Two field experiments were carried out at the Experimental Farm Station of the Faculty of Agriculture Moshtohor, Benha University, Kalubia Governorate, Egypt, during 2012 and 2013 summer seasons. Drip irrigation system was used to apply the levels of water stress in the experiment. This experiment was conducted to study the effect of foliar application with ascorbic acid (200, 400 mg/L), putrescine (10, 20 mg/L) and potassium citrate (250, 500 mg/L) and adding mycorrhiza as well as two levels of water stress (50 and 35% of ETo and 100% of ETo as control) on some growth characters, yield and quality of snap bean plants cv. Bronco. The experiments were laid out in split plot design with three replications. The obtained results showed that water stress levels and applied treatments have significant effect on growth characteristics and yield of snap bean plants. The obtained results indicated that increasing water stress levels to 50% and 35% of ETo of water requirements caused significant decrease in all growth and yield characteristics (i.e., plant height, number of leaves, leaf area /plant and shoots fresh and dry weight as well as number and weights of green pods per plant and total pods yield per feddan. The same trend was obtained in photosynthetic pigments (chlorophyll a, b and carotenoids), minerals (N, P and k) and protein content in green pods of snap bean plants. Data also indicated that the application of ascorbic acid at (400 mg/L), putrescine (20 mg/L), potassium citrate (500 mg/L) and mycorrhiza gave the highest significant increase of the studied growth and yield characteristics as well as photosynthetic pigments (chlorophyll a, b and carotenoids), minerals and protein in green pods. At the highest water stress level (35% of ETo); Plants treated with putrescine (20 mg/L), ascorbic acid (400 mg/L) followed by potassium citrate (500 mg/L) and mycorrhiza , respectively gave the highest values of the previously mentioned growth characters, green pod yield/plant and chemical composition of green pods in the two growing seasons. Generally, it could be concluded that applied antioxidants, potassium and mycorrhiza alleviated the harmful effects of high water stress levels on growth and yield of snap bean plants. So, foliar application with ascorbic acid, putrescine and potassium as well as adding mycorrhiza could be recommend in snap bean cultivation under normal and water stress conditions. |
