本文關(guān)鍵詞：青稞對(duì)低氮脅迫的生理響應(yīng)及交替呼吸途徑影響低氮耐受性的機(jī)理研究　出處：《蘭州大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 青稞 低氮脅迫 硝酸還原酶 谷氨酰氨合成酶 交替呼吸途徑 光合作用 ROS 葡糖糖-6-磷酸脫氫酶 NADP-蘋果酸脫氫酶

【摘要】：低氮脅迫影響植物的生長(zhǎng),限制作物的產(chǎn)量,研究作物對(duì)低氮脅迫的耐受機(jī)理能為培育高效利用氮的作物新品種提供理論依據(jù)。青稞是青藏高原特有的糧食作物。因其惡劣的生存環(huán)境,青稞抵抗環(huán)境脅迫的能力增強(qiáng),是研究作物對(duì)環(huán)境脅迫耐受性的理想材料。本研究以昆侖12(青稞)為材料,并用甘啤6(普通大麥)為對(duì)照,研究青稞對(duì)低氮脅迫的生理響應(yīng),并深入探討交替呼吸途徑在低氮脅迫中的作用,以圖尋找青稞對(duì)低氮脅迫的耐受機(jī)理,主要得到以下結(jié)果:1.低氮脅迫抑制青稞生長(zhǎng),引起硝酸根、可溶性蛋白及葉綠素含量降低,光合作用減弱。在低氮脅迫下,與甘啤6相比,昆侖12表現(xiàn)出相對(duì)較高的生長(zhǎng)量、硝酸根、可溶性蛋白、葉綠素含量及光合作用,說(shuō)明昆侖12對(duì)低氮脅迫的耐受性比甘啤6強(qiáng)。2.低氮脅迫促進(jìn)甘啤6和昆侖12初生根的生長(zhǎng),增加根冠比,有利于吸收更多的氮,并且低氮脅迫對(duì)昆侖12的促進(jìn)效果更加明顯,它們分別增加了101.7%和83.9%,而在甘啤6中它們分別增加了53.9%和50.1%,這可能是昆侖12具有更強(qiáng)低氮耐受性的一個(gè)原因。3.硝酸還原酶(NR)和谷氨酰氨合成酶(GS)是氮同化過(guò)程中的兩個(gè)關(guān)鍵酶。低氮脅迫下甘啤6和昆侖12中NR和GS活性降低,其中甘啤6根中NR和GS活性分別降低了59.9%和33.8%,葉中分別降低了82.2%和24.4%;而昆侖12根中NR和GS活性分別降低了31.3%和18.1%,葉中分別降低了47.9%和11.8%。以上結(jié)果說(shuō)明低氮脅迫下昆侖12具有更好的氮同化能力,這可能是昆侖12低氮耐受性更強(qiáng)的又一個(gè)原因。4.低氮脅迫會(huì)引起甘啤6和昆侖12中活性氧(ROS)的過(guò)量產(chǎn)生,造成膜脂過(guò)氧化,其中甘啤6中產(chǎn)生了更多的ROS,膜損傷更加嚴(yán)重。而且葉中比根中產(chǎn)生了更多的ROS,膜損傷更加嚴(yán)重。低氮脅迫下甘啤6和昆侖12中抗氧化酶及根中葡糖糖-6-磷酸脫氫酶(G6PDH)活性有不同程度的升高,有助于清除ROS。而葉中G6PDH活性并未升高,說(shuō)明G6PDH在根中和葉中的功能存在差異性。5.多種脅迫下,線粒體交替途徑會(huì)增加,有助于控制ROS的產(chǎn)生。本研究發(fā)現(xiàn)低氮脅迫下,甘啤6葉片中交替途徑的容量增加了28.6%,而昆侖12葉中增加的更加明顯(42.0%)。還發(fā)現(xiàn)昆侖12葉片中交替氧化酶(AOX)蛋白含量明顯增加,而甘啤6中并未增加。與葉片中不同,昆侖12根中交替途徑并未增加,暗示交替途徑在根中和葉中功能的差異性。6.低氮脅迫會(huì)導(dǎo)致甘啤6和昆侖12葉綠體中NADPH的積累,引起光合作用的抑制,并導(dǎo)致ROS的過(guò)量產(chǎn)生,該現(xiàn)象在甘啤6中更加明顯。此時(shí)過(guò)量的NADPH會(huì)通過(guò)蘋果酸-草酰乙酸穿梭機(jī)制間接轉(zhuǎn)移到胞質(zhì)或線粒體中,并通過(guò)線粒體交替途徑進(jìn)行消耗,因此交替呼吸途徑可以降低ROS的產(chǎn)生,保護(hù)光合作用的有效進(jìn)行。低氮脅迫下,昆侖12葉中交替途徑增加更加明顯,使其能更好地消耗來(lái)自葉綠體的還原力,從而降低葉綠體中NADPH的積累,減少ROS的產(chǎn)生,因此昆侖12受到的氧化損傷較小,這可能是昆侖12耐低氮脅迫的另一個(gè)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.

【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：S512.3;Q945.78
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本文編號(hào)：1392667