Physiology of Wheat (Triticum Aestivum L) Accessions and the Role of Phytohormones under Water Stress

摘要: The availability of soil moisture is the major factor limiting wheat production. Present study was aimed to determine physiological response local germplasm resources exposed different periods water stress and rewatring at booting grainfilling stages. The four (Triticum aestivum L.) accessions (011251, 011417, 011320 011393) stress exogenously applied abscisic acid (ABA) determined in a pot study. experiment conducted wire house Quaid-i- Azam University, Islamabad during wheat-growing season 2005 2006. Pre sowing seeds treatment with ABA made for 8 h. Water was imposed by withholding supply period 9 d thereafter plants were irrigated. first treatment started 50% second 50 % grainfilling. Sampling done after 3, 6 days induction of stress. Recovery studied 48 72 h re-watering. Changes status leaves along osmoregulation, activities antioxidant enzymes, stomatal conductance, transpiration rate, pigment, phytohormones protein contents measured. Yield parameters also determined. Moreover Random Amplification Polymorphic DNA (RAPD) analysis determine extent genetic variability among to evaluate induced changes profiling grains Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) done. Marked decreases leaf status, rate chlorophyll carotenoid, Indole-3-acetic (IAA), Gibberellins (GA) trans zeatin riboside (t-zr.) associated an increase accumulation (both free bound), sugar, proline, glycine betaine activities enzymes (superoxide dismutase, peroxidase catalase) under Increase content remained dominant except accession 011251. inhibitory effects ameliorated exogenous application this ameliorating effect found be more significant stage as compared particularly accession 011320. Upon rewatering recovery from greater case treated plants. Accession most sensitive all showing higher decrease yield which appears less efficient metabolism evidenced slow accumulation stress-induced ABA did not return pre level but significantly on rewatering moreover t-zr higher. Whereas, 011417 highly tolerant possibly economizing status, control osmolytes, conductance concomitant higher content lesser indole-3-acetic (IAA), gibberellins riboside under Higher upon alsofound in accession. amplification analysis revealed marked diversity and (SDS-PAGE) protein indicated that grain composition are mainly controlled factors. It inferred results adverse become pronounced filling booting. Proline, can serve markers selecting wheat genotypes. seed soaking implicated effective way alleviate relatively