Profiles of Endogenous Plant Hormones during Growth of Strawberry Fruit on Elevated Cultivation Unit

Abstract

In strawberry fruit, it was suggested that IAA synthesized in the fruit migrated to the receptacle and promoted the fruit growth, because the application of auxin to the fruit after removal of the achenes can induce the growth of the fruit of normal size (Nitsch, 1955). However, in many fruits, the application of a combination of plant hormones induces normal fruit growth, and it has been established that fruit growth requires interaction between various plant hormones (Vivian-Smith and Koltunow, 1999). These plant hormones required for fruit growth are mainly synthesized in achenes (Naylor, 1984). Non-climacteric fruits such as strawberries have been studied for the use of various plant hormones for uniform ripening and fruit quality improvement (Symons et al., 2012). In general, auxins, cytokinins (CK), gibberellins (GA) plays a role in inhibiting maturation, while abscisic acid (ABA) is thought to play a role in promoting maturation (Leopold and Kriedemann, 1964). In the application study of in vitro culture of strawberry fruits, auxin and cytokinin inhibited maturation and GA promoted maturation in growing fruits (Kano and Asahira, 1978). In ripening fruits, ABA promoted ripening and CK suppressed ripening (Kano and Asahira, 1981). In strawberries, the presence of outer achenes suppresses receptacle maturation (Given et al., 1988). In strawberries, bioassay for CK and ABA activity in fruits was reported (Kano and Asahira, 1979). Since then, instrumental analysis which is much more reliable than bioassays has been reported. IAA and ABA were determined by GC-MS in achenes and receptacles of developing strawberry (Archbold and Dennis, 1984). Endogenous levels of IAA, ABA, GA1 and castosterone were quantified from flowers to the stage of maturity of developing strawberry by GC-MS or LC-MS / MS (Symons et al., 2012). In this study, major plant hormones, IAA, trans zeatin (Z), isopentenyladenine (iP), gibberellin1 (GA1), GA4, and ABA were analyzed in strawberry achenes and receptacles. The purpose of the study is to gain information about the physiological roles of these endogenous plant hormones.