Annals of Botany 35: 63-74, 1971
© 1971 Annals of Botany Company
RESEARCH-ARTICLE |
Changes in Net Assimilation Rate and Leaf-area Ratio with Time in Dactyl is glomerata L.
Welsh Plant Breeding Station, Aberystwyth
Received: 30 April 1970
Two natural populations of Dactylis glomerata, one from Norway and the other from Portugal, were grown at four temperatures in a 16-h photoperiod. Seedlings were harvested at six equal intervals of 7 days at 5 and 10 °C, and 3.5 days at 20 and 30 °C. Time curves of net assimilation rate (NAR), leaf-area ratio (LAR) and other growth attributes were derived from curves fitted to loge leaf area and loge plant weight as functions of time. Three types of curves were found for both NAR and LAR and these conformed to theoretical expectations. There was a general decline in NAR and LAR with time, but in certain treatments NAR increased during the later harvests, and the possible reasons for this are discussed. A similar rise in NAR was also obtained in an experiment with 12 harvest times.