EFFECT OF PLANT REGULATORS, ZINC NANOPARTICLES AND IRRIGATION INTERVALS ON LEAF CONTENT OF ENDOGENOUS HORMONES AND NUTRIENTS IN SUNFLOWER (HELIANTHUS ANNUUS L.)
Abstract The experiment was conducted in a local nursery belongs to Najaf municipality in the province of Najaf during the spring growing season of 2018 in order to investigate the effect of plant growth regulators (IAA and GA3) and zinc nanoparticles on sunflower leaf content of exogenous hormones and nutrient at different levels of water stress. The experiment was RCBD with three factors including irrigation intervals (3, 6 or 9 days), foliar application with 100ppm of plant growth regulators IAA and GA3 at rates of 0:0, 1:1, 0:1 or 1:0 respectively, and foliar spray with 100ppm of zinc (control, ZnSO4 or Nano-zinc ZnO). Results showed water stress (long irrigation interval) significantly decreased leaf content of IAA, GA3 and zinc and at the mean time significantly increased leaf content of ABA, calcium and potassium. The growth regulators IAA and GA3 individually or combined positively affected all the studied traits. Foliar application with growth regulators and their combinations reduced symptoms of water stress severity and showed an improvement in all growth traits (internal hormonal content (IAA, GA3, ABA), mineral elements (Zn, Ca, K). findings showed that Nano-zinc application was also effective and caused a significant increase in all the above measured plant traits.