A systemic approach to the quantification of the phenotypic plasticity of plant physiological traits

Abstract

The evaluation of plant phenotypic plasticity is an important part of mapping plant performance and adaptation. This is crucial to the understanding of natural vegetation formation, indication of species for recovering of conservation areas and genotypes to crop breeding programs, as well as for modelling of plant behaviour in future climatic conditions. The past and current methods for quantification of plant phenotypic plasticity present multiple limitations, mainly in what concerns data normalization, replication, analysis of multiple environments and coupling of multiple varieties. This study proposed a new method, based on a multivariate statistics technique, the Principal Component Analysis (PCA) and in the calculation of Euclidian distances between PCA scores to evaluate plant plasticity. The Multivariate Plasticity index (MVPi) was applied to leaf physiology data collected from two experimental study cases composed of: a) four Cerrado native species grown under environments of contrasting light and water and b) four sugarcane commercial varieties under different water regimes. The results suggest that the method was efficient in explaining species/varieties behaviour in the different environments and to inform the plasticity of leaf physiological traits. It has also showed potential to overcome the main limitations of other methods and allow an integrated analysis of plant phenotypic plasticity. We recommend the use of the MVPi method as a tool for analysis of phenotypic plasticity as an emergent plant characteristic in the context of a systemic evaluation of plant physiological traits.