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6.2 - Environmental impacts on RGR

Light, CO2, temperature, water and nutrients are key driving variables or limiting factors for growth responses in a wide range of species. Growth indices serve as an indicator of plant response, and of interactions between environmental factors where they occur. Variation in whole-plant RGR can be resolved into contributions from NAR (net assimilation rate) and LAR (ratio of leaf area to total plant mass). LAR in turn can be separated into SLA (ratio of leaf area to leaf mass) and LWR (ratio of leaf mass to total plant mass).

Ecological and agronomic implications for managed and natural communities are considered in this section in the context of growth responses to light, temperature and CO2 concentration. The same principles apply to the analysis of effects of nutrients on growth, and to interactions between environmental variables.