INVESTIGADORES
SANSBERRO pedro Alfonso
artículos
Título:
Shoot growth in Ilex paraguariensis plants grown under varying photosynthetic active radiation is affected through gibberellins levels
Autor/es:
PEDRO ALFONSO SANSBERRO; MROGINSKI, LA; BOTTINI, R. A.
Revista:
PLANT GROWTH REGULATION
Editorial:
Kluwer Academic Publisher
Referencias:
Lugar: The Netherlands; Año: 2002 vol. 38 p. 231 - 236
ISSN:
0167-6903
Resumen:
Ilex paraguariensis (yerba mate) is a species native to South America of economic importance. Plants of yerba mate were grown for 35 days in pots under photosynthetically active radiation (PAR) at intensities varying between 1, 4, 20, 50 and 100% of full sunlight in order to study growth in relation to gibberellins. Internode length of new shoots increased under lower PAR. Uniconazole and Prohexadione-Ca (inhibitors of gibberellin biosynthesis) inhibited shoot length under all light intensities, suggesting that increased levels of gibberellins active on shoot growth may account for longer internodes in shaded plants. Gibberellin A1 and A3 were identified in shoots by capillary gas chromatography-mass spectrometry. Increased levels of the GA1 + GA3 pool (measured by gas chromatography-selected ion monitoring with deutero gibberellins as internal standards) were found in shoots of plants grown under decreasing PAR. However exogenous GA3 at 15, 150 and 1500 mM was ineffective in reversing the stunting effect of 100% PAR. In one experiment GA4 at 150 and 1500 mM lengthened the internodes of plants grown under full sunlight comparable to those grown in the shade, suggesting a differential effect of “active” gibberellins of different molecular structure. These and previous results imply that the photomorphogenetic control of shoot growth by light intensity in Ilex paraguariensis plants grown under different PAR is modulated through the levels of endogenous gibberellins.