不同氮素水平对小麦光合能量转化及水分利用效率的影响

ISWC OpenIR > 水保所知识产出(1956---)

	不同氮素水平对小麦光合能量转化及水分利用效率的影响
	张绪成
学位类型	博士
导师	上官周平
	2008
学位授予单位	中国科学院研究生院
学位授予地点	陕西
学位专业	生态学
其他摘要	提高作物的水分利用效率（WUE）和对干旱的适应能力是生物节水农业的主要研究内容之一，以肥调水尤其是通过氮素营养调控作物WUE和改善抗旱性仍是基础理论和生产实践领域的研究热点。本研究在大田条件下，以两个生态型相近、有明显抗旱性差异的冬小麦品种为试验材料，以不同氮素水平为处理手段，测定了小麦叶片光合气体交换参数、叶绿素荧光参数、ABA含量、NO含量、保护酶系活性、地上生物量、水分状况、产量等指标，来研究小麦叶片NO—ABA—WUE之间的关系、氮素对小麦叶片激发能转化分配的调控机制、叶片全N含量—ABA含量—WUE之间的相互关系以及氮素对小麦叶片膜脂抗过氧化作用的影响，以探明提高小麦抗旱性和改善水分利用状况的生理途径。取得了如下研究结果：（1）初步探明了氮素对小麦叶片NO含量-ABA含量-WUE关系的影响及其对抗旱性的作用机制。分蘖期和拔节期小麦叶片NR活性与NO含量显著线性正相关（R²≥0.568，n=15），氮素通过提高叶片NR活性来提高叶片NO水平进而调控气孔开度；在N₃₆₀处理的叶片ABA含量和NO含量之间为正协同作用关系，而在低氮条件下为负相关关系；抗旱性与气孔对NO含量变化的灵敏度有关，旱地品种对叶片NO含量的变化具有较快速的反应。合理施氮（N₁₈₀处理）能够使得NO含量处于较低水平而诱导气孔开放，促进水地品种气体交换并提高IWUE、提高旱地品种气孔对NO含量和干旱的反应灵敏性。（2）揭示了氮素对小麦叶片激发能转化分配的调控机制。氮素提高了小麦叶片光合色素含量，降低呼吸速率，虽然氮素不能显著改变激发能在光合碳还原（PCR）和光合碳氧化（PCO）之间的分配比例，但提高了在PCR方向的电子流量，过量氮素供应会使叶片暗呼吸作用增强；Φ_PSⅡ随叶片全N含量增加呈先下降后升高的变化趋势，P_n与Φ_PSⅡ线性正相关；氮素能够改善热耗散和光化学反应对激发能的竞争关系，增强光合机构活性以使得更多的光能进入碳同化过程，最终提高IWUE。（3）初步阐明了叶片全N含量—ABA含量之间的关系及其对WUE的影响。施氮后小麦叶片全N和ABA含量呈显著线性负相关，合理施氮能够增强叶片ABA含量和全N含量之间的相互影响。随氮素水平的提高，叶片IWUE对ABA含量的敏感性增强，而GWUE与旗叶ABA含量呈显著的负线性相关。旗叶全N含量和GWUE之间呈显著的负二次相关，合理施氮能够使叶片全氮含量维持在适宜水平，提高P_n以促进干物质积累，提高IWUE，并最终提高子粒产量和水分利用效率。（4）明确了氮素对小麦叶片膜脂抗过氧化作用的影响。施氮提高了小麦叶片CAT和SOD活性，降低了XOD活性、H₂O₂和MDA含量；N₀处理旱地品种较水地品种具有较高的保护酶系活性和较低的XOD活性、H₂O₂和MDA含量，细胞膜稳定性与小麦抗旱性密切相关，氮素能够通过提高叶片膜质抗过氧化能力来增强小麦对干旱的适应。（5）研究证明了氮素对小麦产量和形态发育的影响。氮素能够提高小麦叶片光合色素含量使得P_n显著增加、维持一定的气孔开度而促进了光合气体交换，促进干物质积累；施氮后株高和穗长有明显的增加，虽然千粒重在施氮后有一定程度下降，但穗粒重较N₀处理显著提高；氮素对小麦群体发育也有明显的促进作用，LAI在施氮后显著升高，并最终表现较高的产量、WUE和HI。; To increase crop water use efficiency and drought-resistance is one of the important contents of water-saving agriculture, fertilizing in order to save water, especially, supplying nitrogenous fertilizer to regulate crop water use efficiency and amend the drought-resistant ability are the hotspot both in theory and practice field. The two wheat cultivars with similar ecological characteristics and different drought-resistance had been selected as experimental materials, and the different nitrogen levels also used as treatments in this study. Photosynthetic gas exchange parameters, chlorophyll fluorescence parameters, ABA and NO content, the activity of protectase, aboveground biomas, plant water content and yield were determined. The relationship among leaf NO content, ABAcontent and WUE, the regulating mechamism of nitrogen on the trans-conductance and distribution of excitation energy, the relationship among leaf total N content, leaf ABA content and WUE, and the effects of nitrogen on leaf cell membrane stability had been studied to search the physiological methods which can increase drought-resistance and ameliorate water use status of wheat. The main results described as below. （1）The effects of nitrogenous fertilization on the relationship among leaf NO content, ABA content and water use efficiency and its mechanism regulated the drought-resistant ability was clafiried basically. The leaf NR activity had positively linear correlation with NO content in tillering and jointing stage (R²≥0.68，n=15), leaf NR activity was enhanced with the increasing of nitrogen fertilization content and further to increase NO content and then adjust stomatal opening. The leaf ABA content was positively related with leaf NO content at N₃₆₀ treatment, but negatively related in the lower nitrogen levels. The drought-resistance depend on the stomatal sensitivity to leaf NO content on the stoma level, the stoma of dryland cultivar could rapidly response to the changing of leaf NO content. The reasonable nitrogen application (N₁₈₀treatment) could maintain lower leaf NO content and sustain the stoma opening, to promote the gas exchange and increase IWUE of sensitive cultivar, increase the stomatal sensitivity to leaf NO content of dryland cultivar, enhance the responsible sensitivity of dryland cultivar to drought condition.