Morphological And Physiological Responses Of Sugarbeet Seedlings Under Salt Stress

Sugar beet is one of the main sugar crops in China,mainly distributed in Northeast,Northwest,North China and other arid-semi-arid areas,these areas are relatively lack of precipitation,soil organic matter is poor.At present,with the global climate change,soil salinization has become more and more serious,which has brought serious impact on sugar beet production.It is of great significance to study the effect of salt stress on the growth and development of sugar beet and the physiological mechanism of sugar beet under salt stress.In this experiment,beet T510 with strong salt tolerance and 210 with weak salt tolerance were used as the research materials,and beet was cultivated by indoor hydroponics.To study the changes of external morphology,internal microstructure and physiological indexes of sugar beet seedlings under salt stress.The research results showed that:1.The effect of salt stress on the morphology of beet seedlings was more obvious.Compared with 210,T510 strain had stronger adaptability in morphology,root length,epi-cotyl diameter,leaf area and root area showed a decreasing trend under salt stress.2.The effect of salt stress on the internal microstructure of sugar beet seedlings was obvious.The diameter of xylem and phloem of leaf,petiole and root of beet seedlings increased significantly after salt stress,and the increase of T510 strain was more obvious than that of 210 beet seedlings.The volume of parenchyma cells in petiole of two strains of beet seedlings increased after salt stress,the root epidermal cell wall was obviously thickened after salt stress,and a large number of aerenchyma tissue appeared in parenchyma tissue.Compared with the 210 strain,T510 strain had thicker cell wall,more xylem vessels and larger parenchyma cell space.The stomata of the leaves were almost all closed,and the degree of opening was small if there were a few.3.Under salt stress,the chlorophyll content,net photosynthetic rate,transpiration rate,stomatal conductance and intercellular carbon dioxide concentration of sugar beet of T510 and 210 were decreased.The photosynthetic parameters of T510 were relatively higher than that of 210,and T510 had strong photosynthetic mechanism regulation ability.4.Under salt stress,the contents of soluble protein and soluble sugar in the leaves of the two strains of sugar beet showed an obvious trend of increase,and T510 strain was higher than 210 strain,which indicated that T510 strain had higher ability in osmotic regulation than 210 strain.5.Under salt stress,the two strains sugarbeet antioxidant enzyme system of SOD,POD,APX and CAT enzyme activity also tend to rise,the blade APX enzyme activity increased,the most obvious and T510 strains of four kinds of activity of antioxidant enzymes were higher than 210 strains,explain T510 strains of antioxidant capacity is better than 210 strains,can significantly reduce oxygen anion.6.The electrical conductivity and leaf malondialdehyde of the two strains showed an increasing trend under salt stress,and the electrical conductivity increased greatly,indicating that salt stress had a greater effect on the cell membrane system.