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C J Morris

Publications and source records attributed to C J Morris.

126 records · Page 7Linked to original sources
PubMed1966

Changes in amino Acid content of excised leaves during incubation I. The effect of water content of leaves and atmospheric oxygen level.

Excised leaves were incubated at various water contents to determine the effect of water status on amino acid composition. Considerable proteolysis took place during incubation with a resultant increase in each amino acid in the non-protein fraction. However, serine, proline, gamma-aminobutyric acid and methyleysteine sulfoxide were the only amino acids in which there was an accumulation (i.e., net synthesis). Serine showed a small but consistent accumulation lasting for 6 days. Proline showed a greater accumulation but this ceased after 2 days.To learn more about the control of the proline accumulation during wilting, turgid and wilted leaves were incubated under aerobic and anaerobic conditions. The amino acid analyses showed that turgid leaves did not accumulate proline and that proline and methylcysteine sulfoxide accumulation was abolished by anaerobiosis. With other amino acids, relative concentration changes between wilted and non-wilted leaves were less striking than the difference between aerobic and anaerobic conditions.Under anaerobic conditions there was an increase in alanine and a large increase in gamma-aminobutyric acid which were not evident in air. Serine, aspartic acid, glutamic acid, and glutamine disappeared more rapidly and glycine disappeared less rapidly under anaerobic than under aerobic conditions.On the basis of these results, several pathways of amino acid degradation were suggested.

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PubMed1966

Changes in Amino Acid Content of Excised Leaves During Incubation. III. Role of Sugar in the Accumulation of Proline in Wilted Leaves.

A previously reported accumulation of proline in wilted turnip leaves has been observed in 6 additional species representing 5 different families. The results of experiments on the conditions affecting the behavior of proline in wilted leaves were interpreted to mean that the supply and metabolism of available carbohydrate was essential for proline accumulation.The role of sugar in proline accumulation was determined by incubating wilted leaves with different levels of carbohydrate (produced either by variations in conditions of preillumination or by infiltration with sucrose). The results showed that proline accumulation was greater and most prolonged in wilted leaves with higher sugar and starch contents. No proline accumulation was observed in unwilted leaves. Also some inhibitors of glycolysis and of the tricarboxylic acid cycle prevented proline accumulation in wilted leaves.Based on these results, the interpretation of the role of sugar in proline accumulation is that the oxidation of sugars furnishes alpha-ketoglutarate and NAD(P)H for proline synthesis in wilted leaves.

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