Cr(VI) significantly reduced rates of net photosynthesis and transpiration and of stomatal conductance. Cr(VI) did not affect the Fv/Fm ratio of chlorophyll fluorescence implying that the primary photochemical processes in photosystem 2 were not affected. However, the efficiency of excitation capture by open PS2 centres, in vivo quantum yield of PS2 photochemistry, and electron transport rate were significantly reduced by Cr(VI). The coefficient of photochemical quenching was reduced with a concomitant increase in coefficient of non-photochemical quenching, suggesting reduced demand for ATP and NADPH due to inhibition of CO2 assimilation. Lipid peroxidation was increased by Cr(VI) and the activities of superoxide dismutase and catalase (CAT) were increased. However, the CAT activity was reduced by high Cr(VI) concentration. The activities of ascorbate peroxidase and glutathione reductase were significantly reduced by Cr(VI) treatment.
Sluneční erupce spojené s koronálními výrony hmoty jsou nejenergetičtějšími dynamickými procesy ve sluneční soustavě s dopadem na celou heliosféru, včetně Země a jejího blízkého kosmického okolí. Protože k uvolnění energie v erupcích dochází podle současných představ kaskádním procesem na mnoha škálách, je v tomto článku o numerickém modelování procesů ve slunečních erupcích uplatněno mnohoškálové hledisko: bude představen numerický MHD model erupce na globálních škálách (~10(8) m) i částicové modelování máloškálových (~10 m) plazmových procesů, které mají přímý vztah k disipaci magnetické energie v erupci, k formování svazků urychlenýchh částic a jejich následné termalizaci v bezesrážkovém erupčním plazmatu prostřednictvím vlnově-částicových interakcí., Marian Karlický, Miroslav Bárta., and Obsahuje seznam literatury
Dracunculus globocephalus Mackin, 1927 (Nematoda: Dracunculoidea) is redescribed from specimens collected from the mesentery of the snapping turtle, Chelydra serpentina (L.), in Louisiana, USA. The use of scanning electron microscopy, applied for the first time in this species, made it possible to study details in the structure of the cephalic end and the arrangement of male caudal papillae that are difficult to observe under the light microscope. This species markedly differs from all other species of Dracunculus in having the spicules greatly unequal in size and shape, in the absence of a gubernaculum, and in the disposition of male caudal papillae. The validity of D. globocephalus is confirmed, but the above mentioned morphological differences are not sufficient for listing it in a separate genus. This is the first record of D. globocephalus in Louisiana.
One of the effective ways to address the effects of abnormal climate change on plant is to find germplasms that have better resistance to adverse environments. In this paper, we studied the responses of 5 pepper species Capsicum annuum L. (CA), C. baccatum L. (CB), C. chinense Jacquin. (CC), C. frutescens L. (CF) and C. pubescens Ruiz & Pavon (CP) as well as a wild pepper C. baccatum var. baccatum (CBY) to waterlogging stress. The results showed that warterlogging treatment greatly decreases photosynthetic pigment content, net photosynthetic rate (PN) and stomatal conductance (gs), and dramatically increases proline content and water-use efficiency (WUE) in all tested pepper, suggesting that pepper has weak resistance to waterlogging stress. The results also showed that changes of the above parameters vary in different species. CP had the smallest decreases in photosynthetic pigment content, PN, and gs and greatest increases in proline content and WUE. By contrast, CC had the greatest decreases in photosynthetic pigment content, P N, and gs and smallest increases in proline content and WUE, indicating that different species had different resistance to adverse environment and species CP and CC had the strongest and the weakest resistances, respectively. In addition, the study also demonstrated that wild pepper CBY had better resistance to adverse environment than all the tested species, indicating loss of the stress resistance genes during the process of domestication. Taking together, our study strongly suggests that pepper species should crossbreed with other species and wild pepper to expand genetic diversity, enlarge genetic distance, promote production, and improve the resistance to adverse environments. and L. J. Ou ... [et al.].