Using morphological attributes for the fast assessment of nutritional responses of Buddhist pine (Podocarpus macrophyllus [Thunb.] D. Don) seedlings to exponential fertilization

Abstract

Culturing slowly growing tree seedlings is a potential approach for managing the conflict between the increasing demand for ornamental stock and the decreasing area of farmlands due to urbanization. In this study, Buddhist pine (Podocarpus macrophyllus [Thunb.] D. Don) seedlings were raised in multishelves with light-emitting diode lighting in the spectrum of 17:75:8 (red:green:blue) at 190–320 μmol m-2 s-1 with controlled temperature and relative humidity at 19.5°C and 60%, respectively. Seedlings were fed by exponential fertilization (EF) (nitrogen [N]-phosphorus [P]2O5-K2O, 10-7-9) at eight rates of 0 (control), 20 (E20), 40 (E40), 60 (E60), 80 (E80), 100 (E100), 120 (E120), and 140 (E140) mg N seedling-1 for four months through 16 fertilizer applications. The nutritional responses of Buddhist pine seedlings can be identified and classified into various stages in response to increasing doses, up to and over 120 N seedling-1. Morphological traits, i.e., the green color index and leaf area (LA) obtained by digital analysis and the fine root growth, all remained constant in response to doses that induced steady nutrient loading. LA had a positive relationship with most of the nutritional parameters. A dose range between 60 and 120 mg N seedling-1 was recommended for the culture of Buddhist pine seedlings. At this range of fertilizer doses, measuring the leaf area through digital scanning can easily and rapidly indicate the inherent nutrient status of the seedlings.

Light-emitting diode spectra modify nutritional status, physiological response, and secondary metabolites in Ficus hirta and Alpinia oxyphylla

“…Plant nutritional status refers to the synthesized symptom that is exposed under drivers of biomass accumulation and nutrient assimilation ( Xu et al, 2019;Wei et al, 2020b). Several studies have fully demonstrated that the variation in lighting spectra can shape plant nutritional statuses by modifying nutrient uptake, allocation, and utilization (Li et al, 2017;Li et al, 2018;Wang et al, 2020;Wei et al, 2020a;Wei et al, 2020b).…”

Light spectra modify nitrogen assimilation and nitrogen content inQuercus variabilisBlume seedling components: A bioassay with15N pulses

“…The front layer of leaves was opened as a histogram. The leaf green index (GI) can be directly read from the background data of the histogram [42][43][44]. Leaf area can be calculated as the total pixels of the histogram divided by the square of the dpi [43][44][45].…”

Exponential fertilization on red-seed tree (Ormosia hosiei) seedlings subjected to contrasting light conditions: Do we really need intensive nutrient loading?

“…Exponential nutrient loading mostly synchronizes the pace of biomass accumulation in tree seedlings for most species (Duan et al, 2013;Wang et al, 2016). Exponential fertilization (EF) has been well documented to promote seedling quality through enhancing nutrient uptake to a level higher than needed for growth demand (Hawkins et al, 2005;Xu et al, 2019). The goal of harvesting nutrient-enriched seedlings promotes the interest to feed seedlings with EF at an applicative rate as high as possible.…”