I am familiar with the law of minimum, that is that the growth of the plant is dependent on the least available nutrient/resource.
I visited a farm in which they purposefully shaded tabaco plants to guide the growth of the plant (e.g. to make the plant grow taller and wider leaves with better concentrations of nicotine). I am wondering if this applies to other nutrients/plants. Example: Does deficiency in nutrient X guide the growth of spinach with Y% more iron?