Physiological aspects of seedling development of coffee grown under colored screens

The objective of this work was to evaluate the physiological aspects of the development of coffee seedlings grown under colored screens with different spectral characteristics. Seedlings of Catucai Amarelo 2SL, in the stage known as 'orelha de onca', were arranged in a randomized block design, with five replicates, under structures individually covered with blue, white, gray, black or red screens with 50% shade. Four months after, evaluations were done for seedling growth, pigment content of the leaves, total soluble sugars and starch contents of the leaves and roots. The red screen was the most effective in promoting growth in four out of the seven studied traits: plant height, leaf area and leaf dry weight and total dry matter. For the other characteristics, there was no difference among the screens. The pigment analysis showed that, except for the gray screen, the other ones did not differ for this trait. In leaves, the red screen promoted higher levels of carbohydrates and starch. At the root, carbohydrate contents were higher under the red and black screens. Among the five screen colors, the red one was the most efficient in the production of coffee seedlings with higher vigor and quality, with outstanding carbohydrate contents and biomass. (author)