Paper Details

Abscisic acid and cytokinin-induced carbohydrate and antioxidant levels regulation in drought-resistant and -susceptible wheat cultivar during grain filling under field conditions

Mohammad-Reza Sarafraz-Ardakani, Ramazan-Ali Khavari-Nejad, Foad Moradi, Farzaneh Najafi

DOI: https://dx.doi.org/10.12692/ijb/5.8.11-24

Int. J. Biosci. 5(8), 11-24. October, 2014. (PDF)

Abstract:

The present investigation was conducted to determine the effect of cytokinin (CK), abscisic acid (ABA) and cytokinin/abscisic acid interaction (CK/ABA) on carbohydrate contents, oxidative stress and antioxidant components induced by drought stress in two wheat cultivars (Triticum aestivum L.) of Pishgam and MV-17 as tolerant and sensitive to drought during post-anthesis phase, respectively grown in field conditions during grain filling period. The most considerable effect of the treatments was exhibited 21 days after anthesis. Under drought conditions, the flag leaf carbohydrate content including total soluble carbohydrate and reducing sugars increased in both cultivars while starch content was remarkably decreased in Pishgam as compared to MV-17. Although Pishgam exhibited  a significant increase in glucose,  sucrose and fructose content but MV-17 showed only a significant increase in fructose content. Relatively, CK/ABA increased total soluble carbohydrates, sucrose, and fructose content more than other hormonal treatments. Also, ABA only reduced starch level of Pishgam, significantly. Nevertheless, level of glucose was significantly affected by none of the hormonal treatments. The tolerant cultivar exhibited less accumulation of hydrogen peroxide and malondialdehyde (MDA) in relation to more significant increase of catalase (CAT) and peroxidase (POX) activities and α-tocopherol content under drought conditions. Among hormonal treatments, ABA and CK/ABA resulted in the highest activities of POX and CAT under both irrigation and drought conditions, respectively. But, higher accumulation of α-tocopherol was showed when CK foliar was applied. ABA and CK/ABA could decrease drought-induced hydrogen peroxide and MDA level, to some extent under drought conditions.