Nanophosphorus Fertilizer Stimulates Growth and Photosynthetic Activity and Improves P Status in Rice

The efficiency of nanoparticles covered with type A gel and loaded with KH₂PO₄, as a source of P, was evaluated on growth, phosphorus concentration and accumulation, and photosynthesis-related parameters in rice plants (Oryza sativa L. ssp. indica) cv. Morelos A-2010, under greenhouse conditions. Plants were treated for 14 days with P concentrations equivalent to 50 and 100% of those established in the Yoshida nutrient solution. Sources of P were KH₂PO₄, nano-KH₂PO₄, and nano-KH₂PO₄ with trypsin; control treatments were distilled water and nanoparticles with type A gel. The solutions were renewed every 7 d. Rice plants exhibited differential P absorption in function of the P source tested. P supplied by KH₂PO₄ had a higher uptake rate than P supplied by nano-KH₂PO₄, alone or with trypsin. Nevertheless, nano-KH₂PO₄ promoted higher physiological efficiency for P in both roots and shoots, which consequently induced higher biomass accumulation in these organs. P concentration in shoots, as well as P accumulation in shoots and roots, were positively correlated with the photosynthetic rate. Also, nano-KH₂PO₄ increased instant water use efficiency in rice plants.