Physiological and biochemical responses to drought stress in Barbados cherry

Abstract

To evaluate physiological genotypic differences between two Barbados cherry genotypes (13-and 14-CPA) under water deficit, initial growth, water relations, and organic solute accumulation were evaluated in an experiment performed using four-month-old seedlings, which were subjected to four water treatments (100, 75, 50, and 25% of field capacity), with five replications. Severe water deficit (25% of field capacity) negatively affected plant height, stem diameter, leaf area, dry matter of the leaves and stem to both genotypes, and root dry matter to genotype 13-CPA. Predawn (Y wpd ) and midday leaf water potentials (Y wmd ) were reduced in plants grown under 25% of field capacity, only in the genotype 14-CPA. There was not a change in relative water content, even with the reduction in the leaf water potential. Severe water deficit did not induce organic solutes accumulation, instead it reduced carbohydrate content in leaves of genotypes and aminoacids, proline and proteins, in genotype 13-CPA. In the roots accumulation of all organic solutes studied, it was verified genotype 13-CPA under 25% of field capacity, but only carbohydrates increased in plants under 25% of field capacity to 14-CPA. These results suggest two different mechanisms used by Barbados cherry genotypes to maintain the water status. To the 13-CPA one, the accumulation of soluble organic solutes in the roots is the main mechanism used to maintain the tissue hydration. However, the 14-CPA genotype changed the root to shoot ratio in order to avoid desiccation. Despite the mechanism used by both genotypes, a moderate drought stress does not induce significant morphophysiological changes in Barbados cherry.

Physiological limitations in two sugarcane varieties under water suppression and after recovering

“…Recent studies indicate that the main function of amino acid accumulation may be related to the osmotic adjustment (Sircelj et al 2005, Silva et al 2009, Medeiros et al 2012. In the present work, increases were observed in amino acid concentrations in the water suppression treatment, what may attest the function of osmoregulation and/or osmoprotection of these compounds.…”

“…Increase in soluble carbohydrate content may occur at the beginning of stress as a result of growth cessation and by the intensity of water deficit, due to starch degradation (Pimentel 1999, Sircelj et al 2005, Medeiros et al 2012. In the present study, soluble carbohydrates increased in leaves and roots likely due to growth interruption (Table 6).…”

“…Previous studies have observed an increase in solutes in sugarcane and other species under water-deficient conditions (Ashraf and Foolad 2007, Cha-um e Kirdmanee 2009, Silva et al 2009, Silva et al 2013. Nevertheless, only solute accumulation does not favour the tolerance to drought per se, but the pathway that leads to the mechanism of drought tolerance is strongly influenced by this factor (Hasegawa et al 2000, Medeiros et al 2012. In this study, increments on the concentration of all osmoregulators evaluated in both the varieties under study were observed, and proteins were the major contributors to the osmoregulation of those varieties.…”

“…In situations of water restriction, common physiological alterations include reduced leaf water potential and the relative water content (Nogueira et al 2000, Graça et al 2010, gas exchange, photosynthesis, as well as reduced maximum quantum efficiency of the photosystem II (Inman-Bamber and Smith 2005, Silva et al 2007, Jaleel et al 2009, Gonçalves et al 2010, Graça et al 2010. As a consequence, metabolic changes such as increase in osmoregulators (Nogueira et al 2001, Guimarães et al 2008, Silva et al 2009, Medeiros et al 2012) may occur along with significant alterations on the plant growth, in response to the lower turgor pressure in the cells (Hessini et al 2009). …”

Water deficit‐induced oxidative stress affects artemisinin content and expression of proline metabolic genes in Artemisia annua L.

“…Medeiros et al . have confirmed a drought stress‐related decline in the growth of a diversity of plants. Water stress commonly reduces the FW of crop plants .…”