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| 模拟水分胁迫对乌桕幼苗光响应特征的影响 |
| Effects of Simulated Water Stress on Light Response Characteristics of Sapium sebiferum Seedlings |
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| DOI： |
| 中文关键词: 水分胁迫 光合作用 蒸腾作用 光饱和点 光响应模型 |
| 英文关键词:Water stress Photosynthesis Transpiration Light saturation point Light response model |
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| 中文摘要: |
| 在光合作用中，水分是重要的原料，当供水量不可以满足植物正常的生长时，就会造成水分胁迫。为探明水分胁迫条件下乌桕叶片光响应特征的变化规律，本试验以乌桕实生幼苗作为试材，采用PEG-6000（聚乙二醇）模拟水分胁迫，来测定乌桕叶片的光响应变化趋势，绘制出光响应曲线，并采用光响应模型，通过拟合对比了不同浓度聚乙二醇（CK，5%，10%，15%）处理下的光响应参数差异。结果表明：（1）四个浓度处理下，乌桕叶片的净光合速率（Pn）均在达到光饱和后，随着光合有效辐射强度（PAR）增加而下降，都表现出了光抑制现象。（2）随着胁迫浓度的增加，表观量子效率（AQE）、最大净光合速率（Pnmax）均表现为CK最好，其它处理随胁迫浓度的增加逐渐降低。（3）光饱和点（LSP）和光补偿点（LCP）在PEG浓度为10%时，LSP达到最大，并且高于CK，LCP此时处于最低值。（4）对乌桕幼苗叶片的光响应曲线拟合发现，4种模型中以直角双曲线修正模型最好，直角双曲线模型最差。本研究筛选出模拟乌桕光合特性的最佳光响应模型，对乌桕实际的栽培及水分管理具有重要的理论价值。 |
| 英文摘要: |
| To investigate the changes in the light response characteristics of Sapium sebiferum leaves under water stress, Sapium sebiferum seedlings were used as the experimental material in this study. PEG-6000 (polyethylene glycol) was used to simulate water stress, and the light response curves of the leaves were measured. Light response models were then used to fit and compare the differences in light response parameters under different PEG concentrations (CK, 5%, 10%, and 15%). The results showed that: (1) under the four concentration treatments, the net photosynthetic rate (Pn) of Sapium sebiferum leaves decreased with increasing photosynthetically active radiation (PAR) after reaching light saturation, indicating photoinhibition; (2) with increasing stress concentration, the apparent quantum efficiency (AQE) and maximum net photosynthetic rate (Pnmax) were highest in the CK treatment, whereas those in the other treatments gradually decreased as stress concentration increased; (3) when the PEG concentration was 10%, the light saturation point (LSP) reached its maximum, whereas the light compensation point (LCP) was at its minimum; and (4) fitting analysis of the light response curves of leaves of Sapium sebiferum seedlings showed that, among the four models, the modified rectangular hyperbola model performed best, whereas the rectangular hyperbola model performed worst. This study identifies the optimal light response model for simulating the photosynthetic characteristics of Sapium sebiferum and provides important theoretical support for its cultivation and water management. |
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