Effects of Understory Vegetation and Litter on Plant Nitrogen (N), Phosphorus (P), N∶P Ratio and Their Relationships with Growth Rate of Indigenous Seedlings in Subtropical Plantations

Abstract

Establishing seedlings in subtropical plantations is very important for forest health, succession and management. Information on seedling nutrient concentrations is essential for both the selection of suitable indigenous tree species to accelerate succession of the established plantation and sustainable forest management. In this study, we investigated the concentrations of nitrogen ([N]), phosphorus ([P]), and N∶P ratio in leaves, stems and roots of seedlings of three indigenous tree species (Castanopsis chinensis, Michelia chapensis and Psychotria rubra) transplanted with removing or retaining understory vegetation and litter at two typical subtropical forest plantations (Eucalyptus plantation and native species plantation). We also measured the relative growth rate (RGR) of seedling height, and developed the relationships between RGR and leaf [N], [P] and N∶P ratio. Results showed that treatments of understory vegetation and associated litter (i.e. removal or retained) generally had no significant effects on leaf [N], [P], N∶P ratio and RGR of the transplanted tree seedlings for the experimental period. But among different species, there were significant differences in nutrient concentrations. M. chapensis and P. rubra had higher [N] and [P] compared to C. chinensis. [N] and [P] also varied among different plant tissues with much higher values in leaves than in roots for all indigenous species. RGR of indigenous tree seedlings was mostly positively correlated with leaf [N] and [P], but negatively correlated with leaf N∶P ratio. Considering the low [P] and high N∶P ratio observed in the introduced indigenous tree seedlings, we propose that the current experimental plantations might be P limited for plant growth.

Optimization of Nitrogen, Phosphorus, and Potassium Fertilization Rates for Overseeded Perennial Ryegrass Turf on Dormant Bermudagrass in a Transitional Climate

“…Greater biomass, elevated chlorophyll and higher protein content that were observed in response to NPK fertilization might be other factors that drove increases in Pn, Tr , and Gs (Alderman et al, 2011 ; Grygierzec, 2012 ). P is a vital structural part of nucleic acids (Wang et al, 2013 ) and promotes photosynthesis (Fredeen et al, 1990 ). Elevated levels of P could promote photosynthesis by contributing to the production of the products of noncyclic electron transport, adenosine triphosphate (ATP) and NADPH (Giersch and Robinson, 1987 ).…”

Effects of nitrogen and phosphorus supply on growth and physiological traits of two Larix species

“…constituent of proteins and it determines the photosynthetic capacity (Güsewell, 2004), as up to 75% of N would be involved in photosynthetic processes (Evans, 1989). Although P is an important structural element in nucleic acids that regulate energy storage and transfer (Wang et al, 2013) and photosynthesis requires orthophosphate as a substrate (Sivak and Walker, 1986), the pool of phosphorus involved in photosynthesis is variable and often small (Bieleski, 1973). Thus, an efficient use of N and P is believed to contribute to plant fitness (Aerts and Chapin, 2000) and is thought to influence the nutrient cycling and productivity of terrestrial ecosystems (Vitousek, 2004).…”

Carbon allocation and fate in paddy soil depending on phosphorus fertilization and water management: results of 13C continuous labelling of rice

“…The application of P fertilizer is one of the most important crop management practices (Cordell et al 2009;Singh et al 2013). As a nucleic acid component, P regulates plant performance and energy storage as well as ecosystem C and N cycles (Lin et al 2009;Wang et al 2013b;Zeng and Wang 2015). Meanwhile, P is frequently lost from soil through removal during harvest, soil erosion, leaching to groundwater, and occlusion in highly weathered soils (Vitousek and Sanford 1986;Falkowski et al 2000;Elser et al 2007).…”

“…The addition of P also improved plant root growth and N uptake (Bowatte et al 2006). Supplying P to a P-limited ecosystem might alter the plant leaf N:P ratio, a value indicative of net primary production and soil C dynamics because it correlates with plant photosynthetic capacity, photosynthetic N-use efficiency, and relative growth rate (Wright et al 2005;Wang et al 2013b). Comparatively, fewer studies have addressed the effects of P fertilization on the flow of plant-derived C to paddy soils.…”