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.
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.
Ibañez
Silvina
S
LIEY, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, Miguel Lillo 205, 4000 Tucumán, Argentina.
Rosa
Mariana
M
Hilal
Mirna
M
González
Juan A
JA
Prado
Fernando E
FE
D000818:Animals; D000872:Anthocyanins / Q000032:analysis; D002338:Carotenoids / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D032082:Citrus aurantiifolia / Q000737:chemistry / Q000254:growth & development* / Q000528:radiation effects*; D005419:Flavonoids / Q000032:analysis; D009036:Moths / Q000502:physiology; D010788:Photosynthesis; D010860:Pigments, Biological / Q000096:biosynthesis* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000254:growth & development / Q000528:radiation effects*; D013997:Time Factors; D014466:Ultraviolet Rays; D014867:Water / Q000032:analysis
D000872:Anthocyanins; D005419:Flavonoids; D010860:Pigments, Biological; D014867:Water; D002734:Chlorophyll; D002338:Carotenoids