J Integr Plant Biol. ›› 1955, Vol. 4 ›› Issue (3): -.
• Research Articles •
C. H. Lou
How the plant acts as an entity to adapt itself to the ever changing surroundings is a problem of fundamental
importance[1,7]. The problem has been put forward to the botanists by the theory of Michurin and Parlor,
both of whom have proved with their own experiments that living beings are in unseparable unification with
their environment. As we know, along the evolutionary steps that lead lower and simpler forms of life to
higher and more complicated ones, the more the differentiation of functions among the constituent parts, the
more the needs for closer coordination among them. Hence, the plant must integrate the various processes
in metabolism conducted in its various parts into a united whole in order to "equilibrate" with external
changes. To put it more concretely, in a plant body which is consisted of innumerable cells, each cell being
entirely enclosed in a rigid wall, intimate coordination among its physiological functionings, proper
responses to local and transmitted stimuli, timely translocation of manufactured food and efficient
distribution of absorbed minerals must be effectively maintained. The attempt to solve these problems of
plant integrity is to try to synthesize the individual physiological phenomena on a common ground, to realize
the interlocking connections involved, and, finally, to serve as a more effective guide in controlling nutrition,
growth and development in plants. It has been generally accepted among the botanists that the living cells
constituting a plant are interconnected by protoplasmic threads (Plasmodesmata) so that the plant is a
definitely correlated entity of interconnecting protoplasts (Symplast). So far evidences of protoplasmic
continuity in plants mainly come from anatomical observations on dissected tissues. Based upon these facts,
plasmodesmata have bean suggested as channels of translocation of organic solutes. Consequently, the
symplasmic nature of plant has been incorporated in Münch's theory of mass/low of organic solutes.
Conduction of stimuli has been regarded as a second function (Haberlandt). Direct evidences, however,
for any such role of plasmodesmata are wanting. On other occasions, the presence of plasmodesmata has
been ignored or considered irrelevant. Lund et al, in their investigations on bioelectric fields in plants,
have never taken into consideration how such protoplasmic continuity would affect potential and current
distribution in plants. Lundegardh, in his investigation on the translocation of salts through roots, does
not believe that it is necessary to visualize a symplast to account for this process. The cited examples are
sufficient to indicate that we are altogether uncertain of the role of plasmodesmata in the physiological
functionings of plants and due attention has not been paid to them.
C. H. Lou. Protoplasmic Continuity in Plants[J]. J Integr Plant Biol., 1955, 4(3): -.
Add to citation manager EndNote|Ris|BibTeX