The stabilization of latex in laticifers of the Convolvulaceae: application of freezing methods for scanning electron microscopy

Abstract

The high turgor pressure of many laticifers in the Convolvulaceae causes the cell contents to be disturbed when tissues are excised from the plant before specimen preparation for microscopy. This has been overcome by freezing the tissue intact on the plant, or where this is not practicable, excising a length of the organ and freezing the middle portion. Specimens are frozen and fractured in nitrogen slush, then freeze-dried and examined by scanning electron microscopy. With this method, latex particles were well preserved within the central vacuole and the peripheral cytoplasm was retained in several taxa. The need to freeze bulky pieces of tissue, however, results in poor freeze-fixation of the cytoplasm.