Effects of Water Stress on Growth, Pigments and ¹⁴CO₂ Assimilation in Three Sorghum Cultivars

Abstract

The effects of drought on growth, pigments and 14CO2 assimilation were studied in three sorghum cultivars. Water stress applied either at the vegetative or at the reproductive stage was found to reduce relative growth and net assimilation rates. Root growth was less affected by water stress and in certain cases it was increased; consequently, the root/shoot ratio was improved. The sensitivity to drought stress was greater at the reproductive than at the vegetative stage. Dorado was the most drought‐tolerant and Giza 15 the least drought‐tolerant cultivar, as determined by calculation of the drought susceptibility index for total green leaf area and shoot dry weight. Short‐term water stress in the vegetative phase (7 days) improved the chlorophyll content in leaves, and long‐term stress in the vegetative and reproductive phases reduced chlorophyll content. Carotenoid content, in general, was not changed by drought stress. 14CO2 photoassimilation indicated that soluble, insoluble and consequently total photosynthates were reduced at the end of the stress period at both stages. Drought plus defoliation appeared to increase both chlorophyll content and 14CO2 photoassimilation, to a certain extent, as compared with drought alone.

Alleviation of Adverse Effect of Drought Stress on Soybean (Glycine max. L.) by Using Poultry Litter Biochar

“…Similar results are reported by Ladjal et al (2000); Younis et al (2000) and Terzi et al (2010) in some soybean species and this pigment were sensitive to increasing environmental stress. The decrease in these pigments may have resulted from a decrease in leaf water status in the soybean.…”

The Effect of Water Stress on Leaf Phenolic Composition, Fluorescence Parameters, Xylem Hydraulic Properties and Antiradical Activity of Four Tunisian Olive (Olea europaea L.) Cultivars

“…The significant decrease in total chlorophyll content can be attributed to the sensitivity of this pigment to increasing environmental stresses, especially salinity and drought [18]. The chl(a+b) content in Meski variety showed a larger reduction of this parameter under water deficit compared to other varieties.…”

Effect of moisture stress on morphological and yield attributes of four sorghum varieties

“…Drought stress suppressed shoot growth more than root growth (Salih et al 1999;Younis et al 2000;Okçu et al 2005;Bibi et al 2010). Reduction in seedling growth is the result of restricted cell division and enlargement, as drought stress directly reduces growth by decreasing cell division and elongation (Kramer, 1983).…”