Antioxidant system response of different wheat cultivars under drought: field and in vitro studies

Abstract

The participation of the antioxidant system in the drought tolerance of wheat cultivars (Triticum aestivum L.) was studied under field and in vitro conditions. Under field conditions, drought tolerance was evaluated by the capacity to maintain the grain yield under drought, which was higher in cvv. Elite and La Paz than in the sensitive cvv. Oasis and Cruz Alta. Tolerant cultivars showed lower relative water content (RWC) and lower above-ground vegetative biomass than sensitive cultivars. Field assays did not show a clear correlation between water-stress tolerance and antioxidant system behaviour. However, when leaves of cvv. with contrasting drought tolerance were subjected to osmotic stress in vitro, clear differences in the antioxidant system activity and oxidative damage between cvv. were observed. In the tolerant cultivar Elite, it was possible to observe an increase in ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase (GR) activities, a higher glutathione (GSH) and ascorbate content and less oxidative damage than in the sensitive cultivar Oasis, which showed no changes or only slight decreases in the enzyme activities. These results indicate that water stress tolerance is in part associated with the antioxidant system activity, and suggest that the behaviour of the antioxidant systemin vitro assays can be used as an early selection tool.

Antioxidant and anti-stress compounds improve regrowth of cryopreserved Rubus shoot tips

“…GSH content increases with the accumulation of frost hardiness of Picea abies (Esterbauer and Grill 1978). An increase of GSH was observed after osmotic stress in wheat (Lascano et al 2001), suggesting that GSH aids in controlling the damage associated with osmotic injury. Wang and Deng (2004) found that GSH added during cryopreservation significantly increased regrowth of Citrus shoot tips.…”

Antioxidative protection and proteolytic activity in tolerant and sensitive wheat (Triticum aestivum L.) varieties subjected to long-term field drought

“…For example, WD may have a protective role against heat stress but may exacerbate photoinhibition (Chaves et al 2002). Comparative field and in vitro studies on different wheat varieties established no clear correlation of water stress tolerance with some components of the antioxidant system activity under field conditions, but the existence of such a link was found under osmotic stress in vitro (Lascano et al 2001). Moreover, source-sink relations are a predominant factor at the reproductive stage on plant growth.…”

“…At a whole plant level crops have developed different strategies to counteract the negative effects of water limitation: increased water use efficiency, drought escape by shortening life cycle, dehydration avoidance by maintaining lower water deficit (WD) in the cells, dehydration tolerance at higher WD (Lascano et al 2001). Drought tolerance of crops is regarded as higher yield of a certain genotype compared to others at the same level of stress intensity (Fisher and Maurer 1978).…”

Superoxide dismutase and glutathione reductase overexpression in wheat protoplast: photooxidative stress tolerance and changes in cellular redox state

“…In previous works we have characterized wheat antioxidant system responses under drought, osmotic and photooxidative stresses (Lascano et al 2001(Lascano et al , 2003. With the aim of obtaining transgenic wheat plants, we adjusted a system by microprojectile bombardment, and obtained BASTA resistant plants .…”