Acclimation to UV irradiance inGracilaria chilensisBird, McLachlan & Oliveira (Gigartinales, Rhodophyta)
✍ Scribed by Ximena Molina; Vivian Montecino
- Book ID
- 104623093
- Publisher
- Springer
- Year
- 1996
- Tongue
- English
- Weight
- 414 KB
- Volume
- 326-327
- Category
- Article
- ISSN
- 1573-5141
No coin nor oath required. For personal study only.
✦ Synopsis
Photoautotrophs can cope with an increase in ultraviolet (UV) irradiance in the aquatic environment, through protection and acclimation mechanisms (i .e . synthesis of UV absorbing compounds) . This capacity has been proven to vary according to the organism's sensitivity . To quantify variations of this capacity between the different parts of macroalgae, an in vitro study was performed with the tips, cystocarps and thalli segments of Gracilaria chilensis . Whole algae incubated during 3 days at high and low PAR, supplying UV -B (4 .6 tW cm -2 ) during 2 hours showed, as predicted, an increase in absorption (OD) at 320 nm of the different parts, after the first day of exposure to UV B . The tips presented the highest increase in the standardized OD at 320 nm relative to cystocarps and thalli segments ; their mean percentage of increase was 38% and 29% at low and high PAR, respectively . The lowest sensitivity was consistently found in the thalli segments, while the highest was in the tips . The tips are important for growth and therefore they play a major role in the maintenance of the Gracilaria populations . Acclimation mechanisms that occurred in a short time scale, and mainly in the tips, may allow Gracilaria to have an almost immediate protection to increases in UV-13 fluxes .