青稞对低氮胁迫的生理响应及交替呼吸途径影响低氮耐受性的机理研究

发布时间：2018-01-07 13:08

  本文关键词：青稞对低氮胁迫的生理响应及交替呼吸途径影响低氮耐受性的机理研究　出处：《兰州大学》2016年博士论文　论文类型：学位论文

  更多相关文章： 青稞 低氮胁迫 硝酸还原酶 谷氨酰氨合成酶 交替呼吸途径 光合作用 ROS 葡糖糖-6-磷酸脱氢酶 NADP-苹果酸脱氢酶

【摘要】：低氮胁迫影响植物的生长,限制作物的产量,研究作物对低氮胁迫的耐受机理能为培育高效利用氮的作物新品种提供理论依据。青稞是青藏高原特有的粮食作物。因其恶劣的生存环境,青稞抵抗环境胁迫的能力增强,是研究作物对环境胁迫耐受性的理想材料。本研究以昆仑12(青稞)为材料,并用甘啤6(普通大麦)为对照,研究青稞对低氮胁迫的生理响应,并深入探讨交替呼吸途径在低氮胁迫中的作用,以图寻找青稞对低氮胁迫的耐受机理,主要得到以下结果:1.低氮胁迫抑制青稞生长,引起硝酸根、可溶性蛋白及叶绿素含量降低,光合作用减弱。在低氮胁迫下,与甘啤6相比,昆仑12表现出相对较高的生长量、硝酸根、可溶性蛋白、叶绿素含量及光合作用,说明昆仑12对低氮胁迫的耐受性比甘啤6强。2.低氮胁迫促进甘啤6和昆仑12初生根的生长,增加根冠比,有利于吸收更多的氮,并且低氮胁迫对昆仑12的促进效果更加明显,它们分别增加了101.7%和83.9%,而在甘啤6中它们分别增加了53.9%和50.1%,这可能是昆仑12具有更强低氮耐受性的一个原因。3.硝酸还原酶(NR)和谷氨酰氨合成酶(GS)是氮同化过程中的两个关键酶。低氮胁迫下甘啤6和昆仑12中NR和GS活性降低,其中甘啤6根中NR和GS活性分别降低了59.9%和33.8%,叶中分别降低了82.2%和24.4%;而昆仑12根中NR和GS活性分别降低了31.3%和18.1%,叶中分别降低了47.9%和11.8%。以上结果说明低氮胁迫下昆仑12具有更好的氮同化能力,这可能是昆仑12低氮耐受性更强的又一个原因。4.低氮胁迫会引起甘啤6和昆仑12中活性氧(ROS)的过量产生,造成膜脂过氧化,其中甘啤6中产生了更多的ROS,膜损伤更加严重。而且叶中比根中产生了更多的ROS,膜损伤更加严重。低氮胁迫下甘啤6和昆仑12中抗氧化酶及根中葡糖糖-6-磷酸脱氢酶(G6PDH)活性有不同程度的升高,有助于清除ROS。而叶中G6PDH活性并未升高,说明G6PDH在根中和叶中的功能存在差异性。5.多种胁迫下,线粒体交替途径会增加,有助于控制ROS的产生。本研究发现低氮胁迫下,甘啤6叶片中交替途径的容量增加了28.6%,而昆仑12叶中增加的更加明显(42.0%)。还发现昆仑12叶片中交替氧化酶(AOX)蛋白含量明显增加,而甘啤6中并未增加。与叶片中不同,昆仑12根中交替途径并未增加,暗示交替途径在根中和叶中功能的差异性。6.低氮胁迫会导致甘啤6和昆仑12叶绿体中NADPH的积累,引起光合作用的抑制,并导致ROS的过量产生,该现象在甘啤6中更加明显。此时过量的NADPH会通过苹果酸-草酰乙酸穿梭机制间接转移到胞质或线粒体中,并通过线粒体交替途径进行消耗,因此交替呼吸途径可以降低ROS的产生,保护光合作用的有效进行。低氮胁迫下,昆仑12叶中交替途径增加更加明显,使其能更好地消耗来自叶绿体的还原力,从而降低叶绿体中NADPH的积累,减少ROS的产生,因此昆仑12受到的氧化损伤较小,这可能是昆仑12耐低氮胁迫的另一个原因。
[Abstract]:Effects of low nitrogen stress on plant growth, limiting crop yield, tolerance mechanism of crops to low nitrogen stress to foster efficient use of new varieties of crop nitrogen and provide a theoretical basis. Barley is endemic to Qinghai Tibetan Plateau food crops. Because of its poor living environment, the ability to resist environmental stress in barley enhancement, is an ideal material study on crop stress tolerance to the environment. This study takes Kunlun 12 (barley) as materials, and Ganpi 6 (ordinary barley) as control, to study the physiological responses of barley to low nitrogen stress, and the depth of the effect of alternative respiration pathway in low nitrogen stress in barley, to seek the mechanism of tolerance to low stress n, the main results are as follows: 1. under low nitrogen stress inhibited the growth of barley, caused by nitrate, soluble protein and chlorophyll contents decrease, photosynthesis decreased. In low nitrogen stress and Ganpi 6 compared to 12 in Kunlun showed a relative The amount of growth, high nitrate, soluble protein, chlorophyll content and photosynthesis, Kunlun 12 to low nitrogen stress tolerance pikan Ganpi 6 strong.2. low nitrogen stress promoting Ganpi 6 and Kunlun 12 primary root growth, increase root shoot ratio, to absorb more nitrogen and low nitrogen stress on Kunlun 12 the effect is more obvious, they were increased by 101.7% and 83.9%, while in