Photosynthesis, chlorophyll fluorescence, and water relations in young sugar beet plants as affected by sulfur supply

• Published in: Journal of plant nutrition 2000-08, Vol.23 (8), p.1037-1049
• Main Authors: Kastori, Rudolf, Plesnicar, Marijana, Arsenijevic-Maksimovic, Ivana, Petrovic, Novica, Pankovic, Dejana, Sakac, Zvonimir
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Physiological diseases. Varia; Phytopathology. Animal pests. Plant and forest protection
• ISSN: 0190-4167; 1532-4087
• DOI: 10.1080/01904160009382080

The effect of different concentrations of sulfur (1 and 3 mM) and interruption of sulfur (S) supply for 25 days on the photosynthesis and leaf water relations in young sugar beet plants (Beta vulgaris L.) was studied in water culture, under greenhouse conditions. Interruption of S-supply significantly reduced the content of sulfur, chlorophylls a+b and carotenoids, leaf area, density of stomatal and epidermal cells, transpiration rate and leaf water potential, while it increased the free proline content and stomatal diffusion resistance. An increase in S concentration in the nutrient medium from 1 to 3 mM did not significantly affect the tested parameters, except for an increase in leaf S content and a decrease of leaf water potential. Sulfur deficiency caused a pronounced decrease of the rate and quantum yield of photosynthetic oxygen evolution under non-photorespiratory conditions. This was partly the result of the diminished photochemical efficiency of photosystem II reaction centers. Less efficient excitation of PSII reaction centers is most probably the consequence of higher thermal energy dissipation in the reaction centers of S-starved plants. These data support that S nutrition is one of the factors regulating plant photosynthesis.