不同LED光照强度对盾叶秋海棠生长的影响

Effects of LED Light Intensity on the Growth of Begonia peltatifolia

摘要: 秋海棠属是典型的喜荫观赏植物，但有关荫棚等园艺设施及室内条件下栽培该类植物所需的适宜光照知之甚少。本研究以盾叶秋海棠(Begonia peltatifolia)盆栽苗为材料，在植物栽培室内(26℃)调查LED人工光源400、1500、2000、2500、3000、3500 lx六种光照强度对其生长和生理指标的影响。当光照强度为2000 lx时，盾叶秋海棠的叶片数、叶柄长、叶柄直径、叶面积、地上部分鲜重与干重均出现最大值，分别为14.60、6.76 cm、3.44 mm、42.33 cm²、45.45 g和1.87 g，而地下部分干重及根冠比达到最小，分别为0.31g和0.17；气孔导度与光合作用速率最大，分别为0.077 mol H₂O m⁻²∙s⁻¹和0.65μmol CO₂ m⁻²∙s⁻¹，但胞间CO₂浓度最小，为316.52 μmol CO₂ mol⁻¹，蒸腾速率较低，为1.07 mmol H₂O m⁻²∙s⁻¹。结果表明2000 lx为植物生长的最佳光照强度，可作为室内、荫棚或其它园艺设施内栽培盾叶秋海棠时参考。

Abstract: Begonia is an ornamental plant preferring shady environment for growth. However, little is known on the optimum light intensity for cultivating and producing it inside the building and horticultural facilities such as shade house. The potted seedlings of Begonia peltatifolia were treated by LED light at different light intensities (400, 1500, 2000, 2500, 3000, and 3500 lx) to investigate the effects of light on plant growth in plant growth room at 26˚C. The highest values of leaf number (14.6), petiole length (6.76 cm), petiole diameter (3.44 mm), leaf area (42.33 cm²), fresh weight (45.45 g) and dry weight (1.87 g) of the aboveground part of B. peltatifolia appeared at 2000 lx treatment, while the dry weight of underground part, and root-shoot ratio reached the lowest (0.31 g and 0.17, respectively) at the same light intensity. The highest values of stomatal conductance (0.077 mol H₂O m⁻²∙s⁻¹) and leaf photosynthesis (0.65 μmol CO₂ m⁻²∙s⁻¹) of B. peltatifolia also appeared at 2000 lx, while the intercellular CO₂ concentration reached the lowest (316.52 μmol CO₂ mol⁻¹) and the transpiration rate was relatively low (1.07 mmol H₂O m⁻²∙s⁻¹) under the same light intensity. The optimum light for cultivation of B. peltatifolia was 2000 lx in this study, which can be used as a reference for growing this species in the indoor, shade house and other horticultural facilities.