Application of LED supplementary light in vegetable seedling cultivation

It is an important technology in the field of greenhouse cultivation to regulate plant morphogenesis and growth and development with LED light source. Higher plants can sense and receive light signals through photoreceptor systems such as phytochrome, cryptochrome, and phototropin, and conduct them through intracellular messengers to regulate morphological changes such as plant tissue and organ building. Photomorphogenesis is that plants rely on light to control cell differentiation, changes in structure and function, and the establishment of tissues and organs, including the influence on the germination of some seeds, the promotion of apical dominance, the inhibition of lateral bud growth, the elongation of stems, and the induction of tropism, etc. .

Vegetable seedling cultivation is an important part of facility agriculture. Continuous cloudy and rainy weather will cause insufficient light in the facility, and the seedlings are prone to excessive growth, which in turn affects the growth of vegetables, flower bud differentiation and fruit development, and ultimately affects their yield and quality. In production, some plant growth regulators are used to regulate the growth of seedlings, such as gibberellin, auxin, paclobutrazol and chlormequat, etc. Bad for human health. LED supplementary light has many unique supplementary light advantages, and it is a feasible way to use LED supplementary light to grow seedlings. In the experiment of LED supplementary light [25±5 mol/(m2)] under the condition of low light [0~35 mol/(m2)], it was found that green light promoted the elongation and growth of cucumber seedlings, and red light promoted the growth of cucumber seedlings. Compared with blue light inhibiting seedling growth, compared with the seedling growth index under natural weak light, the growth index of supplemented red and blue light increased by 151.26% and 237.98%, respectively, and compared with monochromatic light quality, the compound containing red and blue components The seedling growth index increased by 304.46% under the treatment of light quality and supplementary light. Supplementing cucumber seedlings with red light can increase the number of true leaves, leaf area, plant height, stem diameter, dry and fresh quality, seedling strength index, root activity, SOD activity and soluble protein content of cucumber seedlings, and supplementing UV-B can improve cucumber seedlings. The content of chlorophyll a, chlorophyll b and carotenoids in the leaves of seedlings; compared with natural light, supplementing LED red light and blue light can significantly increase the leaf area, dry matter, and seedling index of tomato seedlings, and supplementing LED red and green light can make tomato seedlings plant height and stem diameter increased significantly; LED green light supplement light treatment can significantly increase the biomass of cucumber and tomato seedlings, and the fresh and dry weight of seedlings increased with the intensity of green light supplement light, while tomato seedlings had thick, strong stems. The seedling index all increased with the intensity of green light; LED red and blue combined light can increase the stem diameter, leaf area, dry weight of the whole plant, root-shoot ratio, and seedling index of eggplant; compared with white light, LED red light It can increase the biomass of cabbage seedlings, promote the elongation growth and leaf expansion of cabbage seedlings; LED blue light can promote the thickening growth, dry matter accumulation and strong seedling index of cabbage seedlings, and make cabbage seedlings dwarf. The above results show that the advantages of vegetable seedlings cultivated in combination with light regulation technology are very obvious.