小麦籽粒发育及淀粉晶体特性对花后高温胁迫的响应

Response of Grain Development and Starch Crystal Properties to High Temperature Stress after Anthesis in Wheat (Triticum aestivum L.)

选用2个品质类型和成熟期不同的新疆主栽小麦品种‘新春11号’和‘新春39号’,分别进行花后灌浆早期高温(花后5~8d,32℃,T_1)和中期高温(花后15~18d,38℃,T_2)处理,分析花后高温对小麦籽粒发育及淀粉晶体的影响。结果显示:(1)T_1处理明显降低了两品种籽粒长度和粒重,而T_2处理显著影响籽粒宽度和厚度;高温处理虽然降低了籽粒灌浆速率,但两品种灌浆最大峰值出现时间均在花后18d。(2)T_1处理对小麦籽粒A型淀粉粒形态的影响较大,中熟品种‘新春11号’的A型淀粉粒表面在花后10d时可观察到微孔,在花后15~20d时其粒径明显小于同期对照,在花后20~25d时淀粉粒表面压痕增多且A、B型淀粉粒表面出现明显缢缩;而早熟品种‘新春39号’淀粉粒形态和粒径大小受花后高温的影响相对较小。(3)两品种在不同高温处理下,其淀粉粒晶体特性衍射峰出现的位置相同,但淀粉粒的尖峰强度不同,表明高温胁迫不影响淀粉粒的晶体类型,但可能改变了淀粉粒内部的层状结构。研究表明,花后早期高温不仅对小麦籽粒外部形态有较大的影响,同时也影响到籽粒内部淀粉粒的形态和晶体的特性。

In order to study the effects of high temperature on grain development and crystal properties of wheat（Triticum aestivum L.）,we selected the main varieties of XC11 and XC39 with different qualities and maturity stages.They were treated at the early（T_1）and middle（T_2）stage after anthesis under high temperature,respectively.The results showed that：（1）T_1 treatment significantly reduced grain length and grain weight of two varieties,while T_2 treatment had greater effects on grain width and thickness.Al-though the grain filling rate was decreased by high temperature treatment,the maximum peak time of the two varieties appeared at 18 day after anthesis（DAA）.（2）For morphology of starch grains,the influence on the A-type starch granules morphology is more serious under high temperature treatment.Under T_1 treatment,pores of A-type starch granule of XC11 can be observed in surface at 10 DAA,A-type starch granule size significantly less than the same period controlled starch granule size at 15-20 DAA,starch granule surface indentation increased at 20-25 DAA and A and B-type starch granule surface significantly constricted.However,the shape and size of starch granule of early maturing XC39 were less affected by the high temperature after anthesis.（3）Under different high temperature treatments,the diffraction peaks of starch grains were the same,but the peak intensities of starch grains were different between the two varieties.The results showed that high temperature stress did not affect the crystal type of starch grains,but changed the lamellar structure of starch grains.The early high temperature after anthesis not only has a great influence on the grain morphology,but also affects the morphology and crystal characteristics of starch grains in the grains.