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THE HISTOCHEMISTRY AND ULTRASTRUCTURE OF JACK PINE MICROSPORANGIA DURING THE WINTER
Author(s) -
Cecich Robert A.
Publication year - 1984
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.1537-2197.1984.tb14150.x
Subject(s) - biology , staining , ultrastructure , heterochromatin , rna , cytoplasm , dna , endoplasmic reticulum , botany , metaphase , microbiology and biotechnology , chromosome , chromatin , biochemistry , genetics , gene
The development of jack pine ( Pinus banksiana Lamb.) microsporangia from October to April was investigated with a microdensitometer and a transmission electron microscope. DNA, RNA, and protein content of sporogenous cells was measured at monthly intervals. DNA was unreplicated (2C) until March when DNA synthesis was first noted, coinciding with a loss of heterochromatin. Protein content doubled in April. RNA staining increased in December and then decreased. Numerous whorls and stacks of rough endoplasmic reticulum and ribonucleoprotein‐like granules appeared in December and may be related to the RNA increase. A fibrillar, light‐staining region was found in the cytoplasm of the sporogenous cells from November to March. It was hydrolyzed in the presence of protease and may be a winter morphology of microfilament bundles or dictyosomes. Lipid bodies and vacuoles were abundant in the tapetum and sporangial wall cells during the winter. Observations substantiate reports that winter is not a time for cessation of development.