Kinetics of Phosphorus Uptake through Roots of Habanero Pepper ( Capsicum chinense Jacq. cv. Mayapán)

The application of enzymatic kinetics theory on the nutrition of horticultural species is scarce. I ma x and K m describe the kinetics of nutrient absorption by the plant. I max and K m are necessary to predict phosphorus (P) uptake from soil using mathematical models, and their estimation gives information about the efficient use of P in plants. I max and K m for habanero pepper ( Capsicum chinense Jacq. cv. Mayapán) were determined using the modified exhaustion method. Depletion of P by the roots was obtained with 0.01, 0.125, 0.25, 0.50, and 1.00 mM P L −1 . P-depletion data over time were fitted to an exponential-regression model to obtain the initial P-uptake rates by the roots. Initial P-uptake rates were significantly different ( p < 0.001) depending on the levels of P in the solution. I max and K m were predicted by iteratively fitting the initial P-absorption rates in terms of the concentration of P to the Michaelis–Menten model. The average I max was 3.49 × 10 −7 mM cm 2 s −1 and K m was 2.59 × 10 −2 mM P L −1 . These results show that the habanero pepper root can uptake 1.08 × 10 −5 mg P L −1 per cm 2 in the soil solution per second and P transporters are saturated with 2.59 × 10 −2 mM P L −1 .