Growth, biomass accumulation and foliar nutrient status in fragrant rosewood (Dalbergia odorifera T.C. Chen) seedlings cultured with conventional and exponential fertilizations under different photoperiod regimes

Abstract

ABSTRACTIn this study, fragrant rosewood (Dalbergia odorifera T.C. Chen) seedlings were cultured with conventional and exponential fertilization treatments at rates of 2 and 4 g plant−1 (15–9–12), and an unfertilized control under the natural photoperiod and extended photoperiods with supplementary lighting for 3 and 6 h. Seedlings under the extended photoperiods had greater height but less root-collar diameter than those under the natural photoperiod. The extended photoperiod with supplementary lighting for 3 h resulted in the greatest biomass in stem and root. Apparent nutrient dilution was found from October 2015 to January 2016 in most fertilization treatments, which, however, was counted by the treatment of exponential fertilization at 4 g plant−1. Vector analysis indicated that the treatment of extended photoperiod with supplementary lighting for 3 h induced nutrition depletion for nitrogen (N) and phosphorus (P) relative to the natural photoperiod, while the exponential fertilization treatment induced luxury consumption for all elements of N, P and potassium (K) relative to the control. In conclusion, the extended photoperiod of supplementary lighting for 3 h was recommended for the culture of fragrant rosewood seedlings, and the exponential fertilization resulted in better nutritional status by counting nutrient dilution relative to the conventional fertilization.