The Buffer Effect Of Silicon On Zizyphus Jujuba Cv.Jinsi-xiaozao Under Salt Stress

Salinity is agricultural and eco-environmental problem worldwide, and is becoming one of the most serious factors limiting the productivity of agricultural crops and agricultural. So, salty evil is considered a serious barrier to hindrance economical development and ecological equilibrium of the whole world including china. Silicon is generally considered as a beneficial element for the growth of higher plants. Many previous studies have reported the roles of silicon in alleviating both abiotic and biotic stresses in plants. Therefore, the investigation on the mechanisms of alleviating salt toxicity by silicon has been received more attention recently. In this paper, Zizyphus jujuba cv.Jinsi-xiaozao was used as a material in the study. Salt stress was created by adding NaCl .The possible function of exogenous silicon in salt stress was investigated by measuring and analyzing photosynthesis, chlorophyll fluorescence, content of chlorophyll, content of praline and soluble sugars, lipid peroxidation, activity of POD and CAT, and the variation of protein. The objective was to clarify the possible physiological and biochemical mechanisms of silicon on alleviating salt stress in. The main results are summarized as follows:Under salt stress, the Zizyphus jujuba cv.Jinsi-xiaozao grown very weak, the biomass reduced. When executes exogenous silicon into soil, the new breach grows long, the increase of diameter was enhanced, the degree of bearing branch lignifications made enhancement, and the accumulation of biomass was increased. So, in certain degree the exogenous silicon can promotion growth and increase resistance of Zizyphus jujuba cv.Jinsi-xiaozao.The results showed that salt stress significantly decreased plant photosynthesis performance. Photosynthetic pigment content, photosynthetic rate (Pn), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) of Zizyphus jujuba cv.Jinsi-xiaozao leaf were decreased, and midday depression of photosynthesis was delayed by applied exogenous silicon. The fluorescence chlorophyll measurement showed that the effect of silicon promotion the photochemistry reaction of Photoreaction System II and increase the most photochemistry reaction efficiency. When the content of NaCl is lowing 3g/kg, the effect of exogenous silicon can increase the electron transport rate. Some impacts are direct or indirect and perspective with others, generally exogenous silicon can maintain photosynthetic Efficiency in Leaves in a high level for Zizyphus jujuba cv.Jinsi-xiaozao.Through the analysis about the content of osmotic adjustable organic substances in salt stress accumulation of free proline and soluble Sugar presents a trend of escalation. In the degree, silicon can improve the content of free praline and Reduces the content of. The soluble protein content decreased showed that the Inhibition effect of soluble sugar on photosynthesis and availability of sugar was improved.The results showed that the activities of catalase(CAT) and peroxidase (POD) reduced gradually, the content of malondialdehyde (MDA) and relative permeability (RP) of plasma membrane decreased slowly with the arbuscular mycorrhizal fungi (AMF) mycorrhizal infection rate increased. In salt stress, applying silicon can reduces the content of malondialdehyde (MDA) and relative permeability (RP) of plasma membrane in certain degree. Consequently the applying silicon alleviated the inhibition of Zizyphus jujuba cv.Jinsi-xiaozao growth under salt stress. Applying silicon can increase the activities of CAT and POD under salt stress, and improve function of enzymatic reaction system.In salt stress, the content of soluble proteins increases in leaf of Zizyphus jujuba cv.Jinsi-xiaozao, especially the content of protein that molecular weight is 40.1kD and 77.0kD was improved significantly. Effect of applying silicon on expression of proteins is significantly, the content of proteins and protein composition is different.