The Role of Gibberellin, Abscisic Acid, and Sucrose in the Regulation of Potato Tuber Formation in Vitro1

Abstract

The effects of plant hormones and sucrose (Suc) on potato (Solanum tuberosum L.) tuberization were studied using in vitro cultured single-node cuttings. Tuber-inducing (high Suc) and -noninducing (low Suc or high Suc plus gibberellin [GA]) media were tested. Tuberization frequencies, tuber widths, and stolon lengths were measured during successive stages of development. Endogenous GAs and abscisic acid (ABA) were identified and quantified by high-performance liquid chromatography and gas chromatography-mass spectrometry. Exogenous GA 4/7 promoted stolon elongation and inhibited tuber formation, whereas exogenous ABA stimulated tuberization and reduced stolon length. Indoleacetic acid-containing media severely inhibited elongation of stolons and smaller sessile tubers were formed. Exogenous cytokinins did not affect stolon elongation and tuber formation. Endogenous GA 1 level was high during stolon elongation and decreased when stolon tips started to swell under inducing conditions, whereas it remained high under noninducing conditions. GA 1 levels were negatively correlated with Suc concentration in the medium. We conclude that GA 1 is likely to be the active GA during tuber formation. Endogenous ABA levels decreased during stolon and tuber development, and ABA levels were similar under inducing and noninducing conditions. Our results indicate that GA is a dominant regulator in tuber formation: ABA stimulates tuberization by counteracting GA, and Suc regulates tuber formation by influencing GA levels.

In vitro proliferation and triterpenoid characteristics of licorice (Glycyrrhiza uralensis Fischer, Leguminosae) stolons

“…Procedures for producing stolons followed those of Xu et al (1998) for potato. Stem segments (1 cm) with axillary buds were cultured in 100 ml MS liquid medium containing 3% sucrose (15 segments per polycarbonate culture bottle, f 80ϫ102 mm; Figure 2B).…”

“…To our knowledge, this is the first report of the culture of G. uralensis stolons in an in vitro system. Xu et al (1998) produced potato stolons from the in vitro culture of single-node cuttings.…”

Aplicación periódica de bajas concentraciones de paclobutrazol y ácido salicílico en papa en invernadero

“…El proceso de tuberización está influenciado por fotoperiodo, temperatura, condiciones que regulan los niveles endógenos de los reguladores de crecimiento Mauk y Langille (1978), incremento de carbohidratos en el ápice del estolón, baja en la concentración de giberelinas Martínez et al (2001) y un incremento de ácido absícico Xu et al (1998). Las giberelinas actúan como inhibidor de la tuberización Krauss (1985), así, en condiciones de inducción de la tuberización el bajo aporte de nitrógeno altero el radio de hormonas ácido absicico: giberelinas, incrementó el ácido absicico y decreció la cantidad de giberelinas, lo que coincidió con el inicio de la tuberización Krauss y Marschner (1981).…”

Microtuberização in vitro de cultivares de mandioca: aspectos morfológicos e anatômicos

“…Outro ponto chave deste processo são os níveis de açúcares presentes no meio de cultura, especialmente a sacarose. Xu et al (1998) trabalhando com batata, e Omokolo et al (2003) com taioba constataram que concentrações elevadas de sacarose também afetam a tuberização in vitro. Em estudo realizado com batata, Peres et al (2005) confi rmaram a importância da sacarose no meio de cultura e ressaltaram a importância da relação fonte-dreno entre a parte aérea e o tubérculo em desenvolvimento.…”