White-light emitting diodes’ spectrum effect on photosynthesis and nutrient use efficiency in Podocarpus macrophyllus seedlings

Abstract

Fast urbanization and population increase resulted in the demand for ornamental seedling supply in a high efficiency under the culture of continuous artificial lighting. Light emitting diode (LED) can be considered as the replacement of high-pressure sodium (HPS) lamps by providing lights with specific wavelengths for plant growth at low energy cost. In this study, nutrient use efficiency was detected in Podocarpus macrophyllus seedlings under lighting spectra generated by white light-emitting diodes (LEDs) (red (R)/green (G)/blue (B)=8.4:75:16.6) and high-pressure sodium (HPS) lamps (R/G/B/=4.3:69.3:26.5). Compared to seedlings under the HPS spectrum, those under white LED spectrum had better growth, greater biomass accumulation, higher photosynthesis and gas exchange. In contrast, LED-spectrum treated seedlings had greater nitrogen (N) and phosphorus (P) contents than HPS-spectrum treated ones. The LED spectrum promoted nutrient use index for both N and P in seedlings compared to the HPS spectrum. The LED spectrum induced steady-state uptake of P but resulted in the dilution of N. In conclusion, white LED can be considered to replace the usage of HPS lamps for the culture of tree seedlings due to the spectrum effect on N utilization, P uptake and the use efficiencies of N and P.

Keywords:

• Artificial illumination
• exponential nutrient loading
• macro-nutrient
• N and P utilizations
• nutrient uptake
• photobiology

Additional information

Funding

This study was supported by the Jilin Province Science and Technology Development Project of Jilin Provincial Science and Technology Department (grant number 20190304014YY), the Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDA23070503), the Regional Key Project in S&T Services Network Program of Chinese Academy of Sciences (grant numbers KFJ-STS-QYZD-044; KFJ-STS-ZDTP-048), the National Natural Science Foundation of China (grant numbers 41971122; 41861017; 31600496), the National Key Research and Development Program of China (grant number 2016YFC0500300), the Funding for Jilin Environmental Science (grant number 2017-16), and CAS Scholarship for Overseas Study.