Leaves of Citrus aurantifolia exhibit a different sensibility to solar UV-B radiation according to development stage in relation to photosynthetic pigments and UV-B absorbing compounds production

J Photochem Photobiol B. 2008 Mar 28;90(3):163-9. doi: 10.1016/j.jphotobiol.2008.01.002. Epub 2008 Jan 18.

Abstract

Plants of Citrus aurantifolia grown in a greenhouse without solar UV radiation (UVR) were transferred outdoors to evaluate the effect of solar UV-B radiation (UVBR, 280-315 nm) in prior-developed leaves, constituted by apical bud and those fully expanded before being taken outdoors, and post-developed leaves, formed by those expanded outdoors. Results demonstrated that over a 40 d outdoor period leaf chlorophyll content and distribution pattern were different with and without solar UVBR. Chlorophyll a, chlorophyll b and total chlorophyll contents in both treatments were higher in prior-developed leaves than in post-developed ones. However, highest values were observed in prior-developed leaves under solar UVBR, whereas in post-developed leaves an opposite trend was observed. Carotenoids content in prior-developed leaves was higher with solar UVBR, whereas in post-developed leaves there were no significant differences in both with and without solar UVBR. In addition, prior-developed leaves under solar UVBR accumulated flavonoids, but not anthocyanins. Growth parameters (e.g. DW, DW/FW ratio, LMA, plant height, length and width of foliar lamina) did not show significant differences between plants grown with and without solar UVBR. Thus, our results demonstrated that C. aurantifolia leaves exhibited a different sensibility to solar UVBR according to development stage in relation to photosynthetic pigments and UV-B absorbing compounds production. In addition, the solar UVBR was not necessary as inductor of photosynthetic protection mechanisms in a short-time growth period. On the other hand, our results also demonstrated that solar UVBR acted as an effective feeding deterrent against citrus leafminer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anthocyanins / analysis
  • Carotenoids / analysis
  • Chlorophyll / analysis
  • Citrus aurantiifolia / chemistry
  • Citrus aurantiifolia / growth & development*
  • Citrus aurantiifolia / radiation effects*
  • Flavonoids / analysis
  • Moths / physiology
  • Photosynthesis*
  • Pigments, Biological / biosynthesis*
  • Pigments, Biological / metabolism
  • Plant Leaves / chemistry
  • Plant Leaves / growth & development
  • Plant Leaves / radiation effects*
  • Time Factors
  • Ultraviolet Rays*
  • Water / analysis

Substances

  • Anthocyanins
  • Flavonoids
  • Pigments, Biological
  • Water
  • Chlorophyll
  • Carotenoids