Paramagnetic Manganese and Associated Resonances in Isolated Cucumber (Cucumis sativusL. var. long green) Cotyledons in Light and Dark

Publisher Website
Google Scholar
Abstract
Electron spin resonance spectra of cucumber cotyledons show that paramagnetic manganese exists in three different forms in biological systems. Different resonances appear along with the manganese signal. Resonances due to copper ions appear along with the third peak of the manganese signal from the low-field side of the spectrum. Some photo-induced signals appear superimposed over the fourth peak of the manganese sextet corresponding to m/2. The first peak, however, remains unaffected by any detectable resonance and line broadening effects. Since signal height is taken as a measure of manganese concentration, the height of the fourth peak or averaging the height of all the six peaks may give false results in biological systems. Manganese feeding has a general promotive effect on all the six peaks of Mn(II) and the first peak shows most marked changes. The height of the first peak, therefore, can safely be taken as a measure of manganese concentration in a tissue. The resonances causing baseline drift of the sextet disappear with the growth of the cotyledons in light. The loss of their paramagnetic property may either be due to complex formation or change in their redox state.

This publication has 2 references indexed in Scilit: