Effects of Potassium Deficiency on Photosynthesis, Respiration and the Utilization of Photosynthetic Reductant by Mature Bean Leaves¹

Biochemical Basis for Effects of K-Deficiency on Assimilate Export Rate and Accumulation of Soluble Sugars in Soybean Leaves

“…Effects of K-stress on certain photosynthetic parameters of the first trifoliolate leaf, which had expanded with adequate K, are shown in Figure 2. In leaves of control plants, leaf K concentration increased initially and then decreased as the leaf aged, as has been observed previously (19,20) and is typical of a phloem mobile element. The initial increase in K concentration was not observed in the first trifoliolate leaf of stressed plants.…”

Photorespiratory Phenomena in Maize

“…4) suggests the possibility of two separate processes involving 0, uptake, one of which is saturated at about 2% 02 whereas the other is linearly related to 02 concentration at least to 8% 02. The 02 exchange phenomena in maize are similar to those reported previously for Phaseolus vulgaris and Glycine max (32,35,36), both of which are high r species. As in maize, 02 uptake was stimulated upon transition to r and was directly related to 02 concentration.…”

“…Since the photophosphorylation occurs during transfer of electrons from H20 to 02, this process has been called "oxygen-linked noncyclic photophosphorylation" (1). Its importance may lie in providing sufficient ATP, in addition to that produced during NADP synthesis, to convert CO. to the level of carbohydrate (13,16,36). Heber (13) has proposed that the relative transfer of electrons to NADP and 02 during photosynthesis is regulated by the NADPH/NADP ratio.…”

Determination of the Rate of CO2 Evolution by Green Leaves in Light

“…Althlouigh Ozbuin et al (31,32) report that the rate of CO., evolution was reduiced by 300 ft-c of light their data ( photosynthesis. In addition evolved CO., maxy be reabso,rbed bv the leaf-both events would decrease thle mieastired CO2 evolution froml the leaf.…”