Tomato root growth and phosphorus absorption kinetics by tomato plants as affected by phosphorus concentration in nutrient solution

• Autor(a) principal: Fontes, Paulo Cezar Rezende
• Data de Publicação: 2014
• Outros Autores: Barber, Stanley A.
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/16112
• topic: phosphorus uptake; Michaelis-Menten parameters; Lycopersicon esculentum; parâmetros de Michaelis-Menten; Lycopersicon esculentum

To evaluate the effects of P concentrations in nutrient solution on root growth and on root physiological characteristics involved in P uptake by tomato Lycopersicon esculentum Mill plants, six seedlings were grown in nutrient solution at initial concentrations of 48.5, 97, 194 and 388 µM P until one day before harvest. They were then transferred to solutions with P at 20 µM and 30 µM, and the depletion curves and Michaelis-Menten parameters were determined. Increases in the initial P concentration increased plant dry weight and shoot: root dry weight ratio. Imax values decreased with the increase in the concentration of P in the treatment solution; however, these were not significantly affected by P concentration in the depletion solution. Variation in KM values were not statistically significant. The relative net P influx increased with decreased P concentrations in the nutrient solution, mainly due to increase Imax values. The conclusions were that as P supply increased and as the plant P contents are sufficient for maximum growth, the rate of P uptake tends to be lower. The results also indicate that total P uptake by tomato seedlings depends on the amount of root surface area exposed to P.