Differences in light usage among three fern species of genus <Emphasis Type="Italic">Blechnum</Emphasis> of contrasting ecological breadth in a forest light gradient |
| |
Authors: | Alfredo O Saldaña Carolina Hernández Rafael E Coopman León A Bravo Luis J Corcuera |
| |
Institution: | 1.Departamento de Botánica,Universidad de Concepción,Concepción,Chile;2.Instituto de Silvicultura, Facultad de Ciencias Forestales,Universidad Austral de Chile,Valdivia,Chile |
| |
Abstract: | In Chilean evergreen temperate forest, fern species of the genus Blechnum occur in diverse microhabitats in a light gradient. We hypothesized that differences in the habitat preferences of three
co-occurring Blechnum species would be associated with differences in the magnitude of responses of light capture chlorophyll (Chl) content] and
use (photosynthetic capacity and performance) to light availability. We measured the abundance, chlorophyll content, photosynthetic
capacity (A), and photosynthetic performance (chlorophyll fluorescence of photosystems I and II) of juvenile individuals of each species
growing in different light levels in the field. While Blechnum magellanicum covers a broad light environments range, B. mochaenum is restricted to shade, and B. penna-marina occupies full sun sites. Despite significant interspecific differences in average total chlorophyll content, this trait did
not differ among species along the light gradient. There was significant interspecific variation in both the mean value and
the plasticity of Chl a:Chl b ratio and A to light availability. While B. penna-marina showed a flatter reaction norm (lower response) of Chl a:Chl b ratio to light availability than its two congeners, B. mochaenum showed a lower response of A to light availability. B. penna-marina and B. magellanicum individuals from open sites had higher light saturation points of the electron transport rate (ETR) of both photosystems
(ETRLSP I and II) and photochemical quenching (qL and NA) than the shade restricted B. mochaenum. Additionally, non-photochemical quenching values for both photosystems (NPQ and ND) were higher in ferns species occurring
in shaded sites. The adjustment of the photosynthetic capacity and performance to light availability appears to be an important
mechanism of acclimation in these three Blechnum species that differ in their habitat preferences across a light gradient. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|