Stimulation by auxin and sucrose of bulbil formation in vitro by single leaf cultures of Narcissus

Abstract

SUM M.A RYBulbil formation in vitro by single leaf explants from shoot clump cultures was investi^iiied for Sarctssus cultivars ftt Kfverne and Ilaweva. Smgie leaf explants (30 50 mm leaf with attached basal plate tissue) formed bulbils very mfrequently unless cultured on media containing both auxin and a high concentration of sucrose wbereas auxin was not necessary for bulbil formation by sboot clump cultures. As well as showing mucb stronger stimulation by auxin, bulbil initiation and development were more stronglv inhibited by BA in single leaf cultures than in shoot clump cultures. Partitioning of dry matter into bulbils was generally lower in single leaf cultures tban in shoot clump cultures but was more sensitive to growth regulators.Optimal sucrose and auxin concentrations for bulbil development b> single leaf cultures were investigated. Bulbil formation in the presence of NAA was strongly stimulated bv 176 mM sucrose for both cultivars but ibere w^ere genotypic differences m auxin responses. St Keverne showing good bulbil dex elopment witb 054 //M NAA, 5-4//M IAA and 5-4 ^/M lBA and Hawera responding only to 27/'M IA.A.It is concluded tbat single leaf cuhures could provide a simple system for investigation of the regulation i>f Narcissus bulb initiation and development.

Narcissus bulblet formation in vitro: effects of carbohydrate type and osmolarity of the culture medium

“…Increasing the sucrose supply from 30 to 60 g l )1 did not affect shoot multiplication of Narcissus shoot clump cultures but stimulated bulblet formation and dry matter accumulation, as reported previously (Staikidou et al, 1994). Bulblet formation was not stimulated when a sugar which does not act as a substrate for growth, either sorbitol or mannitol, was added to increase the osmolarity of culture medium containing 30 g l )1 sucrose (Table 2).…”

“…Stimulation of vegetative storage organ formation in vitro by increasing sucrose concentration in the culture medium has been reported for many species (Hussey and Stacey, 1984;van Aartrijk and van der Linde, 1986;) including Narcissus (Chow et al, 1992a;Staikidou et al, 1994;Santos et al, 1998Santos et al, , 2002. Seabrook (1990) reported that in vitro bulb initiation by Narcissus cv.…”

“…Thus the strong sucrose stimulation of bulblet formation reported by Chow et al (1992a) could be an osmotic effect rather than a substrate effect. Staikidou et al (1994), using single leaf cultures, found that increasing sucrose concentration from 88 to 176 or 264 mM in the presence of auxin not only increased bulblet numbers but also greatly increased total dry matter accumulation. This indicates an important substrate role for sucrose in bulblet growth and development.…”

Effect of radiation on regeneration of Chinese narcissus and analysis of genetic variation with AFLP and RAPD markers

“…Shoot regeneration via organogenesis and somatic embryogenesis has been reported in many Narcissus species (Hussey 1982;Steinitz and Yahel 1982;Chow et al 1992;Staikidou et al 1994;Santos et al 1998;Sage et al 2000;Sochacki and Orlikowska 2005). Bulb scales are the most commonly used primary explants for micropropagation (Santos et al 1998).…”

Micropropagation of Narcissus (Daffodils)

“…These explants (see Sect. 2.2) are more sensitive to growth regulators than shoot clump cultures (Table 7) and rarely form bulbils unless sucrose concentration is increased above 30 g I-I and auxin is included in the medium (Staikidou et al 1994). Genotypic differences in auxin responses were demonstrated using this single leaf culture system, cv.…”