Involvement of aba in flower induction of Pharbitis nil

Emilia Wilmowicz,Jan Kopcewicz,Jacek Kęsy,Kamil Frankowski,Paulina Glazińska

doi:10.5586/asbp.2011.003

Emilia Wilmowicz, Jan Kopcewicz + Show 3 more

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https://doi.org/10.5586/asbp.2011.003

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Abstract

Flowering of plants is controlled by hormones among which both stimulators and inhibitors are present. The role of abscisic acid (ABA) in flower induction of the short day plant Pharbitis nil was shown in our experiments through exogenous applications and endogenous level determination of the hormone in cotyledons of seedlings grown under special light conditions.The application of ABA to cotyledons or shoot apices during the first half of a 24-h long inductive night inhibits flowering. The same compound applied towards the end of or after a 14-h long subinductive night increases the number of flower buds produced by these plants.Exposing P. nil seedlings at the beginning of a 24-h long inductive night to far red light (FR) decreases the level of endogenous abscisic acid in cotyledons and leads to flower inhibition. However, a pulse of red light (R) reversing the inhibitory effect of far red light on the flowering of P. nil increases the ABA content.The results obtained confirm previous observations that ABA may play a dual and an important role in the regulation of floral bud formation in P. nil. The flowering occurs when the level of endogenous abscisic acid is low at the beginning and is high toward the end of the inductive night.

Highlights

One of the main environmental factors determining the proper growth and development of a plant is light
Effect on flowering of exogenous abscisic acid (ABA) applied during a 24-h long inductive night
Exogenous ABA at a concentration of 0.01, 0.1 and 1 mM applied on cotyledons or shoot apices of 4-day old P. nil seedlings during a 24-h long inductive night decreases the number of flower buds produced by the plants

Summary

Introduction

One of the main environmental factors determining the proper growth and development of a plant is light. Research done on Arabidopsis thaliana indicates that light regulates flowering time along two independent pathways: the first one is controlled by inductive photoperiod, while the other one depends on light quality (Cerdan and Chory 2003; Ausin et al 2005). In photoperiod-sensitive plants, a proper day-night ratio starts a chain of reactions leading to the initiation in the shoot apex of changes necessary for a functional transformation of the vegetative meristem into the generative one, which in turn leads to flower formation (Vince-Prue et al 1993). One of the bestknown and described photoreceptors is phytochrome. It appears in two photoreversible forms, distinguished by their spectral properties (Pr, λ = 660 nm; Pfr, λ = 730 nm), as well as by their biological functions

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