Ten day old pea plants {Pisum sativum L., cv. Ran) were ušed to analýze the effects of Cu2+ ions on the dry mass, chlorophyll, carotenoid and proline contents, rates of photosynthesis (En) and transpiration {E), stomatal resistance {r^, carboxylation enzymes activities (RuBPC, PEPC), RNA and protein syntheses and changes in chloroplast structure. Cu^^ treated plants showed lower chlorophyll a and carotenoids contents, and higher than Controls. Pii, E and protein synthesis were significantly reduced. Four days after metal treatment P^ was 5-7 % at 500 and 1000 pM Cu2+ from the Controls, was reduced and E was increased by all ušed metal concentrations. The lower RuBPC activity after the 4 d treatment by 1000 pM Cu2+ could be due to the inhibition of de novo protein synthesis. The higher proline content was probably due to the same reason. Cu2+ ions did not change RNA synthesis in pea leaves. We foímd complete disintegration of chloroplast lamellar systém 4 d after 1000 pM Cu2+ treatment, which confirmed the observed ftmctional changes.
Fibres, cables, wires and fibres can play an important role in design of many machines. One of the most interesting applications is replacement of chosen rigid elements of a manipulator or a mechanism by cables. The main advantage of this design is the achievement of a lower moving inertia, which leads to a higher mechanism speed, and lower production costs. An inverted pendulum attached and driven by two fibres serves as a typical testing system for the investigation of the fibres properties influence of the system dynamic response. Motion of the pendulum of this nonlinear system is investigated using the alaska simulation tool and an in-house program created in the MATLAB system. Since mass of fibres can influence employed types of fibre models, chosen dynamic quantities (e.g. pendulum angle, vibration amplitude etc.), are investigated in dependence on the excitation frequency for various fibres weights. and Obsahuje seznam literatury
Wheat (Triticum aestivum L.) cv. Jimai22 was used to evaluate the effect of ethylene evolution rate (EER) and 1-aminocyclopropane-1-carboxylic acid (ACC) and their relations with photosynthesis and photochemical efficiency in plants well-watered (WW) and under a severe water deficit (SWD). SWD caused a noticeable reduction in the grain mass. The marked increases in both EER and the ACC concentration were observed under SWD; it was reversed effectively by exogenous spermidine (Spd) or amino-ethoxyvinylglycine (AVG). Thermal images indicated that SWD increased obviously the temperature of flag leaves, mainly due to the decrease in transpiration rate under SWD. Exogenous Spd or AVG decreased to some extent the temperature of the flag leaves. The strong decline in photosynthetic rate (PN) and stomatal conductance as well as the photodamage of PSII were also observed under SWD after 14 and 21 days after anthesis (DAA). Intercellular CO2 concentration was reduced at 7 DAA, but slightly increased at 14 and 21 DAA under SWD, indicating that the decreased PN at 7 DAA might result from stomatal limitations, while the decline after 14 and 21 DAA might be attributed to nonstomatal limitations. Correlation analysis suggested that EER and ACC showed negative relations to photosynthesis and photochemical efficiency. Data obtained suggested that the effects of SWD were mediated predominantly by the increase in EER and ACC concentration, which greatly decreased the leaf photosynthesis and photochemical efficiency, and, therefore, reduced the grain mass. Application of Spd or AVG reduced the EER and ACC, and thus positively influenced photosynthesis and photochemical efficiency under SWD., W. Yang, Y. Yin, W. Jiang, D. Peng, D. Yang, Y. Cui, Z. Wang., and Obsahuje bibliografii