Effect of solar radiation (UV and visible) at high altitude on CAM-cycling and phenolic compound biosynthesis in Sedum album

• Published in: Physiologia plantarum Vol. 104; no. 2; pp. 203 - 210
• Main Authors: Bachereau, F., Marigo, G., Asta, J.
• Format: Journal Article
• Language: English
• Published: Copenhagen Munksgaard International Publishers 01.10.1998; Blackwell
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Biological and medical sciences; CAM-cycling; cyanidine-3-glucose; Fundamental and applied biological sciences. Psychology; Metabolism; phenolics; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; Plants and fungi; Sedum album; solar irradiance; ultraviolet radiation; UV-A; UV-B; Provence Côte d'Azur; Hautes-Alpes; France; Europe; Ultraviolet radiation; CAM-Type; Crassulaceae; Dicotyledones; Angiospermae; Phenols; Spermatophyta; Metabolism; Photosynthesis; Solar radiation; Altitude
• ISSN: 0031-9317; 1399-3054
• DOI: 10.1034/j.1399-3054.1998.1040208.x

The field experiment was carried out in order to compare the response of a CAM plant, Sedum album L., to solar radiation at a high altitude (2 100 m) with that at a low altitude location with respect to CAM and phenolic content. Treatment sites included (1) sun‐exposed, low altitude, (2) sun‐exposed, high altitude with different light treatments, including UV‐B and UV‐B + A screening, and (3) shade at high altitude. After a 70‐day treatment period, CAM‐cycling and phenolic compound content were analysed, and high altitude treatments were compared to the low altitude control. The sun‐exposed low altitude control was characterized by CAM‐cycling and a low phenolic compound content during the experiment. In plants transplanted to the high altitude, only the shaded group maintained a CAM‐cycling and a phenolic compound content similar to those of the sun‐exposed low altitude control. Samples under UV‐B and UV‐B + A filters showed similar responses, suggesting the absence of a specific UV‐A radiation effect. The screening of UV‐B or UV‐B + A radiation allowed plants to partially maintain a CAM‐cycling and induced a decrease in phenolic compound content. These responses under UV filters were, however, intermediate between those observed in sun‐exposed and shaded groups. These results demonstrate a specific effect of radiation from both visible (400–800 nm) and UV‐B (280–320 nm) bands on both CAM‐cycling and phenolic biosynthesis in S. album L. plants. These light‐dependent effects are discussed on a physiological basis and a possible interaction between CAM‐cycling and phenolic metabolism is suggested.