William T. Molin. Associate Professor, Department of Plant Sciences. Ph.D., North Carolina State University. (80% Research; 20% Instruction)

• Office: Marley, #541E (621-7611)
• Laboratory: Marley, #504 (621-9734)
• e-mail: wmolin@ag.arizona.edu

Herbicide resistance and metabolism, and the mechanism of action of herbicides and safeners.

The goals of my research are to identify and characterize crop varieties with unique or superior herbicide detoxification mechanisms as a means to select for improved tolerance. Our approach has been to determine the basis for herbicide selectivity in crops and weeds exhibiting differential tolerance. Improved herbicide tolerance, especially in crops where marginal tolerance currently exists, is desirable because increased profitability can be realized with better weed control and reduced injury.

Our current efforts are focused on cotton cultivars with differential tolerance to the photosynthetic electron transport inhibitor, prometryn. This tolerance is not the result of differences in metabolism, uptake, translocation or binding at the active site. Hence, there are other mechanisms for tolerance that remain to be characterized. This research provides a means to characterize new detoxification mechanisms as well as responses to abiotic stresses using modern biochemical and physiological research methodologies.

The chemical basis for the allelopathic properties of weed species, such as purple nutsedge, on crops important to Arizona's agriculture is also of interest. We are conducting studies on the physiological effects of allelochemicals on cotton with the goal of understanding the identity of the toxic compounds.

W.T. Molin, C.A. Porter, J.P. Chupp, K. Naylor. 1990. Differential inhibition of anthocyanin synthesis in etiolated sorghum (Sorghum bicolor (L.) Moench) mesocotyls by rotomeric 2-halo-N-methyl-N-phenylacemtamides. Pesticide Biochem. Physiol. 36:277-280.

B.L. Armbruster, W.T. Molin, M.W. Bugg. 1991. Effects of the herbicide dithiopyr on cell division in wheat root tips. Pesticide Biochem. Physiol. 39:110-120.

W.T. Molin and R.A. Khan, 1995. Micro-bioassays to determine the activity of membrane disrupter herbicides, Pestic. Biochem. Physiol. (in press).

W.T. Molin and R.A. Khan. Mitotic Disrupter Herbicides: Recent Advances and Opportunities in "Reviews in Pesticide Toxicology", Vol. 4, 1996.

R.A. Khan and W.T. Molin. 1996. Photosynthetic electron transport in thylakoids from cotton cultivars (Gossypium sp.) differing in tolerance to prometryn, Plant Cell Reports (accepted).

W.T. Molin and R.A. Khan. 1996. Differential tolerance of cotton (Gossypium sp.) Cultivars to the herbicide prometryn, Pesticide Biochem. Physiol. (submitted).