水稻叶片非光化学猝灭对环境因子的光合响应

发布时间：2018-08-17 16:08

【摘要】：非光化学猝灭(NPQ)是指植株叶片光合系统II内以热能的形式耗散吸收的光能,可减少活性氧的产生,有效避免光抑制的发生,是一种重要的光保护机制。本文以叶色具有显著差异的近等基因系水稻浙辐802、始绿-8和Fgl为材料,研究水稻叶片NPQ对光照强度、氮浓度及干旱胁迫的光合响应,及NPQ的产生及调控机制,并通过转录组测序了解光合作用的复杂遗传调控途径,为进一步提高水稻光合效率和氮利用效率提供理论参考。主要结果如下:1、尽管浅叶色品种始绿-8叶绿素含量约为浙辐802的1/3,但始绿-8的光合速率显著高于浙辐802;在光照强度为600和1200μmol m-2 s-1下,相对于浙辐802,始绿-8均表现出较高的NPQ、能量猝灭和较低的光抑制猝灭(q I)。始绿-8叶片丙二醛、H_2O_2含量及O2-产生速率均显著低于浙辐802,并且1200μmol m-2 s-1下的过氧化物含量增加幅度小于浙辐802,光破坏现象轻于浙辐802。供试两品种间CO_2同化能力差异和气孔限制对光合作用的影响均较小。由此可推断无论是浅叶色的始绿-8还是深叶色的浙辐802,当光照强度大于600μmol m-2 s-1,叶片通过增加NPQ的产生,减少光破坏发生,促进光合速率的提高,增强叶片的光照适应性。2、随着氮浓度的增加,叶绿素含量显著增加。浙辐802叶片叶绿素含量显著高于Fgl,特别是高氮处理。但高氮处理没有显著增加两品种叶片CO_2的同化能力。浙辐802高氮处理的NPQ与中氮处理差异相对较小。浙辐802高氮处理叶片H_2O_2、丙二醛含量、qI显著高于中氮处理,浙辐802的H_2O_2含量、qI显著高于Fgl,由此可得出,高氮处理下的浙辐802叶片不能消耗由较多叶绿素所吸收的过剩光能,存在相对严重的光氧化胁迫。相对于中氮处理,低氮处理两品种叶片NPQ诱导显著增强;较高的玉米黄素含量有利于NPQ的诱导,这可能是水稻光合作用对缺氮响应的重要途径。3、喷施ABA明显缓解干旱对水稻叶片光合作用的抑制作用,并显著增加浙辐802和Fgl叶片NPQ,NPQ的显著增加可能是外源ABA提高水稻抗旱性的原因。Fgl叶片卷曲程度和净光合速率下降幅度均显著低于浙辐802,表现出较强的抗旱特性,叶片茉莉酸甲酯和生长素含量的差异以及叶绿素含量差异与Fgl的抗旱性密切相关。4、始绿-8较少且较薄的基粒片层不利于捕光色素复合体的附着,与其叶色较浅密切相关。在600μmol m-2 s-1下,玉米黄素含量和RVDE1、PsbS1的表达与NPQ的诱导有关;在1200μmol m-2 s-1下,NPQ的诱导主要受玉米黄素含量和RVDE1的表达量有关。叶片中吲哚乙酸、赤霉素和脱落酸(ABA)含量变化可能与水稻光照适应以及不同光照环境的NPQ的诱导有关。5、光合作用受复杂的基因差异表达调控,除直接参与光合作用的差异基因外,参与氧胁迫响应、能量代谢和硝酸根代谢的差异基因协同调控光合效率。信号传导的差异基因协调多个代谢途径对光合作用进行调控。富集到叶绿体(GO:0009507)的差异表达基因是叶绿体显微结构差异的遗传基础。综上,当光照强度大于600μmol m-2 s-1时,较高的NPQ诱导与较少的叶绿素含量有利于减少光合系统内过剩的光能,降低过氧化物的生成,缓解高光照下的光破坏,增强叶片的光照适应性。不仅高光照才能引起光能捕获过剩,其他环境因子也会影响光能的吸收与利用。高氮环境下叶片不能消耗由较多叶绿素所吸收的过剩光能,存在相对严重的光氧化胁迫。低氮环境下叶片NPQ的增强有利于减少低光合系统内过剩光能,可能是光合作用对缺氮的适应性响应。干旱胁迫下NPQ的显著增加可能是外源ABA提高水稻抗旱性的原因。
[Abstract]:Non-photochemical quenching (NPQ) is an important mechanism of photoprotection, which means the energy dissipated and absorbed by photosynthetic system II in the form of heat energy. It can reduce the production of reactive oxygen species and effectively avoid the occurrence of photoinhibition. The main results are as follows: 1. Chlorophyll content in light-leaved cultivar Shilu-8 was detected, although light-leaved cultivar Shilu-8 contained chlorophyll. The photosynthetic rate of Eogene-8 was significantly higher than that of Zhefu 802. Compared with Zhefu 802, Eogene-8 exhibited higher NPQ, energy quenching and lower photoinhibition quenching (q I) at 600 and 1200 micromol m-2 S-1 irradiation intensities. Malondialdehyde, H_2O_2 content and O2-production rate of Eogene-8 leaves were significantly lower than that of Zhefu 802. The increase of peroxide content in 1 200 micromol m-2 S-1 was less than that in Zhefu 802, and the light damage was less than that in Zhefu 802. The difference of CO_2 assimilation ability and stomatal limitation between the two cultivars had little effect on photosynthesis. - 1. The photosynthetic rate and photosynthetic adaptability of the leaves were enhanced by increasing NPQ production. 