| 摘要: 在异质性光环境中, 植物通常会表现出光合补偿现象以增强对光能的利用。而有些植物的光合补偿会受到明显的限制, 但其中所涉及的生物学特征和机制并不清楚。本研究以光合补偿受限的玉米植株为材料, 对比分析了异质性光(HL)和同质性光(FL)下未遮光叶片的形态解剖结构、气体交换特征、光合同化物及关键合成酶含量。结果表明: 与FL相比, HL处理下叶片的厚度、相对叶肉细胞面积(SMC)、相对维管束鞘细胞面积(SBSC)、相对维管束面积(SVB)和维管束鞘与维管束接触面积(ILBSC-VB)较小。同时，HL处理下叶片的净光合速率(Pn)和气孔导度(Gs)较低。此外, HL处理下叶片的淀粉含量较低, 蔗糖含量变化不大, 而蔗糖磷酸合成酶(SPS)含量较高。因此, HL处理下光合补偿受限与叶片形态解剖结构限制及气孔行为相关。光合补偿受限时, 未遮光叶片中光合产物合成减少, 但其会更多地向蔗糖合成方向分配。然而，由于形态解剖结构的限制, 叶片蔗糖的输出能力较弱。这些结果为进一步解析植物适应异质性光环境的特征和机制, 以及选育适合间套作等栽培模式的品种提供了基础。 |
| 关键词: 玉米 异质性光 光合补偿限制 光合同化物 |
| 中图分类号:S513 |
| 基金项目:国家重点研究发展计划项目 |
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| Relationship between photosynthetic compensation limitation and photoassimilates of maize under heterogeneous light* |
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MA Cuie, LIU Yu, QIU Xi, Du Junbo, SUN Xin
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College of Agronomy,Sichuan Agricultural University
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| Abstract: Plants usually show photosynthetic compensation to enhance the utilization of light energy under heterogeneous light environment. The photosynthetic compensation of some plants is obviously limited, but the biological characteristics and mechanisms involved are not clear. In this study, the morphological and anatomical structure, gas exchange characteristics, photosynthetic assimilates and key synthase contents of unshaded leaves under heterogeneous light (HL) and homogeneous light (FL) were compared in maize plants with limited photosynthetic compensation. The results showed that the leaf thickness, relative mesophyll cell area (SMC), relative bundle sheath cell area (SBSC), relative bundle area (SVB) and bundle sheath and bundle contact area (ILBSC-VB) of leaves under HL treatment were smaller than those under FL treatment. Meanwhile, the net photosynthetic rate (Pn) and stomatal conductance (Gs) of leaves under HL treatment were lower. In addition, the starch content of the leaves under HL treatment was lower, the sucrose content was little changed, and the sucrose phosphate synthetase (SPS) content was higher. Therefore, the restriction of photosynthetic compensation under HL treatment is related to the restriction of leaf morphological and anatomical structure and stomatal behavior. When the photosynthetic compensation was limited, the synthesis of photosynthetic products in the unshaded leaves decreased, but more photosynthate was allocated to sucrose synthesis. However, due to morphological and anatomical limitations, the output capacity of leaf sucrose was weak. These results provided a basis for further analysis of the characteristics and mechanisms of plant adaptation to heterogeneous light environment, and for breeding varieties suitable for intercropping. |
| Keyword: Maize Heterogeneous light Photosynthetic compensation restriction Photoassimilate |