146
L. W. WOODSTOCK
7. NEIDHARDT, F. c., andB. MAGASANIK: Biochem. Biophys. Acta 42, 99 (1960).
8. NILSON, E. G., and A. W. PAULI: Crop. Sci. 4, 149 (1964).
9. NUTILE, G. E., and L. W. WOODSTOCK: Physiol. Plant., in press (1967).
10. PFEFFER, W.: The physiology of plants. London: Oxford University Press.
Transl. by A. J. Ewart 1900.
11. POLLOCK, B. M., and V. K. TOOLE: Plant Physiol. 41, 221 (1966).
12. SAX, K.: Rad. Bot. 3, 179 (1963).
13. SKOOG, P.: J. Cell. Compo Physiol. 7, 227 (1935).
14. WATSON, J. D.: Molecular Biology of the Gene. New York: W. A. Benjamin,
Inc., 1965.
15. WOODSTOCK, L. W.: Bioscience 15, 783 (1966).
16. -, and D. F. GRABE: Plant Physiol., in press (1967).
17. -, and O. L. JUSTICE: Rad. Bot. 7, 129 (1967).
18. -, and B. M. POLLOCK: Science 150,1031 (1965).
19. -, and F. SKOOG: Amer. J. Bot. 47, 713 (1960).
Discussion
KLAMERTH:
Is there any correlation between growth rate and synthesis of rapidly labelled
RNA? Could there be a possibility that preformed nucleotide triphosphates
in a pool supply the whole RNA synthesis you mentioned?
WOODSTOCK:
We have in fact found relationships between RNA contents and growth.
Yes, it may be that there exists such a pool.
PAYNE:
Can you distinguish between your first hypothesis (a) that growth is limited
by total respiratory energy, and the possibility that the rate of transport of
nutrient substrate is itself the factor limiting overall metabolism?
WOODSTOCK:
If nutrients were limiting for growth then we have to assume that their sum
is also limiting for the uptake of oxygen. We cannot distinguish between the
two hypotheses.
KACSER:
The growth rate was not constant; it would not be the same at 4 days or at
3 days after planting. However, when growth at one period is compared to
growth at some later period, the two are positively correlated. "Growth"
measured as length increase in etiolated seedlings may not be the same as
growth measured by dry weight, because under these conditions dry weight
decreases. But, under normal conditions growth measured as elongation
parallels protein synthesis, cell formation and the criteria of growth.
WOODSTOCK:
We measure the growth of a seedling in the dark. If we measure the rate of
growth in terms of dry weight, we measure growth rate of decrease in
dry weight.
L. W. WOODSTOCK
7. NEIDHARDT, F. c., andB. MAGASANIK: Biochem. Biophys. Acta 42, 99 (1960).
8. NILSON, E. G., and A. W. PAULI: Crop. Sci. 4, 149 (1964).
9. NUTILE, G. E., and L. W. WOODSTOCK: Physiol. Plant., in press (1967).
10. PFEFFER, W.: The physiology of plants. London: Oxford University Press.
Transl. by A. J. Ewart 1900.
11. POLLOCK, B. M., and V. K. TOOLE: Plant Physiol. 41, 221 (1966).
12. SAX, K.: Rad. Bot. 3, 179 (1963).
13. SKOOG, P.: J. Cell. Compo Physiol. 7, 227 (1935).
14. WATSON, J. D.: Molecular Biology of the Gene. New York: W. A. Benjamin,
Inc., 1965.
15. WOODSTOCK, L. W.: Bioscience 15, 783 (1966).
16. -, and D. F. GRABE: Plant Physiol., in press (1967).
17. -, and O. L. JUSTICE: Rad. Bot. 7, 129 (1967).
18. -, and B. M. POLLOCK: Science 150,1031 (1965).
19. -, and F. SKOOG: Amer. J. Bot. 47, 713 (1960).
Discussion
KLAMERTH:
Is there any correlation between growth rate and synthesis of rapidly labelled
RNA? Could there be a possibility that preformed nucleotide triphosphates
in a pool supply the whole RNA synthesis you mentioned?
WOODSTOCK:
We have in fact found relationships between RNA contents and growth.
Yes, it may be that there exists such a pool.
PAYNE:
Can you distinguish between your first hypothesis (a) that growth is limited
by total respiratory energy, and the possibility that the rate of transport of
nutrient substrate is itself the factor limiting overall metabolism?
WOODSTOCK:
If nutrients were limiting for growth then we have to assume that their sum
is also limiting for the uptake of oxygen. We cannot distinguish between the
two hypotheses.
KACSER:
The growth rate was not constant; it would not be the same at 4 days or at
3 days after planting. However, when growth at one period is compared to
growth at some later period, the two are positively correlated. "Growth"
measured as length increase in etiolated seedlings may not be the same as
growth measured by dry weight, because under these conditions dry weight
decreases. But, under normal conditions growth measured as elongation
parallels protein synthesis, cell formation and the criteria of growth.
WOODSTOCK:
We measure the growth of a seedling in the dark. If we measure the rate of
growth in terms of dry weight, we measure growth rate of decrease in
dry weight.