Euploidy in Ricinus1: EUPLOIDY EFFECTS ON PHOTOSYNTHETIC ACTIVITY AND CONTENT OF CHLOROPHYLL-PROTEINS
AUTOR(ES)
Timko, Michael P.
RESUMO
The effects of nuclear genome duplication on the chlorophyll-protein content and photochemical activity of chloroplasts, and photosynthetic rates in leaf tissue, have been evaluated in haploid, diploid, and tetraploid individuals of the castor bean, Ricinus communis L. Analysis of this euploid series revealed that both photosystem II (2,6-dichlorophenolindophenol reduction) and photosystem I oxygen uptake (N,N,N′,N′-tetramethyl-p-phenylenediamine to methyl viologen) decrease in plastids isolated from cells with increasingly larger nuclear complement sizes. Photosynthetic O2-evolution and 14CO2-fixation rates in leaf tissue from haploid, diploid, and tetraploid individuals were also found to decrease with the increase in size of the nuclear genome. Six chlorophyll-protein complexes, in addition to a zone of detergent complexed free pigment, were resolved from sodium dodecyl sulfate-solubilized thylakoid membranes from cells of all three ploidy levels. In addition to the P700-chlorophyll a-protein complex and the light-harvesting chlorophyll a/b-protein complex, four minor complexes were revealed, two containing only chlorophyll a and two containing both chlorophyll a and b. The relative distribution of chlorophyll among the resolved chlorophyll-protein complexes and free pigment was found to be similar for all three ploidy levels.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=425839Documentos Relacionados
- Hierarchical Response of Light Harvesting Chlorophyll-Proteins in a Light-Sensitive Chlorophyll b-Deficient Mutant of Maize 1
- Effect of Nuclear Mutation in Maize on Photosynthetic Activity and Content of Chlorophyll-Protein Complexes 1
- P700 Activity and Chlorophyll Content of Plants with Different Photosynthetic Carbon Dioxide Fixation Cycles 1
- Effects of Polyamines on Chlorophyll and Protein Content, Photochemical Activity, and Chloroplast Ultrastructure of Barley Leaf Discs during Senescence 1
- Water Stress Effects on the Content and Organization of Chlorophyll in Mesophyll and Bundle Sheath Chloroplasts of Maize 1