PALYNOLOGICAL STUDIES FOR SOME CULTIVATED SPECIES OF PINUS L., 1753 (PINALES, PINACEAE) IN EGYPT

Abstract

Pollen grains of the five cultivated species of Pinus L., 1753 from Subsect. Pinaster (Order Pinales, Family Pinaceae) were collected from the Orman Botanic Gardens at Giza in addition to the herbarium specimens. They were examined by light and scanning electron microscopy to detect the taxonomic value of their pollen characteristics. The pollen grains were bisaccate. An artificial key constructed according to the morphology of pollen grains recognizes the five species that belong to Pinus: P. pinea Linnaeus, 1753; P. canariensis Smith, 1828; P. halepensis Miller, 1768; P. roxburghii Sargent, 1897; and P. brutia Tenore, 1811. The differential items included the presence or absence of apertures, e.g. the monosulcate colpus that presents in P. pinea and P. brutia; pollen shape without sacci that could be perprolate as in P. pinea or prolate as in the remaining species; pollen shape (outlined with sacci) in polar view that could be haploxylonoid as in P. pinea and P. roxburghii or diploxylonoid as in the remaining species; in addition to cappa and sacci exine sculpture. A dendrogram from the Community Analysis Package statistical program for data analysis supported the separation of five species of Pinus in Egypt and showed that P. canariensis and P. halepensis were closely related, as well as P. brutia and P. roxburghii. The cluster separated P. pinea into a separate group, but it was more closely related to P. canariensis and P. halepensis. The cluster tree was illustrated, visualized, and confirmed by a heat map based on the R programming language for effective manipulation of the data.