Effects of ozone and Fusarium root and crown rot on the growth and decline of Alfalfa, Medicago sativa L

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6449811

Cooley, D R

Research examined the reaction of several major alfalfa cultivars to ozone fumigations in chambers using ozone concentrations simulating ambient levels observed in Massachusetts. These cultivars were all shown to be susceptible in varying degrees to such ozone stress. Further experiments showed that ozone at these concentrations not only reduced growth, but also altered photoassimilate partitioning. Greatest weight reductions occurred in roots, followed by leaves, and then stems. Ozone-stressed plants produced fewer leaves which weighed less per unit area than control leaves. Classic and functional growth analyses were used to examine such parameters as net assimilation rate and relative growth rate. Ozone-stressed plants fixed dry matter less efficiently than control plants, in terms of both leaf area and existing dry matter. In a final study, alfalfa was grown in the presence of isolates of pathogenic Fusarium, or to soil from a diseased alfalfa field, and concurrently fumigated with ozone. There was no significant interaction between pathogen and air pollutant, but each stress significantly reduced alfalfa growth independently.

• Research Organization: Massachusetts Univ., Amherst (USA)
• OSTI ID: 6449811
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
ALFALFA
BACTERIA
EXPOSURE CHAMBERS
FEDERAL REGION I
FUNGI
FUSARIUM
GROWTH
INFECTIVITY
LEGUMINOSAE
MASSACHUSETTS
MICROORGANISMS
NORTH AMERICA
OZONE
PARASITES
PLANT GROWTH
PLANTS
POLLUTION
RHIZOBIUM
SENSITIVITY
SIMULATION
TOXICITY
USA