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  • Author or Editor: Paul M. Hasegawa x
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Abstract

In vitro-derived shoot tips of ‘Improved Blaze’ rose (Rosa hybrida L.) proliferated on a medium containing MS salts, thiamine·HCl (0.5 mg/liter), pyridoxine·HCl (0.5 mg/liter), nicotinic acid (0.5 mg/liter), glycine (2.0 mg/liter), i-inositol (100 mg/liter), sucrose (30 g/liter), Bacto agar (8 g/liter), indoleacetic acid (IAA) (0.3 mg/liter) and 6-benzylamino purine (BA) (1.0, 3.0, or 10.0 mg/liter). A 6-fold multiplication could be obtained after 4 weeks; no further increase in multiplication was obtained by extending the length of the culture period. In vitro-proliferated shoots cultured for 10 to 14 days on the basal medium without growth regulators initiated roots and could be successfully transplanted into soil; however, both root formation and transplantability were enhanced by α-naphthaleneacetic acid (NAA) (0.03 or 0.10 mg/liter) or IAA (1.0 mg/liter) and by lowering the MS salt concentration to ¼ or ½ strength. Although the degree of root initiation and successful establishment in soil was variable, 90 to 100% successful transfer to soil could be obtained.

Open Access

Abstract

Cultured shoot tips and lateral buds from greenhouse-grown rose (Rosa hybrida L. cv. Improved Blaze) proliferated multiple shoots on a basal medium (MS salts, vitamins, glycine, sucrose, and agar) supplemented with 3.0 mg/liter 6-benzylamino purine (BA) and 0.3 mg/liter indoleacetic acid (IAA). A 3-fold multiplication was achieved from freshly explanted terminal shoot tips or lateral buds after 8 weeks. Reculture of in vitro-derived shoots onto the same medium resulted in a 6-fold increase in 8 weeks. Roots could be initiated from about 50% of these shoots after transfer to a medium containing 0.3 mg/liter IAA and 0 or 0.3 mg/liter BA. Regenerated plants were successfully transferred to soil after 2 weeks.

Open Access

Abstract

Callus was initiated from cultured immature inflorescences of Hosta plantaginea Asch. ‘Grandiflora’ in darkness on a basal medium containing Murashige and Skoog salts, vitamins, glycine, i-inositol, sucrose, agar, and 10 mg/liter naphthaleneacetic acid (NAA) and 0.1 mg/liter 6-benzylamino purine (BA). Reculture of the callus onto a medium containing 0.01 mg/liter NAA and 5 mg/liter BA, resulted in the formation of numerous adventitious shoots. Adventitious shoots were initiated also from leaves and segments of leaves from shoots formed in vitro when cultured on a medium supplemented with 0.01-1 mg/liter NAA and 5 mg/liter BA. Root formation was achieved when individual shoots were excised and transferred to a medium containing the basal constituents without growth regulator supplements. Rooted plants were successfully transferred to soil.

Open Access

Abstract

The effects of the components of Lam's 1977 potato nutrient medium on adventitious shoot formation were systematically evaluated. A low concentration (0.03 mg/liter) of naphthaleneacetic acid (NAA) stimulated shoot initiation and increased survival of tuber discs of potato (Solanum tuberosum L.). Indoleacetic acid (IAA), however, did not affect shoot initiation in the concentration range from 0 to 10 mg/liter. Both 6-benzyl-amino purine (BA) at 0.3, 1.0, and 3.0 mg/liter and N6-(4-hydroxy-3-methyl-but-2-enylamino)-purine (zeatin) at 0.3 and 1.0 mg/liter stimulated adventitious shoot formation while N6-furfurylaminopurine (kinetin) had no effect. Sucrose was essential for shoot formation with a concentration of 30 g/liter being optimal. Although not essential, i-inositol enhanced the initiation of adventitious shoots at concentrations of 60 and 100 mg/liter. Casein hydrolysate and additional inorganic phosphate had no promotive effect on shoot formation and adenine sulfate was inhibitory at all concentrations examined.

