种衣剂处理对低温胁迫下花生种子萌发及幼苗生长和生理特性的影响

Effects of Seed Coating Treatment on Seed Germination,Seedling Growth and Physiological Characteristics of Peanut at Low Temperature

花生播种期易受低温胁迫,为明确种衣剂处理对低温胁迫下花生种子萌发、幼苗生长和生理特性的影响,以常温(25℃)处理为对照(CK),设8℃和10℃两个低温胁迫处理,各温度下设种衣剂包衣和清水浸润对照两种处理方式,研究种衣剂处理对低温胁迫下花生种子活力、幼苗干物质积累、根系形态特征和光合生理的影响。结果表明,相对于常温处理,8℃低温胁迫处理显著降低了花生种子发芽势(5.9%)、发芽率(7.7%)、发芽指数(11.0%)、种子活力指数(6.9%)和幼苗叶片SPAD值(11.4%),同时对幼苗根系生长产生抑制作用,其根长、根表面积和根体积较25℃常温和10℃低温胁迫处理分别显著降低50.0%~50.2%、44.9%~48.1%、48.2%~48.5%,但8℃低温胁迫处理对花生幼苗地上部和地下部干物质积累、最大光化学效率及胞间二氧化碳浓度、气孔导度、净光合速率和蒸腾速率等光合参数均无显著影响;种衣剂处理显著提高了8℃低温胁迫下花生种子的发芽势(8.2%)、活力指数(10.9%)和花生幼苗根长(45.1%)及根表面积(38.4%),但对10℃低温胁迫和常温处理均无显著影响,同时,种衣剂处理还显著提高了常温处理下花生幼苗干物质积累、最大光化学效率和功能叶片光合特性以及10℃低温下地上部干物质积累和最大光化学效率,但对8℃低温胁迫无显著作用。综上,花生种子萌发和幼苗根系生长对低温胁迫的响应更加显著,而种衣剂处理可以通过改善上述指标缓解低温胁迫,改善轻度低温胁迫和常温处理下花生幼苗生长的干物质积累和光合生理。

Peanut is susceptible to low temperature stress during sowing stage.In order to clarify the effect of seed coating treatment on seed germination,seedling growth and physiological characteristics of peanut under low temperature stress,the normal temperature(25℃)treatment was used as the control(CK),two low temperature stress treatments of 8℃and 10℃were set,and seed coating and water wetting were set under each temperature.The effects of seed coating treatment on seed vigor,dry matter accumulation,root morphological characteristics and photosynthetic physiology of peanut under low temperature stress were studied.The results showed that compared with the normal temperature treatment,the low temperature stress at 8℃significantly reduced the germination energy(5.9%),germination percentage(7.7%),germination index(11.0%),seed vitality index(6.9%),and the SPAD value of seedling(11.4%).At the same time,low temperature stress at 8℃inhibited the growth of seedling root system,the root length,root surface area and root volume were significantly reduced by 50.0%~50.2%,44.9%~48.1%and 48.2%~48.5%,respectively,compared with those under normal temperature and low temperature stress at 10℃.However,low temperature stress at 8℃had no significant effects on the dry matter accumulation,maximum photochemical efficiency,intercellular carbon dioxide concentration,stomatal conductance,net photosynthetic rate and transpiration rate of peanut seedlings.Seed coating treatment significantly increased germination energy(8.2%),seed vitality index(10.9%),root length(45.1%)and root surface area(38.4%)of peanut seedlings under low temperature stress at 8℃,but had no significant effect on these physiological characteristics under low temperature stress at 10℃and normal temperature treatments.Mean while,seed coating treatment also significantly improved the dry matter accumulation,maximum photochemical efficiency and photosynthetic characteristics of functional leaves of peanut seedlings under normal temperature treatment,and the dry matter accumulation of above ground and maximum photochemical efficiency under low temperature stress at 10℃,but had no significant effect on these characteristics under low temperature stress at 8℃.In conclusion,peanut seed germination and seedling root growth responded more significantly to low temperature stress,while seed coating treatment alleviated low temperature stress by resume the above indicators,and improved dry matter accumulation and photosynthetic physiology of peanut seedling under mild low temperature stress and normal temperature treatment.