种子引发对盐渍土壤条件下高粱芽苗生理特性的影响

摘要

To explore the physiological effects of sorghum seedlings by seed priming under saline soil conditions and enhance the salt tolerance of sorghum at sprouting and seedling stages ,a pot culturing experiment was employed in this study to investigate complex salt priming (CSP) ,single salt priming (SSP) ,none salt priming (NSP) on sorghum seeds that were sown in the sandy soil conditions treated with 0 ,40 ,80 ,120 mmol·L - 1 and 160 mmol·L - 1 salt solution irri-gations .Consequently ,seed germination and seedling physiological characteristics were studied .The results showed that seed priming could improve the seed germination rate ,emergence rate and vigor index of sorghum seeding ,especially through the effect of complex salt initiator (CSP) treatment with NaCl and Na2SO4 under different soil salt stresses .In addition ,after seed priming ,especially when treated by CSP ,it could significantly relief the relative reduction of water content in leaves and roots ,particularly under middle and high salt stresses .Also ,the amounts of chlorophyll a + b and chlorophyll a showed a slow decline .When the concentration of salt was no more than 80 mmol·L - 1 (Salt -80) ,the net photosynthesis showed a little reduction ,and stomatal conductance and transpiration rate were consistent with the varying trend .Moreover ,seed priming enhanced the SOD ,POD ,CAT and APX activities ,while reduced the MDA and O ·2 . MDA ,O·2 and POD were the more sensitive factors than others .The effects on the antioxidant system were in the order of the following :complex salt priming (CSP)> single salt priming (SSP)> complex salt priming (NSP) .In conclusion , seed priming with NaCl and Na2SO4 complex solution could enhance the physiological adaptation of sorghum seedlings and improve the salt tolerance of sorghum at the sprouting and seedling stages .%为探索引发种子对不同盐渍土壤条件下高粱芽苗的生理效应，增强高粱芽苗期的耐盐能力，采用盆栽沙培试验，将氯化钠和硫酸钠复配引发（CSP）、氯化钠单独引发（SSP）和不引发（NSP）处理后的高粱种子分别播种在0、40、80、120 mmol·L －1和160 mmol·L －1盐溶液漫灌的细沙盐渍土壤条件下，研究上述各种状态下种子萌发和幼苗生理特性。结果表明：种子引发可提高盐胁迫下高粱的发芽率、成苗率和活力指数，尤其是盐复配引发（CSP）效果更为明显；引发后的种子（特别是 CSP）可显著减少中、高盐胁迫条件下叶片和根系相对含水量的下降幅度，减缓叶绿素 a ＋ b 、叶绿素 a 的下降；氯化钠和硫酸钠复配引发（CSP）下净光合速率在盐浓度低于80 mmol·L －1时下降幅度较小，气孔导度和蒸腾速率与之变化趋势基本一致；种子引发增强了 SOD 、POD 、CAT 和 APX 活性，同时减少了MDA 和 O·2，其中 MDA 、O·2和 POD 反应较为敏感，三种种子引发处理对高粱芽苗期抗氧化系统的影响效应表现为：复配引发（CSP）＞单盐引发（SSP）＞不引发（NSP）。盐渍土壤条件下种子引发，特别是氯化钠和硫酸钠复配引发种子可增强其生理适应性，进而提高高粱芽苗期的耐盐性。