Transplantation Studies with Immature Fruit of Normal, and rin and nor Mutant Tomatoes

Abstract

The aim of the work reported herein was to determine whether the lack of normal ripening in fruits of rin and nor tomato mutants is due to the presence of ripening inhibitors or to the lack of ripening factors in the fruit. A fruit tissue transplantation technique was developed for this purpose.Disks of pericarp tissue were transplanted reciprocally between tomato fruits (Lycopersicon esculentum Mill.) of the rin and nor mutants and fruits of ;Rutgers,' a normally ripening cultivar. CO(2) and ethylene evolution rates were measured daily. To test whether materials are translocated between receptor fruits and transplanted disks, fruits were vacuum-infiltrated with (14)C-labeled amino acids and implanted with disks from unlabeled fruits.Normal ripening was not induced in disks of rin and nor tissues implanted in Rutgers fruit although development of yellow or yellow-orange colors associated with senescence of the mutant fruits was accelerated. Disks of Rutgers fruit tissue implanted in fruits of rin and nor ripened normally and concomitant with the intact Rutgers control fruits. The transplanted disks contained 28.8% as much label as found in disks of receptor fruits; thus, significant translocation into the implanted disks occurred. It is concluded that fruits of the mutants do not contain translocatable ripening inhibitors or lack translocatable ripening factors.