Effect of simulated acid rain on vegetation

Book · Tue Jan 01 04:00:00 EST 1974

OSTI ID:6093930

Ferenbaugh, R W

Experiments were performed to determine the effects of simulated acid rain on Chenopodium quinoa, Hordeum vulgare and Phaseolus vulgaris. Detailed experiments were conducted only on Phaseolus vulgaris. Sulfuric acid solutions covering a pH range of 1.5 to 3.5 were used. Gross morphological effects noted at lower pH values included failure to attain normal height, necrosis and wrinkling of leaves, excessive and adventitious budding, and premature abscission of primary leaves. Histological effects included smaller cell size, a decreased amount of intercellular space, hypertrophied nuclei and nucleoli, and a reduction in the size of starch granules within the chloroplasts. Dry weight remained an approximately constant percentage of fresh weight, and chlorophyll analyses showed that both chlorophyll concentration and ratio of chlorophyll to chlorophyll also remained constant. Respirometer studies showed that respiration rate increased slightly and photosynthetic rate increased dramatically. Quantitative analyses indicated that carbohydrate content was reduced at low pH values. Root biomass was also reduced. Application of Congo red indicator solution to the acid treated tissue showed that it was being acidified to a pH of below 4. Experiments involving aspiration of control tissue in acid solutions suggest that the increase in photosynthetic rate and the decreases in carbohydrate content and root biomass were caused by an uncoupling of photophosphorylation of adenosine diphosphate. Uncoupling was probably caused by hydrogen ion interference with proton pumps associated with the electron transport chain in the light reactions of photosynthesis. 128 references. (MDF)

• OSTI ID: 6093930
• Country of Publication: United States
• Language: English

Related Subjects

500200 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560303* -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
ATMOSPHERIC PRECIPITATIONS
BARLEY
BIOLOGICAL EFFECTS
BIOLOGICAL STRESS
CARBOHYDRATES
CEREALS
CHEMICAL REACTIONS
DATA
EXPERIMENTAL DATA
GRASS
HYDROCARBONS
INFORMATION
LEGUMINOSAE
METABOLISM
MORPHOLOGICAL CHANGES
NUMERICAL DATA
ORGANIC COMPOUNDS
PHASEOLUS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
PRECIPITATION SCAVENGING
RAIN
RESPIRATION
SEPARATION PROCESSES
SIMULATION
SYNTHESIS