Cyanide-resistant respiration in photosynthetic organs of freshwater aquatic plants. [Myriophyllum spicatum]

Journal Article · Wed Jul 01 04:00:00 EDT 1987 · Plant Physiol.; (United States)

OSTI ID:6016691

Azcon-Bieto, J; Murillo, J; Penuelas, J

The rate and sensitivity to inhibitors (KCN and salicylhydroxamic acid(SHAM)) of respiratory oxygen uptake has been investigated in photosynthetic organs of several freshwater aquatic plant species. The oxygen uptake rates on a dry weigh basis of angiosperm leaves were generally higher than those of the corresponding stems. Leaves also had a higher chlorophyll content than stems. Respiration of leaves and stems of aquatic angiosperms was generally cyanide-resistant. The cyanide resistance of respiration of whole shoots of two aquatic bryophytes and an alga was lower. These results suggested that the photosynthetic tissues of aquatic plants have a considerable alternative pathway capacity. The angiosperm leaves generally showed the largest alternative path capacity. In all cases, the respiration rate of the aquatic plants studied was inhibited by SHAM alone by about 13 to 31%. These results were used for calculating the actual activities of the cytochrome and alternative pathways. These activities were generally higher in the leaves of angiosperms. The basal oxygen uptake rate of Myriophyllum spicatum leaves was greatly increased by CCCP, either in the presence or in the absence of substrates. These results suggest that respiration was limited by the adenylate system, and not by substrate availability. The increase in the respiratory rate by CCCP was due to a large increase in the activities of both the cytochrome and alternative pathways. The respiration rate of M. spicatum leaves in the presence of substrates was little inhibited by SHAM alone, but the SHAM-resistant rate (that is, the cytochrome path) was greatly stimulated by the further addition of CCCP. Similarly, the cyanide-resistant rate of O/sub 2/ uptake was also increased by the uncoupler.

• Research Organization: Universitat de Barcelona, Spain
• OSTI ID: 6016691
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 84:3; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200 -- Biochemistry
560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALGAE
ALKALI METAL COMPOUNDS
AQUATIC ORGANISMS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLOROPHYLL
CYANIDES
CYTOCHROMES
ELEMENTS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INHIBITION
LEAVES
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYTOCHROMES
PIGMENTS
PLANT STEMS
PLANTS
PORPHYRINS
POTASSIUM COMPOUNDS
PROTEINS
RESPIRATION
SYNTHESIS
TOLERANCE
UPTAKE