative effect. It appeared distinct difference existed amongdifferent-site leaves for the content of nutritional ingredients. Content of total P, anthraquinone and soluble protein in the upper leaves were higher compared with that of the other leaves, similar situation for total N in down-site leaves was observed as well.In the different-site leaf of Aloe vera, K+, Ca2+ content were all improved by the application of nitrogen, whereas the content of Na+, Cl" were restrained in some extent at the same time. K+/Na+ and Ca2+/Na+ were enhanced by the application of nitrogen under NaCl stress; Distribution of K+, Ca2+ content were affected by nitrogen level: the lowest content of Na+ was observed in down-site leaves, while the accumulation of Cl" in up-site leaves was higher than that of in other-site leaves; There was a distinct positive correlation existed both between Na+ content and electric leakage, and the content of Na+ and MDA, while a negative correlation existed both between Ca2+ content and EL, and the content of Ca2+ and MDA; It also showed that a positive correlation existed between Cl" content and electric leakage, while no correlation existed between the content of Cl" and MDA.The content of proline and soluble sugar in leaves of Aloe vera were increased under NaCl stress when nitrogen was supplied, and the increment on proline and soluble sugar content were much more higher when optimal concentration of nitrogen was supplied; Proline content was higher in up-site leaves compared with other-site leaves, and the highest content of soluble sugar was observed in the middle-site leaves.Leaf water content of either sea salt of 8.3 g·L~-1 ( S1) or 16.7 g·L~-1 ( S2) treated Aloe vera were lower in contrasted with that of control(non sea salt treatment), and no difference existed in root water content between sea salt treated Aloe vera and non sea salt treated Aloe vera, In some extent, water content and root/shoot of Aloe vera were impro...
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