In order to investigate the effects of different far-red and green light intensities on the growth and photosynthetic characteristics of melon seedlings, 'Emerald ' was used as the test material. Three different intensities of far-red and green light were added basis on a fixed ratio of red to blue light (R:B=4:1) and photosynthetically active radiation (200 μmol/ (m2·s)). The red to far-red light ratios of each treatment were 10 (L-FR), 1.2 (M-FR) and 0.8 (H-FR), respectively. The ratio of green light was set at 10% (L-G), 20% (M-G) and 30% (H-G), corresponding to intensities of 20, 40 and 60 μmol/ (m2·s), respectively. The results showed that: the height of melon seedlings increased significantly with the increase of far-red light intensity, and increasing the proportion of green light in the light quality within the appropriate range could increase both fresh weight and dry weight of seedlings; the palisade tissue, spongy tissue and leaf thickness of melon seedlings showed a decreasing tendency with the increase of far-red light intensity; while increasing the proportion of green light primarily affected the spongy tissue of melon leaves; the stomatal density of melon plants significantly increased with the increase of far-red light intensity in the three treatment groups; Stomatal density significantly increased with higher far-red light intensity in the three treatment groups. Furthermore, the transpiration rate (E), intercellular CO2 content (Ci), and stomatal conductance (Gsw) all increased with the rising far-red light intensity. While increasing the green light ratio decreased the stomatal pore area, but increased the leaf stomatal density. The net photosynthetic rate of melon seedlings in the M-G treatment was significantly higher than that in the other treatments. In conclusion, appropriately adding far-red and green light during plant growth can enhance seedling growth rate, increasing stomatal density, and improve the photosynthetic capacity of plants.

中文翻译：

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不同强度的远红和绿光对甜瓜幼苗生长和光合特性的影响


为探究不同远红光和绿光强度对甜瓜幼苗生长和光合特性的影响，以'翡翠 ' 为供试材料。在红蓝光 （R：B=4：1） 和光合有效辐射 （200 μmol/ （m2·s） 的固定比例基础上添加三种不同强度的远红光和绿光。各处理的红光与远红光比分别为 10 （L-FR） 、 1.2 （M-FR） 和 0.8 （H-FR）。绿光比例设置为 10% （L-G） 、 20% （M-G） 和 30% （H-G），分别对应于 20、40 和 60 μmol/ （m2·s） 的强度。结果表明：甜瓜幼苗高度随远红光强度的增加而显著增加，在适当范围内增加光质中绿光的比例可以提高幼苗的鲜重和干重;甜瓜幼苗的栅栏组织、海绵组织和叶片厚度均随远红外光强度的增加而呈减小趋势;而绿光比例的增加主要影响甜瓜叶片的海绵组织;3个处理组甜瓜植株气孔密度随远红光强度的增加而显著增加;3 个处理组气孔密度随着远红光强度的增加而显著增加。此外，蒸腾速率 （E） 、胞间 CO2 含量 （Ci） 和气孔导度 （Gsw） 均随着远红外光强度的增加而增加。在增加绿光比的同时，减小了气孔孔隙面积，但增加了叶片气孔密度。 M-G 处理甜瓜幼苗的净光合速率显著高于其他处理。综上所述，在植物生长过程中适当添加远红光和绿光可以提高幼苗生长速度，增加气孔密度，提高植物的光合能力。