Leaf Structural Traits Vary With Plant Size in Even-Aged Stands of Sapindus mukorossi.

Yunni Chang,Shihe Zhang,Junxin Zhou,Quanlin Zhong,Hong Yang,Baoyin Li,Chaobin Xu,Weiping Hua

doi:10.3389/fpls.2021.692484

Abstract

Sapindus mukorossi Gaertn., an important oleaginous woody plant, has garnered increasing research attention owing to its potential as a source of renewable energy (biodiesel). Leaf structural traits are closely related to plant size, and they affect the fruit yield and oil quality. However, plant size factors that predominantly contribute to leaf structural traits remain unknown. Therefore, the purpose of this study was to understand the associations between leaf structural traits and plant size factors in even-aged stands of S. mukorossi. Results showed that leaf length (LL) and leaf area (LA) markedly increased with the increasing diameter at breast height (DBH) and tree height (TH), although other leaf structural traits did not show noticeable changes. Difference in slopes also indicated that the degree of effect of plant size factors on leaf structural traits was in the order of TH > DBH. Leaf structural traits showed no systematic variation with crown width (CW). LA was significantly positively correlated with LL, leaf width (LW), LL/LW, and leaf thickness (LT) and was significantly but negatively correlated with leaf tissue density (LTD) and leaf dry mass content (LDMC). Specific leaf area showed a significantly negative correlation with LT, LDMC, and LTD. LTD showed a significantly positive correlation with LDMC, but a negative correlation with LT. The results were critical to understand the variability of leaf structural traits with plant size, can provide a theoretical foundation for further study in the relationship between leaf structural traits and fruit yield, and regulate leaf traits through artificial management measures to promote plant growth and fruit yield.

Highlights

Leaves are a vital component of the photosynthetic apparatus of a plant and play key roles in longterm adaptations to environmental changes (Liu et al, 2017; Guo et al, 2018; Song et al, 2018; Cai et al, 2020)
leaf length (LL) and leaf area (LA) were significantly and positively correlated with diameter at breast height (DBH) (p < 0.05), while there were no significant correlation between the leaf width (LW), LL/LW, leaf thickness (LT), specific leaf area (SLA), leaf dry mass content (LDMC), leaf tissue density (LTD), and leaf relative water content (LRWC) with DBH (p > 0.05)
LL, LL/LW, and LA showed a modest increase with tree height (TH) (p < 0.05), and there were no significant correlation between LW, LT, SLA, LDMC, LTD, and LRWC with TH (p > 0.05); these relationships showed low R2 values

Summary

Introduction

Leaves are a vital component of the photosynthetic apparatus of a plant and play key roles in longterm adaptations to environmental changes (Liu et al, 2017; Guo et al, 2018; Song et al, 2018; Cai et al, 2020). Plant growth is driven by factors that affect resource (light, nutrients, and water) gain and utilization (Richards et al, 2010; Li et al, 2017). Leaf traits reflect both resource uptake strategies and resource use efficiency and are expected to affect plant growth (Fichtner et al, 2013; Li et al, 2017). SLA, as a measure of resource allocation, reflects the potential light capture per unit LA per unit organic matter content invested into leaves (Wright and Westoby, 1999). In Betula platyphylla, LT, SLA, and LDMC showed significant differences between adult trees and saplings at different growth stages (Jin et al, 2018)

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