Efecto de temperaturas supraóptimas sobre el sistema radical, el crecimiento y la absorción y translocación de nutrimentos en café cultivado en solución nutritiva

Abstract

Coffee seedlings, Coffey arabica cr. Casual, were grown in nutrient solution for a period of six months after germination, in six special containers, with 25 seedlings in each. The temperature of the nutrient solution in the containers ms kept constant at each of the Jbllowing levels: 27, 29, 30, 31, 32 and 33 degrees centigrade. After six months plant height, fresh weight of roots and tops, and their contents in N, P, K, Ca and Mg were determined. Between 29°C and 33°C the increase of just one degree centigrade in the temperature of the root system resulted in a pronounced decrease in the growth of the plants. At higher root temperatures the phosphorus and magnesium contents of the root system increased markedly while the reverse was observed in the tops This seems to indicate that the hanslocation of those elements from the roots to the tops was adversely affected by the increase of the root temperature. Potassium was markedly accumulated both in roots and tops at the higher root temperatures tried.