Effects of light intensity on growth of four Mosla species

We compared the growth characteristics of four Mosla species that occurred under three light conditions that simulated shaded forest understory, forest edge, and open land. Root mass (M-root), stem mass (M-stem), leaf mass (M-leaf), total mass (M-total), root mass ratio (RMR), and root shoot ratio (R/S) all decreased with decreasing light intensity while specific leaf area (SLA), leaf area ratio (LAR), and height ratio (HR) increased as growth light declined. At low light intensity, M scabra, acclimating to a shade environment, had the highest biomass, RMR, R/S, SLA, and LAR, but its plasticity in response to light intensity was lower than that of the other three shade-intolerant species. The results supported the hypothesis that shade-intolerant species have greater plasticity than shade-tolerant species. Compared with M scabra and M dianthera, M hangchowensis and M chinensis had lower competitive ability for water, nutrients and light (indicated by lower RMR, R/S and HR values), which could cause their endangerment and rarity, respectively.