HEAT-INDUCED REGULATION OF ANTIOXIDANT DEFENSE SYSTEM AND NUTRIENT ACCUMULATION IN HEXAPLOID BREAD WHEAT (TRITICUM AESTIVUM L.)

摘要

Ten cultivars (five registered S-24, Inqlab-91, Saher-2006, Fsd-2008, and Lasani, and five candidate cultivars P.B-18,M.P-65, S.H-20, AARI-10, and G.A-20) of spring wheat (Triticum aestivum L.) were examined for high temperature stresstolerance. Plants were grown in soil filled pots in the Botanical Garden of the Department of Botany University ofAgriculture Faisalabad, Pakistan. Three different temperature regimes (30, 40 and 50°C) were applied at two differentgrowth stages (tillering and boot) for three temperature durations 30, 60 and 90 min in a growth chamber. The leaf and rootsamples were collected after two weeks of temperature treatment and then analyzed for enzymatic and non-enzymaticantioxidants as well as inorganic nutrients (N, P, K+, Ca2+). At the end, data obtained were statistically analyzed todistinguish heat tolerant from non-tolerant wheat cultivars. After appraisal of growth, antioxidant defense system and uptakeof nutrients it was found that cvs. S-24, Inqlab-91, Saher-2006, Fsd-2008, Lasani and G.A-20 exhibited better thermotolerancecapabilities than the other wheat cultivars (P.B-18, M.P-65, S.H-20, AARI-10). Among the thermo-tolerant wheatcultivars, G.A-20 and Lasani were superior in maintaining shoot fresh weights and shoot length, high antioxidant activitiesand better nutrient uptake at both tillering and boot stages. The response of all cultivars to heat stress applied at the tilleringstage or boot stage was almost the same.