2. The chlorophyll content of the leaves of Zhefu 802 increased significantly with the increase of nitrogen concentration. The chlorophyll content of the leaves of Zhefu 802 was significantly higher than that of Fgl, especially in high nitrogen treatment. The content of H_2O_2, malondialdehyde and qI in leaves of Zhefu 802 under high nitrogen treatment were significantly higher than those under middle nitrogen treatment. The content of H_2O_2 and qI in leaves of Zhefu 802 under high nitrogen treatment were significantly higher than those under Fgl treatment. It was concluded that the leaves of Zhefu 802 under high nitrogen treatment could not consume excess light energy absorbed by more chlorophyll. Relatively severe photooxidative stress. Compared with medium nitrogen treatment, the NPQ induction in leaves of low nitrogen treatment increased significantly; higher zeaxanthin content was beneficial to the induction of NPQ, which may be an important way for rice photosynthesis to respond to nitrogen deficiency. 3. ABA spraying significantly alleviated the inhibition of drought on Photosynthesis of rice leaves, and increased significantly. The remarkable increase of NPQ and NPQ in leaves of Zhefu 802 and Fgl may be the reason why exogenous ABA could improve the drought resistance of rice. The leaf curl degree and net photosynthetic rate of Fgl were significantly lower than those of Zhefu 802, showing strong drought resistance. The differences of methyl jasmonate and auxin contents in leaves and chlorophyll contents were closely related to the drought resistance of Fgl. Correlation. 4. Less and thinner grana lamellae of Eoglobin-8 were not conducive to the attachment of light-harvesting pigment complexes, which was closely related to the light color of leaves. Zeaxanthin content and RVDE1, PsbS1 expression were related to the induction of NPQ at 600 micromol m-2 s-1, and the induction of NPQ was mainly related to zeaxanthin content and RVDE1 expression at 1200 micromol m-2 s-1. Indoleacetic acid, gibberellin and abscisic acid (ABA) contents in the tablets may be related to light adaptation and NPQ induction in different light environments. 5. Photosynthesis is regulated by complex gene differential expression, which is not only directly involved in photosynthesis, but also in oxygen stress response, energy metabolism and nitrate metabolism. Differentially expressed genes enriched in chloroplasts (GO:0009507) are the genetic basis for the differences in chloroplast microstructure. In conclusion, higher NPQ induction and lower chlorophyll content are beneficial when light intensity is greater than 600 micromol m-2 s-1. In order to reduce the excess light energy in photosynthetic system, reduce the generation of peroxides, alleviate the light damage under high light, and enhance the light adaptability of leaves, not only high light can cause excess light capture, but also other environmental factors can affect the absorption and utilization of light energy. The increase of NPQ in leaves under low nitrogen environment was beneficial to reduce the excess light energy in the low photosynthetic system, which may be the adaptive response of photosynthesis to nitrogen deficiency.
【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S511

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