Identification of Tree Fruit Species by Pollen Ultrastructure1

Abstract

Abstract Differences in size and surface ultrastructure of pollen grains are useful for distinguishing species of tree fruits. Peach (Prunus persica [L.] Batsch) and nectarine (P. persica var. nectarina [Ait.] Maxim.) have the largest pollen grains, about 62 × 32 μm, and have similar surface markings. Apricot (P. armeniaca L.), like peach, pollen has ridges of exine which are generally longitudinal and shallow, but the grains are slightly smaller. Pollen of European plum (P. domestica L.) is slightly shorter and comparatively wider than that of peach and has the most prominent and complex exine ridging of the tree fruit species. Japanese plum (P. salicina Lindl.) pollen has similar conformation and surface appearance to that of peach but is only one-half as large. Sweet cherry (P. avium [L.] L.) and apple (Malus domestica Borkh.) pollens are about three-fourths the dimensions of those of peach and have narrower ridges. Apple has the least coarse ridges of any of the tree fruits. Sweet cherry has many abortive grains and its exine ridges are more distinct than those of apple. Sour cherry (P. cerasus L.) pollen is about one-half the size of peach pollen and has prominent ridges and many abortive grains. Pear (Pyrus communis L.) pollen is also about one-half the length of peach pollen but comparatively wider; it has shallow but distinct and complex ridges and some abortive grains.