Browsing by Author "Turner, David Langley Arthur"

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The Differential Action of 2,4 –Dichlorophenoxyacetic Acid on the Hypocotyl and Radicle of Germinating Seedlings
(Te Herenga Waka—Victoria University of Wellington, 1966) Turner, David Langley Arthur
Studies with the germination inhibitors 2,4-dichlorophenoxyacetic acid (2,4-D) and 4 amino-3,5,6-trichloropicolinic acid (Tordon) have shown that seedlings, treated with concentrations of these inhibitors which just permit germination, are considerably shortened in length and frequently terminate in dome-like callus growths. The callus-tissue-distortion seemed confined to the radicle, suggesting that the cells of the radicle might be in some way distinct from those of the hypocotyl. Germinating seeds treated with 2,4-D at concentrations ranging from 0.1 to 1000 parts per million show a decreasing percentage of germination corresponding to the rise in 2,4-D concentration. Observations at set time intervals after imbibition reveal not only that there is a similar correlation in the reduction of overall seedling length, but also that the ratio of hypocotyl length to radicle length is altered by increasing 2,4-D concentrations. Such observations suggest that the cells of the radicle might be physiologically distinct from those of the hypocotyl.