A role of G-proteins and calcium in light-regulated primary leaf formation in Sorghum bicolor

Author: Sanan N   Sopory SK  

Publisher: Oxford University Press

ISSN: 1460-2431

Source: Journal of Experimental Botany, Vol.49, Iss.327, 1998-10, pp. : 1695-1703

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Abstract

Primary leaf development of Sorghum bicolor is a phytochrome-mediated response. Primary leaves are not produced in Sorghum seedlings even after 10 d of germination if grown in darkness. However, 5 min irradiation with white light or red light given to 5 d etiolated seedlings resulted in the formation of etiolated leaves. This effect of red light was reversed by far-red light. When calcium (3-5 mM) was added exogenously, complete leaf formation was obtained in darkness; however, the kinetics of the response was slower than that seen with light irradiation. This effect was also obtained with potassium ions but magnesium ions had no effect. Light- and calcium-mediated leaf development could be arrested at the stage of leaf emergence or leaf expansion by the addition of inhibitors of G-proteins or by calcium channel blockers suggesting a role of G-proteins and calcium in phytochrome signal transduction during primary leaf development. Key words: Leaf formation, G-proteins, calcium, potassium, Sorghum bicolor.