The Cold Tolerance And Accumulation Characteristics Of Post-anthesis Sugar And Mineral In Two Senescence Types Of Wheat

The non-sequential senescence of wheat leaves refers to the aging of the flag leaves earlier than the inverted two leaves at the late stage of grain filling.The senescence method can transport the nutrients to the grain quickly and increase the spike weight and 1000-grain weight.It can be used as one of the traits for breeding high-yield,tolerant wheat varieties.This paper mainly studied the changes of water content,soluble sugar,starch,proline and soluble protein in stems-sheaths and roots during the overwintering period of sequential and non-sequential senescence wheat,and explored the difference of cold resistance ability of two senescence wheat cultivars at seedling stage.By measuring the change of soluble sugar content in the flag leaf,flag leaf sheath and peduncle and spike weigh and grain weigh of post-anthesis,the relationship between the accumulation of soluble sugar in the vegetative organs and leaf senescence and grain yield was revealed.we measured the content of potassium,calcium,and magnesium in the flag leaf and grain,so the accumulation and transport of potassium,calcium and magnesium in flag leaf and grain of two senescent types of wheat were revealed,which provides breeding theoretical guidance of a new high-yielding and high-quality wheat cultivar.The main conclusions of the paper are as follows:1.During the overwintering period of wheat,the water content in stems-sheaths showed a downward trend of both senescent types wheat,soluble sugar and starch content increased,and the soluble protein content first decreased and then increased.The water content and starch content of stems-sheaths of non-sequential senescence wheat "Wenmai19" and "Lankaoaizao8" were higher than that of sequential senescence wheat "Xinong88" and "NR9405",while the soluble sugar content and soluble protein content were lower.During the overwintering period,there was no significant difference in the proline content in stems-sheaths of the two senescent types of wheat.The sequential senescence wheat has higher content of soluble sugar and soluble protein in stems-sheaths during the overwintering process,so its cold-resistance ability and ability to deliver are higher.2.After anthesis,the soluble sugar content of flag leaves in non-sequential senescence wheat cultivars "cp98(1)1","Xinong805","Zhoumai22","Wenmai19" and "Lankaoaizao8 " was significantly higher than that of the sequential senescent wheat cultivars "9430","Shaan229","Yanshi9hao","Xinong88" and "NR9405" in the late growth stage;and the soluble sugar content of flag leaf sheath and peduncle in non-sequential senescence wheat is basically higher than that of the sequential senescence wheat after anthesis.Non-sequential senescence wheat was also higher than the sequential senescence wheat in yield such as spike weight,spike grain weight,one-grain weight,and 1000-grain weight.The correlation analysis showed that there was a significant positive correlation between the high soluble sugar content of non-sequential senescent wheat and its higher grain yield.3.After anthesis,the accumulation of potassium in the flag leaves continued to decline both two senescence types of wheat,and the accumulation of calcium and magnesium increased first and then decreased.The grain shows a continuous increase in the accumulation of potassium,calcium,and magnesium.There was no significant difference in accumulation of potassium,calcium,and magnesium of flag leaves in the two senescence types.However,in grains,"Wenmai19" and "Lankaoaizao8" were higher than "Xinong 88" and "NR9405",so the accumulation and transfer of potassium,calcium,and magnesium in the flag leaves was not the cause of flag leaf senescent,but the higher accumulation of potassium,calcium,and magnesium in the non-sequential senescent wheat grains indicated that the quality was better.