Physiological Characteristics Under Salt Stress Of Oat And Its Regulation Through Agronomic Measures

Saline soil biological utilization is the effective measure to enhance the utilization of land and improve ecological environment. Oat has extensive adaptabilities in arid and semiarid region of high vulnerable ecological environment, and it is the characteristic and green health care crop of Inner Mongolia and can reclaime saline soils. The study through the methods of indoor culture dish germination method, potted in canopy, combined with the natural saline field test method, analyzed on differences of oat seed salt tolerance and studied the physiological and biochemical characteristics of salt-tolerant on oat seedlings, such as oats growth and physiological differences under salt stress of different varieties, nutritional factors, cultivation and tillage measures affected soil salt changes and oats adaptabilities. The main details of the result were as follows:1. Seed germination and seedling growth of oat were inhibitted significantly by salt stress, and compared with oat seedling growth the inhibitory effect was much significant than seed germination, compared with root the inhibitory effect was much significant than seedling. Salt concentration 0.4% had significant synergistic effect on oat seed germination and seedling growth, and salt concentration 2.0% was the critical salt concentration of oat seedling growth, and salt concentration 3.2% was the critical salt concentration of oat seed germination. Salt concentration 1.2% can be used as the optimal salt concentration to identify the oat's salt tolerance ability, and the main indexes were relative germination rate, germination index, relative simple activity index and total dry weight. The thirty-six varieties of oats can be divided into salt-tolerant, moderate salt-tolerant and non-tolerant types, and the salt-soluble protein andα-amylase activity of three types'seed were different significantly.2.Different varieties of oat growth and physiological characteristics were great difference under salt stress. With the strengthen of salt stress different varieties morphology inhibitory increased, total chlorophyll content decreased; leaves'plasma membrane, malondialdehyde content, praline content, soluble sugar content and Na+ content in stem increased, and K+/Na+ decreased. Moderate salt-tolerant variety can endure salt concentration 0.32%, and all varieties can not endure salt concentration 0.68%. Salt tolerance of Avena sativa and naked oat were not significant.3. Oat growth and physiological characteristics can be affected seriously under salt stress, even salt concentration 0.2% can enhance oat growth. Oat growth can endure salt concentration 0.3%, germination lethal salt concentration was 1.0%, grain yield limit salt concentration was 0.7%; With the strengthen of salt stress, oat leaf chlorophyll content decreased and photosynthetic rate decreased for non stomata factors; Oat seedling leaves'plasma membrane, per oxidation products, osmotic adjustment substances, and protective enzyme activities increased under salt stress. The Orders of protective effects on osmotic adjustment substances were praline >soluble sugar>soluble protein, and the orders of protective enzyme activities were CAT>POD>SOD; Ion absorption and transportation were choosed selectively by oat root, transportation of K+ and Na+ was significantly higher than absorption of K+ and Na+. In order to adapt to salt stress more Na+ was storied in the stems of oats; The main physiological and biochemical indexes which can response the oat seedlings'salt-tolerant traits were as follows, such as relative conductivity, malondialdehyde content, soluble sugar content, praline, CAT activity, chlorophyll content, Na+ content, Cl- content and K+ content, K+/ Na+ value, leaf area, photosynthetic rate and yield.4.Through the study of oat growth, plasma membrane, K+ content and Na+ content, it can be concluded that different regulatory effects of nutritional factors nitrogen, phosphorus and calcium can improve the growth of oat and decrease injure of plasma membrane with salt stress, different degrees increased K+ content and K+/Na+ ratio and yield and decreased Na+ content. The most ability optimal nutrition regulation of oat was the fifth treatment which is high nitrogen (2.00 g/pot) low phosphorus (0.65 g/pot) calcium (10 g/pot). In these treatments, oat had a relatively high tolerance to salt stress, and ratio K+/Na+ and yield were highest.5.Those measures plowing, suitable sowing depth, oat and other crops mixed cropping, cover cultivation can effectively improve the ability to adapt to saline soil and can fall desalination role. Through the analysis of morphological index, physiological indexes, K+/ Na+ value and the selective absorption and transportation, production quality, different treatments showed that mixed cropping>sole cropping, conventional tillage > no-tillage, cover> not covered. Oats and alfalfa mixed cropping was the better planting pattern in saline soil, its dry matter accumulated rapidly, membrane damage was low, leaf chlorophyll content was high, and kept the rapid photosynthetic performance and yield formation was high, next was conventional tillage 7cm, no-tillage 7cm was equal to the conventional tillage 3cm. Conventional tillage 9cm and 11cm emergence rate were less than 15.0%, they were not the suitable patens to plant on the saline soil, cover 5～7㎝ was better. The order of salt stress decreased the quality yield indexes were: hay yield > grain yield >grass yield > coarse fat >crude fiber. The quality yield of Moderate salt-tolerant variety Nei Nong Da You 1 was higher than non-tolerant variety Avena magna. Salt-tolerant variety, oat and alfalfa mixed cropping, conventional tillage 7 cm and cover measures can effectively improve the ability to adapt to saline soil and decrease salinity of cultivated horizon.The research supplied important theoretical basic in saline soil resource utilization, oat salt-tolerant cultivation and salt resistance breeding.