Exposure of Zea mays L. plants to unfavorable temperature (45°C) for 1-3 h caused reduction in chlorophyll content, photosystem II activity, total available carbohydrates (TAC) and total proteins (TP) in the leaves of the plant. During the heat stress (HS) and recovery period, there was a significant increase in chl.a/chl.b and carot/chl.a+b ratios that may shift off the photooxidation process. Also, the increase of invertase hydrolyzate sugares (IHS) and total phenolic components play an important acclimative role as ROS scavengers and osmoprotectant agents. Furthermore, the decline of oxidative potentials (ASA/DHASA) and (GSH/TG) indicate the stimulation of ascorbate-glutathione cycle for reduction HS-induced oxidative stress. Expression of new polypeptides (including HSP100, HSP90 and small HSPs families) under HS could be considered as a defense mechanism. These results may indicate that different non-enzymatic antioxidants systems are developed in Zea leaf cells in response to heat stress (HS).
Key words: Non-Enzymatic Antioxidants, Zea mays L. Leaves, Heat Stress