Light-emitting diodes (LEDs) in development and response to water stress in Eucalyptus benthamii seedlings (Myrtaceae)

ABSTRACT: Plants use light as a source of energy in the process of photosynthesis. Different levels of luminosity cause physiological and morphological changes in the plant, and its success depends on its adaptation to these different levels. Light emitting diodes (LED) have been proposed as a light source in controlled environments. The present research evaluated physiological and morphological aspects in Eucalyptus benthamii (Myrtaceae) seedlings kept under different colors of LED lamps and submitted to water stress. The experiment was carried out in a completely randomized design, in which the treatments were defined as: T1 (control, with white light); T2 (blue light); T3 (red light) and T4 (mixed blue and red light). Red light resulted in the best response to most morphological variables in plant growth. In response to water stress, blue light LEDs resulted in a better seedling response, with slower reduction of photosynthetic rate and other variables. This may indicate the possibility of reducing water deficit damage in seedlings acclimated to blue light prior to field planting.

摘要：植物在光合作用过程中以光能作为能量来源。不同光照强度可诱导植物产生生理与形态变化，植物的生长表现取决于其对不同光照强度的适应能力。发光二极管（Light Emitting Diode，LED）已被提议作为可控环境中的人工光源。本研究针对处于不同颜色LED灯照环境下且经受水分胁迫的本哈姆桉（Eucalyptus benthamii，桃金娘科(Myrtaceae)）幼苗的生理与形态指标进行了评估。本实验采用完全随机设计，共设置4组处理：T1（对照组，白光照射）、T2（蓝光照射）、T3（红光照射）以及T4（红蓝混合光照射）。红光处理下，植物生长的多数形态指标均呈现最优响应。在水分胁迫条件下，蓝光LED处理的幼苗响应更优，其光合速率及其他指标的下降速率更为缓慢。这表明，在田间定植前对幼苗进行蓝光驯化，或可降低水分亏缺对其造成的损伤。