The relative leaf width growth rate was calculated as (RLWGR): RLWGR = (LWn/LW0)/t,
where LW0 is the leaf width of the seedlings at the final measurement and LWn is the leaf width of the seedlings at the end
of the experiment, and t is the elapsed time.
For analysis using RLLGR and RLWGR as response variables, we fitted general linear mixed models appropriate for unbalanced data (some treatments were contaminated by fungi and were discarded) using the lme4 package in R, specifying the media as the fixed effect and replication of growth jars as a random effect. Within the context of the fitted model, single degree of freedom contrasts were calculated using Tukey adjustments (alpha = 0.05) to compare between media, using mvtnorm and multcomp packages of R.