Morphological, biochemical, and physiological responses of canola cultivars to drought stress

Drought stress is one of the major abiotic stresses that impair the growth and production of canola plants in arid and semi-arid zones, which necessitates the development of drought-resilient cultivars. The study aimed at determining the morphological, biochemical, and physiological responses of six different canola cultivars under three drought stresses imposed by polyethylene glycol. The main and interaction effects of cultivar and drought stress were determined using analysis of variance. The results showed a considerable decline in root length due to drought stress regardless of the cultivar. A significant interaction between cultivar and stress was detected on dry weight, height, and leaf area traits. Accordingly, growth parameters were observed to be linked with drought tolerance, and Hyola308 and Sarigol were identified as the most drought tolerant and sensitive cultivars, respectively. The values of chlorophyll contents in Hyola308 cultivar were remarkably higher than those in Sarigol under moderate-drought stress, while Sarigol maintained higher chlorophyll contents under severe stress. Increasing drought stress enhanced proline content and antioxidant enzyme activities (catalase and peroxidase) regardless of the cultivar. But a significant decrease in total soluble sugar was observed as drought intensity increased. This reduction in total soluble sugar content was about 38% lower in Hyola308 than in Sarigol. Therefore, some canola cultivars might mitigate drought stress effects by enhancing their proline and antioxidant system during drought stress. Furthermore, maintaining higher soluble sugar levels and greenness stability in response to increased drought stress might be a part of Hyola308's cultivar stress management strategy.

Automated summary

Drought stress is a significant factor that affects the growth and productivity of canola plants in arid and semi-arid regions. This study investigated the responses of six canola cultivars to three levels of drought stress. The results showed that root length decreased under drought stress irrespective of the cultivar. Cultivar and drought stress interacted to affect dry weight, height, and leaf area. The cultivars Hyola308 and Sarigol were identified as the most drought tolerant and sensitive, respectively. Drought stress increased proline content and antioxidant enzyme activities, while total soluble sugar content decreased. Hyola308 exhibited higher chlorophyll contents and lower reduction in total soluble sugar compared to Sarigol. These findings suggest that some canola cultivars can alleviate drought stress through proline and antioxidant system enhancement, and Hyola308 possesses a stress management strategy involving higher soluble sugar levels and greenness stability.