Plant cells contain far more compounds than are produced by the basic metabolism. Terpenes, waxes, alkaloids and pigments are just some key words that illustrate what is meant. The term basic metabolism comprises all pathways necessary for the survival of the cells, while secondary plant products are such that occur usually only in special, differentiated cells and are not necessary for the cells themselves but may be useful for the plant as a whole.
Examples are flower pigments and scents or stabilizing elements.
Both metabolisms are overlapping since it is often not understood why a certain compound is produced. Furthermore exists no typical cell so that some compounds may be necessary for the survival of some cells but not for that of others. Plant cells produce a vast mount of secondary products. Many of these are highly toxic and are often stored in specific vesicles or in the vacuole . Several studies indicate that this kind of storage functions on one hand as a detoxification of the plant itself and generates on the other hand a reservoir of, for example, nitrogen-rich molecules.