Differences in water deficit adaptation during early growth of Brazilian dry forest Caatinga trees

Abstract

SUMMARYPrevious studies have shown that adaptation to drought in Brazilian Caatinga trees may involve different physiological and morphological strategies. Particular climatic and soil characteristics occur along this dry ecosystem leading to non-homogeneous water availability. Therefore, in certain niches, some species predominate over others, indicating that best performance of a species is not widespread. We studied changes in initial growth, which is the most critical factor during the life of a plant, of two common species of Caatinga (Erythrina velutina Willd. and Enterolobium contortisiliquum (Vell.) Morong) with variable occurrence through the ecosystem. Young plants were subjected to three water regimes: 450 (control), 225 (moderate stress) and 112.5 mm (severe stress) of water spread over 40 days, which represent years with heavy, moderate and scarce rainfall, respectively. Analyses were performed at 20 and 40 days after the initiation of treatments. When compared to the control group, treatments with water restriction reduced the growth of shoots and roots, the number of leaves and leaflets, the total biomass and the leaf area more in E. velutina than in E. contortisiliquum. Taking into account the adaptation of both species in Caatinga, we present evidence of different drought tolerance strategies. The ecological importance of early changes in the growth of species is discussed in the paper.

Respostas fisiológicas de mudas de Aspidosperma pyrifollium (Apocynaceae) à ciclos de suspensão de rega

“…Aliado a isso, a espécie ainda consegue manter a turgescência dos seus tecidos, o que, em conjunto, podem ter conferido um incremento no seu crescimento, mesmo sob estresse. Comparando estes resultados com outras espécies ocorrentes na Caatinga, mas não endêmicas, verificamos que algumas não apresentam esse tipo de comportamento em relação à seca, havendo redução no crescimento em situação de déficit hídrico no solo, como observado para Erythrina velutina [8] e Enterolobium contortisiliquum [22]. Esses resultados demonstram a variação de respostas para espécies que habitam regiões semiáridas.…”

Partitioning and Modeling of Biomass in Caatinga Legume Seedlings in Different Water Conditions

“…The species from the Caatinga have developed morphophysiological and biochemical mechanisms to withstand adverse environmental conditions (Costa et al, 2015;Figueiredo-Lima et al, 2018), particularly the water deficit. However, the responses depend on the species, degree of stress and time of occurrence, especially in the initial stage of growth, which represents the most sensitive phase to the establishment of the plant in the environment (Lúcio et al, 2017).…”