Convergent Variations in the Leaf Traits of Desert Plants.

Muhammad Adnan Akram,Weigang Hu,Xiaoting Wang,Jianming Deng,Jinzhi Ran,Yahui Zhang,Yan Deng,Junlan Xiong

doi:10.3390/plants9080990

Abstract

Convergence is commonly caused by environmental filtering, severe climatic conditions and local disturbance. The basic aim of the present study was to understand the pattern of leaf traits across diverse desert plant species in a common garden, in addition to determining the effect of plant life forms (PLF), such as herb, shrub and subshrub, phylogeny and soil properties on leaf traits. Six leaf traits, namely carbon (C), nitrogen (N), phosphorus (P), potassium (K), δ13C and leaf water potential (LWP) of 37 dominant desert plant species were investigated and analyzed. The C, N, K and δ13C concentrations in leaves of shrubs were found higher than herbs and subshrubs; however, P and LWP levels were higher in the leaves of subshrubs following herbs and shrubs. Moreover, leaf C showed a significant positive correlation with N and a negative correlation with δ13C. Leaf N exhibited a positive correlation with P. The relationship between soil and plant macro-elements was found generally insignificant but soil C and N exhibited a significant positive correlation with leaf P. Taxonomy showed a stronger effect on leaf C, N, P and δ13C than soil properties, explaining >50% of the total variability. C3 plants showed higher leaf C, N, P, K and LWP concentration than C4 plants, whereas C4 plants had higher δ13C than C3 plants. Legumes exhibited higher leaf C, N, K and LWP than nonlegumes, while nonlegumes had higher P and δ13C concentration than legumes. In all the species, significant phylogenetic signals (PS) were detected for C and N and nonsignificant PS for the rest of the leaf traits. In addition, these phylogenetic signals were found lower (K-value < 1), and the maximum K-value was noted for C (K = 0.35). The plants of common garden evolved and adapted themselves for their survival in the arid environment and showed convergent variations in their leaf traits. However, these variations were not phylogenetics-specific. Furthermore, marks of convergence found in leaf traits of the study area were most likely due to the environmental factors.

Highlights

Convergence is the tendency or ability of different organisms to evolve phenotypically related traits under similar natural environments and it commonly appears in extreme ecological conditions [1].Similar environments, microsites and living behaviors should cause similar pressure for selectivity that consecutively supports morphophysiological plant traits, which exploit the competitive ability and fitness under such environments and bring about evolutionary convergence among species despite many differences among their forefathers [2,3]
It is noted that the mean leaf C concentration of all 37 plant species (Table 2) was higher than that in leaves of plant species studied across the China [32], plants of the Taklamakan Desert [33]
Results of the current study further investigated that the mean leaf N concentration (Table 2) significantly higher than the global plants [35], China’s terrestrial ecosystems [32], herbs studied across China [36] and markedly lower than the KMUNR desert plants [37]

Summary

Introduction

Convergence is the tendency or ability of different organisms to evolve phenotypically related traits under similar natural environments and it commonly appears in extreme ecological conditions [1].Similar environments, microsites and living behaviors should cause similar pressure for selectivity that consecutively supports morphophysiological plant traits, which exploit the competitive ability and fitness under such environments and bring about evolutionary convergence among species despite many differences among their forefathers [2,3]. Environmental filtering decides which species can survive in their populations in a specific environment [5]. This deterministic filtering finds the existence probability of species and low existence probability species are considered as sifted out [6]. Abiotic conditions influence the existence probability of species as well as their abundance. These two effects on existence and abundance of species are the marks of trait convergence [7]. Habitat filtering is believed to be one of the main divers for community assembly, which causes trait convergence in severe environmental conditions [8]

Objectives

Methods

Results

Discussion

Conclusion