Abstract
It has been proposed that Fe stress may be used in the study of limiting factors in photosynthesis as an experimental means of varying photochemical capacity in vivo (Plant Physiol 1980 65: 114-120). In this paper the effect of Fe stress on photosynthetic unit number, size, and composition was investigated by measuring P700, cytochrome (Cyt) f, chlorophyll (Chl) a, and Chl b in sugar beet leaves. The results show that when Fe stress reduced Chl per unit area by 80% (from 60 to 12 micrograms per square centimeter), it decreased the number of P700 molecules per unit area by 88% and Cyt f per unit area by 86%; over the same range the Chl to P700 ratio increased by 37% but there was no significant change in the Chl to Cyt f ratio. These data suggest that Fe stress decreases photochemical capacity and Chl per unit area by diminishing the number of photosynthetic units per unit leaf area.
The ratio of Chl a to Chl b did not change with Fe stress. This suggests that the proportion of light-harvesting Chl a/b-protein complex within the photosynthetic unit remained constant. Electron microscopy of chloroplasts revealed that the decrease in the number of photosynthetic units which occurred during Fe stress was accompanied by a reduction in the number of granal and stromal lamellae per chloroplast and by a reduction in the number of thylakoids per granum.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alberte R. S., Hesketh J. D., Hofstra G., Thornber J. P., Naylor A. W., Bernard R. L., Brim C., Endrizzi J., Kohel R. J. Composition and activity of the photosynthetic apparatus in temperature-sensitive mutants of higher plants. Proc Natl Acad Sci U S A. 1974 Jun;71(6):2414–2418. doi: 10.1073/pnas.71.6.2414. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boardman N. K. The photochemical systems of photosynthesis. Adv Enzymol Relat Areas Mol Biol. 1968;30:1–79. doi: 10.1002/9780470122754.ch1. [DOI] [PubMed] [Google Scholar]
- Forti G., Bertolè M. L., Zanetti G. Purification and properties of cytochrome f from parsley leaves. Biochim Biophys Acta. 1965 Sep 27;109(1):33–40. doi: 10.1016/0926-6585(65)90087-7. [DOI] [PubMed] [Google Scholar]
- Genge S., Pilger D., Hiller R. G. The relationship between chlorophyll b and pigment-protein complex II. Biochim Biophys Acta. 1974 Apr 23;347(1):22–30. doi: 10.1016/0005-2728(74)90196-0. [DOI] [PubMed] [Google Scholar]
- Highkin H. R., Boardman N. K., Goodchild D. J. Photosynthetic Studies on a Pea-mutant Deficient in Chlorophyll. Plant Physiol. 1969 Sep;44(9):1310–1320. doi: 10.1104/pp.44.9.1310. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hiyama T., Ke B. Difference spectra and extinction coefficients of P 700 . Biochim Biophys Acta. 1972 Apr 20;267(1):160–171. doi: 10.1016/0005-2728(72)90147-8. [DOI] [PubMed] [Google Scholar]
- Nielsen N. C., Smillie R. M., Henningsen K. W., Von Wettstein D. Composition and Function of Thylakoid Membranes from Grana-rich and Grana-deficient Chloroplast Mutants of Barley. Plant Physiol. 1979 Jan;63(1):174–182. doi: 10.1104/pp.63.1.174. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Okabe K., Schmid G. H., Straub J. Genetic characterization and high efficiency photosynthesis of an aurea mutant of tobacco. Plant Physiol. 1977 Jul;60(1):150–156. doi: 10.1104/pp.60.1.150. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sane P. V., Goodchild D. J., Park R. B. Characterization of chloroplast photosystems 1 and 2 separated by a non-detergent method. Biochim Biophys Acta. 1970 Aug 4;216(1):162–178. doi: 10.1016/0005-2728(70)90168-4. [DOI] [PubMed] [Google Scholar]
- Shiozawa J. A., Alberte R. S., Thornber J. P. The P700-chlorophyll a-protein. Isolation and some characteristics of the complex in higher plants. Arch Biochem Biophys. 1974 Nov;165(1):388–397. doi: 10.1016/0003-9861(74)90177-5. [DOI] [PubMed] [Google Scholar]
- Stocking C. R. Iron deficiency and the structure and physiology of maize chloroplasts. Plant Physiol. 1975 Apr;55(4):626–631. doi: 10.1104/pp.55.4.626. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Terry N. Limiting Factors in Photosynthesis: I. USE OF IRON STRESS TO CONTROL PHOTOCHEMICAL CAPACITY IN VIVO. Plant Physiol. 1980 Jan;65(1):114–120. doi: 10.1104/pp.65.1.114. [DOI] [PMC free article] [PubMed] [Google Scholar]