| PEG模拟干旱胁迫对五唇兰光合系统的影响 |
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| 引用本文： | 张瀚,李晗,陈奇,杨福孙.PEG模拟干旱胁迫对五唇兰光合系统的影响[J].热带作物学报,2021,42(9):2645-2652. |
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| 作者姓名： | 张瀚 李晗 陈奇 杨福孙 |
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| 作者单位： | 海南大学热带作物学院,海南海口 570228 |
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| 基金项目： | 国家自然科学基金项目(31660227) |
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| 摘 要： | 以3年生红背型五唇兰组培苗为试验材料,分别用5%、10%、20%的PEG 6000溶液处理模拟干旱胁迫,研究不同程度的干旱对五唇兰光合系统的影响,结果表明：（1）干旱导致叶片的气孔密度、开度、长度逐渐降低,且随PEG胁迫时间的延长下降趋势越明显,处理15 d后PEG 10%以上处理与CK差异达显著水平。（2）干旱导致叶片中苹果酸含量逐渐降低,随着PEG处理时间的延长,五唇兰叶片的苹果酸含量下降趋势减缓,凌晨叶片的苹果酸含量显著高于傍晚,处理15 d后PEG 20%处理下傍晚的苹果酸含量差异达显著水平,与CK相比降低了27.16%。（3）干旱导致叶片的净光合速率、蒸腾速率、气孔导度逐渐降低,随PEG胁迫时间的延长下降越显著,胞间CO2浓度的变化趋势则相反,水分利用效率呈先升高后降低的趋势,处理后第15天PEG 5%以上处理与CK差异均达显著水平。（4）干旱导致五唇兰叶片叶绿素的初始荧光值（Fo）逐渐升高,可变荧光值（Fv）、最大荧光值（Fm）、PSⅡ实际光化学效率（Fv/Fm）、PS Ⅱ潜在光化学效率（Fv/Fo）则逐渐降低,表观电子传递速率（ETR）、光化学淬灭系数（qP）、PSⅡ实际光量子效率（Yield）随着PEG胁迫程度的增加而逐渐降低。非光化学淬灭系数（NPQ）随PEG胁迫浓度的增加显著提高,处理15 d后PEG 5%以上处理与CK差异达显著水平。结果表明,10%、20% PEG处理能够在较短时间内通过影响叶片的气孔关闭、降低气孔密度进而降低光合作用和阻碍光合代谢产物苹果酸的合成,同时影响五唇兰叶片对光能的吸收传递以及光化学转换,5% PEG处理在处理10 d后才表现出光合生理受到抑制的现象,说明中度、重度干旱能够在较短时间内影响五唇兰叶片的气孔性状,进而降低叶片的光合能力,导致光合产物的合成受阻,最终导致光合系统受到抑制。
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| 关 键 词： | 五唇兰 PEG胁迫 光合特性 苹果酸 |
| 收稿时间： | 2020-11-05 |
Effects of PEG Drought Stress on Photosynthetic System of Phalaenopsis pulcherrima |
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| ZHANG Han,LI Han,CHEN Qi,YANG Fusun.Effects of PEG Drought Stress on Photosynthetic System of Phalaenopsis pulcherrima[J].Chinese Journal of Tropical Crops,2021,42(9):2645-2652. |
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| Authors: | ZHANG Han LI Han CHEN Qi YANG Fusun |
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| Institution: | College of Tropical Crops, Hainan University, Haikou, Hainan 570228, China |
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| Abstract: | Three year old tissue culture seedlings of Phalaenopsis pulcherrima were treated with 5%, 10% and 20% PEG 6000 solution respectively to study the effects of drought on photosynthetic system. Drought led to the decrease of stomatal density, opening and length, and the decreasing trend became more obvious with the prolongation of PEG stress time. More than 10% treatments were significantly different from CK. With the extension of PEG treatment time, the decline trend of malic acid content was slowed down. The content of malic acid in leaves measured in the early morning was significantly higher than that in the evening. After 15 days of treatment, the difference of malic acid content between PEG 20% treatment and CK was significant, which was 27.16% lower than that of CK. The net photosynthetic rate, transpiration rate and stomatal conductance of leaves decreased gradually with the prolongation of PEG stress time. The change of intercellular CO2 concentration showed an opposite trend, and water use efficiency increased first and then decreased. After 15 days of treatment, the difference between the treatment of PEG 5% and CK was significant. Drought caused the initial fluorescence value (Fo) to increase gradually, but the variable fluorescence value (Fv), maximum fluorescence value (Fm), PSⅡ actual photochemical efficiency (Fv/Fm), PSⅡ potential photochemical efficiency (Fv/Fo) decreased gradually. The apparent electron transfer rate (ETR), photochemical quenching coefficient (qP), and PSⅡ actual quantum efficiency (Yield) decreased with the increase of PEG stress. The non photochemical quenching coefficient (NPQ) increased significantly with the increase of PEG stress concentration. After 15 days of treatment, the difference between the treatment of PEG 5% and CK was significant. Conclusion: 10%, 20% PEG treatment could reduce photosynthesis and inhibit the synthesis of malic acid by affecting stomatal closure and stomatal density of leaves in a short period of time. At the same time, it affected the absorption and transmission of light energy and photochemical conversion in leaves of P. pulcherrima. 5% PEG treatment did not show the phenomenon of inhibition of photosynthetic physiology until 10 days after treatment, indicating that moderate and severe drought could be achieved in a short time. The stomatal characters of leaves were affected, and the photosynthetic capacity of leaves was reduced. Finally, the synthesis of photosynthetic products was blocked, and the photosynthetic system was inhibited under drought stress. |
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| Keywords: | Phalaenopsis pulcherrima PEG stress photosynthetic characteristics malic acid |
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