Changes in the composition of the xylem exudate of tea plants (Camellia sinensis L.) during recovery from pruning
1970
Selvendran, R.R.
A method of collecting the xylem sap from tea plants in quantities sufficient for analysis is described. Organic nitrogenous compounds accounted for most of the nitrogen present in the sap. Glutamine, theanine, glutamic acid, aspartic acid, and lysine were quantitatively the most important nitrogenous compounds. Also present in lesser amounts were leucine/isoleucine, phenyl alanine, valine, and asparagine. Inorganic phosphate, sulphate, glucose, fructose, and sucrose were also present. Phosphoryl choline was not detected. During recovery from pruning there was a definite change in proportions of some of the constituents in the sap. The total amino-acid content decreased to a very low level 9 days after pruning followed by an increase with bud break. Glutamine and theanine were the most important constituents quantitatively. These tended to decrease relatively more than the other amino acids during the first few days after pruning. The increase in glutamine and, to a lesser extent, theanine was more marked with bud break. Phosphoryl choline was not detected in the sap at any stage during the recovery period. The changes in the level of phosphate, sulphate, and sugars were somewhat parallel to the changes in the level of amino acids. All these constituents decreased to a low level a few days after pruning and increased with bud break. These findings suggest that new growth was made largely at the expense of translocated nitrogenous and other compounds.
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