Redistribution of 45ca in Trifolium Subterranevm L. and Antirrhinum Majus L.

Abstract

SummaryInjection of non·radioactive calcium into leaf 3 of normal· or low-calcium T. 8ubterraneum plants immediately after transfer to tracer-free solutions caused changes in the distribution of 450a in the low-calcium plants only. In these plants the mean 450a concentration in the laminae of all leaves was appreciably increased as a result of the influx of 450a from the petioles.For both normal-and low-calcium plants 2 weeks growth in tracer-free solutions resulted in a reduction of the mean 450a concentration in both laminae and petioles of the old leaves, while the isotope appeared in riew leaves produced during this period.A calcium injection at the end of this growth period caused a further reduction in mean 450a concentration in laminae and petioles of the old leaves, and movement of the isotope into the new leaves. This movement was mainly into the lamina centre of the low-calcium and, to a much lesser degree, into the petioles of the normal-calcium leaves.Dialysis of 450a in leaf 2 showed that these changes in ooncentration of the isotope were restricted to the water-soluble fraction in the normal-calcium samples. In the low-calcium samples most of the change also occurred in the water-soluble fraction, but small changes were also recorded in the fractions extracted by sodium chloride, magnesium chloride, and hydrochloric acid.With A. majus plants a much greater redistribution of previously deposited 450a occurred in both original and new leaves of low-calcium plants transferred to tracer-free, normal-calcium solutions than in plants transferred to low-calcium solutions.Redistribution of 450a occurred also in normal-calcium plants transferred to normal-calcium solutions and to a lesser extent in normal plants transferred to low-calcium solutions. This redistribution of 450a continued between days 8 and 16 after transfer to tracer-free solutions. 450a artefacts were produced in autoradiographs by drying A. majus plants grown in normal but not in low-calcium nutrient solutions.

The Mobility of 65zn In Trifolium Subterraneu M L. and Antirrhinum Majus L.

“…This immobility of 65Zn contrasts strongly with the considerable redistribution of 45Ca within the same plant species (Millikan and Hanger 1967b).…”

Retention of Calcium-45 by Dogwood Trees

“…The relatively slow movement of calcium through plants and its relative immobility within plants, compared with other elements, is well documented (2,3,5,6,14,15,19,20). However, evidence that calcium is redistributed within plants is increasing (4,(7)(8)(9)(10)(11)(12)(13). This communication reports the amounts of 45Ca available for transport from woody tissue to foliage during three growing seasons after stem inoculation of dogwood (Cornus florida L.) trees.…”