| 缺氮对槟榔幼苗叶片光合特性的影响 |
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| 引用本文： | 崔闯,吴娇,刘东峻,黄书怡,万迎朗.缺氮对槟榔幼苗叶片光合特性的影响[J].热带生物学报,2020,11(4):446-454. |
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| 作者姓名： | 崔闯 吴娇 刘东峻 黄书怡 万迎朗 |
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| 作者单位： | 海南大学 热带作物学院，海口 570228 |
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| 基金项目： | 国家自然科学基金;海南省科技重大专项;研究生创新项目 |
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| 摘 要： | 以‘热研一号’槟榔幼苗为试验材料，通过缺氮处理，观测槟榔苗生长状态；测定槟榔苗的生物量、叶绿素含量、叶绿素荧光参数，并结合气体交换指标,分析缺氮胁迫对槟榔幼苗叶片光合特性的影响。结果显示，与对照（CK）相比，缺氮胁迫下，槟榔苗地上部矮小，叶片发黄，生物量降低但差异不显著；而地下部根系发达，根冠比显著升高。缺氮处理的槟榔苗各叶序叶片叶绿素a、b含量均显著低于对照，且叶绿素b含量降低幅度更大。缺氮胁迫还导致槟榔苗各叶序叶片的光合速率、蒸腾速率、气孔导度、最大光化学效率（Fv/Fm）、实际光化学效率Y（Ⅱ）、光化学淬灭参数qP等均显著下降，而细胞间CO2浓度、非光化学淬灭参数NPQ显著上升。缺氮胁迫还导致槟榔苗各叶序叶片的叶肉细胞密度显著低于对照。结果表明，缺氮胁迫使槟榔苗叶片叶绿素合成受到抑制，PSⅡ反应中心活性下降，光合效率降低，导致整株生物量下降；在缺氮条件下，槟榔苗会通过调整地上部与地下部的生物量的分配以维持根系与地上部的生长平衡，同时槟榔苗可通过采取降低叶绿素b在光合色素中的比例以及提高叶片厚度和上表皮细胞厚度等策略来增强热耗散机制，从而适应热带高温、强光的生存环境。
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| 关 键 词： | 缺氮胁迫 槟榔苗 生长状态 叶绿素含量 光合特性 |
| 收稿时间： | 2020-04-23 |
Effects of Nitrogen Deficiency on the Photosynthetic Characteristics of Areca catechu L. Seedling Leaves |
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| Affiliation: | College of Tropical Cros, Hainan University, Haikou, Hainan 570228, China |
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| Abstract: | The growth and leaf microstructure of seedlings of arecanut (Areca catechu L.) under nitrogen deficiency were observed, and the biomass, chlorophyll content, chlorophyll fluorescence parameters and gas exchange index of the arecanut seedling leaves were determined to analyze the effect of nitrogen deficiency stress on photosynthetic characteristics of arecanut seedling leaves. The results showed that compared with the control the arecanut seedlings were shorter in the aboveground part, yellow in the leaves and lower in the biomass but without significant difference, while they were well developed in the root system in the underground part and had a significantly high ratio of root to crown. The contents of chlorophyll a, b in each leaf of the first three leaves from the top of the arecanut seedlings was significantly lower under the nitrogen deficiency stress than in the control, and the content of chlorophyll b decreased more significantly. The nitrogen deficiency stress reduced significantly leaf chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance, the maximal photochemical efficiency (Fv/Fm), actual photochemical efficiency Y (Ⅱ) and photochemical quenching coefficient qP but increased the intercellular CO2 concentration and the non-photochemical quenching coefficient NPQ significantly. The density of mesophyll cells in all the first three leaves of the arecanut seedlings was significantly lower in the nitrogen deficiency treatment than in the control. The results showed that nitrogen deficiency stress inhibited the synthesis of chlorophyll, and reduced the activity of PSII reaction center and the photosynthetic efficiency, leading to lower production of the biomass of the arecanut seedlings. Under nitrogen deficiency the arecanut seedlings regulate their biomass distribution between the aboveground and underground parts to maintain their balanced growth between the aboveground part and the root system, and at the same time they may reduce the proportion of chlorophyll b in the photosynthetic pigments and improve the thickness of leaves and the cells of the upper epidermis of the leaves to enhance their heat dissipation mechanism for their adaptation to the environment of high temperature and strong sunlight in the tropics. |
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