Low uptake rates One way that a lot of plants appear to adapt to low nutrient environments is to be able to survive at those low nutrient levels. A high Imax entails lots of membrane-bound pumps and channel proteins, which is N expensive. This means that their growth rates are often slower. Root exudates Plants are remarkable in that they can exude organic compounds out of their roots to help acquire nutrients. One of the main nutrients sought in this manner is phosphorus.
P is probably second only to N in terms of nutrients limiting plant productivity.
In the tropics, it is probably the most limiting soil nutrient. There is some evidence that species differ in their capacity to dissolve P from rocks. This enzyme breaks down organic P into inorganic PO4-3, which can be taken up by roots. Several micronutrient metal ions like Fe, Zn, and Cu are taken up after organic molecules bind them and allows them to diffuse to the root surface. Little is known about species differences in this parameter.