A brief history of the lysigenous gland hypothesis

This paper summarizes the early history of the lysigenous gland concept, tr aces its evolution to recent times, and explores some possible causes of co nflicting reports of lysigeny and schizogeny. Secretory cavities and ducts are generally thought to form either through the schizogenous separation of cells or through lysigeny (cell lysis). Gland lysigeny was first proposed in 1857 by Karsten, who believed that plant tissues represent solidificatio ns of humoral fluids and that plant secretions are formed by the resorption of previously solidified cells. The lysigenous gland concept has modernize d as our understanding of cytology has improved, but it was established ear ly, from Karsten's hypothesis, long before the influence of artifacts of sp ecimen preparation was appreciated. Different methods of specimen preparati on, including variations in the mounting media used to mount freehand secti ons, may have caused some of the discrepancies between the findings of lysi genists and schizogenists. Tschirch and Haberlandt promoted the schizolysig eny concept, and believed that the conflicting reports resulted from incomp lete observations of a developmental process that included both schizogenou s separation of cells and cell lysis to form secretory cavities and ducts. Both lysigeny and schizogeny have been reported in the recent literature, a lthough most reports of lysigeny have been opposed by conflicting observati ons of schizogeny, and lysigeny may represent a false category of gland dev elopment caused by the misinterpretation of artifacts.