Fig. 3.

Relative variation around the observed mean values for phytomer appearance rate, individual leaf area, internode length, internode linear weight and area leaf weight (for the description of the variables, see Table 4), as a function of variation around the mean for increase in whole-plant biomass for ‘control’, ‘control with clusters’ and ‘dark control’ treatments. The lines represent the linear regression for ‘control’, ‘dark control’ and ‘control with clusters’ treatments. Each point corresponds to the mean value for plants subjected to the same treatment in each experiment (except in expt 6). R₁² is the coefficient of determination for the linear regressions, and a₁ is the slope of the linear regression line. The significance of the regressions was assessed with Pearson's test: ***, significant at P < 0·001; n.s., not significant.