Photosynthetic carbon metabolism of isolated corn chloroplasts.

Chloroplasts have been isolated from 4- to 6-day-old corn (Zea mays) leaves capable of assimilating 45 micromoles CO(2) per milligram chlorophyll per hour. The effects of various factors such as inorganic phosphate, reducing agents, inhibitors, intermediates of the photosynthetic carbon reduction cycle, organic acids, and oxygen on the photosynthetic rate and on the distribution of (14)C within the products by these chloroplasts were determined. The photosynthetic carbon metabolism of the corn plastids appeared to be similar to that already observed in spinach and pea chloroplasts.

Tritiated Water as a Tool for Ecological Field Studies.

Tritium was used to investigate the withdrawal by small trees of water from soil at three depths. Within 4 hours of placement at each depth, tritium was detected in the transpired water from nearby trees. On the 3rd day after application, 38 times more tritium (per unit volume) was present in transpired water drawn from soil at a depth of 0 to 30.