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叶脉是植物叶片光合作用水分输送的重要结构。为阐述叶脉与光合特性之间的关系,以C4植物高粱(Sorghum bicolor)、C3植物紫苏(Perilla frutescens)为实验材料研究了叶脉密度和光合特性之间的关系。结果表明,与紫苏相比,高粱叶片叶脉密度大,导水能力强,蒸腾速率高,但气孔密度小。进一步分析表明,高粱叶片近轴侧气孔密度占总气孔的比例明显高于紫苏。叶脉密度大的高粱具有较高的净光合速率;而紫苏叶脉密度小,净光合速率也较低。由此表明,较高的叶脉密度有利于支持较高的光合速率,但研究表明叶脉密度和气孔密度可能不存在严格的协同变异关系。研究结果对理解植物光合作用适应有重要意义。
Vein is the important structure of photosynthetic water transport in plant leaves. In order to elucidate the relationship between leaf veins and photosynthetic characteristics, the relationship between leaf vein density and photosynthetic characteristics was studied using C4 sorghum bicolor and C3 plant perilla frutescens. The results showed that compared with perilla, sorghum leaf veins density, water conductivity, transpiration rate, but stomatal density is small. Further analysis showed that the ratio of stomatal density to total stomata in the paraxial side of sorghum was significantly higher than that of perilla. Sorghum with high leaf density had a higher net photosynthetic rate (Pn); however, the density of Perilla frutescens leaf veins was small and the net photosynthetic rate was also lower. Thus, higher leaf vein density is favorable for supporting higher photosynthetic rate. However, studies have shown that there is no strict co-variation relationship between leaf vein density and stoma density. The research results are of great significance for understanding the adaptation of plant photosynthesis.