The Mechanisms Of Response Under Salt-Alkali Stress About Sorghum

Alkali Stress is one of the adverse abiotic environmental factors in the growth process of plants are often subjected,Crop production decreased caused by salinity stress is an issue in agricultural production often encountered.Sorghum is one of the world’s top five crops.plays a vital role in our national economy. Researching differences of Sorghum about the salt tolerance, distinguish the difference of Sorghum for different types of saline-alkali soil stress response mechanisms,screening different types sorghum varieties suit different soil is the most urgent current problems to be solved.This experiment carried out in 2012-2014 in College of Agriculture laboratory,Agricultural University of Hebei.Research eight varieties of sorghum of Hebei widely planted by the climate chamber and the soil of different proportions saline.Researching the circumstances about germination and plant growth under analog salt stress and alkali stress by two neutral salt Na Cl,Na2SO4 and two alkaline salts Na2CO3,Na HCO3 molar ratio of 1: 1.Researching the salt-alkali tolerance in the whole growth period of Sorghum with different proportions of mixed alkali soil. Major conclusions as follows:1.The circumstances of seed germination and seedling growth negative correlation with the level of salt-alkali stress.The suppression of different varieties is difference under one level.In the lower salt stress(40mmol/L), all varieties of sorghum germination rate substantially unaffected individual species and even have an increasing trend.In the high salt stress(160mmol/L) treatment, the seeds still have a part of germination, but individual species germination potential is reduced to zero.When the alkali stress greater than 40mmol/L,all the index lower than under same salt stress treatment.When the alkali stress greater than 120mmol/L, although the sorghum seed germination, but its vitality index declined more than the decline at the same concentration of salt stress. 160mmol/L of salt solution, 120mmol/L of alkali solution can be used as sorghum salt, alkaline identification concentration.2.By principal component analysis respectively sorghum germination salt and alkali resistance evaluation, The 10 identified indicators classified as two principal component under salt stress and three principal component under alkali stress.Principal component analysis, in the salt stress, root and leaf fresh weight, germination potential for maximum load index can be used as the main indicator of salt tolerance of sorghum germination in alkaline stress root dry weight, germination potential, leaf fresh weight, dry weight of the biggest indicators of load can be used as the main indicator of sorghum germination alkali resistance identification. According to principal component analysis, the experiment eight sorghum varieties for salt tolerance sort Gaoliangzhe>Kang 4>623A/Gaoliangzhe>Nongdahong1>Qiansan>TX623B>Nongdabai 1>Henong16;alkali resistance of the order of Gaoliangzhe>Kang4>Nongdahong1>623A/Gaoliangzhe> TX623B>Qiansan>Nongdabai 1>Henong16.3. Under salt stress, sorghum RGR decreased with increasing salt concentration. In 40mmol/L stress concentration,Na+ content changed slightly in all parts of Sorghum, Na+ content in the root was significantly higher compared in the leaves. Under salt stress, Na+ content in root decrease on the tolerant varieties Gaoliangzhehe higher than the salt-sensitive species Henong16, but leaf Na+ content was significantly lower than the Henong16, indicating that the salt tolerant varieties Gaoliangzhehe has a higher regulation than the sensitive cultivar Henong16 when the environment sodium change. The effect of K+ absorbing in the leave under salt stress is also larger than the blade root, salt-sensitive varieties Henong16 root K+ declined more than tolerant varieties Gaoliangzhehe, in all treatment levels, K+ content of sorghum cane roots greater than Henong16. The same concentration of alkaline stress on sorghum especially for root were significantly greater than the salt stress, accompanied by increased root RGR alkali stress intensity are maintained at a low level, Na+ and K+ increase in the magnitude of the decline when more than salt stress. Especially for salt-sensitive varieties Henong16, the K+ content decrease more rapid. This experiment proved the alkali stress is an important environmental stress factor limiting the growth of sorghum.4.The photosynthetic indicators of Sorghum in the all growth period changes over time change, photosynthetic rate, SPAD reached the maximum at heading date, stomatal conductance, intercellular CO2 concentration in different varieties reached the highest value in the period, water use efficiency is essential there is no law. With the higher of salinity stress, the net photosynthetic rate, transpiration rate, stomatal conductance, SPAD basic downward trend, CO2 concentration in the intercellular rise. 5.In the same processing time(6h),sb DREB2 expression increased in sorghum with increased levels of salinity stress.The expression in roots increased greater than the expression in leaves; At the same stress concentration(160mmol/L), sb DREB2 expression in sorghum roots increases with the amount of time increases, salt stress basically no change in expression levels after 12 h and 12 h after alkali stress stress decreased expression levels; Different sorghum varieties in the same under the stress of time and stress concentration, sb DREB2 roots expression vary, the expression in the tolerant varieties of Gaoliangzhe greater than the salt-sensitive species Henong16.