Comparison of photosynthetic activities of spinach chloroplasts with those of corn mesophyll and corn bundle sheath tissue

Journal Article · Sun Jan 01 04:00:00 EST 1978 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.62.1.59· OSTI ID:5301267

Hardt, H; Kok, B

Bundle sheath and mesophyll chloroplasts from Zea mays showed comparable rates of O/sub 2/ evolution, which amounted to about half of the rate observed in spinach (Spinacia oleracea) chloroplasts. Ratios of 4.5, 4.6, and 6.2 Mn/sup 2 +/ atoms per 400 chlorophylls were observed in mesophyll, bundle sheath, and spinach chloroplsts, respectively. These ratios roughly correspond to the observed O/sub 2/ evolution rates. Rates of electron transport from water to methylviologen (photosystem I and II) in both types of corn chloroplasts were about one-third that in spinach. Compared to spinach, transport rates from reduced diaminodurene to methylviologen (photosystem I) were about one-third and greater than one-half in mesophyll and bundle sheath material, repsectively. In both types of corn chloroplasts, electron flow from photosystem II to P700 was abnormal. This observation, together with the low rates of all activities, suggests tht damage occurred during isolation. Such damage may limit the quantitative significance of observations made with these materials (including the following data). Measurements of flash yields of O/sub 2/ evolution or O/sub 2/ uptake showed that the size of the photosynthetic unit was the same in photosystems I and II and in all three types of chloroplasts (about 400 chlorophylls per equivalent). Similarity of the photochemical cross-section of the two photosystems in the three preparations was also found in optical experiments: that is the half-times of the fluorescence rise in the presence of 3-(3,4-dichlorophenyl)-1,1-dimentylurea (DCMU) (photosystem II) and of the photooxidation of P700 (photosystem I). The ratio of P700 to chlorophyll appered to be about 2-fold higher in bundle sheath chloroplasts than in the other materials (1/200 versus 1/400).

• Research Organization: Martin Marietta Labs., Baltimore, MD
• OSTI ID: 5301267
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 62; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

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59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CEREALS
CHEMICAL REACTIONS
CHLOROPHYLL
CHLOROPLASTS
COMPARATIVE EVALUATIONS
CRYOGENIC FLUIDS
DATA
DATA FORMS
ELECTRON TRANSFER
ELEMENTS
EXPERIMENTAL DATA
FLUIDS
GRAMINEAE
GRASS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INFORMATION
ISOLATED VALUES
KINETICS
MAIZE
NONMETALS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHYTOCHROMES
PIGMENTS
PLANT CELLS
PLANT TISSUES
PLANTS
PORPHYRINS
REACTION KINETICS
SYNTHESIS