Abstract
Drought is the most limiting environmental factor to crop productivity and presents a great variability in the degree of tolerance among and within species, among varieties. The aim of this study was to characterize sugarcane accessions regarding tolerance to water stress during in vitro cultivation based on changes in biometric, physiological and biochemical characteristics, within species and among species, to support future breeding programs. Adventitious shoots of five sugarcane accessions: Saccharum robustum, Saccharum spontaneum and Saccharum officinarum species, cultivated in Murashige and Skoog medium supplemented with 2% sucrose and 4 g/l Phytagel were used in five water potentials, 0, -0.3, -0.6, -0.9, -1.2 MPa, induced by mannitol. Survival, length of shoots and roots, number of shoots and roots, biomass, proline content in leaves and activity of antioxidant enzymes were analyzed. There is difference among species, and also, within the same sugarcane species when submitted to in vitro drought stress, and S. officinarum was shown to be the most tolerant. Proline can be used as a biochemical indicator of response to drought in sugarcane accessions and its accumulation was intensified in S. robustum and S. spontaneum accessions. Catalase activity remained unchanged with increased drought in sugarcane accessions evaluated.
Highlights
Drought stress is one of the environmental factors that causes great damage to the physiological and metabolic processes of plants (Taiz & Zeiger, 2009), and one of the most studied due to its strong impact on crop productivity (Filippou et al, 2014)
There is great variability in the degree of drought tolerance among species, and even among varieties of a species. This difference is observed through the value of the ideal water potential for plants and the development stage in which the stress occurs (Inmam-Bamber & Smith, 2005; Pimentel, 2004)
The osmotic adjustment is considered an active mechanism of accumulation of solutes in cells with reduction of the cell water potential without decreasing in turgidity or in cell volume and, the maintenance of the turgor pressure, which provides the maintenance of the plant vital processes (Basu et al, 2016)
Summary
Drought stress is one of the environmental factors that causes great damage to the physiological and metabolic processes of plants (Taiz & Zeiger, 2009), and one of the most studied due to its strong impact on crop productivity (Filippou et al, 2014). There is great variability in the degree of drought tolerance among species, and even among varieties of a species This difference is observed through the value of the ideal water potential for plants and the development stage in which the stress occurs (Inmam-Bamber & Smith, 2005; Pimentel, 2004). Among four distinct growth stages, tillering and rapid growth have been identified as critical for water demand (Ramesh, 2000), causing severe production losses In these stages, 70-80% of all biomass accumulated during the crop cycle are produced (Oliveira et al, 2010). Drought tolerance is a mechanism that allows plant to maintain its metabolism, even with reduction of the water potential of tissues (Taiz & Zeiger, 2009), mainly due to the accumulation of compatible solutes and the antioxidant capacity (Verslues et al, 2006). These mechanisms include antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidases such as ascorbate peroxidase (APX) (Mittler, 2002), which jas.ccsenet.org
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