F. Tivet et al., Leaf blade dimensions of rice (Oryza sativa L. and Oryza glaberrima Steud.). Relationships between tillers and the main stem, ANN BOTANY, 88(3), 2001, pp. 507-511
The effects of genotype and environment on the leaf area index of rice are
well documented, but the rules governing leaf area distribution among main
stem and tillers are less well understood. This study investigated the onto
genetic patterns of leaf blade area and dimensions on the main stem and til
lers of three rice cultivars, IAC47, Java (Oryza sativa L.) and CG14 (O. gl
aberrima Steud.) grown in pots without competition among plants. No differe
nces in phyllochron were observed among calms, but leaves on tillers appear
ed 0.5 to 0.8 phyllochrons earlier than the genealogically corresponding le
aves on the main stem (system of Katayama). Cohorts were thus not fully syn
chronized. All culms produced their largest leaves soon after panicle initi
ation (PI), despite differences in tiller age. Leaves that appeared subsequ
ently were smaller owing to reduced length but not width, which remained co
nstant. Three different hypothetical rules governing the behaviour of culms
were tested: (1) tillers behave as clones of the main stem; (2) cohorts be
have uniformly, and (3) behaviour is determined by leaf position (sum of ge
nealogical leaf and tiller indices). The results were best explained by hyp
otheses (2) and (3), with leaf blade width and length showing markedly diff
erent patterns. (C) 2001 Annals of Botany Company.