Effect of Foliar Application of Salicylic Acid and Chelated Zinc on Growth and Productivity of sweet pepper ( Capsicum annuum l.) Under Autumn Planting

摘要

The field experiment was conducted to study the effect of foliar application with 50 & 100 ppm of salicylicacid (SA) and 50 & 100 ppm chelated zinc (Zn) and their combination on some growth aspects, photosyntheticpigments, minerals, endogenous phytohormones, fruiting and fruit quality of sweet pepper cv. CaliforniaWonder during autumn 2009 and 2010 seasons. Results indicated that different applied treatments significantlyincreased all studied growth parameters, namely, number of branches and leaves per plant, leaf area per plantand leaf dry weight. Besides, the two concentrations of each applied salicylic acid or chelated zinc obviouslyincreased photosynthetic pigments, N,P,K, Zn, total sugars, total free amino acids and crude proteinconcentrations in leaves of treated plants as compared with those of untreated ones. Also, all treatmentsincreased auxin, gibberellin and cytokinin levels in sweet pepper shoots at 95 days after transplanting during2010 season whereas abscisic acid was decreased. Furthermore, the highest early, marketable and total yields aswell as physical characters of sweet pepper fruits were obtained with 100 ppm salicylic acid plus chelated 50ppm zinc followed by 50 ppm SA plus 100 ppm Zn. Moreover, different applied treatments induced reduction inthe peroxidase, catalase and superoxide dismutase actives as compared with those of the untreated plants insweet pepper leaves at 100 days after transplanting during 2009 and 2010 seasons. In addition, chemicalcomposition of minerals and some bioconstituents (carbohydrates, vitamin C and total soluble solids) in sweetpepper fruits were also increased at the same treatments. Hence, it could be recommended that foliar sprayingwith salicylic acid at 100 ppm and chelated zinc at 50 ppm can be used to increase the final yield and fruitquality of sweet pepper plant during the low temperatures of autumn plantations.