Microspore wall morphogenesis of isoetes piedmontana (pfeiffer) reed

Microspore wall morphogenesis of Isoetes piedmontana was studied with SEM and TEM. The microspore wall consists of four layers: Perispore, paraexospore, exospore, and endospore. Immediately after meiosis, the paraexospore forms around the microspore. The exospore forms next between the cell membrane and the paraexospore. Finally, the perispore is deposited on the paraexospore, and the endospore is formed within the exospore. The paraexospore, exospore, and endospore are largely derived from the cytoplasm of the microspore. The sporopollenin materials of the perispore are derived from the secretory tapetal cells along the inner sporangial wall. © 2011 by The University of Chicago. All rights reserved.