Response of Salt-Stressed Common Bean Plant Performances to Foliar Application of Phosphorus (MAP)

The study objective is to evaluate the effect of mono-ammonuim phosphate (MAP; 0, 10, and 20 mM) applied as foliar application on the growth traits, green and dry yields characteristics, leaf photosynthetic pigments, chlorophyll fluorescence, and leaf contents of nutrients of common bean (Phaseolus vulgaris L., cv. “Bronco”) plants grown under saline soil conditions. To perform this objective, two field trials were conducted at the Experimental Farm of Faculty of Agriculture, Fayoum University during the 2016 and 2017 summer seasons. The obtained results showed that, Na⁺ content was significantly declined, while the all other tested parameters such as growth characteristics (i.e., shoot length, number of leaves per plant, area of leaves per plant, and shoot fresh and dry weights), yield characteristics of green pods and dry seeds (i.e., average pod weight, number of pods per plant, pods weight per plant, dry seed weight per plant and 100-seed weight), leaf photosynthetic pigments (i.e., total chlorophylls, total carotenoids) contents and leaf chlorophyll fluorescence (i.e., Fv/Fm and PI), leaf contents of N, P, K⁺, and Ca²⁺, and the ratios of K⁺/Na⁺, Ca²⁺/Na⁺ and K⁺+Ca²⁺/Na⁺ were significantly increased by the two levels (i.e., 10 and 20 mM) of MAP compared to the controls (without MAP). The two MAP levels conferred the same results for most of the all tested parameters; particularly growth and yields characteristics, with some exceptions. Therefore, results of this study recommend using 10 mM MAP as foliar application to optimize the common bean performances in saline soils. Keywords: Common beans, Salinity, Phosphorus, Plant performance, Antioxidant defense systems, Photosynthesis, Water relations.