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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 8, No. 1, 2005, pp. 17-23
Bioline Code: ej05004
Full paper language: English
Document type: Research Article
Document available free of charge

Electronic Journal of Biotechnology, Vol. 8, No. 1, 2005, pp. 17-23

 en Growth responses of Betula pendula check for this species in other resources ecotypes to red and far-red light
Tsegay, Berhanu A.; Lund, Leidulf; Nilsen, Jarle; Olsen, Jorunn E.; Molmann, Jorgen M.; Ernsten, Arild & Juntttila, Olavi


The effect of Red light (R), Far-red light (FR) and R/FR combinations on shoot growth of latitudinal ecotypes of B. pendula was studied using special diodes that emit monochromatic lights. When a 12 hrs PAR (110 μmol m-2 s-1) was extended with R, FR or R/FR ratios, lower intensities of monochromatic lights could not prevent growth cessation. At 25 μmol m-2 s-1, FR compared to R enhanced stem elongation in all ecotypes. This was due to the inhibitive effect of R on internode elongation. When day-length was extended by R/FR at various ratios, there was continuous shoot elongation, but was found to be declining with increasing ratios. The more the R, the shorter were the internodes of each plant. B. pendula ecotypes produced branches when PAR light during the day was extended by incandescent light, but did not do so when the light extensions were made by monochromatic R or FR or their combination. Branching increased with decreasing latitude of the ecotype.

diode, ecotype, monochromatic, photomorphogenesis, phytochrome, photosynthetically active radiation (PAR).

© © 2005 by Pontificia Universidad Católica de Valparaíso -- Chile
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