Variations in leaf gas-exchange characteristics, PSII activity, leaf pigments, and tuber yield were investigated in seven wild and one cultivated species of Dioscorea from Koraput, India, in order to find out their overall adaptability to the environment. The leaf photosynthetic rate, transpiration, stomatal conductance, water-use efficiency, carboxylation efficiency, and photosynthetic pigments were significantly higher in some wild species compared to the cultivated species. In addition, some wild species showed better photochemical efficiency of PSII, photochemical quenching, and electron transport rate in comparison to cultivated one. Furthermore, leaf dry matter accumulation and tuber yield was also higher in some wild species compared to the cultivated species. Taken together, the wild species, such as D. oppositifolia, D. hamiltonii, and D. pubera, showed the superior photosynthetic efficiency compared to the cultivated D. alata and they could be used for future crop improvement programs., B. Padhan, D. Panda., and Obsahuje bibliografii
The present research was conducted to assess physiological responses of ‘Malas-e-Saveh’ (Malas) and ‘Shishe-Kab’ (Shishe) pomegranates to water of different salt content and electrical conductivity (1.05, 4.61, and 7.46 dS m-1). Both cultivars showed a reduced trunk length due to salinity. Relative water content and stomatal conductivity of both cultivars were significantly reduced under salt stress, but ion leakage increased. In both cultivars, total chlorophyll (Chl) and carbohydrates decreased with rise in salinity, while proline accumulation increased. With salinity increment, the Chl fluorescence parameters (maximum photochemical efficiency of PSII and effective quantum yield of PSII) declined significantly in both cultivars, with higher reduction observed in Shishe. Generally, more Na+ accumulated in shoots and more Cl- was observed in leaves. Cl- accumulation increased by salinity in leaves of Malas, but it was reduced in Shishe. The K+/Na+ ratio in leaves decreased in both cultivars by salinity increment. Malas was less affected by osmotic effects of NaCl, but it accumulated more Cl- in its leaves. Thus, Malas might be more affected by negative effects of salinity., M. Khayyat, A. Tehranifar, G. H. Davarynejad, M. H. Sayyari-Zahan., and Obsahuje bibliografii
Among various epiphytic ferns found in the Brazilian Atlantic Forest, we studied Vittaria lineata (L.) Smith (Polypodiopsida, Pteridaceae). Anatomical characterization of the leaf was carried out by light microscopy, fluorescence microscopy, and scanning electron microscopy. V. lineata possesses succulent leaves with two longitudinal furrows on the abaxial surface. We observed abundant stomata inside the furrows, glandular trichomes, paraphises, and sporangia. We examined malate concentrations in leaves, relative water content (RWC), photosynthetic pigments, and chlorophyll (Chl) a fluorescence in control, water-deficient, and abscisic acid (ABA)-treated plants. Plants subjected to drought stress (DS) and treated by exogenous ABA showed significant increase in the malate concentration, demonstrating nocturnal acidification. These findings suggest that V. lineata could change its mode of carbon fixation from C3 to the CAM pathway in response to drought. No significant changes in RWC were observed among treatments. Moreover, although plants subjected to stress treatments showed a significant decline in the contents of Chl a and b, the concentrations of carotenoids were stable. Photosynthetic parameters obtained from rapid light curves showed a significant decrease after DS and ABA treatments., B. D. Minardi, A. P. L. Voytena, M. Santos, Á. M. Randi., and Obsahuje bibliografii
