USING FRUIT-BEARING EXPLANTS FOR PHYSIOLOGICAL EXPERIMENTS

One- and three-node nectarine explants were compared with intact potte d units of similar dimension. The explants and intact plants performed similarly as judged by rate of leaf photosynthesis, leaf and fruit re spiration, and changes in fresh and dry weights. Water loss and transp iration 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 sys tem is useful for primary testing of hypotheses, screening of chemical s, and evaluating species response for tater testing of selected param eters in the field. Three-node explants containing fruit are reliable for experiments lasting up to 4 days. Chemical names used: succinic ac id 2,2 dimethylhydrazide [daminozide (SADH)]; l]-alpha-(1,1-dimethylet hyl)-1H-1,2,4-triazole-1-e thanol [paclobutrazol (PBZ)].