Amino Acids as Sources of Nitrogen for the Growth of Isolated Oat Embryos

Harris, G. P.

doi:10.1111/j.1469-8137.1956.tb05284.x

Cited by 44 publications

(22 citation statements)

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“…Secondly, the amide glutamine serves as an efficient source of nitrogen for the growth in culture of embryos of a number of plants (Rijven, 1956;Matsubara, 1964). Thirdly, mutual antagonism and synergism has been shown to exist between different amino acids in the growth of embryos (Sanders and Burkholder, 1948;Harris, 1956;Bright et al, 1978;Green and Donovan, 1980).…”

Section: Metabolic and Morphogenetic Studiesmentioning

confidence: 99%

One hundred years of zygotic embryo culture investigations

Raghavan

2003

In Vitro Cell. Dev. Biol. - Plant

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SummaryIsolation of zygotic embryos from seeds and their culture in a defined medium, initiated by Hannig in 1904, has proved to be a promising method to study the factors that control growth and differentiation of embryos. Using this technique, several investigations have focused on the carbohydrate and nitrogen nutrition during germination of cultured seed embryos and on the effects of plant hormones on their morphogenesis. Culture of immature embryos leads to their germination into weak seedlings, skipping the later stages of embryogenesis, by a process known as precocious germination. Progressively smaller embryos have been cultured by supplementation of the medium with coconut milk or hormonal additives or by osmotic adjustment of the medium by high concentrations of sucrose or mannitol. Although methods have not been developed for large-scale isolation and culture of zygotes, zygotes of maize isolated from embryo sacs and those obtained by in vitro fertilization have been grown in culture into full-term embryos. Embryo culture techniques are widely used to rescue embryos from seeds of wide crosses which usually abort and to overcome dormancy of recalcitrant seeds.

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Section: Metabolic and Morphogenetic Studiesmentioning

confidence: 99%

One hundred years of zygotic embryo culture investigations

Raghavan

2003

In Vitro Cell. Dev. Biol. - Plant

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“…They were grown on Harris's medium (Harris, 1956). Other parts of the grain were removed from dry caryopses, surface sterilized with o. i % mercuric chloride, rinsed in sterile distilled water, and placed in standard germination conditions.…”

Section: Methodsmentioning

confidence: 99%

PHYSIOLOGICAL STUDIES OF GERMINATION IN THE GENUS AVENA

Drennan

Berrie

1962

New Phytologist

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Summary The development of amylase activity has been studied in dormant and germinating grains of Avena sativa, A. fatua and A. ludoviciana. Little activity was present in dry grains but activity increased considerably during the first few days in germination conditions in non‐dormant grains. Dormant grains showed no increased activity during considerable periods in the imbibed condition. α‐Amylase development was responsible for the bulk of the increased amylase activity but β‐amylase development also occurred. The increased amylase activity was first noted in the endosperm and did not take place until after the resumption of growth in the embryo in all three species. Parts of grains of A. sativa cultured independently showed no capacity to develop increased amylase activity in a manner similar to that of the whole grain. It is suggested that the development of amylase activity is brought about in the endosperm in response to a stimulus from the growing embryo, and that development of increased amylase activity is thus a post‐germination change. The association of this aspect of metabolism with the dormant condition in the wild oats must therefore be dismissed as a potential cause of dormancy.

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“…Oat and barley embryos which grow feebly when removed from their storage parts are at least partially revived by additions of amino acids (9,12). This suggests that the systems for the transformation of carbohydrate into amino acids are inadequate in the young embryo.…”

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The Requirement for Organic Nitrogen in Zea mays Embryos

Oaks

Beevers

1964

Plant Physiol.

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Previous investigations have shown that, during germination, there is a transfer of organic nitrogen from storage tissues to the developing embryo (16). Indeed in both barley (10) and pea (5) specific storage proteins are the first components to disappear. (7), and which have been grown to maturity (1), present an apparent exception to the general picture. However, Nason (18) has shown that excised maize embryos have abnormally low levels of trypotophan, and when our own preliminary investigation showed that the amount of protein in such embryos was drastically reduced, an investigation was made of the importance of organic nitrogen normally supplied by the endosperm. A progress report of this work has appeared previously (20). MethodsMaize grain (hybrid variety Wf 9 X 38-11) was sterilized briefly with chlorox, rinsed, and allowed to germinate on a thin layer of agar (1.5%) in the dark at 260. When the root was 2 cm long (about 40 hr) the embryos (including scutella) were removed by sterile excision. Three or four normal seedlings (intact) or excised embryos were transferred to 10 ml of a mineral-salts solution (14,18) for soluble nitrogen and a-amino nitrogen determinations. The amino acids were washed free of other components in the alcohol extract by passage through a 6 X 1-cm column of Dowex-50 X 8 (H+) cation exchange resin and eluted with iN NH4OH. They were further fractionated into acidic, neutral, and basic amino acids by the procedures of Hirs, Moore and Stein (13,17). In this procedure glutamic and aspartic acids were adsorbed on a 20 X 1-cm Dowex-1 X 10 (acetate) column. Glutamine and asparagine in the water effluent from this column were hydrolyzed in iN HCl for 4 hours at 1000. The resulting glutamic and aspartic acids were adsorbed on a second Dowex 1-X 10 (acetate) column. The water effluent from this column was passed through a 15 X 1 cm Dowex-50 X 98 (Na +) column to adsorb the neutral and basic amino acids. The neutral amino acids were eluted with 15 nml of 0.1 mr Na citrate (pH 5.0) and the basic amino acids, including y-amino butyric acid, with 0.5 m Na citrate (pH 7.5). Glutanlic and aspartic acids were eluted serially from the Dowex-1 X 10 (acetate) columns with 0.2 N acetic acid. After each step in the procedure the eluates were dried and the a-amino nitrogen of each fraction was determined with ninhydrin (24). ResultsTransfer of Nitrogen front the Endosperm to tihe Embryo. Results with intact maize seedlings (fig 1) showed that during germination the alcohol-insoluble nitrogen fraction increased in the embryo while it declined in the endosperm. The level of alcoholsoluble nitrogen increased temporarily in the endosperm and had not fallen below the initial level at 96 hours. There was a progressive increase in this fraction in the embryo after 20 hours. Usually about three-quarters of the loss front the endosperm was recovered as embryo nitrogen. This picture is sufficiently similar to well documented results obtained with barley (10, 11) to assume that organic nitrogen is transferre...

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Amino Acids as Sources of Nitrogen for the Growth of Isolated Oat Embryos

Cited by 44 publications

References 18 publications

One hundred years of zygotic embryo culture investigations

One hundred years of zygotic embryo culture investigations

PHYSIOLOGICAL STUDIES OF GERMINATION IN THE GENUS AVENA

The Requirement for Organic Nitrogen in Zea mays Embryos

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