Effect Of Mineral Nutrition on Metabolic Change Induced in Crop Plant Roots (I) |
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| Authors: | Goro Izawa |
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| Institution: | Hyogo University of Agriculture , Hyogo |
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| Abstract: | Attempts have long been made to study the effect of mineral nutrition on the metabolic substances in excised roots from a numcer of plant species, but very little attention has teen given to an approach to the problem by using the bleeding sap from crop plants. Recently, however, an increasing number of reports about the occurrence of organic substances in bleeding sap from crop plants has completely revised an old view that xylem sap was essentially a rather dilute aqueous solution of inorganic salts. Evidence has already been obtained which suggests a significant role for the root system as a centre of metabolism and an upward transport of metabolites from the root via the xylem to the leaf. Although analyses of the nitrogenous compounds present in bleeding sap from herbaceous plants have shown glutamine and asparagine to be the most important constituents, in some species of plants nitrate nitrogen may be a predominant nitrogenous compound. Besides ami des and nitrate, the presence of amino acids in bleeding sap has ceen shown by Kulayeva, Silina, and Kursanov 1) for pumpkins, Wieringa and Bakhuis 21 for Lupins, and DIE3) for cucumbers and tomatoes. |
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