Carbohydrates and Cell Walls

Abstract

In most pollen, carbohydrates constitute the major dry matter fraction (Table 8-1). Polysaccharides, primarily starch and cell wall consituents, may comprise up to 50% of the dry weight. Low molecular weight carbohydrates average 4 to 10% of the pollen dry weight. Carbohydrate levels vary with the species (Nielsen et al., 1955). Gymnosperm pollen, e.g. Pinus, is generally low in total carbohydrates (Table 9-1). In angiosperms, the trinucleate pollen of Zea mays is high in total carbohydrates, but the trinucleate pollengrains of Beta and Ambrosia are reported to be low (Lundén, 1954). Binucleate angiosperm pollen may also be either high or low. The number of nuclei is apparently not directly correlated with carbohydrate content. Table 9-1 gives a few examples of between species variation in carbohydrate content of pollen collected directly from the plant.