源库调控对玉米叶片衰老和氮素转移的影响及其生理机制

发布时间：2018-06-30 18:57

本文选题：源 + 库　；参考：《中国农业大学》2016年博士论文

【摘要】：在叶片衰老的过程中,营养器官中的氮会活化后再转移到籽粒中。这个过程受到各种因素的控制,如源库关系、激素、土壤中的水分状况和植株营养状态等。籽粒氮的来源分为花前氮的转移以及花后氮的吸收,这个过程与叶片的衰老关系密切。为更好的理解源库关系对玉米叶片衰老和氮素转移的调控机理,本研究设计实施了两年田间试验和三年温室试验,主要研究结果如下：1)运用15N标记示踪技术,研究玉米花前氮和花后氮的动态变化以及其与源库调控的关系。结果发现：在吐丝后20天里,相对于花后氮的吸收,花前氮的转移对籽粒氮的贡献更大；随着籽粒不断灌浆,籽粒氮中来自花后氮的吸收比例逐渐增加。阻止授粉后,即使没有籽粒建成,叶片中花前氮的转移效率也能高达33%。’5N示踪结果表明,花前氮有62%转移到籽粒中,而花后氮有76%到了籽粒中,这说明,相对于花前氮的转移,提高花后氮的吸收更有可能增加籽粒氮积累。2)以1个农家种和在1973年到2000年间中国主推的10个玉、米品种为材料,研究阻止授粉对不同年代玉米品种叶片衰老,花后干物质积累,氮积累以及各器官氮转移的影响。结果表明：与正常授粉处理比较,当在吐丝期对玉米进行套袋阻止授粉后,在生理成熟期时,品种农大60,沈单7,掖单13和郑单958叶片延缓衰老；而对于白马牙,丹玉、6,掖单2和先玉335来说,其叶片叶面积影响较小；相反,中单2,丹玉13和掖单4,阻止授粉后,加快了叶片的衰老。从生理学角度,叶片氮转移效率可以从一定程度上解释不同品种叶片衰老速度对阻止授粉的响应差异。3)以郑单958和中单2为试验材料,通过两年的温室盆栽试验,研究源库关系对花后氮吸收及叶片衰老的影响,得出以下结论：郑单958在阻止授粉后,叶片中协同衰老的蛋白酶-豆荚蛋白的基因ZmSee2β表达量显著下调,叶片衰老延缓,原因是在吐丝后,叶片中氮的输入大于输出。中单2在阻止授粉后,氮吸收在减少而蛋白质分解速率提高,同时糖含量也有所增加,叶片衰老加快,其原因可能是存在着某个信号同时控制着叶片的衰老和氮的移动。综上所述,源库关系能调控玉米植株干物质和氮的积累,而植株叶片衰老和氮转移对源库调控的响应有基因型差异。在保证花前施氮量满足玉米正常生长的前提下,适当增加灌浆期的施氮比例有利于籽粒氮的累积。源强或库强减小,籽粒氮累积减少,因此合理调控源库比是获得高产的前提。
[Abstract]:During leaf senescence, nitrogen in vegetative organs is activated and then transferred to grains. This process is controlled by a variety of factors, such as source-sink relationships, hormones, soil moisture status and plant nutritional status. The source of grain nitrogen can be divided into pre-anthesis nitrogen transfer and postanthesis nitrogen absorption, which is closely related to leaf senescence. In order to better understand the regulation mechanism of source-sink relationship on senescence and nitrogen transfer in maize leaves, two years field experiment and three years greenhouse experiment were carried out in this study. The main results were as follows: 1) 15N marker tracer technique was used. To study the dynamic changes of preanthesis nitrogen and postanthesis nitrogen and their relationship with the regulation of source and sink. The results showed that the transfer of pre-anthesis nitrogen contributed more to grain nitrogen than post-anthesis nitrogen absorption during 20 days after silking, and the proportion of grain nitrogen absorbed from postanthesis increased with grain filling. After stopping pollination, even if no seeds were built, the efficiency of nitrogen transfer in leaves before anthesis was as high as 33.5N. The results showed that 62% of pre-anthesis nitrogen was transferred to grains, and 76% of post-anthesis nitrogen was transferred to grains. Compared with pre-anthesis nitrogen transfer, increasing post-anthesis nitrogen uptake was more likely to increase grain nitrogen accumulation (.2).) A farm species and 10 Chinese jade and rice varieties, which were mainly promoted from 1973 to 2000, were used as materials. The effects of stopping pollination on leaf senescence, dry matter accumulation after anthesis, nitrogen accumulation and nitrogen transfer in different organs of maize varieties were studied. The results showed that the leaves of Nongda 60, Shendan 7, Yedan 13 and Zhengdan 958 were delayed senescence at physiological maturity stage, compared with the normal pollination treatment, while the leaves of white horse tooth were treated with bagging and stopping pollination at silking stage, while the leaves of Nongda 60, Shendan 7, Yedan 13 and Zhengdan 958 were delayed senescence. The effect of leaf area on leaf area of Danyujian6, Yedan 2 and Xianyu335 was small, whereas Zhongdan 2, Danyu 13 and Yedan 4 accelerated leaf senescence after pollination was stopped. From the physiological point of view, the leaf nitrogen transfer efficiency can explain to a certain extent the different responses of leaf senescence rate of different varieties to stopping pollination. 3) Zhengdan 958 and Zhongdan 2 were used as experimental materials, and two years of greenhouse pot experiment were conducted. The effects of source-sink relationship on postanthesis nitrogen absorption and leaf senescence were studied. The following conclusions were drawn: after stopping pollination, the expression of ZmSee2 尾, a protease-pod protein gene, was significantly down-regulated in leaves of Zhengdan 958, and the senescence of leaves was delayed. The reason is that after spinning, the input of nitrogen in the leaf is larger than the output. After stopping pollination, nitrogen absorption decreased, protein decomposition rate increased, sugar content increased and leaf senescence accelerated, which may be due to the existence of a signal controlling leaf senescence and nitrogen movement simultaneously. In conclusion, the relationship between source and sink can regulate the accumulation of dry matter and nitrogen in maize plants, and the responses of leaf senescence and nitrogen transfer to the regulation of source and sink have different genotypes. On the premise of ensuring that the amount of nitrogen applied before anthesis can meet the normal growth of maize, it is beneficial to the accumulation of nitrogen in grain to increase the proportion of nitrogen applied at grain filling stage. As the source strength or sink strength decreased, the grain nitrogen accumulation decreased, so the reasonable regulation of the ratio of source to sink was the prerequisite for obtaining high yield.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S513

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