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 Google Scholar Google Scholar Articles by McCree, K. J. Articles by Kresovich, S. Search for Related Content PubMed Articles by McCree, K. J. Articles by Kresovich, S. Agricola Articles by McCree, K. J. Articles by Kresovich, S.

Growth and Maintenance Requirements of White Clover as a Function of Daylength¹

Carbon dioxide exchange rates of white clover (Trifolium repens L.) stands were monitored for several days at 30 C, a high light level (2.0 mE.s^–1.m^–2), and different day/night lengths in the range 6/18 to 18/6 hours. The plants were then kept in continuous darkness for 2 days. Thornley's growth and maintenance coefficients were calculated from the 24 hour CO₂ exchange rates. The yield of new biomass carbon (C) per unit of C input into growth (Y_g) was found to be independent of daylength, the average value being 0.74 ± 0.01. The maintenance loss rate of C per unit of biomass C present (m), increased from 36 to 53 mg.g^–1 24hour^–1 as the daylength increased from 6 to 18 hours. This was shown to be an indirect effect of the seven-fold increase in the growth rate (24 hour net gain) from 12 to 90 g Co₂.m^–3.24hour^–1. No direct effect of daylength on either growth or maintenance requirements was found.

Key Words: Respiration • Photosynthesis • CO₂ exchange

² Associate professor and former graduate assistant, Dep. of Soil and Crop Sciences, Texas A&M Univ., College Station, TX 77843.

Received for publication February 22, 1977.