Nutrient assimilation and utilization in korean pine (Pinus koraiensis) seedlings exposed to exponential fertilization under contrasting spectra

Abstract

ABSTRACT Pine trees are important for the agroforestry ecosystem due to their significance in nut production and ecological restoration. Korean pine (Pinus koraiensis Siebold & Zucc.) seedlings were cultured as model materials exposed to exponential fertilization (EF) at rates of 20 (E20), 80 (E80), and 140 mg nitrogen (N) plant−1 (E140) under high-pressure sodium (HPS) lamps (proportion in photosynthetic photon flux density: 43.9% red, 54.7% green, and 1.5% blue lights) and light-emitting diode (LED) (6.6% red, 75% green, and 8.4% blue lights) spectra. A high rate of EF at 140 mg N plant−1 under the LED spectrum tended to increase shoot biomass at the cost of phosphorus (P) dilution due to P assimilation through acid phosphatase activity and starch depletion. The uptake of N was not used for utilization but instead, for N storage in the biomass that assimilated through glutamine synthetase activity. Therefore, we conclude that the assimilation and utilization of P determined the growth and biomass in Korean pine seedlings while N can be absorbed and stored for reserve.