Investigating the Phenotypic Plasticity of the Invasive Weed Trianthema portulacastrum L.

Marwa A Fakhr,Mohamed Elhady,Faten Y Ellmouni,Iman H Nour,Amr Elkelish,Albaraa Elsaied,Yasser S A Mazrou

doi:10.3390/plants11010077

Abstract

Phenotypic plasticity is frequently highlighted as a key factor in plant invasiveness, as it enables invasive species to adapt to diverse, complicated habitats. Trianthema portulacastrum is one of the most common aggressive species that threaten different crops around the world. Phenotypic plasticity in T. portulacastrum was investigated by comparing variation in germination, vegetative macromorphology, photosynthetic pigments, stomatal complexes, and seed micromorphological traits of 35 samples collected from 35 different localities. One-way cluster analysis and principal component analysis (PCA) were used to classify samples into homogeneous groups based on the measured traits. Pairwise statistical comparisons were conducted between the three resulting groups. The phenotypic plasticity index (PI) was calculated and compared among different groups of characters. Results showed that photosynthetic pigments and macromorphological characteristics had the highest PI, followed by seed micromorphology, and then stomatal complex traits, while germination parameters showed the lowest PI. We propose that soil moisture, salinity, and temperature are the most determinative and explanative variables of the variation between the three classified groups. We strongly believe that the phenotypic plasticity of T. portulacastrum will support species abundance and spread even under expected changes in climatic conditions, in contrast to the vulnerable traditional crops.

Highlights

IntroductionPhenotypic plasticity is a key factor in the invasion process, promoting the adaptability and invasiveness of an alien species by increasing or maintaining population growth in unusual environmental conditions [1,2,3]
This study aims to investigate the phenotypic plasticity of T. portulacastrum spreading in the Fayoum Depression by addressing its macro- and micromorphological and physiological traits, as well as to assess the phenotypic plasticity index of the species, which can be relevant for plant invasiveness
The analyses reveal that the content of chlorophyll pigments differed significantly in in Yousef El-Seddik (0.63 mg/g Fwt; sample 31) and Senouris (1.89 mg/g Fwt; sample 18), the different habitats

Summary

Introduction

Phenotypic plasticity is a key factor in the invasion process, promoting the adaptability and invasiveness of an alien species by increasing or maintaining population growth in unusual environmental conditions [1,2,3]. Investigations of trait variation along environmental gradients can provide vital data for recognizing drivers of plant invasions and for deriving management strategies [5]. The plastic responses of the plant organs induced by the environment contribute to morphological and physiological behavioral changes among species inhabiting heterogeneous and variable conditions [7,8]. Phenotypic plasticity has been displayed to reflect genetic correlations. Monitoring the environmental effects on the micromorphology of the leaves and seeds indicates that the plants adapt their morphology to the new environmental conditions [10,11]. Many authors have reported the taxonomic significance of the macro- and micromorphological characteristics of Aizoaceae leaves and seeds [12,13,14,15,16,17,18]

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