On the Nature of the Stimulus Causing the Change of Form and Structure in Proserpinaca palustris

William Burnet McCallum
1902 Botanical Gazette  
ALTHOUGH heterophylly in amphibious plants has long been a subject of observation and experiment, as yet we are in ignorance of the real factors that determine which type of leaf such a plant shall assume. The environment of a submerged water plant is certainly a complex one, and there has not been anything like a definite analysis of it. If we are to understand the behavior of a plant when submerged, it is clear that there must be a definite knowledge of the various factors concerned , and of
more » ... concerned , and of the influence of each one upon the plant. The literature on the subject in the main discusses such topics as water medium, diminished light relations, different oxygen and carbon dioxide conditions, buoyancy, nutrition, and the like; but such terms are general and indefinite, and convey little real information as to the actual factors acting upon the primordial cells of the plant. The demands of physiology can only be satisfied by a detailed analysis of all the possible factors, each of which is a complex in itself, and a determination of the direct action of each resolved component upon the protoplasm of those portions of the plant involved. Of course such an aim is only ideal and at present cannot be realized, but it is, nevertheless, the ultimate goal to be reached before we can read the plant in terms of its environment. In the hope of obtaining some information upon this question, experiments were begun on Proserpinaca palustris in the autumn of i900, and are still in progress. The plants used have been grown from seed or obtained from the low-lying lands about 1902]
doi:10.1086/328269 fatcat:txd2ec4m2vewdmk5n76kbogqgy