3rd National Congress on Medicinal Plants 14, 15 May 2014 Mashhad- Iran EFFECTS OF FOLIAR APPLICATION OF NANO ZINC CHELATE AND ZINC SULFATE ON CHLOROPHYLL CONTENT, PHOTOSYNTHETIC PARAMETERES, ESSENTIAL OIL CONTENT AND YIELD OF HOLY BASIL (OCIMUM SANCTUM) Zohreh Moghimi Pour,1,* Mohammad Mahmoodi Sourestani,1 Naser Alamzade Ansari,1 Zahra Ramezani,2 1 Department of Horticultural Science, College of Agriculture, Shahid Chamran University, Ahvaz, Iran 2 College of Pharmacy, Jundishapur University, Ahvaz, Iran E-mail: [email protected] Holy basil (Ocimum sanctum), belonging to the lamiaceae family, is a perennial subshrub plant. Essential oil of holy basil contains estragol, linalool, eugenol and methyl chavicol. This plant is known as “Queen of plants” the mother medicine of nature ranks among the most important aromatic herbs for its enormous medicinal properties [1]. Essential oil biosynthesis of medicinal plant is strongly influenced by Zn and the stresses caused by deficiency of other elements [2]. In order to evaluate the effect of foliar application of zinc fertilizer on chlorophyll content, photosynthetic parameteres, essential oil content and yield of holy basil at first and second harvests, an experiment was conducted at research farm of faculty of agriculture, Shahid Chamran University of Ahvaz based on randomized complete block design, with three replications. The treatments were nano zinc chelate (zero, 0.5, 1 and 1.5 gr.lit-1) and zinc solfate fertilizers (1 and 1.5 gr.lit-1). Foliar application of fertilizer was done at six to eight leaf stage and was repeated with interal 15 days until the end of the study. The net photosynthesis (Pn), stomatal conductance (gs), transpiration rate (E), quantum yield (QY), water use efficiency (WUE) and chlorophyll content were measured on adult leaf at begining of flowering. Then, the plants were harvested at full bloom stage and dried in shade. The essential oil was extracted by a clevenger apparatus. The results showed that the effect of foliar application of zinc fertilizer on Pn, gs, E, QY, chlorophyll content, essential oil content and yeild of holy basil were significant (p≥0.01). There was no significant difference between treatments in water use efficiency (WUE). The highest values of Pn (11.75 μmol CO2 m-2s-1), gs (0.31 mmol H2O m-2 s-1), E (2.80 mmol H2O m-2 s-1), QY (6.10 μmol CO2 μmol. photon-1), chl a, chl b and total chlorophyll (0.99, 0.20 and 1.19 gr.kg-1(FM)), essential oil content (2.11%) and yeild (39.13 gr.m-2) were obtained in plant sprayed with 1.5 gr.lit-1 nano zinc chelate. In total, chlorophyll content, photosynthetic parameteres, essential oil content and yeild of holy basil were increased by foliar application of zinc and 1.5 gr.lit-1 nano zinc chelate was recommended. References [1] Singh, V.; Amdekar, S.; Verma, O. Webmedcentral pharmacology. 2010, 1(10), 01–07. [2] Misra, A.; Dwivedi, S.; Srivastava, K. A.; Tewari, D. K.; Khan, A.; Kumar, R. Scholars Research Library. 2007, 4(1): 01-05. 266