Differential response to water deficit stress and shade in two wheat (Triticum durum Desf.) cultivars: growth, water relations, osmolyte accumulation and photosynthetic pigments

Abstract

This study was conducted to investigate the effects of water deficit stress and shading on two wheat cultivars (Triticum durum Desf. cv Om Rabiaa and cv Maali). Comparison was based on growth, leaf water relations, photosynthetic pigments and the accumulation of organic solute. In both cultivars, water stress deficit significantly decreased total dry mass (TDM), leaf area (LA), water potential (Ψw), osmotic potential (Ψπ) and relative water content (RWC). Photosynthetic pigments, i.e. chlorophyll a (Chl a), chlorophyll b (Chl b) and total chlorophyll (Tot Chl), decreased while carotenoids (car) increased. Proline concentration increased significantly in water stressed plants under full light conditions while sugar accumulated more under shade conditions. In addition, shade improved leaf area, leaf water potential, and osmotic potential as well as alleviated the negative drought impact on photosynthesis performance. For the Maali cultivar, the reduction in RWC and its inability to achieve osmotic adjustment (OA) emphasize this cultivar's sensitivity to water deficit stress. For the Om Rabiaa cultivar, the ability to avoid relative tissue dehydration and preserve a higher RWC with a significant increase in OA in shade-treated plants were tolerance mechanisms enabling this cultivar to absorb water effectively and sustain normal growth and productivity under water stress conditions.

Seasonal analysis of leaf antioxidant activity in Colombian eliteHevea brasiliensisgenotypes as a breeding strategy to enhance water deficit tolerance under Amazonian environmental conditions

“…The high content of carotenoids and soluble sugars indicated greater tolerance of the ECC 64 genotypes and the control (IAN 873) under water deficit conditions (regardless of the site), contributing to the regulation and maintenance of the physiological process activity within the plant. The trend of these results was consistent with the findings of Chen et al [68], Wang [12], Gharbi et al [69], Oliveira dos santos [5], and opposed to those of Pasaribu et al [70], where the concentrations of total sugars and proline stood out with lower water content in rubber plants, identifying that water scarcity does not cause the same metabolic responses and that these vary within the species itself, depending on each genotype and its developmental stage.…”

“…[68], Wang [12], Gharbi et al [69], Oliveira dos santos [5], and opposed to those of Pasaribu et al [70], where the concentrations of total sugars and proline stood out with lower water content in rubber plants, identifying that water scarcity does not cause the same metabolic responses and that these vary within the species itself, depending on each genotype and its developmental stage.…”

“…[68], Wang [12], Gharbi et al [69], Oliveira dos santos [5], and opposed to those of Pasaribu et al [70], where the concentrations of total sugars and proline stood out with lower water content in rubber plants, identifying that water scarcity does not cause the same metabolic responses and that these vary within the species itself, depending on each genotype and its developmental stage. The biochemical response during the rainy period showed the highest contents of proline (ECC 66, ECC 73, and the control IAN 873) and total sugars (ECC 64, ECC 35, and ECC 25), possibly attributed to nutrient reserves in the form of carbohydrates and energy transfer for leaf development and shoot growth [32].…”