Estudos sobre a nutrição mineral do arroz: VIII. marcha de absorção de macronutrientes na variedade IAC-25

Rice plants, IAC 25 variety, were grown in nutrient solution; samples were taken for analysis at different intervals, namely 21, 50, 79, 91 and 112 days after germination. Main conclusions were the following: (1) both dry matter production and accumulation of macronutrients as a function of time were described by typical sigmoide curves; (2) in the period between the second and third sampling the rate for both processes reached maximum values; (3) dilution effects were observed in the content of all the elements except Ca; (4) Ca also was the only macronutrien which does not seem to be translocated from leaves for grainfiling.Foram estudadas, em condições controladas, a acumulação de matéria seca e a acumulação de macronutrientes pela variedade de arroz IAC 25. Como regra verificou-se que a acumulação de matéria seca e de macronutrientes obedeceu a sigmoides típicas, ambos os processos ocorendo com maior velocidade no período aproximado de 5O-9O dias após a germinação