Growth, Nutrient Assimilation, and Carbohydrate Metabolism in Korean Pine (Pinus koraiensis) Seedlings in Response to Light Spectra

Abstract

A need is growing to plant superior Korean pine (Pinus koraiensis Siebold & Zucc.) seedlings to cope with the degradation of secondary forests in Northeast Eurasia. The goal of this study was to detect the physiological effect on the quality of Korean pine seedlings exposed to a range of spectra. One-year-old seedlings (n = 6) were cultured in three light-emitting diode (LED) spectra (69‒77 μmol m−2 s−1) of 13.9% red (R) + 77.0% green (G) + 9.2% blue (B) (R1BG5), 26.2% R + 70.2% G + 3.5% B (R2BG3), and 42.3% R + 57.3% G + 0.4% B (R3BG1). The spectrum of high-pressure sodium (HPS) lamps (43.9% R + 54.7% G + 1.5 B) was taken as the reference. Results showed that LED-lighting resulted in shorter seedlings with a greater diameter, shoot biomass, assessed quality, and sturdiness compared to those under the HPS-lighting. The R3BG1 spectrum reduced the shoot nitrogen (N) deficiency induced by the HPS spectrum, while the R1BG5 treatment induced a steady-state uptake of N and phosphorus (P) in whole-plant organs. The R1BG5 spectrum also resulted in a higher soluble sugar concentration and higher activities of glutamine synthetase and acid phosphatase in needles compared to the control. Seedlings in the R2BG3 spectrum had the highest concentrations of chlorophyll and soluble protein in the leaves. Overall, the R-high LED-spectrum could stimulate biomass accumulation in shoot, but meanwhile resulted in a P deficiency. Hence, the LED lighting in the R1BG5 spectrum is recommended to promote the quality of Korean pine seedlings.