Photosynthetica 2012, 50(4):630-634 | DOI: 10.1007/s11099-012-0075-x

Dimethoate-induced slow S to M chlorophyll a fluorescence transient in wheat plants

J. K. Pandey^1,*, R. Gopal²

¹ M.N. Saha Center of Space Studies, IIDS, Nehru Science Center, University of Allahabad, Allahabad, India

² Laser Spectroscopy and Nanomaterial Laboratory, Department of Physics (UGC-CAS), University of Allahabad, Allahabad, India

In eukaryotic oxygenic photosynthetic organisms (both plants and algae), the maximum fluorescence is at peak P, with peak M lying much lower, or being even absent. Thus, the PSMT phase, where S is semisteady state, and T is terminal state, is replaced by a monotonous P→T fluorescence decay. In the present study, we found that dimethoate-treated wheat plant leaves showed SM transient, whereas in the case of control plants monotonous P→T fluorescence decay occured. We suggest that this was partly due to quenching of fluorescence due to [H⁺], responsible for P to S (T) decay in control plants (Briantais et al. 1979) being replaced by state transition (state 2 to state 1) in dimethoate-treated plants (Kaňa et al. 2012).

Keywords: chlorophyll a fluorescence; dimethoate; Kautsky transient; slow fluorescence transient; state transition; wheat

Received: July 7, 2011; Accepted: August 25, 2012; Published: December 1, 2012Show citation