554
E.-D. Schulze and M.M. Caldwell
tribution, and (4) scaling information on photosynthetic behaviour of leaves
to canopies, landscapes, and even attempts to a global level.
Global concerns of climate change and man's land-use patterns, highlighted in the forthcoming International Geosphere-Biosphere Programme,
are requiring answers from the ecophysiology community on questions such
as vegetation response to elevated levels of CO 2 • How plants respond to
greater CO2 in the field would seem to be rather straightforward. However,
to our surprise, we find that we are not capable of making predictions for
the scales of time and space needed to address the questions presented.
This book attempts to summarize the research that can serve as a basis to
the larger questions of the future.
26.2 Methodology
Following the flourish of technological development during the "gasexchange cuvette era" of photosynthetic ecophysiology, several new methodological achievements have been made:
- Automated porometers have made gas exchange measurements globally
accessible (Pearcy et ai. 1989). Large mobile field laboratories seem to be
relics of the past.
- Florescence techniques are giving insight into the biochemical processes
of photosynthesis even under field conditions (see Schreiber et aI., Chap.
3, this VoI.).1
- Molecular biology and the production of "antisense" mutants are providing a powerful tool to separate coincidence and correlation from mechanistic function (Stitt and Schulze 1993; see also Trebst, Chap. 1; Schulze
and Schulze, Chap. 6). For example, studies with mutants have shown
that previous models of photosynthesis were of a correlative nature and,
thus, not suitable to make predictions in the future if the baseline conditions such as atmospheric CO2 change (Fichtner et aI., Chap. 7).
- The use of stable isotopes has allowed investigation of plant photosynthetic behaviour on a broad geographic scale, which would never have
been possible by use of gas exchange chambers (Ehleringer, Chap. 18).
- Simulation modeling has reached a level such that highly interactive
processes can be examined at canopy and landscape scales (Beyschlag et
aI., Chap. 20; Tenhunen et aI., Chap. 21).
- Remote sensing is being increasingly used to monitor global surface
processes; attempts are even being made to measure transpiration,
photosynthesis, and protective pigment conversions from space (Field,
Chap. 24; see also Fig. 26.1).
1 All chapters referred to here are in the present volume.
E.-D. Schulze and M.M. Caldwell
tribution, and (4) scaling information on photosynthetic behaviour of leaves
to canopies, landscapes, and even attempts to a global level.
Global concerns of climate change and man's land-use patterns, highlighted in the forthcoming International Geosphere-Biosphere Programme,
are requiring answers from the ecophysiology community on questions such
as vegetation response to elevated levels of CO 2 • How plants respond to
greater CO2 in the field would seem to be rather straightforward. However,
to our surprise, we find that we are not capable of making predictions for
the scales of time and space needed to address the questions presented.
This book attempts to summarize the research that can serve as a basis to
the larger questions of the future.
26.2 Methodology
Following the flourish of technological development during the "gasexchange cuvette era" of photosynthetic ecophysiology, several new methodological achievements have been made:
- Automated porometers have made gas exchange measurements globally
accessible (Pearcy et ai. 1989). Large mobile field laboratories seem to be
relics of the past.
- Florescence techniques are giving insight into the biochemical processes
of photosynthesis even under field conditions (see Schreiber et aI., Chap.
3, this VoI.).1
- Molecular biology and the production of "antisense" mutants are providing a powerful tool to separate coincidence and correlation from mechanistic function (Stitt and Schulze 1993; see also Trebst, Chap. 1; Schulze
and Schulze, Chap. 6). For example, studies with mutants have shown
that previous models of photosynthesis were of a correlative nature and,
thus, not suitable to make predictions in the future if the baseline conditions such as atmospheric CO2 change (Fichtner et aI., Chap. 7).
- The use of stable isotopes has allowed investigation of plant photosynthetic behaviour on a broad geographic scale, which would never have
been possible by use of gas exchange chambers (Ehleringer, Chap. 18).
- Simulation modeling has reached a level such that highly interactive
processes can be examined at canopy and landscape scales (Beyschlag et
aI., Chap. 20; Tenhunen et aI., Chap. 21).
- Remote sensing is being increasingly used to monitor global surface
processes; attempts are even being made to measure transpiration,
photosynthesis, and protective pigment conversions from space (Field,
Chap. 24; see also Fig. 26.1).
1 All chapters referred to here are in the present volume.