Inside the plant body water flows up from the roots, into the vascular system, and eventually out through pores, all part of the process of photosynthesis.
Nutrients flow from the roots, but also from the photosynthetic parts of the plant, nourishing flowers, fruit, and buds.
The roots of the plant, which are not photosynthetic, cannot nourish themselves. In order to grow and survive they depend on carbohydrates that are formed through the photosynthetic process. Some of those carbohydrates may be stored in the roots of certain plant species.
In their hundreds of millions of years of evolutionary history plants have experienced flow from one ecosystem to the next. across continents, up and down mountain ranges, and through time.
Plants provide us with a kind of living memory of the flow of life and its many complex processes.