Responses to drought were studied using two maize inbred lines (B76 and B106) and a commercial maize hybrid (Zea mays L. cv. Silver Queen) with differing resistance to abiotic stress. Maize seedlings were grown in pots in controlled environment chambers for 17 days and watering was withheld from one half the plants for an additional 11 days. On the final treatment date, leaf water potentials did not differ among genotypes and were -0.84 and -1.49 MPa in the water sufficient and insufficient treatments, respectively. Greater rates of CO2 assimilation were retained by the stress tolerant maize inbred line, B76, in comparison to the other two genotypes 11 days after watering was withheld. Rates of CO2 assimilation for all three genotypes were unaffected by decreasing the measurement O2 concentration from 21 to 2% (v/v). Activities of phosphoenolpyruvate carboxylase (PEPC), NADP-malic enzyme (NADP-ME), and NADP malate dehydrogenase were inhibited from 25 to 49% by the water deficiency treatment. Genotypic differences also were detected for the activities of NADP-ME and for PEPC. Changes of transcript abundance for the three C4 pathway enzymes also varied among watering treatments and genotypes. However, examples where transcripts decreased due to drought were associated with the two stress susceptible genotypes. The above results showed that enzymes in the C4 photosynthetic pathway were less inhibited by drought in stress tolerant compared to stress susceptible maize genotypes., R. Sicher, J. Bunce, J. Barnaby, B. Bailey., and Obsahuje bibliografii
On the occasion of the 50th anniversary of the international journal Photosynthetica in 2017 we briefly report on the establishment of this journal and on Dr. Zdeněk Šesták, the renowned researcher of photosynthesis processes who, in cooperation with the Czechoslovak Academy of Sciences, founded this essential science journal in Prague in 1967., H. K. Lichtenthaler., Obsahuje bibliografii, and Ozvláštněné číslování stránek článku 1-6. teprve na ně se napojuje pokračování stránkování navazující na 1. číslo časopisu
Zévy (Tridacnidae) jsou mezi mořskými mlži výjimečné velikostí i způsobem získávání potravy. V jejich plášti se vyskytují mikroskopické řasy zooxantely, které fotosyntézou produkují sacharidy, o něž se dělí s hostitelem. Za nápadné zbarvení pláště vděčí zévy zooxantelám a specializovaným buňkám iridocytům., Giant clams (Tridacnidae) are exceptional among sea clams for their size and the way they acquire food. On their shells microscopic zooxanthella algae occur, producing saccharides through photosynthesis, which they share with the host. The conspicuous coloring of the shells is due to the clams’ zooxanthellae and specialized iridocyte cells., and Nicole Černohorská.
Accumulation and distribution of zinc within Miscanthus x giganteus plants grown on elevated Zn concentrations and their photosynthetic performance were investigated. High concentrations of Zn in soils caused an increase of its concentrations in all plant organs. The bioconcentration factor, bioaccumulation factor, and translocation factor were lower than one indicating that M. x giganteus is an excluder plant species. Excessive Zn induced visible leaf damage, i.e. chlorosis and necrosis, only in the oldest leaves, pointing to Zn accumulation. Elevated amounts of Zn in leaves significantly lowered the photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO2 concentrations, parameters of chlorophyll a fluorescence, and chlorophyll b content. Despite Zn excess in leaves, there was no severe reduction in the maximal quantum yield of PSII photochemistry, indicating a high photosynthetic capacity, high tolerance to elevated Zn concetrations, and ability of M. x giganteus to grow on Zn-contaminated soils., G. Andrejić, G. Gajić, M. Prica, Ž. Dželetović, T. Rakić., and Obsahuje bibliografii
Zinc is a critical mineral nutrient that protects plant cells from salt-induced cell damage. We tested whether the application of Zn at various concentrations [0, 5, 10, or 20 mg kg-1(soil)] would protect almond (Prunus amygdalus) seedlings subjected to salt stress (0, 30, 60, or 90 mM NaCl). All concentrations of Zn, particularly the application of 10 and 20 mg kg-1, increased the net photosynthetic rate, stomatal conductance, the maximal efficiency of PSII photochemistry, and a proline content in almond seedlings grown under salt stress; 20 mg(Zn) kg-1 was the most effective concentration. The activity of superoxide dismutase showed a significant increase under salinity stress and Zn application. The catalase activity decreased in the salt-treated seedlings, but recovered after the Zn treatment. Our results proved the positive effects of Zn on antioxidant enzyme activity scavenging the reactive oxygen species produced under salt stress., A. Amiri, B. Baninasab, C. Ghobadi, A. H. Khoshgoftarmanesh., and Obsahuje seznam literatury