HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McCree, K. J. Articles by Silsbury, J. H. Search for Related Content PubMed Articles by McCree, K. J. Articles by Silsbury, J. H. Agricola Articles by McCree, K. J. Articles by Silsbury, J. H.

Growth and Maintenance Requirements of Subterranean Clover¹

The growth and maintenance requirements of young communities of subterranean clover (Trifolium subtermneum L.) were determined from CO₂ exchange rates, through the equation: N = kD + (l+k)cW, where and D are the nighttime and daytime 12 hour totals of CO₂ exchanged, W is the CO₂ equivalent of the dry weight, and k and c are growth and maintenance coefficients, respectively. Values of k and c were obtained from steady state tests in which the plant communities were allowed to equilibrate for several days, first with 19 hours of full light and 12 hours of darkness, and then in continuous darkness. The dynamic responses of the plants were determined in other tests, in which D and N were varied by changing the photon flux at 24 hour intervals and a linear regression of N against D was formed. Both sets of experiments were repeated at different temperatures in the range 10 to 35 C. At the lower temperatures the slope of the regression line in the dynamic response tests tended to be lower than the steady state values of k. This was interpreted to mean that the plants were not reaching a steady-state of substrate production and use within 24 hours of a change in photon flux. A steady-state condition is implicit in the equation since it does not include a storage term. The steady state values of k were virtually independent of temperature, while the value of c was an increasing exponential function of temperature, with a Q₁₀ of 1.S1. The values of k and c at 30 C (0.14 g.g–¹ and 18 mg.g–¹.12h–¹ respectively) were not significantly different from those obtained in parallel experiments with white clover (Trifolium repens L.) (0.15 g.g–¹ and 22 mg-g–¹.12h–¹). for subterranean clover, the value of Thornley's maintenance coefficient m was 48 mg.g–^l-24h–¹ at 30 C, with a Q₁₀ of 1.85, which is consistent with the idea that the protein turnover rate determines the maintenance loss rate. The yield of new biomass carbon (C) per unit of C used (Thornley's Y_g) was 0.75, which is consistent with estimates from quantitative biochemistry.

Key Words: Respiration • Photosynthesis • CO₂ exchange • Trifolium subterraneum L.

² Associate professor, Dep. of Soil & Crop Sciences, Texas A&M Univ., College Station, TX 77843, and senior lecturer in agronomy, Waite Agric. Res. Inst., Glen Osmond, SA 5064, Australia, respectively.

Received for publication December 17, 1976.

This article has been cited by other articles:

				K. J. Boote and T. R. Sinclair Crop Physiology: Significant Discoveries and Our Changing Perspective on Research Crop Sci., September 8, 2006; 46(5): 2270 - 2277. [Abstract] [Full Text] [PDF]