Effects of light of different wavelengths, produced by light-emitting diodes (LEDs), on the germination of seeds of Pinus nigra Arn. and on the growth of the plantlets resulted from their embryos

摘要

After 21 days of exposure of the black pine seeds (Pinus nigra Arn.), putted to germinate - and ulterior - of the plantlets resulted from their embryos, at white fluorescent light, or at light produced by Light-Emitting Diodes (LEDs), in regime 16 hours / day, with a light intensity of 1200 lux, comparative with similar samples maintained at natural light, in a laboratory with northern exposition, it was found that the white light of LEDs has largely increased the germination of the seeds, while the yellow or green light of LEDs caused a reduction to almost a half of the percentage of seeds germination. On the other hand, the white light, emitted by fluorescent tubes, has stimulated with 45.3% the growth in size of the plantlets, and with 50.7 the dry weight of them. The white light of LEDs grew with just 18.7% the growth of the plantlets and with 24.2% their dry weight. At the plantlets exposed to the red light of LEDs, the size of the plantlets has been increased with 39.8%, and their dry weight with 47.1%; the blue light of LEDs has enhanced only with 10% the growth of the plantlets, respectively with 16.7% the dry weight of them. Instead, the plantlets illuminated with yellow or green light emitted by LEDs have presented values close to those of the control variant, regarding both the size and the dry weight of the plantlets.