Dear Dawei Cheng ,

Leaf area index (LAI) is a measure of the total area of leaves per unit ground area in a plant canopy. It is a commonly used indicator of plant productivity, but it is not directly related to plant root distribution.

Nonetheless, LAI can be used as an indirect indicator of plant root distribution by assuming a relationship between leaf area and root mass. For example, root-to-shoot ratios, which indicate the proportion of root mass to shoot mass, can be used to estimate root distribution based on LAI. However, using a fixed shoot:root ratio would be an oversimplification. This ratio changes based on the genotype (G), environment (E) and management (E, in case of crops), and their interaction GxExM. Extensive work is still required in crop systems biology and modelling in order to obtain accurate models.