Open Access

Abstract

Shoot tips proliferated in vitro were used as explants to determine the effects of various nutrient medium components and environmental conditions on shoot multiplication of Hosta decorata L. H. Bailey ‘Thomas Hogg’. The rate of axillary shoot multiplication was stimulated by the addition of either 0.01 or 0.10 mg×liter α-naphthaleneacetic acid (NAA) to medium containing 5 mg×liter 6-benzylamino purine (BA). Indoleacetic acid (IAA) and indolebutyric acid (IBA) did not promote axillary shoot formation. All 3 auxins were effective in promoting adventitious shoot initiation. In medium with 0.1 mg/liter NAA, BA at 5 mg/liter stimulated a higher number of shoots of axillary origin than did N6-isopentenylaminopurine (2iP) or N6-furfurylaminopurine (kinetin). However, equivalent or greater proliferation of adventitious shoots was achieved with 2iP or kinetin. Sucrose was essential for shoot multiplication and 30 g×liter was optimum. Inorganic phosphate (NaH2PO4 · H2O) and adenine sulfate stimulated growth and shoot multiplication while i-inositol, although not essential, enhanced shoot formation at 30 mg×liter. Axillary and adventitious shoot multiplication was optimum under photosynthetkally active radiation (PAR) of 70 or 130µE m-2s-1 at 21°C and under PAR of 70 µE m-2s-1 at 26°C. Rooting of shoots in vitro was obtained on basal medium without growth regulators or on medium containing 0.01 mg/liter NAA, and the plants were successfully established in soil. Plants obtained from culture which had lost leaf margin variegation regained it after receiving a cold room treatment of 3-6°C for 20 weeks.

Open Access

Abstract

Cotyledonary development of asexual embryos of cacao (Theobroma cacao L.) in liquid medium on a rotary drum apparatus was similar to that of zygotic embryos in vivo. Immature zygotic and asexual embryos synthesized anthocyanins, characteristic of the developing zygotic embryo in vivo, when cultured in vitro in liquid or on semisolid media containing high concentrations of sucrose.

Open Access

Abstract

Cultured immature sexual embryos of Theobroma cacao proliferated asexual embryos, but embryogenesis was not observed from leaf, pericarp, or ovule tissues. Cotyledons from immature, unpigmented embryos (2.5 to 10 mm long) were highly embryognie, while larger more mature, pigmented cotyledons initiated roots as their only form of organized development. Embryogenesis occurred in light and darkness when a basal medium was supplemented with coconut water and 1.5 mg/liter NAA. Proliferated embryos recultured in a liquid medium continued development.

Open Access

Abstract

In the paper “Stimulation of Root Initiation from Cultured Rose Shoots through the Use of Reduced Concentrations of Mineral Salts” by Scott E. Hyndman, Paul M. Hasegawa, and Ray A. Bressan (HortScience 17(l):82–83.1982) figures 1 and 2 were mis-positioned on the page. The correct placement of the figures, along with their captions, appears below.

Open Access

Abstract

Adventive embryos of ‘Golden Delicious’ apple (Malus domestica Borkh.), with differentiated cotyledons and axes, were initiated from micropylar halves of nucellus cultured in darkness on Murashige and Skoog’s salts, vitamins, glycine, and sucrose. Embryos were observed 50 days after culture. Reculture of embryos onto the same medium resulted in proliferation of embryo-like structures from their cotyledons.

Open Access

Abstract

In vitro-derived shoots of ‘Improved Blaze’ rose (Rosa hybrida L.) were used to investigate the cause of improved root initiation obtained by lowering the concentration of the Murashige and Skoog (MS) salt formulation in the nutrient medium. The number and length of roots per explant increased as the concentration of total nitrogen in the MS salt formulation was reduced from 60 to 7.5 mm. There was no effect on rooting with as much as a 16-fold reduction in the concentration of the remaining MS salts from that of the normal MS formulation, when total nitrogen was kept at a constant 7.5 mm. When nitrogen was maintained at 7.5 mm and the concentrations of the remaining salts were maintained at 1/2 times that of the MS salt formulation, rooting was unaffected by raising the total solute concentration with NaCl to that when the medium contained the full MS nitrogen salt complement. These results show that lowering the total mineral salt level in the nutrient medium provides a more favorable nitrogen salts concentration for rhizogenesis than that provided by the MS salt formulation.

Open Access