Chloroplast anatomy

See also Chlorophyll a. Chlorophyll b, Light-Harvesting Complexes, Reaction Center, Chloroplast Anatomy, Phytanic Acid, Porphyrin and Heme Metabolism... 

See also Figure 17.4c, Figure 17.16, Thylakoid Lumen, Chloroplast Anatomy, Stroma, CFO-CFl Complex, Chloroplast Anatomy, Grana, Stroma, Mitochondrial Structure and Function, Photosystem II, Photosystem I, CFO-CFl Complex... 

See also Mitochondrial Structure and Function (from Chapter 15), Basic Processes of Photosynthesis, Light Gathering Structures, Chloroplast Anatomy, Thylakoid Lumen, Chlorophyll, Chloroplasts... 

See also Chloroplast Anatomy, Stroma, Thylakoid Membrane, The Chloroplast, Thylakoid Lumen, Photosystem II, Photosystem 1, Figure 17.12... 

See also Reaction Center, Chloroplasts, Chloroplast Anatomy, Chlorophyll, Figure 17.6... 

See also Light Absorbing Pigments, Chloroplast Anatomy, Photosystem II, Photosystem I, The Chloroplast, Chlorophyll, Chlorophyll a, Chlorophyll b... 

Unlike the RPP cycle in which carboxylation and carbon reduction are restricted to the chloroplast, the C4 pathway involves the interaction of two cell types and several different compartments within these cells. C4 plants are characterized by a radial leaf anatomy (Kranz anatomy) in which one cell type, the mesophyll cells, surrounds the other type, bundle sheath cells. This arrangement of the cell types and the division of labor between them is central to the functioning of the C4 pathway. Carbon dioxide is first captured in the outer tissues (mesophyll) and then transported to the inner tissues (bundle sheath) where CO2 and reducing... 

There has been considerable speculation regarding connection between "Kranz" anatomy and the physiology of C type carbon assimila-tion(l),Plant tissue culture offers an opportunity to study the mechanism of photosynthesis at cellular level. Development of photosynthetic apparatus has been studied in several dicot callus cultures(2). However it has been relatively difficult to induce greening in callus cultures derived from monocot C. plants (3). The present investigations were undertaken with an object to study the chloroplast development in the callus cultures, derived from a monocot C. plant maize, in relation to "Kranz" anatomy and chloroplast dimorphism. 

C- plants (9). One of the features of C. plants, is the presence of "Kranz" anatomy. There is compartmentalization of enzymes in "Kranz" anatomy viz PEPC in the cytosol of mesophyll cells and RuBISCO in the chloroplasts of the bundle sheath cells(ll). Accordingly in the present study, predominent activity of PEPC in the partially green maize callus cultures and lowest portion of young leaf lacking well developed chloroplasts can be explained. 

These two forms possessed anatomical structures of culms clearly differing from each other. The terrestrial forms had an unusual Kranz type of anatomy which is characterized by the presence of colourless mestome sheath cells intervening between the mesophyll cells and the Kranz cells (1,2,3). The chloroplasts with well-developed grana and many large mitochondria were scattered in the Kranz cells, although the terrestrial forms had biochemical features of the NAD-malic enzyme C4 subtype (2,3). The submersed forms possessed large spherical mesophyll cells and reduced vascular bundles, which are characteristic of submersed aquatic plants (2,4). Kranz cells contained relatively smaller chloroplasts than the Kranz cells of the terrestrial forms. 

Fig. 2.2. Structure of parenchymatous plant cells. A. Cell from the petiole of a sugar-beet leaf. It has vacuolated cytoplasm with mitochondria, chloroplasts and nucleus. B. Starch sheath cells from young stem of tobacco, showing prominent starch grains in the chloroplasts. (Both xll90.) (From K. Esau, Plant Anatomy, John Wiley Sons, Inc., New York, 1953.)...

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