TOXICITY OF BISULFITE TO PHOTOSYNTHESIS AND RESPIRATION1

Inhabition of photosynthesis in Chloroccoum sp by bisulfileion was the reciprocal of the light intensity curve. Respiration was least affected of the bisulfite after endogenous substrate was reduced by incubation in darkness. Maximum areduction in growth occurred with bisulfile treatment at or above optimal growth temperatures. Maximum phytotoxicity correlated with conditions resulting in maximum metabolic activity. The order of toxicity was –H₂SO₃HSO₃^?SO₃.     

ON THE BEHAVIOR OF NICKEL CARBONATE IN RELATION TO PHOTOSYNTHESIS

The writer was unable to prepare a sample of nickel carbonate which would give any indication of photosynthetic activity. If Professor Baly''s preparations are really active, I believe there is some detail in his procedure which he has failed to mention.     

SPECIALIZATION OF MESOPHYLL MORPHOLOGY IN RELATION TO C4 PHOTOSYNTHESIS IN THE POACEAE

Our current understanding of the photosynthetic process in species utilizing the C₄ photosynthetic pathway suggests that photosynthetic efficiency should be enhanced by: 1) maximizing the conductance of the gas phase transport pathway from the leaf exterior to the mesophyll cell surfaces; 2) maximizing cytoplasmic connections and metabolite transport between bundle sheath and mesophyll parenchyma cells; and 3) minimizing the conductance of the gas phase transport pathway from the bundle sheath cells to the leaf exterior. In this study we have examined several species in the Poaceae with C₄ photosynthesis to determine if there is any evidence for anatomical specialization which would lead to enhanced photosynthetic efficiency by these processes. Observations with light and scanning electron microscopes revealed specializations in mesophyll cell morphology and arrangement which include branched cells forming intercellular channels. These specializations are hypothesized to contribute to photosynthetic efficiency through its influence on the above transport processes.     

THE PHYSIOLOGY OF THE RESPIRATION OF FISHES IN RELATION TO THE HYDROGEN ION CONCENTRATION OF THE MEDIUM

1. The ability of marine fishes to absorb oxygen at low tension from the sea water is more or less dependent upon the hydrogen ion concentration of the water. 2. The ability of fishes to withstand wide variations in the range of hydrogen ion concentration of the sea water can be correlated with their habitats. The fishes that are most resistant to a wide variation in the hydrogen ion concentration are most cosmopolitan in their habitat. Those that are least resistant to a variation in the hydrogen ion concentration are the most restricted in their range of habitat. 3. There is a close correlation between the optimum condition of the sea water for the absorption of oxygen at low tension by the herring (Clupea pallasii), the condition of the sea water to which they react positive and that in which they are found most abundantly. 4. It is suggested that the variation in the ability to absorb oxygen at low tension at a given pH of individuals of a species is dependent upon the alkaline reserve of the blood of the individual fish.     

COMPARATIVE STUDIES ON RESPIRATION : X. TOXIC AND ANTAGONISTIC EFFECTS OF MAGNESIUM IN RELATION TO THE RESPIRATION OF BACILLUS SUBTILIS.

1. Concentrations of MgCl₂ up to 0.01 M have little effect upon the rate or respiration of Bacillus subtilis; at 0.03 M there is an increase in the rate, while in the higher concentrations there is a gradual decrease. 2. There is a well marked antagonism between MgCl₂ and NaCl, and a very slight antagonism between MgCl₂ and CaCl₂.     

MORPHOLOGY AND PHOTOSYNTHESIS OF CAULERPA (CHLOROPHYTA) IN RELATION TO GROWTH FORM

Morphological and photosynthetic performance were analyzed in species of the genus Caulerpa from an exposed coral reef and a sheltered reef lagoon. Morphological characters, such as distance between modules, number of modules, stolon branches and rhizoid clusters per centimeter of stolon, indicated a uniformity among species within a specific habitat. "Guerilla," or diffusive, growth forms were characteristic for lagoon species and "phalanx," or compact, growth forms for reef species. Differences in photosynthesis were found between Caulerpa species. Sun-tolerant species were found on the reef, and both sun- and shade-tolerant species were present in the lagoon. In the lagoon, shade-tolerant species, such as C. lanuginosa J. Agardh, were found growing in the understory, and sun-tolerant species, such as C. paspaloides (Bory) Greville, formed the canopy. C. cupressoides (West in Vahl) C. Agardh was the only species found in both environments; it showed higher photosynthetic rates and a compressed morphology when growing on the reef and lower photosynthetic rates and expanded morphology for lagoonal ramets. These results suggest that C. cupressoides possesses a broad phenotypic ability to acclimate to lagoonal and reef settings in comparison to other Caulerpa species, enhancing its ecological success in this particular system.