Daniel I. Arnon

TL;DR: The advantages of this “dark” method, described herein, over the photochemical method for the study of the mechanism of TPN reduction in chloroplasts are that (a) it eliminates the interference of chloroplast pigments and of act and (b) it dispenses with the “grana” portion of the chloroplast, thereby making it possible to replace the grana-bound ferredoxin-TPN reductase with the crystalline enzyme.

TL;DR: The preliminary findings that molybdenum, in minute amounts, improved the growth of barley plants in a culture solution supplied with ammonium salts as the sole source of nitrogen, supported the view that the list of essential elements for higher plants is incomplete and suggested the desirability of determining whether or not moly bdenum is essential in the nutrition of higher plants.

TL;DR: It has been shown that ferredoxin can catalyse, by two distinct photochemical reactions, the production of ATP in cell-free photosynthetic systems at rates comparable with the maximum rates of photosynthesis in vivo.

TL;DR: There is considerable doubt at present about the precise meaning of a soil pH measurement obtained by standard procedures including the glass electrode, and there is a dearth of information about the effects of hydrogen ion concentration on plant growth, with other factors of the nutrient environment held constant.