Further Studies on Transport in the Cotton Plant IV. On the Simultaneous Movement of Solutes in Opposite Directions through the Phloem1

Abstract

IT type would of mechanism appear that involved plant physiologists in the longitudinal are not transport yet agreed of as materials to the type of mechanism involved n the lon itudinal ransport of m terials through the sieve-tube. Munch (8) has elaborated a theory involving a directed mass flow of solution, while others (1, 4) favour a movement of solute rather than solution and stress (2) the resemblance between the gross phenomena of transport and diffusion. The Druckstrom theory possesses a completeness and simplicity that has much to recommend it, while the theory of activated diffusion is rather vague concerning the method whereby diffusion through the sieve-tube is accelerated. As protoplasmic streaming has apparently to be rejected as a method of accelerating diffusion, and as respiration appears to be a factor in transport, the suggestion (7) has been 1 Paper No. 13 from the Physiological Department of the Cotton Research Station, Trinidad. [Annals of Botany, Vol. L. No. CXCVII, January, 1936.] M