Ganpi 6 they were increased by 53.9% and 50.1%, this may be the Kunlun 12 has stronger low nitrogen tolerance of a.3. nitrate reductase (NR) and glutamine synthetase (GS) are two key enzymes of nitrogen assimilation in the process of decreasing. Under the low nitrogen stress Ganpi 6 and Kunlun 12 NR and GS activity, the Ganpi 6 root NR and GS activity were decreased by 59.9% and 33.8%, leaves were decreased by 82.2% and 24.4%; and Kunlun 12 root NR and GS activity were decreased by 31.3% and 18.1% in the leaves branch Don't be reduced more than 47.9% and 11.8%. results show that the nitrogen assimilation capacity under low nitrogen stress in Kunlun 12 has better, this may be another reason for.4. low N Kunlun 12 low nitrogen tolerance stronger stress will cause the Ganpi 6 and Kunlun 12 reactive oxygen species (ROS) overproduced, resulting in membrane lipid peroxidation. The Ganpi more ROS 6, membrane damage is more serious. But in the leaf root generate more ROS, membrane damage is more serious. Under the low nitrogen stress Ganpi 6 and 12 Kunlun root antioxidant enzymes and glucose -6- phosphate dehydrogenase (G6PDH) activity increased in different degrees, to help remove ROS. and the activity of G6PDH in leaves did not increase, indicating the presence of G6PDH in root and leaf of the difference of function.5. stress, mitochondrial pathway will increase, helps to control the production of ROS. The study found that under low nitrogen stress, Ganpi 6 leaves alternate route capacity Volume increased by 28.6%, increased 12 in the leaves of Kunlun is more obvious (42%). Kunlun also found in the leaves of 12 alternative oxidase (AOX) protein content increased significantly, while the Ganpi 6 did not increase. Unlike in the leaves of Kunlun, alternating 12 root way does not increase, the difference of.6. low nitrogen suggest alternative pathway the function in the root and leaf of stress could cause the NADPH Ganpi 6 and Kunlun 12 in the chloroplast accumulation caused by inhibition of photosynthesis, and lead to excessive production of ROS, this phenomenon is more obvious in Ganpi 6. At this time the excess NADPH will pass the malate oxaloacetate shuttle mechanism indirectly transferred to the cytoplasm or mitochondria and, through the mitochondrial alternative pathway of consumption, so the alternative respiratory pathway can reduce the production of ROS, the effective protection of photosynthesis. Under low nitrogen stress, Kunlun 12 leaves alternate ways to increase more obviously, so it can be better to consume Since the reducing power of chloroplasts reduces the accumulation of NADPH in chloroplasts and reduces the production of ROS, the oxidative damage of Kunlun 12 is relatively small, which may be another reason why Kunlun 12 is resistant to low nitrogen stress.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S512.3;Q945.78
，

本文编号：1392667