The role of amino acids glycine and phenylalanine in some physiological characteristics of guava seedlings newly introduced to Iraq

This work uses environmentally acceptable amino acids as biomolecules to support important physiological processes and increase tolerance to biotic and abiotic environmental challenges in recently imported Psidium guajava L. in Iraq. Some amino acids affect the later growth of guava seedlings in a new environment. A fully randomized block design factorial experiment on guava seedlings examined the effects of glycine and phenylalanine at three concentrations each (0, 250 and 500 mg L-1 for glycine and 0, 150 and 300 mg L-1 for phenylalanine). Combining glycine (500 mg L-1) with phenylalanine (300 mg L-1) resulted in significant increases in all guava seedling parameters, surpassing their individual effects. These gains included increased leaf chlorophyll, carbohydrate content and decreased nutrient leaching. The results show that foliar spraying with glycine and phenylalanine improved the physiological and phenological features of guava seedlings. The study found that foliar spraying with glycine and phenylalanine improved guava seedling development, productivity and quality in Iraq.