Crescimento de mudas de caré (Coffea arabica L. var. Bourbon) sob diferentes níveis de luz

Resumo

Seedlings from Coffea arabica, var. bourbon, transplanted at the “butterfly” stage (cotiledonary leaves fully open), and grown in straw pots_under four levels of sunlight, namely 100 per cent (open sun), and 75, 50 and 25 per cent, as transmitted by lath shades, gave the following results, 140 days aiter transplanting:

1) Average dry weight, average total leal area, and average number of leaves, per plant, increased as the light level decreased down to 50 per cent, but at 25 per cent the values decreased. Poorest results were given by full sunlight.

2) Average area of leaves increased as the light radiation decreased, the same holding for the ratio of leaf area to leaf dry weight.

3) The leaf area ratio (ratio of leaf area to total dry weight of plants) increased as the light level lowered. The leaf weight ratio (ratio of leaf dry weight to total dry weight) was inconsistently affected by the illumination levels.

4) The top-to-roots ratio was not affected by the levels of light.

5) Best growth of 5— month — old coffee seedlings, as measured by increase in total dry weight, total leaf area and number of leaves, was given by 50 per cent light level, the so-called “half-shade”.