Alternative respiratory path capacity in plant mitochondria: effect of growth temperature, the electrochemical gradient, and assay pH. [Zea mays L. , Vigna radiata L. , Symplocarpus foetidus L. , Sauromatum guttatum Schott]
Influence of growth temperature on the capacity of the mitochondrial alternative pathway of electron transport was investigated using etiolated corn (Zea mays L.) seedlings. These seedlings were grown to comparable size in either a warm (30/sup 0/C) or a cold (13/sup 0/C) temperature regime, and then their respiration rates were measured as O/sub 2/ uptake at 25/sup 0/C. The capacity of the alternative pathway (KCN-insensitive O/sub 2/ uptake) was found essentially to double in shoots of cold-grown seedlings. When mitochondria were isolated from the shoots a greater potential for flow through the alternative path was observed in mitochondria from the cold-grown seedlings with all substrates used (an average increase of 84%). Using exogenous NADH as the substrate, the effect of the electrochemical gradient on measurable capacities of the cytochrome and alternative pathways was investigated in mitochondria from both etiolated seedlings and thermogenic spadices. In corn shoot and mung bean (Vigna radiata L.) hypocotyl mitochondria increased flow through the cytochrome chain in the absence of the electrochemical gradient was found not to influence the potential for flow through the alternative path. However, in mitochondria from skunk cabbage (Symplocarpus foetidus L.) and voodoo lily (Sauromatum gutatum Schott) spadices increased flow through the cytochrome chain in the absence of the gradient occurred at the expense of flow through the alternative pathway. This experiment also revealed that the potential for respiratory control is largely dependent upon the assay pH.
- Research Organization:
- Univ. of Pennsylvania, Philadelphia
- DOE Contract Number:
- AC02-82ER12028
- OSTI ID:
- 5531525
- Journal Information:
- Plant Physiol.; (United States), Vol. 80:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
HYPOTHERMIA
BIOLOGICAL EFFECTS
MITOCHONDRIA
BIOLOGICAL PATHWAYS
ELECTRON TRANSFER
PLANTS
CYANIDES
CYTOCHROMES
EXPERIMENTAL DATA
LEAVES
MAIZE
NADH2
OXYGEN
PH VALUE
PLANT GROWTH
POTASSIUM COMPOUNDS
RESPIRATION
SEEDLINGS
SUBSTRATES
TEMPERATURE EFFECTS
UPTAKE
ALKALI METAL COMPOUNDS
BODY TEMPERATURE
CELL CONSTITUENTS
CEREALS
COENZYMES
DATA
ELEMENTS
GRASS
GROWTH
INFORMATION
NONMETALS
NUCLEOTIDES
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANOIDS
PIGMENTS
PROTEINS
550500* - Metabolism
560203 - Thermal Effects- Plants- (-1987)