Different Light Quality Effects on the Growth and Pigment Accumulation of Regenerated Plants of Caladium bicolor

Abstract

【Objective】Caladium bicolor is a foliage plant in the Araceae family, characterized by rich colors and diverse patterns on its leaves, making it widely used for indoor and outdoor ornamental purposes and possessing good economic value. C. bicolor is often cultivated in greenhouses without additional lighting measures, which limits the quality and efficiency of seedling production due to weather conditions, making it difficult to guarantee the production efficiency and standardization of commercial seedlings. Light is an important factor in the growth and pigment accumulation of C. bicolor. The study aims to explore suitable types of light quality for tissue-cultured C. bicolor seedlings, providing a theoretical basis for improving the production efficiency and seedling quality of C. bicolor plants.【Method】We used white fluorescent light as a control and employed 7 different light quality types including LED white light, LED red light, LED blue light, LED red-blue-white 1:1:1, LED red-blue-green 1:1:1 and LED red-blue-white-green 1:1:1:1 light to treat tissue-cultured regenerated plants of C. bicolor. Various growth indicators such as leaf size, leaf thickness, plant height, number of roots, and pigment content of C. bicolor after different light quality treatments were measured to evaluate and select effective light qualities that could enhance the quality of commercial C. bicolor seedlings.【Result】Compared to fluorescent light, LED red light treatment was detrimental to the increase in the number of leaves and the thickness of petioles in C. bicolor, which were 5.3 pieces and 3.42 mm, respectively; it hindered the accumulation of total chlorophyll content and relative anthocyanin content on the leaf surface, which were 2.0 mg/g and 1.0 U/g respectively; and it was also unfavorable for the maximum photochemical efficiency of PSII (Fv/Fm) and the actual quantum yield of photosystem II〔Y(II)〕, with values of only 0.64 and 0.60, respectively. LED blue light treatment promoted the increase in plant height, petiole thickness and accumulation of relative anthocyanin content in C. bicolor, which were 21 cm, 4.6 mm and 6.1 U/g, respectively. However, it was not beneficial for the increase in the number of roots in C. bicolor. For the light combination treatment, LED red blue white green 1:1:1:1 was beneficial for the increase of leaf area, reaching 98.8 cm2. The relative anthocyanin content on the leaf surface was highest under this treatment, reaching 8.23 U/g. LED red blue green 1:1:1 treatment was not conducive to increasing plant height, petiole thickness and leaf thickness, which were 10.6 cm, 3.9 mm, and 0.70 mm, respectively. The relative anthocyanin content on the petioles of C. bicolor under LED red blue white 1:1:1, LED red blue green 1:1:1, and LED red blue white green 1:1:1:1 treatments was significantly lower than that under white fluorescent lamp light treatment.【Conclusion】Different light qualities influence the growth and pigment accumulation of regenerated plants of C. bicolor. LED blue light treatment is the most effective in increasing plant height, petiole thickness and relative anthocyanin content in C. bicolor. LED red blue white green 1:1:1:1 treatment is the most effective in increasing leaf area and relative anthocyanin content on the leaf surface. By selecting the appropriate light quality ratio based on actual conditions in production, the efficiency of standardized production of C. bicolor seedlings can be effectively improved.

Keywords

• ornamental plant
• light quality
• caladium bicolor
• regenerated plant
• morphogenesis
• anthocyanin