30.01.2013 Views

References

References

References

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

378 E. Wagner et al.<br />

Fig.25.5. Time course of adenylate kinase (AK), NAD- and NADP-glyceraldehyde-3phosphate<br />

dehydrogenase (GPD) activity during darkness. C. rubrum (ecotype 184/68)<br />

seedlings germinated in alternating light intensity and temperature for 4.5 days. Thereafter<br />

constant 20 ◦ C, 6,000 lx fluorescent white light for 24 h followed by a dark period of varied<br />

duration (3-h increments). The enzyme activities were measured at the end of each respective<br />

dark period. The dark period medium was either Hoagland’s solution or 0.4 M glucose<br />

in Hoagland’s solution under sterile conditions. There are semicircadian oscillations with an<br />

inverse phase relationship between photosynthetic NADP-GPD and glycolytic NAD-GPD.<br />

Glucose feeding in darkness has no effect on NADP-GPD but stimulates the other enzyme<br />

activities (Frosch et al. 1973)<br />

25.6<br />

Hydraulic–Electrochemical Integration of the Whole Plant<br />

The integration of metabolic activity of C. rubrum plants on a hydraulic–<br />

electrochemical level is represented by a diurnal rhythm in compound<br />

surface-membrane potential (Fig. 25.2). Spontaneous surface-membrane<br />

action potentials could be shown to correlate with turgor-controlled hydraulic<br />

growth movements of leaves and stem extension (Fig. 25.11), which<br />

are controlled by the photoperiod. Recorded electrophysiograms can be

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!