Immature Embryo Culture Research Articles

Inhibitory effect of streptomycin on rice tissue cultures and the selection of resistant callus clones

Callus tissues were initiated from seed, radicle and anther cultures of rice (Oryza sativa L.) in order to study the effect of streptomycin on callus growth. Our results showed that the addition of 250 μg/ml or more streptomycin to the culture medium caused a significant inhibition of callus proliferation. The degree of inhibition depended upon the genotype, the drug concentration and the tissue source of callus. Selection of resistant cell lines began with seed and immature embryo cultures grown on various levels of streptomycin. The fastest growing sectors of callus were subcultured for additional selection. In this way, a total of 11 comparatively vigorous callus clones were isolated after 7 or 12 subcultures. Some of these clones exhibited a significant increase of resistance index when compared with unselected starting material. After 5 or 6 selection cycles, 79 plantlets were regenerated from resistant callus, but none grew to maturity because all were white (albino).

Chromosome doubling of the wheat haploids obtained from crosses with Hordeum bulbosum L.

In wheat (Triticum aestivum L.) a successful chromosome doubling of haploids (2n=21) is essential for the production of homozygous plants, following the intergeneric cross with tetraploid Hordeum bulbosum L. and the in vitro culture of immature haploid embryos. The effects of colchicine treatment on haploid wheat plants at different developmental stages were investigated. The result showed that the haploid plants treated at the 2- to 3-tiller stage with 0.10% colchicine solution produced seeds at frequency of 95.6% of treated plants.

In vitro Culture of Immature Soybean Embryos

Immature embryos of soybean [Glycine max (L.) Merr., cvs. Beeson, Chippewa, Swift, and Tonica] ranging from globular to cotyledon stages were cultured in vitro. A variety of media consisting of 24 combinations of basic media salts, growth regulators, and carbon sources was tested in conjunction with initial exposure of cultures to light or darkness. The best combination tested was B5 medium supplemented with 0.1 mg · 1(-1) indole-3-butyric acid (IBA) and an intitial exposure to darkness for two weeks. The survival rate increased progressively with embryo age and stage of development. Approximately 10% of late globular-early heart stage embryos survived to sexual maturity and produced seed whereas virtually 100% of the cotyledon stage embryos produced plants which flowered and set fruit. Approximately 25% of the globular stage embryos were induced to initiate a hypophysis but they subsequently either formed callus or died within a week. Although plants resulting from in vitro culture of immature embryos were diminutive, they otherwise were morphologically normal and produced seed of normal size and weight, as did their progeny.

Interspecific hybridization in the genus Gossypium through embryo culture

With embryo rescue and culture techniques interspecific hybrids have been obtained amongst diploid cultivated (Gossypium arboreum, G. herbaceum) and wild species (G. stocksii, G. anomalum) of cotton. The early abscission of the young bolls was prevented by repeated application of growth regulators followed by the culture of immature hybrid embryos (15 days after pollination). The best growth and development were obtained on modified Murashige and Skoog's medium with supplements. The plants were stouter when the cultures were first incubated in the dark for 15–25 days, followed by exposure to light. The hybrid plants transferred to soil developed further and matured, and were more or less intermediate between their respective parents.

Plant regeneration from cultured immature embryos and inflorescences ofTriticum aestivum L. (wheat): Evidence for somatic embryogenesis

Tissue cultures ofTriticum aestivum L. (wheat) initiated from young inflorescences and immature embryos possessed the potential for regeneration of whole plants. Both a friable and a compact type of callus were produced on Murashige and Skoog's medium with 2 mg/l 2,4-dichlorophenoxyacetic acid. The friable callus contained meristematic centers in which the peripheral cells ceased dividing, elongated, and could be easily separated. Roots were frequently formed in this type of callus. The compact, yellowish, and nodular callus arose from the epithelial and sub-epithelial cells of the embryo scutellum, and the rachis and glumes of the young inflorescence. Such callus had a smooth surface and characteristic chlorophyllous areas. Plants were regenerated only from the compact callus. The first sign of differentiation in the compact callus was the formation of a cleft or notch on the smooth surface, followed by the appearance of trichomes and the direct development of leafy structures which were not associated initially with any shoot meristems. Multiple shoots subsequently arose at the bases of the leafy structures, which are considered modifications of the scutellum, a definitive part of the cereal embryo. Accordingly, we suggest that while typical bipolar embryos are generally not formed, plant regeneration nevertheless takes place through embryogenesis and the precocious germination of the embryoids. Plants regenerated from immature embryo and inflorescence cultures were grown to maturity in soil, and were shown to have the normal chromosome number of 2n=6x=42.

