Phosphite (Phi), a reduced form of phosphate (Pi), is emerging as a novel biostimulator in horticulture. Though there is still no consensus on its physiological function as a P-source for plant nutrition, experimental evidence has shown that Phi can act as a biocide and affect plant production and productivity. Positive effects of Phi on plant metabolism are more evident when applied to the roots in hydroponic systems or to the leaves in the form of foliar sprays in the presence of sufficient Pi.
Phosphite is emerging as a potential inductor of beneficial metabolic responses in plants, as it has demonstrated its effectiveness against different stress factors and has improved crop yield and quality. As a biostimulant, Phi has been proved to improve nutrient uptake and assimilation, abiotic stress tolerance and product quality. Moreover, Phi promotes root growth, yield and nutritional value of horticultural crops.