2种生态条件下冬小麦非顺序衰老过程中同化物积累及转运特性

Assimilate accumulation and transport characteristics of winter wheat during sequential and non-sequential senescence under two ecological conditions

【目的】研究正常天气和遮阴2种生态条件下,小麦正置茎和倒置茎地上器官同化物的积累及转运特性,为进一步研究小麦叶片非顺序衰老的生理生化机制提供理论依据。【方法】在正常天气和遮阴处理条件下,以3种小麦品种温麦19、豫麦19和兰考矮早8顺序衰老(正置)和非顺序衰老(倒置)茎为材料,在小麦叶片非顺序衰老发生开始时和发生后第5天,采用系数法和称质量法测定小麦正置茎和倒置茎顶三叶的绿叶面积和地上器官的干物质积累量。【结果】无论是正常天气条件还是遮阴条件下,温麦19、豫麦19和兰考矮早8正置茎顶三叶绿叶面积大小次序为旗叶>倒二叶>倒三叶,而倒置茎表现为倒二叶>旗叶>倒三叶,遮阴条件下小麦顶三叶的绿叶面积较正常天气条件下大。小麦正置茎旗叶和倒二叶干物质积累量无明显差异,而倒置茎倒二叶干物质积累量显著高于旗叶。正置茎和倒置茎旗叶、倒二叶、倒三叶叶鞘干物质积累大小次序一致,均为旗叶鞘>倒二叶鞘>倒三叶鞘。倒置茎茎秆和剩余叶(除旗叶、倒二叶和倒三叶外)、颖稃片和穗轴以及籽粒的干物质质量均明显高于正置茎。正置茎花前地上器官同化物转运量、转运率及对籽粒的贡献率均明显大于倒置茎,而花后则相反。在成熟期,倒置茎千粒质量和穗粒数均大于正置茎。遮阴条件引起小麦地上营养器官干物质积累量减少和籽粒千粒质量降低,但对穗粒数影响不大。【结论】无论在正常天气条件还是遮阴条件下,小麦灌浆结实后期叶片的非顺序衰老有利于小麦籽粒的充实。

【Objective】Under normal weather and shading conditions,assimilate accumulation and transport characteristics of wheat leaf during sequential and non-sequential senescence were researched to provide guidance for understanding physiological and biochemical mechanism during non-sequential senescence of wheat leaf.【Method】Three wheat varieties,Wenmai 19,Yumai 19 and Lankaoaizao 8were studied under normal weather and shading conditions.In non-sequential senescence period of wheat leaves,the top3-leaves green area and dry weight of vegetative organs of conventional stems and inverted stems were measured using coefficient method and weighting method.【Result】In normal weather and shading condi-tions,the top 3leaves green areas of Wenmai 19,Yumai 19 and Lankaoaizao 8of conventional steams were in the rank of flag leaf >top 2nd leaf >top 3rd leaf,while the rank of inverted stems was top 2nd leaf>flag leaf>top 3rd leaf.The top 3leaves green areas in shading condition were larger than in normal weather.The dry matter accumulation had no significant difference between flag leaf and top 2nd leaf in conventional stems,but the top 2nd leaf dry matter accumulation was significantly higher than that of flag leaf in inverted stems.In both conventional stems and inverted stems,orders of dry matter accumulation of top 3leaf sheaths were flag leaf>top 2nd leaf>top 3rd leaf.Dry matter accumulation of stem and residual leaf and sheath,peristachyum and palea and spike stalk,and grain in inverted stems were significantly higher than in conventional stems.Assimilation transportation,transporting rate and contribution rate before anthesis in conventional stems under both ecological conditions were significantly higher than in inverted stems,but assimilation transportation,transporting rate and contribution rate after anthesis were in opposite.In the mature period,the 1 000-grain weight and spike grain number in inverted stems were greater than in conventional stems.【Conclusion】In both normal weather and shading conditions,non-sequential senescence of wheat leaf in late grain-filling period was beneficial to the grain filling.