Physiological responses of tung tree (Vernicia fordii) saplings to different red, white, and blue light-emitting diodes

Authors: GU, YIYANG - Central South University Of Forestry And Technology; ZHANG, FANHANG - Central South University Of Forestry And Technology; ZENG, YANLING - Central South University Of Forestry And Technology; ZHANG, LIN - Central South University Of Forestry And Technology; TAN, XIAOFENG - Central South University Of Forestry And Technology; Cao, Heping; LI, ZE - Central South University Of Forestry And Technology

Submitted to: International Journal of Agriculture and Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2019
Publication Date: 9/1/2019
Citation: Gu, Y., Zhang, F., Zeng, Y., Zhang, L., Tan, X., Cao, H., Li, Z. 2019. Physiological responses of tung tree (Vernicia fordii) saplings to different red, white, and blue light-emitting diodes. International Journal of Agriculture and Biology. 22:569-577.

Interpretive Summary: Tung tree is a fast-growing tree with high photosynthetic efficiency. Tung oil from its seeds exhibits traits that are highly valued in many industrial applications including rapid drying, chemical resistance, adhesiveness and sleekness. Additionally, tung oil is the preferred material for manufacturing environmentally friendly paint. With decreases in crude oil, and increasing pressure for environmental protection, tung tree has become an excellent bio-energy tree and makes enormous contributions to industry. Light is one of the important elements for the growth of tissue culture seedlings. Rapid growth of tissue culture seedlings will make more efficient testing possible. Our observations indicate the seedlings of tung tree grow slowly under white light-emitting diodes, which results in poor quality of transplanted seedlings in greenhouse lower regeneration activity. The objective of this study was to investigate the effects of different supplemental light qualities on the growth, photosynthesis, chlorophyll fluorescence parameters, leaf thickness, and stomata status of tung tree seedlings grown in an artificial chamber. The results showed that tung tree adapts to growing under blue light. We recommend blue light condition to ensure tung tree proper growth in the greenhouse.

Technical Abstract: Tung tree (Vernicia fordii) is a fast-growing heliophile with high photosynthetic efficiency. The objective of this study was to investigate the effects of different supplemental light qualities on the growth, photosynthesis, chlorophyll fluorescence parameters, leaf thickness, and stomata status of tung tree seedlings grown in artificial chamber. The plantlets were exposed to four light qualities with equal quantum irradiance at 100 µmol·m-2·s-1: white light-emitting diodes (LEDs) as a control (CK), red and blue (R:B=8:2) LED (RB), red LED (R) and blue LED (B). The growth, chlorophyll content (Chl), photosynthesis and physiological activity were quantified at 20 and 40 d after treatment (DAT). Compared to the control, at 40 DAT, the stem length, Chl content, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), photochemical quenching coefficient (qP) and electron transfer rate (ETR) of the seedlings with supplemental B light were significantly increased by approximately 7%, 60%, 59%, 195%, 129%, 35% and 56%, respectively (P<0.05). The leaf number and seedling height under R light were significantly decreased by 12% and 15%, respectively (P<0.05), and the leaves exhibited obvious sagging phenomenon. Furthermore, the leaf thickness, the palisade cell length, SOD activity and POD activity with supplemental R light were significantly increased by 27%, 19%, 337% and 203%, respectively compared to CK. The promotion and inhibition of RB light were relatively slow in various aspects. We conclude that tung tree adapts to growing under blue light and suggest that blue light condition is recommended to ensure tung tree proper growth in the greenhouse.