Prevention of EPTC—Induced Epicuticular Wax Aggregation on Corn (Zea mays) with R-25788

Abstract

Scanning electron microscopy (SEM) showed that EPTC (S-ethyl dipropylthiocarbamate) caused an aggregation of the epicuticular wax layer of corn (Zea maysL.). R-25788 (2,2-dichloro-N,N-diallylacetamide) prevented this aggregation when applied in combination with EPTC. Neither EPTC, metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], nor R-25788 changed the weight of chloroform extractable epicuticular wax on corn leaves. EPTC apparently does not block lipid synthesis in corn as it does in other plant species. Thus R-25788 does not protect corn from EPTC or metolachlor by overcoming such a block. EPTC did affect wax arrangement on the leaf surface and caused an increase in the cuticular transpiration of corn and predisposed corn to injury from subsequent postemergence applications of paraquat (1,1′-dimethyl-4,4′-bipyridinium ion). R-25788 protected corn against these deleterious effect.

Interactions of the herbicides EPTC and EPTC + R-25788 with ozone and antioxidants in corn

“…Extensive research on the mode of the antidotal action of R-25788 has resulted in a plethora of proposed mechanisms, none of which is unequivocally accepted. Among the mechanisms proposed, two that have attracted considerable attention are those proposing either a counteraction of EPTC phytotoxicity by R-25788 Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061. through a competitive inhibition at some common site within the protected plant (Ezra and Gressel, 1982; Ezra et al, 1982;Gorog et al, 1982;Leavitt and Penner, 1979a;Stephenson et al, 1978Stephenson et al, ,1979; Wilkinson and Smith, 1975) or an increase in the rate of metabolic detoxication of EPTC caused by the antidote R-25788 (Carringer et al, 1978; Kómives and Dutka, 1980; Lay and Casida, 1976; Leavitt and Penner, 1979b; Rennenberg et al, 1982).…”

Comparative studies of safeners for the prevention of EPTC injury in maize

“…t Daia are the mean of 30 samples from three experiments. has not been established (Leavitt & Penner. 1979).…”

“…A further important metabolic effect of EPTC is the suppression of desaturation oflipids (Wilkinson & Hardcastle, !970: Wilkinson & Smith, 1975) which causes the changes in the epicuticular wax pattern (Gentner, 1966;Still et at.. 1970;Wyse et al, 1976: Leavitt & Penner. 1979, Each of these herbicidal actions of EPTC was counteracted not only by R-25788 but also by AD-2 and AD-67.…”

“…Between 50 and 150 leaves were washed twice with chloroform (Analar, analytical grade), first with 50 ml for 30 s, then with 30 mi for 15 s. Both washes were combined and the solution was filtered through Whatman 1 filter paper into pre-weighed aluminium pans. After the chloroform was evaporated for 18 h. the pans were re-weighed and the weight of epicuticular wax per 100 cm-leaf area was calculated (Leavitt & Penner, 1979),…”

Nutrients translocation & plant growth in tissue culture

“…Nevertheless, other cuticle formation inhibitors could be beneficial to promote transpiration, such as trichloroacetate (TCA) or EPTC (S-ethyl dipropylthioarbarnate) (Dewey et al, 1956;de Klerk and Pramanik, 2017). EPTC impaired the proper cuticle arrangement on corn leaf surfaces and caused a higher cuticular transpiration ex vitro (Leavitt and Penner, 1979). Apart from this cuticle removal by rubbing with solvents, such as chloroform, hexane and diethyl ether (Figure 6) proved unsuccessful in increasing transpiration and shoot growth.…”