Abstract
Light and nitrogen availability are among the most important environmental factors influencing leaf and root morphological traits and forest ecosystems. Understanding the variation in leaf and root traits is pivotal to the adaptive plasticity and leaf-root-specific traits in response to low light and N availability. The effects of light and N availability on leaf and root traits and their interrelations are still not clear. We aimed to measure the response of leaf and root traits and their interrelations to light and N availability in a temperate region. Thus, a factorial experiment was conducted with two angiosperm tree species under two light (L+, L−) and two nitrogen (N−, N+) levels. Results showed that the leaf density (LD) and leaf mass per area (LMA) increased, while leaf thickness (LT) decreased under low light availability. Under N availability, the LD and LMA decreased, while LT increased in sun-exposed plots and remained stable under low light availability across two species. The root diameter, root length, specific root length (SRL), and specific root area (SRA) decreased, while the root tissue density (TD) increased under low light availability. Root diameter, root length, SRA, and SRL increased, while the TD decreased under N+ in L+ plots and remained stable under L− plots. LMA and LT were significantly positively correlated to root length and SRL while significantly negatively correlated to TD. However, LD was significantly positively correlated to TD. We observed that low light availability has significantly decreased the plant biomass and root mass fraction (RMF) and increased the leaf mass fraction (LMF), while the stem mass fraction (SMF) remained stable―indicating the shade in-tolerances in both species. Correlation analyses revealed that LMF is generally, and particularly under L− conditions, less related to leaf and root morphological traits, while RMF was frequently positively correlated to both leave and root traits under all environmental conditions. This illustrates a divergent regulation of morphological traits above and below ground under varying biomass allocation patterns.
Highlights
Light is a highly heterogeneous environmental factor influencing plant growth and survival and competitive interactions within plant communities [1,2]
At the time of harvest, the total plant biomass differed by species with higher bioAt the time of harvest, the total plant biomass differed by species with higher biomasses masses in Tilia amurensis and was significantly modified by light and partially by the N
This should be a note of caution about the generality of trait interrelation, which needs to be explored across contrasting environmental gradients
Summary
Light is a highly heterogeneous environmental factor influencing plant growth and survival and competitive interactions within plant communities [1,2]. Acquisition and efficient use of active photosynthetic radiation (light) are among the most significant factors influencing seedling survival and development in understorey forest layers [3]. A major trait for seedling growth, development, and survival under low light availability and key for influencing the forest composition, dynamics, and structure [4,5]. It determines the species’ life-history strategies but in some species the position along with the growth survival trade-off [6,7]. Low light availability in the understorey of natural communities primarily results from overlying plant canopies and the potential occurrence of differently sized gaps; the dynamics and composition of understorey plant communities in forests are to a large extent, the result of a contrasting light availability [2,8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
