| 宋海星,李生秀.限根条件下供氮对玉米光合作用有关生理特性的影响[J].干旱地区农业研究,2004,(4):28~32 |
| 限根条件下供氮对玉米光合作用有关生理特性的影响 |
| Effect of nitrogen on some physiological characteristics in relation with photosynthesis of maize under restricted roots |
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| DOI：10.7606/j.issn.1000-7601.2004.04.04 |
| 中文关键词: 玉米 水分 氮素 光合速率 |
| 英文关键词:maize water nitrogen photosynthetic rate |
| 基金项目:2004-06-27 基金项目：国家重点基础研究专项（ G1999011707） ；国家自然科学基金重点项目（30230230） ；面上项目（30070429，40201028） 资助 |
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| 中文摘要: |
| 以玉米为供试作物,在遮雨棚内进行了微区田间试验,在不同水分与供氮条件下,分期测定了玉米自由水与束缚水比值和细胞汁液浓度、气孔导度和细胞间隙CO2浓度、核酮糖-1,5二磷酸羧化酶(RuBPCase)活性和叶绿素含量、以及叶片的光合速率和作物产量,研究供氮对玉米光合作用有关生理特性的影响。结果表明,氮素对光合生理特性的影响受水分供应状况的制约:水分供应较好时,供氮提高了叶片自由水与束缚水比值,降低了叶肉细胞汁液和细胞间隙CO2浓度;增加了气孔导度,提高了RuBPCase活性和叶绿素含量,既有利于改善气孔因素,也有利于改善非气孔因素,显著提高光合速率和作物产量。水分胁迫较轻时,供氮降低了气孔导度,增加了CO2进入气孔的阻力,不利于光合作用,但却提高了叶片自由水与束缚水比值,降低了叶肉细胞汁液和细胞间隙CO2浓度,增加了RuBPCase活性和叶绿素含量。在这种情况下,光合作用的气孔因素受到影响,非气孔因素不但没有减弱,反而有所增强,因而光合速率和产量都有所提高。水分胁迫严重时,供氮不但抑制了光合作用的气孔因素,还更严重地抑制了非气孔因素,导致光合速率和作物产量严重下降。供氮对光合作用影响的水分依赖性为调控氮素营养提供了有力依据。 |
| 英文摘要: |
| A field experiment with micro-plots was conducted under rain-preventing condition for studying the effects of N supply on some physiological characteristics related with photosynthesis of maize. With application of different rates of N and water, determinations were made for the ratio of free water to bound water in leaves, cell sap concentrations, stomatal conductance, intercellular CO2concentrations, RuBPCase activity, chlorophyll contents, leaf photosynthesis rate at different time, and finally the biomass yields. The results showed that the effect of N on photosynthesis was determined by water supply. When water supply was relatively sufficient, input of N raised the ratio of free water to bound water in leaves, decreased sap in diachyma cells and intercellular CO2concentrations, raised stomatal conductance, RuBPCase activity and chlorophyll contents. This was not only beneficial to improvement of the stomatal factors but also to the non-stomatal factors, and consequently resulted in significant increase in photosynthesis rate and biomass production. When water was slightly stressed, input of N decreased stomatal conductance, and increased the resistant force for CO2entering stomata, being detrimental to photosynthesis, but it raised the ratio of free water bound water, decreased in diachyma cells sap concentration and intercellular CO2concentration as well as RuBPCase activity and chlorophyll contents. In this case, N input mainly affected the stomatal factors of photosynthesis, but the non-stomatal factors were not decreased, but increased, and therefore photosynthesis rate and biomass were raised. In contrast, when water was seriously stressed, input of N did not only inhibit the stomatal factors but also seriously inhibited the non-stomatal factors as major causes, resulting in photosynthesis rate and biomass decline. The effect of N input on photosynthesis being dependant on water supply provides a basis for regulation of N nutrition. |
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