Sequential Effects of Acidic Precipitation and Drought on Photosynthesis and Chlorophyll Fluorescence Parameters of Pinus radiata D. Don Seedlings

• Published in: Journal of plant physiology Vol. 156; no. 1; pp. 84 - 92
• Main Authors: Mena-Petite, A., González-Moro, B., González-Murua, C., Lacuesta, M., Muñoz Rueda, A.
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 2000; Elsevier
• Subjects: Acid rain; Biological and medical sciences; CO 2 assimilation; electrolyte leakage; fluorescence; forest decline; Fundamental and applied biological sciences. Psychology; Non agrochemicals pollutants; photosynthetic quantum yield; Phytopathology. Animal pests. Plant and forest protection; Pollution effects and side effects of agrochemicals on crop plants and forest trees. Other anthropogenic factors; Pollution effects. Side effects of agrochemicals; radiata pine; stomatal conductance; transpiration; water potential; stomatal conductance; A; E; SAR; Ci; WUE; Fm; Acid rain; QY; Fo; forest decline; electrolyte leakage; Ωw; Fv; radiata pine; transpiration; water potential; CO 2 assimilation; fluorescence; Fv/Fm; photosynthetic quantum yield; Chlorophyll; Plant juvenile growth stage; Stomatal conductance; Water use efficiency; Pinus radiata; Softwood forest tree; Gymnospermae; Pigments; Air pollution; Coniferales; Spermatophyta; Photosynthesis; Drought
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/S0176-1617(00)80276-X

We studied the sequential effect of simulated acid rain (SAR) and water stress on net photosynthesis (A), internal CO
2 concentration (
Ci), stomatal conductance (g), and instantaneous water use efficiency (A/E), and the photochemical damage caused by these stressors by analysing chlorophyll fluorescence parameters such as Fv/Fm, Fv/Fo and Fm/Fo. SAR caused inhibition of photosynthesis. The depletion of CO
2 assimilation seems not to be solely a stomatal effect as effects on chloroplasts contribute to this photosynthetic inhibition. No noticeable damage seems to occur to the photochemical apparatus since well-watered plants treated with acid rain did not show any change in the chlorophyll fluorescence. Water stress produced a large effect on both gas exchange and chlorophyll fluorescence parameters, indicating structural and functional damage. Interactions among SAR and drought had a larger impact on all parameters studied. However, after rewatering, significant recovery in both gas exchange and chlorophyll fluorescence parameters occurred within 6 days, although the values measured prior to the imposition of treatments were not recovered. We conclude that
Pinus radiata exposed to acid rain were affected in a wide range of components in the photosynthetic apparatus, thereby modifying its response to sequential drought stress.