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- Author or Editor: John M. Love x
- HortScience x
Abstract
The chemical pinching agent ethyl 5-(4-chlorophenyl)-2H-tetrazole acetate (PP 528) was tested for its effects on net photosynthesis (Pn) rates of leaves of 1-year-old container-grown apple (Malus domestica Borkh. cvs. Sturdeespur Delicious, Starking Delicious, Starkspur Ultrared Delicious, Starkspur Golden Delicious and Golden Delicious). Treatment with PP528 did not affect the Pn rate of leaves of either strain of ‘Golden Delicious’. Pn rates of all 3 strains of ‘Delicious’ leaves were depressed for a week after treatment with PP 528 at 30, 40, and 60 ppm, whereas 20 or 10 ppm had no significant effect. The shoot apices on both strains of ‘Golden Delicious’ trees were pinched at 60 ppm, whereas apices of the 3 strains of ‘Delicious’ were pinched at both 30 and 60 ppm.
Abstract
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.