Perloočky rodu Daphnia jsou intenzivně studovaní vodní bezobratlí. Proto byl pro nás velkým překvapením objev pro vědu nového druhu tohoto rodu v tůni na Kokořínsku. Druh byl pojmenován po významném českém hydrobiologovi Jaroslavu Hrbáčkovi, ale jeho jméno odkazuje i na hrbatý tvar těla. Jeho doposud známé lokality jsou pouze v Čechách a na Slovensku., Species of water fleas that belong to the genus Daphnia have been used intensively in studies as “model organisms”. The discovery of a new Daphnia species in a pool in Central Bohemia was, therefore, a surprise. All known localities of this species, which we named after the prominent Czech hydrobiologist Jaroslav Hrbáček, are restricted to Czechia and Slovakia., and Adam Petrusek, Petr Jan Juračka.
Czech botanists have studied the vegetation of Northern Biljefjorden (Central Spitsbergen) since 2007. Their activities include vegetation mapping of the whole area (repeated also after 70 years), assessment of vegetation development in deglaciated areas and analysis of clonal growth forms. and Jitka Klimešová, Karel Prach.
Chloroplasts are commonly the site of the earliest abiotic injury visible in plant ultrastructure. In this study, six inbred lines of maize (Zea mays L.) were used to analyze changes in the ultrastructure of chloroplasts and related physiological parameters under conditions of drought stress simulated by 20% polyethylene glycol 6000 (-0.6 MPa) for two days. Chloroplasts of three maize lines proved to be more sensitive. They showed changes in the ultrastructure in response to drought, including damage of thylakoid membranes, an increase in the number and size of plastoglobuli, swelling of thylakoid membranes both stromal and granal, disorganization of the thylakoid membrane system, an obvious increase in the intrathylakoid space, and a decrease in the
length-to-width ratio and area of chloroplasts. In addition, the contents of malondialdehyde increased markedly in the sensitive lines. Contrary to the sensitive lines, stable structures and shapes of chloroplasts were observed in the drought-resistant lines; it could be considered as an advantage contributing to drought tolerance in the plants. In addition, the drought index of leaf fresh mass (LMDI) in the drought-sensitive lines was ≤ 0.5, which was also associated with a lower content of leaf chlorophyll. In contrast, drought tolerance coincided with lesser growth reduction, and higher LMDI and leaf chlorophyll content., R. X. Shao, L. F. Xin, H. F. Zheng, L. L. Li, W. L. Ran, J. Mao, Q. H. Yang., and Obsahuje seznam literatury