（2）The regulated mechanism of nitrogen on the trans-conductance and distribution of excitation energy were revealed. Nitrogen improved the photosynthetic pigment content in leaves of different drought resistance cultivars, decreased respiration rate. Although nitrogen could not significantly change the distribution ratio of excitation energy between PCR and PCO, but it improved the electron flow at the PCR direction. Excessive nitrogen fertilization could enhance the dark respiration of leaf. Φ_PS_Ⅱdecreased first and then increased as the increasing of leaf total N. There was linear positive correlation between P_nand Φ_PS_Ⅱ. These proved that nitrogen could ameliorate the competition relationship of excited energy between heat dissipation and photochemistry reaction and increase the ability of photosynthetic instruments so that more light energy could enter the process of carbon assimilation, and increase IWUE finally. （3）The relationship between leaf total N content and ABA content and its effects on WUE was primarily clarified. Leaf total N and ABA content of the two cultivars were significant negative linear correlation when nitrogen supplied, reasonable nitrogen fertilization could strengthen the reciprocal effects between ABA content and total N content in flag leaves, whereas, excessive N did decrease this interaction. The sensitivity of leaf IWUE to ABA content was increased with the increasing of nitrogen fertilization; GWUE had negatively linear correlativity with ABA content in flag leaves. The total N content and GWUE had significant negatively quadric correlation with each other in flag leaves, which showed that appropriate application of nitrogen content can maintain the reasonable level of leaf total N content, increase photosynthetic rate to accelerate accumulation of dry matter and enhance instantaneous WUE to bring about the increment of wheat yield and water use efficiency. （4）The effects of nitrogen application on celluar membrane anti-peroxidation of wheat leaves was explicited. The application of nitrogen increased leaf CAT and SOD activity, decreased XOD activity、H₂O₂ and MDA content. N₀treatment in dryland cultivar had higher activity of protectase and lower XOD activity、H₂O₂ and MDA content than sensitive cultivar. Cellular membrane stability have close correlation with wheat resistance to drought, thereby nitrogen application enhanced the adaptability to drought by increasing leaf anti-peroxidation of wheat. （5）The effects of nitrogen application on yield and configuration developing of wheat was validated. Nitrogenous fertilizer could increase leaf photosynthetic pigment in order to increase P_n, and it also could maintain the stoma opening and improve gas exchange, and the dry matter assimilation was enhanced. The plant height and spike length was increased after nitrogen supplied, although kilo-grain weight was decreased but the spike grain weight was increased compared the N₀treatments. The group growth was improved by nitrogen fertilizer, the leaf area index was increased significantly after nitrogen supplied, and the yield, water use efficiency and harvest index were enhanced finally.
文献类型	学位论文
条目标识符	sbir.nwafu.edu.cn/handle/361005/4087
专题	水保所知识产出(1956---)
推荐引用方式 GB/T 7714	张绪成. 不同氮素水平对小麦光合能量转化及水分利用效率的影响[D]. 陕西. 中国科学院研究生院,2008.