is as expected from the ‘functional equilibrium’ concept: plants decrease LMF and increase RMF when grown at high light levels as compared to low light. At low nutrient levels they invest more in roots and less in leaves as compared to high nutrient supply. However, changes are often smaller at different water supply, and effects of CO2 concentration, UV-B radiation, ozone and salinity on allocation are generally negligible. Plants growing at higher temperature mostly decrease RMF and increase LMF. A point of attention in the analysis of mass fractions is whether or not to correct for differences in size, when comparing plants that have been treated differently, or in the comparison of species. The rationale behind this is that mass factions often change with plant size (and developmental phase), and different treatments may have caused growth differences as well. Thus, for an assessment of whether plants actively changed their allocation scheme, plants of similar size should be compared. If size corrections are required, one could do an allometric analysis. A simple alternative is to plot mass fractions against total plant mass. Differences between species Species of different families may have different allocation patterns. For example, species belonging to the Solanaceae have high LMF values, whereas Fagaceae have low LMF values, even after size-corrections. Grasses generally have lower LMF values that herbaceous dicots, with a much higher proportion of their biomass present in roots. Large evergreen trees have a larger fraction of their biomass allocated to leaves (LMF ~0.04) than deciduous species (LMF ~0.01). See also Allometry Biomass partitioning Plant growth analysis References Biomass Plant ecology Plant physiology