Influence of root temperature on potassium nutrition of tomato plant

Abstract

The interaction between root temperature and potassium concentration in nutrient solution has been studied in hydroponic culture on young tomato plant (Lycopersicon esculentum Mill.). These two factors affect plant growth but the potassium absorption only varies according to concentration in nutrient solution. The plants grown for 2 weeks in a nutrient solution maintained at 11 °C with 0.5 mM L ⁻¹ of potassium synthesize 6.0 g of total dry matter with 0.58 g in roots corresponding to 952 cm² area; while at 3.0 mM L ⁻¹, the plant gives 6.1 g of total dry matter with 0.65 g in the roots corresponding to 1028 cm². On the other hand, at 21 °C, we can see the following synthesis: at 0.5 mM of K ion, 6.43 total dry matter with 0.90 in the roots and a 1412 cm² area and respectively 7.03, 0.78 and 2096 cm² with 3.0 mM L⁻¹ of potassium. These results point out that the root surface are not limiting factors for potassium absorption by young tomato plants during a short period of treatment.