Analysis of particle motion in sieve tubes of Heracleum

Abstract

We have cine-filmed the random motion of ixiicroscopic particles, tnostly starch grains frotn rupt-ured plastids, in sieve tubes of Heracleum friantegcizzianum L, and H. sphondylium Sotiitn, and Lev, Our ftame-by-fratne analysis of the positions of the particles shows that they move tnuch less than calculated when genetally accepted estitnates for the viscosity of sieve-tube sap are inserted in the Stokes-Einstein and other equations for Brownian tnotion. Our analysis of a film, of similar particles, made by previous workers leads us to disagree with their conclusion that particle movement in sieve tubes was preater than should be expected for otdinaty Browtiian motion. Particles iti their liltn atid iti ours moved less than expected even when we allow for the possibility that the particles are restricted by cell walls and by each other. We suggest thai the particles tnove less than expected because the viscosity of sieve-tube sap may be higher than has been assutned by physiologists,

Invasion of the Giant Hogweed and the Sosnowsky’s Hogweed as a Multidisciplinary Problem with Unknown Future—A Review

“…The hogweed organs, e.g., leaves, phloem, xylem, have been used to isolate specific chemical compounds in many biochemical studies that have provided an insight into the diverse properties of extracts obtained from invaders, including the potential of substances as inhibitors and toxins affecting various processes in studied invaders [135][136][137][138][139][140][141][142][143][144][145][146][147]. Some biochemical studies were closely related to histology and cell biology explaining the mechanisms of physiological processes in Caucasian hogweeds at the level of tissues and cell structures [148][149][150][151][152][153][154]. It has been elucidated what hogweeds chemicals might be responsible for the phenomenon of allelopathy and what was the composition of the soil at the site of invading hogweeds [155][156][157].…”