Two cultivars of common buckwheat (Fagopyrum esculentum), Pyra and Siva, were exposed to three treatments: water deficit (WD), foliar spraying by selenium (as Na2SeO4) (Se), and the combination of both. In WD-plants the stomatal conductance (gs) was significantly lower, while WD+Se-plants of Siva had significantly higher gs. None of the treatments resulted in significant differences of potential photochemical efficiency of photosystem 2 (PS2). A significantly higher actual photochemical efficiency of PS2 was obtained in Siva WD-plants and in Pyra Se-and WD-plants which was possibly due to improvement of plant water management during treatment. A significant interaction was observed between the effects of WD and Se on respiratory potential in Pyra. WD, Se, and the WD+Se combination resulted in shorter Pyra and Siva plants, with a reduced number of nodes. WD slightly negatively affected the yield per plant. The yield was highest in plants exposed to Se only. In Siva the number of seeds was triple while the average seed mass remained unchanged. and N. Tadina ... [et al.].
Simultaneous measurements of leaf gas exchange and chlorophyll fluorescence for Koelreuteria paniculata Laxm. at 380 ± 5.6 and 600 ± 8.5 μmol mol-1 were conducted, and the photosynthetic electron flow via photosystem II (PSII) to photosynthesis, photorespiration, and other electron-consuming processes were calculated. The results showed that the photosynthetic electron flow associated with carboxylation (Jc), oxygenation (Jo), and other
electron-consuming processes (Jr) were 72.7, 45.7, and 29.4 μmol(e-) m-2 s-1 at 380 μmol mol-1, respectively; and 86.1, 35.3, and 48.2 μmol(e-) m-2 s-1 at 600 μmol mol-1, respectively. Our results revealed that other aspects associated with electronconsuming processes, except for photosynthesis and respiration, were neither negligible nor constant under photorespiratory conditions. Using maximum net photosynthetic rate (Pmax), day respiration (R), photorespiration rate (Rl), and maximum electron flow via PSII
(Jmax), the use efficiency of electrons via PSII at saturation irradiance to fix CO2 was calculated. The calculated results showed that the use efficiency of electrons via PSII to fix CO2 at 600 μmol mol-1 was almost as effective as that at 380 μmol mol-1, even though more electrons passed through PSII at 600 μmol mol-1 than at 380 μmol mol-1., Z. P. Ye, Q. Yu, H. J. Kang., and Obsahuje bibliografii