|
| Plant Respiration |
 |
| Plants possess an energetically wasteful respiratory
pathway in their mitochondria termed the (alternative¦ pathway.
Large amounts of potential harvested crop yield may be lost through
the operation of this pathway. Although the role of the alternative
pathway in metabolism is not known, it is found in all plants, suggesting
an important metabolic function. Knowing under what circumstances
electrons derived from respiratory substrates are diverted from the
main, energy-producing respiratory pathway onto the alternative pathway
is crucial to discovering the alternative pathway¦s role. Studies
of the distribution of electrons between the two respiratory pathways
are possible through a technique based on differential use of the
stable isotope oxygen-18 by the two oxidases that terminate the two
pathways. The continued development and application of this technology
will allow characterization of alternative pathway activity during
respiration by intact plant tissues responding to two environmental
stresses, low temperature and phosphorus deprivation. These studies
will be carried out using plants having the "normal" alternative
oxidase, the enzyme that comprises the alternative pathway, and transgenic
plants expressing an altered form of the enzyme that cannot be inactivated
by normal regulatory mechanisms. This research will improve our understanding
of conditions under which the alternative pathway is active, which
is essential for any future agricultural application of transgenic
plants with modified levels of the alternative pathway. |
|
