USING FRUIT-BEARING EXPLANTS FOR PHYSIOLOGICAL EXPERIMENTS

One- and three-node nectarine explants were compared with intact potted units of similar dimension. The explants and intact plants performed similarly as judged by rate of leaf photosynthesis, leaf and fruit respiration, and changes in fresh and dry weights. Water loss and transpiration were less in explants than intact plants after 24 h. Explants with fruit of nectarine, olive, and prune were used to evaluate uptake and distribution of C-14-labeled paclobutrazol (PBZ), daminozide, and sucrose in plant parts. These comparisons reveal that the explant system is useful for primary testing of hypotheses, screening of chemicals, and evaluating species response for tater testing of selected parameters in the field. Three-node explants containing fruit are reliable for experiments lasting up to 4 days. Chemical names used: succinic acid 2,2 dimethylhydrazide [daminozide (SADH)]; beta-[(4-chlorophenyl)methyl]-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-e thanol [paclobutrazol (PBZ)].