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  • Author or Editor: Richard E. Litz x
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Abstract

Callus was induced from adventitious embryos of nucellar origin in cultured ovules from immature fruits of the jaboticaba (Myrciaria cauliflora D.C. Berg.; Myrtaceae) a woody, perennial, tropical fruit tree with naturally occurring nucellar poly embryony. Optimum culture conditions for callus induction consisted of Murashige and Skoog medium that had been modified accordingly: half-strength major salts plus (per liter) 60 g sucrose, 400 mg glutamine, 100 mg ascorbic acid, and 2 mg 2,4-dichlorophenoxyacetic acid (2,4-D). Two months after culturing, a loose callus was induced from the hypocotyls of adventitious embryos from which limited somatic embryogenesis and occasionally organogenesis occurred. Following the subculture of this callus onto solid or liquid medium without 2,4-D, somatic embryogenesis occurred from the callus although this occurred more efficiently and rapidly in liquid medium. Mature embryos germinated normally on hormone-free medium or on medium containing coconut water.

Open Access
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Abstract

Slowly growing calli were induced in vitro from nucellar explants excised from fertilized ovules of immature 4.0-4.8 cm long monoembryonic mango fruitlets. The medium consisted of Murashige and Skoog formulation that had been modified accordingly: half strength major salts, 60 g/liter sucrose, 400 mg/liter glutamine, 100 mg/liter ascorbic acid, 1.0 mg/liter 2,4-dichlorophenoxyacetic acid (2,4-D), and 8 g/liter Difco Bacto agar. Somatic embryogenesis occurred from callus on this medium and following subculture to medium without growth regulators. Maturation and limited germination of somatic embryos occurred in the absence of growth regulators.

Open Access
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Abstract

Ovules were excised from immature fruit of 2 naturally polyembryonic, tropical trees, Eugenia jambos and E. malaccensis. Immature, adventitious embryos were removed from the ovules and were cultured on modified Murashige and Skoog (MS) medium that contained either 0-10 mg/liter benzylaminopurine (BA) or 0-10 mg/liter 2,4-dichlorophenoxyacetic acid (2,4-D). Depending on the developmental stage of the adventitious embryos, proliferation of axillary buds occurred on media with 2-10 mg/liter BA, whereas germination occurred on lower BA concentrations or in the absence of growth regulators. Root formation only was induced on media containing 3-10 mg/liter 2,4-D. Embryogenic callus was formed from adventitious embryos from 1-2 cm fruitlets on 1-2 mg/liter 2,4-D. The 2 species responded in a similar manner.

Open Access
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Abstract

Suspension cultures derived from Carica papaya L. ovular callus were subcultured on modified Murashige and Skoog medium containing 60 g·liter−1 sucrose, 400 mg·liter−1 glutamine, 9 μm 2,4-D, and either 0–0.45 m sodium chloride (NaCl) or the osmotically equivalent concentrations of mannitol. After 4 successive subcultures (120 days), the suspensions from each NaCl treatment were inoculated into the entire range of salt-containing media, and were subcultured on the same media formulations for 4 months. Cultures grown in the presence of mannitol were treated in the same manner. Sodium chloride generally inhibited somatic enbryogenesis; however, somatic embryogenesis was stimulated greatly following subculture from media with 0.18 m NaCl into media containing lower concentrations of salt. Enhancement of somatic embryogenesis also occurred following preconditioning with 0.30 m and 0.45 m mannitol. The increased rate of somatic embryogenesis was lost after 2 to 3 subcultures in media having lower osmolarities. Chemical names used: (2,4-dichlorophenoxy)acetic acid (2,4-D).

Open Access

Abstract

Somatic embryogenesis was induced in cell suspension cultures of callus derived from peduncle explants of Carica stipulata Badillo. The presence of activated charcoal stimulated embryogenesis particularly when BA and NAA were both in the growth medium. Plantlets derived from embryos have been successfully transferred to potting mixture.

Open Access

Abstract

Leaf tissue extracts of Musa acuminata Colla diploid subspecies malaccensis, diploid M. balbisiana Colla, the triploid dessert banana cultivar ‘Valery’, the interspecific hybrid (acuminata × balbisiana) cooking banana cultivars ‘Chato’ and ‘Peli-pita’ and the triploid putative balbisiana-derived cultivars ‘Saba’, ‘Saba Puti’, and ‘Cardaba’ were subjected to isozyme analysis for four different enzymes. Isozyme banding patterns of the interspecific hybrids were generally additive and were a composite of the species-specific forms of each enzyme. Banding patterns for shikimate dehydrogenase, malate dehydrogenase, peroxidase, and phosphoglucomutase indicate that ‘Saba’, ‘Saba Puti’, and ‘Cardaba’ are acuminata × balbisiana hybrids.

Open Access

Mango (Mangifera indica L.) somatic embryos representing various developmental stages were subjected to various concentrations of kanamycin in the culture medium. The level of kanamycin necessary for growth inhibition was dependent on the size and stage of the somatic embryos at the time of treatment and the kind of exposure. Growth of proembryos in liquid suspension was arrested at 12.5 μ g·ml-1, while the maturation of later stages of somatic embryos on solid medium was inhibited at 200 μg·m l-1.

Free access

Abstract

Callus was initiated from seedling leaf explants and from leaves of recent vegetative flushes of mature Averrhoa carambola L. trees on solid Murashige and Skoog medium with added growth regulators. Seedling-derived callus demonstrated a strong dependence on the presence of exogenous cytokinin, 1-5 mg/liter 6(γ, γ-dimethylallylamino) purine (2iP) with 0.2 mg/liter 2,4-dichlorophenoxyacetic acid (2,4-D), for induction and growth. Shoot differentiation was stimulated from seedling callus by increasing the concentration of available cytokinin. Callus induction and growth from young leaves of mature trees was auxin-dependent (2-5 mg/liter 2,4-D with 0.5 mg/liter 2iP. Organogenesis from callus cultures of mature leaf origin was not obtained.

Open Access

Abstract

Shoot tips were removed from field-grown staminate, pistillate and bisexual selections of Carica papaya L. at intervals during a 21 month period, and were cultured in vitro on a sterile establishment formulation consisting of Murashige and Skoog basal medium (MS) supplemented with 50 μm kinetin and 10 μm naphthaleneacetic acid (NAA) in a growth room at 25°C and with a 16 hr photoperiod at 1.5 klx. Established expiants were transferred to proliferation medium consisting of MS with 2 μm 6-benzylaminopurine (BA) and 1 μm NAA. Establishment of expiants was influenced by season, sex type and degree or type of microbial infection. Proliferation rates varied for different clones and declined sharply after about 13 subcultures. Bacterial contamination was a severe problem; however the nearly ubiquitous Pseudomonas sp. contaminant did not cause mortality. Expiants could not be established from stock plants affected by a disease of unknown etiology that appeared in experimental plantings. Frequency of rooting on MS media with or without auxin declined with increased time in culture.

Open Access