The Effects of Ethyl 5-(4-chlorophenyl)-2H-tetrazole-2-acetate on Net Photosynthesis, Stomatal Resistance, and Transpiration in ‘Delicious’ and ‘Golden Delicious’ Apple Leaves1
in HortScienceAbstract
The chemical pinching agent ethyl 5-(4-chlorophenyl)-2H-tetrazole-2-acetate (PP528) was tested for its effects on rates of net photosynthesis (Pn) and transpiration (Tr), and on stomatal resistance (rs) in leaves of 1-year-old container-grown apple (Malus domestica Borkh. cvs. Golden Delicious and Starking Delicious). ‘Delicious’ leaves treated with 80 ppm PP 528 exhibited lower rates of Pn and Tr and higher rs than control leaves. ‘Golden Delicious’ leaves were unaffected by 80 ppm PP 528. We conclude that PP 528 was translocated from the leaf surface to the apical meristem and that stomatal aperture in ‘Delicious’ was reduced by PP 528.
Contributor Notes
Received for publication December 11, 1978. The cost of Publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper must therefore be hereby marked advertisement solely to indicate this fact.
The authors thank ICI United States, Inc., Goldsboro, NC for supplying formulation JFU 5775 and financial support.
