Influence of growth regulators on plant regeneration in tomato

Abstract

ABSTRACT:We studied the effect of different plant growth regulators on in vitro regeneration and plant growth of three cultivars of tomato (Lycopersicon esculentum Mill.) from explants derived from hypocotyls and cotyledons of aseptically grown seedlings. The regeneration capacity was significantly influenced by cultivar and explant type. The highest number of shoots regenerated in both types of explants was recorded on MS medium supplemented with 1.0 mg/dm 3 zeatin and 0.1 mg/dm 3 IAA. The cultivar UC 82 showed the best regeneration capacity on all types of used media. The most responsive explants were hypocotyls with 90-92% regeneration in dependence on the used cultivars and mean production from 0.18 to 0.38 shoots per explant. 119of MURASHIGE and SKOOG (1962) (hereinafter abbreviated as MS), 100 mg/dm 3 myo-inositol, 2 mg/dm 3 thiamine.HCl, 0.5 mg/dm 3 pyridoxine. HCl, 0.5 mg/dm 3 nicotinic acid, 1% (w/v) sucrose and 0.7% (w/v) agar. The cultures were initially kept in the dark at 27 ± 1°C for two days and then maintained under a 16 h photoperiod at 50 µmol m 2 s, with day/night temperature of 25°C/20°C. Hypocotyl and cotyledon segments were cut from the seedlings grown in vitro. The hypocotyls were cut into three segments. Each cotyledon was transversally cut into two segments. Hypocotyls were transversally cut into 4-7 mm segments and leaf-blades into pieces of 30-40 mm 2 . The hypocotyl explants were placed horizontally on the medium surface and cotyledon explants with the adaxial surface in contact with the medium. Regeneration was induced on MS medium supplemented with different concentrations of cytokinins (ZEA, BAP, TDZ) and auxin (IAA) (Table 1). After 3 weeks cultured explants were transferred on: 1) MS without plant growth regulators (PGRs), 2) MS medium contains half concentration of PGRs and 3) MS medium with full concentration of PGRs (Fig. 1). The media were adjusted to pH 5.8 prior to autoclaving. Glass containers with 25 cm 3 of medium were used.Six weeks later the regeneration capacity of explants was assessed. The following parameters were evaluated: the frequency of regeneration (percent of regenerating explants) and the number of shoots per explant. Data on regeneration frequency (%) were transformed by arcsin√x prior to statistical analysis. The experiment was repeated twice using 30 explants per variant. Significance of difference between the results was estimated by analysis of variance (ANOVA). Variation among means was analysed using LSD (P ≤ 0.05) procedure. RESULTSThe effect of different tomato cultivars and different PGRs concentrations on shoot regeneration from aseptically grown hypocotyls and cotyledons showed significant variation in both the genotype and PGRs. A large variability in the number of shoots was observed between cultivars and between the different PGRs concentrations (Table 2). Cultivar mean comparisons (least significant difference, LSD, P ≤ 0.05) showed only two classes differing in the induction potential. The cultivar which produced the most shoots on hypocot...

Morphogenetic Potential of Tomato (Lycopersicon esculentum) cv. ‘Arka Ahuti’ to Plant Growth Regulators

“…Results of this experiment confirmed the positive influence of growth regulator on the number of shoots regenerated from tomato cotyledons, leaf and hypocotyls. Our experiments supported the results of other authors (Nogueira et al, 2001;Gubis et al, 2004) where most efficient medium for in vitro regeneration of tomato was induction medium supplemented with a cytokinin. Devi et al (2008), studying the morphogenesis in 4 cultivars of tomato viz.…”

“…Various combinations of auxins/cytokinins have been used to study their effect on regeneration (Rao et al, 2005). Gubis et al (2004), observed that zeatin (1 mg/L) and IAA (0.1 mg/L) supplemented media had 100% regeneration frequency with hypocotyl explants in all genotypes studied. However, we obtained a regeneration frequency of 74%, 71% and 64% for hypocotyls explants in medium C, B and A, respectively.…”

“…In vitro regeneration through organogenesis and somatic embryogenesis are being used for multiplication of genetically identical clones and it is an integral part of genetic transformation procedures (Plastira and Perdikaris, 1997;Oktem et al, 1999;Gubis et al, 2004;Rashid and Bal, 2010). Specific plant growth regulator requirements for each genotype make the tissue culture task in tomato quite difficult and researchers need to deal with each genotype individually (Bhatia et al, 2004;Sheeja et al, 2004).…”

In vitro propagation of Ethiopian mustard (Brassica carinata A. BRAUN)

“…The in vitro morphogenetic responses of cultured plants are affected by different components of the culture media and therefore, it is important to evaluate their effects on plant callus induction and regeneration (Gubis et al, 2004). The surface sterilized germinating seeds were used as sources of explants for callus induction.…”

“…Various authors (Munshi et al, 2007;Gubis et al, 2004) reported that hypocotyl explants were superior to cotyledon in shoot regeneration efficiency and shoot length. MS medium supplemented with 2 mg/L BAP was the most effective in adventitious shoot formation and shoot length in both explants and cultivars.…”