Physiological Studies in Plant Nutrition: VI. The Relation of Respiration Rate to the Carbohydrate and Nitrogen Metabolism of the Barley Leaf as determined by Nitrogen and Potassium Deficiency

The Effect of Salt Concentration Upon the Metabolism of Potato Discs and the Contrasted Effect of Potassium and Calcium Salts Which Have a Common Ion

“…4, by the difference between the corresponding potassium and calcium cultures in table II. In the order SO4 < Br < Cl < NO3 will be recognized the relative order of the anions with respect to certain physical properties but, more particularly, their relative effect upon the absorption of a common cation4-a fact which constitutes strong evidence that the observed differences are not merely due to the presence of the salts in the external solution but that they also involve their absorption.5 In order to explain how potassium-and calcium salts affect 3 It is possible that the contrasted effects of K and Ca salts may be associated with the fact that in K salts equal uptake of cation and anion usually occurs in potato discs whereas in calcium salts excess uptake of anion is to be expected. 4 Results privately communicated.…”

Respiration and Salt Absorption by Excised Barley Roots.

“…When the accumulation of inorganic anions from the medium is proceeding at the maximum possible rate, i.e., when the oxidized cytochrome molecules are "saturated" with such ions and are not transporting any internally produced anions, the value of this ratio must be maximal at 4. This postulate is derived simply from the fact that 4 electrons are accepted in the reduction of each molecule of oxygen utilized in the reoxidation of cytochrome oxidase.…”

“…These values were found to be variable and in some cases to exceed considerably the maximum postulated by the Lundegardh hypothesis. 4. The possible depressant effect of Ca-+ upon the ground respiration was investigated by measurement of salt respiration in KBr solutions to which was added CaSO4.…”

Glutamine in the Metabolism of Barley Plants

“…GLUTAMINE AND THE METABOLISM OF NITROGEN DURING GROWTH AND DEVELOPMENT Gregory (1937), Richards (1936) and their collaborators have shown that an important characteristic of the metabolism of nitrogen in barley plants is the extensive movement of nitrogenous constituents from senescent tissues to developing and meristematic parts. The final phase of the annual cycle of development is the transfer of nitrogen to the grain, where it is stored mainly in the reserve proteins of the endosperm.…”

“…4. The view that the total nitrogen of the tissues is the resultant balance between synthetic and downgrade activities (Mothes, 1933;Gregory & Sen, 1937), implies that a greater proportion of the nitrogen of the grain may have been derived from vegetative parts than is indicated by these analyses. Considered in terms of the metabolism of protein, there is little doubt that the changes in the distribution of nitrogen involve an extensive breakdown of cytoplasmic and chloroplastic proteins of the leaves and other vegetative parts and their translocation to the grain, where they are condensed mainly as the reserves of the endosperm.…”