Mitigative Effect Of Exogenous Substances On Maize Budseedling Under Salt Stress

This study takes108maize inbred lines of Heilongjiang province as materials and screens4different salt tolerance inbred varieties based on salt tolerance test in the bud seedling to analyze their morphology and physiological and biochemical indexes. At the same time, under salt stress, appropriate amount of exogenous substance salicylic acid, CaCl2, platycodon root polysaccharide is supplied on leaf surface to explore the effect of relief material on their growth under salt stress. The results are as follows:1、By analyzing the salt damage extent of all indexes of108maize inbred lines salt damage effect under stress fluid, we can get the result:when the salt stress Na2CO3solution is15mmol/L, the index has significant effects on the difference of maize inbred lines; when sorting on saline alkali tolerance of108varieties, we choose salt tolerant DL, A71and not salt tolerant South26, agricultural M1to conduct alleviation effects of salt stress and exogenous substance.2、Under different concentrations stress of Na2CO3, plant height, stem diameter, main root length, root diameter, length of leaves, leaf width, dry weight, fresh weight, water content and other morphological indicators of4maize inbred lines bud seedling are affected at various degrees. With the increase of salt concentration, salt damage degree of inbred lines increase; index variation of salt tolerant varieties is smaller than that of salt sensitive varieties and with a lesser degree of damage. Saline alkali resistant varieties have less damage extent than salt sensitive cultivars.3、Two salt tolerant maize inbred lines DL, A71and two non salt tolerant maize inbred line south26, agricultural irrigation M1are irrigated by concentration of15mmol/L of Na2CO3. When the seedling growth is15d, salicylic acid, CaCl2, platycodon root polysaccharide solution are supplied on leaf surface to measure physiological and biochemical indexes, such as results chlorophyll content, proline content, MDA content, soluble protein content, peroxidase activity. The result is:three different concentration of salicylic acid play the role of mitigation on different maize inbred lines, the optimal concentration of salicylic acid is60mg/L; CaCl2solution also make some physiological biochemical indexes eased, and has significant difference compared to salt stress group, the best concentration of CaCl215mmol/L; while with platycodon root polysaccharide solution treatment, physiological and biochemical indexes of all varieties have not significant difference compared to salt stress group which demonstrates that alleviation of platycodon root polysaccharide is less than salicylic acid and CaCl2on maize inbred lines.4、By observing the ultrastructure of chloroplast and leaf epidermal morphology of4maize inbred lines under salt stress and exogenous substance remission through electron microscope and scanning electron microscope, we can get that the chloroplast structure integrity of various varieties of material of maize inbred lines sprayed by alleviator is better than salt stress group, similar with the control group, while under scanning electron microscope the stomatal length of various varieties of material of maize inbred lines sprayed by alleviator alleviate various varieties is longer than that of salt stress group and smaller stomatic density which shows that alleviator plays a protective role for maize seedlings under salt stress In general, CaCl2and salicylic acid have significant soothing effect for maize inbred lines and platycodon root polysaccharide is relatively weaker.