知识与财富的链接
以冷敏感早稻品种华矮21为材料,利用CaCl2、 无机盐混合试剂、 水杨酸（SA）和茉莉酸（JA）分别与γ-PGA组合引发水稻种子36 h,研究了在水培条件下生长7 d的水稻幼苗在6 ℃低温处理2 d和常温恢复生长3 d的生长表现和生理特性。结果表明,在低温胁迫下,不同复合引发剂引发处理水稻种子可以提高幼苗的耐冷性,可溶性糖增加,MDA含量降低,APX和SOD酶活性明显增强。综合生长与生理指标的表现可以看出,无机盐混合试剂与γ-PGA复合引发处理的效果最好。利用RT-PCR方法检测6个低温响应基因经此复合引发处理后的水稻幼苗在受低温处理后转录水平变化。结果表明,在低温胁迫下,OsICE1基因转录水平无变化,其他5个低温响应基因的转录明显增强,其中OsDREB1B和OsCDPK7基因受无机盐混合试剂与γ-PGA复合引发处理的诱导表达, OsMYBS3 和OsFAE2基因表达不受种子引发处理的影响,OsLIP19基因的表达受到了一定程度的抑制。这揭示无机盐混合试剂与γ-PGA复合引发处理可能通过增强水稻低温信号传导转录途径ICE1-DREB1B的表达而提高水稻的耐冷性。这些结果为复合型γ-PGA种子引发处理在提高早稻耐冷性中的应用提供了理论依据。
Improving chilling tolerance of early rice is important for alleviation of chilling injury to early rice seedlings. Seeds of early rice Hua′ai 21, a chilling-sensitive variety, were first subjected to treatments for 36 h with CaCl2, inorganic salt mixture, salicylic acid（SA） and jasmonic acid（JA） in combination with γ-polyglutamic acid（PGA）, respectively. The seedlings of seven-day old were then grown under chilling（6 ℃） for 2 days followed by 25 ℃ for 3 days. Their growth and physiological characteristics were studied in hydroponic conditions. Seed treatments with different chemical compounds improved seedling tolerance to chilling stress, and increased soluble sugar contents and APX and SOD activities, but decreased MDA contents with the greatest effects observed in the treatment with inorganic salt mixture in combination with γ-PGA. Under chilling stress, the transcription level of OsICE1 gene did not change, whereas that of other 5 cold-responsive marker genes was enhanced. Inorganic salt mixture in combination of γ-PGA induced genes OsDREB1B and OsCDPK7 expression, but, inhibited OsLIP19 gene expression. It is concluded that seed treatment with inorganic salt mixture combined with γ-PGA could enhance the chilling tolerance of early rice seedlings.