Regeneration of plants from mesocotyl tissue cultures of immature embryos of Zea mays L.

Callus cultures have been established from mesocotyl tissues taken from immature embryos of one experimental hybrid homozygous fl 2. They were initiated and maintained on a modified Murashige and Skoog medium. Regeneration of Complete plants from these calluses was accomplished by a subculture of the callus on a medium containing 0.25 mg 2,4-D and NAA for 40 days. Afterwards they were transformed to a medium containing NAA and 2iP free of 2,4-D.

ユリの遠縁種間交雑に関する研究 (第4報)

1. Use of normal endosperm as nurse tissue.Normal endosperm obtained from inter-clonal crossing was used as nurse tissue for the culture of immature hybrid embryos (0.3_??_0.4mm in length).About 60 percent of the immature embryos could be cultured by putting them on normal endosperm.The growth pattern of the embryos was ‘embryonic growth’ similar to the normal pattern seen in vivo, and was different from the ‘seedling growth’ usually seen on artificial mediums; it appears that the endosperm contains a kind of ‘embryo factor (s)’ which was absent in the artificial medium.2. Culture on artificial medium containing amino acids.Free amino acids contained in the normally developing endosperm were analyzed qualitatively and quantitatively and an artificial medium of the same amino acid composition was prepared.The survival percentage of hybrid embryos was somewhat increased on prepared medium as compared with on basic medium, but it appears that the prepared medium used here was still lacking the so-called ‘embryo factor(s)’ since the growth pattern of the embryos was similar to ‘seedling growth’.

The Culture of Immature Pea Embryos

The Culture of Immature Pea Embryos

The In Vitro Culture of Immature Barley Embryos on Different Culture Media

The In Vitro Culture of Immature Barley Embryos on Different Culture Media

In Vitro Culture of Immature Embryos of American Elm1

Abstract Immature 2n embryos of Ulmus americana L. were excised aseptically from seeds to 20 different media. A low salts medium with coconut water allowed the largest number of embryos to become green and begin stem elongation and true leaf formation. None of the resulting plants survived transplanting.

ユリの遠縁種間交雑に関する研究

1) The embryo culture technique was applied to the immature hybrid embryos for the purpose of enhancing their growth. The embryos used as materials were from 2 crosses between distantly related species or hybrids: L. longiflorum X L. 'Sugehime'and L.'Shikayama'X L. henryi.2) The Murashige & Skoog medium was recognized as the most suitable among the three basic media for the culture of immature embryos when it was adjusted at pH 5.0 and supplemented with 20-40g/l sucrose. Higher sucrose concentrations than the above mentioned generally enhanced root growth and inhibited shoot growth.3) The addition of 10-4-10-2mg/l NAA to the basic media was effective for the direct germination of immature embryos and the addition of BA tended to lead them to calluses in some degree. Higher NAA concentrations than the above mentioned promoted root growth and inhibited normal shoot growth, while the higher BA concentrations sometimes gave the reverse result to NAA.

Sterile Culture of Immature Maize Seeds and Embryos1

We cultured immature maize (Zea mays L.) seeds and excised embryos (sampled at 5‐day intervals from 5 through 30 days after pollination) on solid‐agar nutrient medium containing 2% sucrose. Immature, intact seeds germinated poorly under our sterile culture conditions. Embryos germinated within seeds, but were incapable of emerging from the seed coat (even at 30 days postpollination). Excised embryos 15 days old and older germinated and developed normally.

Embryo culture of rice on sterile medium

The culture of immature rice embryos is possible on a sterile medium made of 5 g of a mixture of mineral salts, 20 g dextrose and 7 g agar per liter water.