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ULTRASTRUCTURAL INVESTIGATIONS ON THE TWO‐NUCLEATE POLLEN GRAIN OF TILLANDSIA CAPUT‐MEDUSAE MORR. (BROMELIACEAE)
Author(s) -
Brighigna Luigi,
Fiordi Ambretta Cecchi,
Palandri Maria R.
Publication year - 1981
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1981.tb06386.x
Subject(s) - biology , bromeliaceae , botany , ultrastructure , pollen
The fine structure of the pollen grain of Tillandsia caput‐medusae Morr. (Bromeliaceae) prior to germination has been studied. The development, after the first mitosis, is here schematized in three stages which are in accordance with the main steps described in angiosperms. The ultrastructural modifications occurring in the generative and vegetative cells are discussed in view of their different destiny. The results obtained are compared with the data known about tropical orchids and epiphyteic plants like Tillandsia . The following differences have been observed: a large vacuole in the vegetative cell; rapid thinning of the wall between the generative and vegetative cells; great quantity of ribosomes and rough endoplasmic reticulum surrounding the vacuoles in the generative cell. The above‐listed ultrastructural features may have a meaning, considering the peculiar environmental conditions in which the epiphytism of Tillandsia is achieved.