Development of the Almond Nut (Prunus dulcis (Mill.) D. A. Webb). Anatomy and Chemical Composition of Fruit Parts from Anthesis to Maturity

The growth of the fruit of two varieties of almond (Prunus dulcis(Mill.) D. A. Webb) was studid from anthesis (week 0) to maturity(week 32). The dimensions, fresh weight, moisture content, anatomyand chemical composition of the pericarp, testa, embryo, endospermand nucellus are recorded diagrarnmatically, graphically andby micrographs for one variety. Of the two ovules present atflowering only one normally developed further. By 12 weeks afterflowering the whole fruit had reached full size. The space encloscdby the pericarp was filled by nuallus until weck 10, with subsequentenlargement of both endosperm and embryo. From week 16 to week20 the embryo increased to full size with a concumnt decreasein the size of the endosperm. Sixteen weeks after flowering,the embryo began to accumulate protein and lipid, little ofwhich originated from either the nucellus or endosperm. Theembryo contained no starch or reducing sugar but up to 3% sucrosein the early stags which dtcreascd as lipid and protein increased.Starch and sucrose levels were high in the testa at week 16but subsbquently dropped, starch more rapidly than sucrose.The role of the testa in transport of metabolites to the embryois discussed. Prunus dulcis, almond, fruit development, anatomy, embryo, endosperm