Changes in chloroplast fine structure during the senescence of Populus deltoides leaves.
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Aging↗
Biomedical subjects
R Hernández-Gil
Publications and source records attributed to R Hernández-Gil.
Functional and Structural Changes in Senescing Populus deltoides (Bartr.) Chloroplasts.
Chloroplasts isolated from Populus deltoides leaves were used to study age-dependent changes in the rate of cyclic photophosphorylation. Single leaves were used to measure CO(2) fixation by leaf discs, chlorophyll concentration, and ATP synthesis. The ability of chloroplasts to synthesize ATP diminished steadily from the time of full leaf expansion, regardless whether the results are expressed on a leaf area or chlorophyll basis. This decline in the rates of ATP synthesis was paralleled by the decline in the rate of CO(2) fixation. The results suggest that the efficiency of the membrane-bound ATP synthesizing system declines with age.
Journal Article↗
Photophosphorylation and Carbon Dioxide Fixation by Chloroplasts Isolated from Populus deltoides.
A system has been developed for the isolation of photosynthetically active chloroplasts from leaves of Populus deltoides. A high proportion of the chloroplasts appeared intact. The maximum rates of different photosynthetic processes were as follows: CO(2) fixation 3.5 micromoles per milligram chlorophyll per hour, noncyclic ATP synthesis 10 micromoles per milligram chlorophyll per hour, and cyclic ATP synthesis 300 micromoles per milligram chlorophyll per hour.
Journal Article↗