| Biography | |
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 Prof. Irina Shtangeeva Institute of Earth Sciences, St. Petersburg State University, Russia |
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| Title: Short-term variations of organic compounds, macro- and trace elements in different plant species and in the rhizosphere soil | |
| Abstract: Elemental composition of plants is not constant. Among others, temporal variations are of special interest. Till now, however, little is known about short-term (for example, during hours) variations of element concentrations in different plants and in the rhizosphere soil. Meanwhile, it is known that living organisms have own biological clock that regulate their physiological processes. The rhythmic variations can influence on photosynthesis in chloroplasts and transpiration rates resulting in changes in the nutrient transport. Unfortunately, there are still many uncertainties regarding mechanisms controlling these processes in plants. In particular, up to now little is known about circadian rhythms in concentrations of macro- and trace element in plants. The aim of the research was to study diurnal changes in concentrations of organic compounds and different macro- and trace elements in several widely distributed plant species and in the rhizosphere soil of the plants. For this purpose, in the course of three last years several experiments were carried out. The plant and soil samples were collected in a field from small sites over a daytime. It was found that during day, the variations of the total amounts of C and N as well as stable isotopes of the elements in the rhizosphere soil can be rather marked and different for the soils taken from roots of different plants. The concentrations of some other elements in the rhizosphere soil of the plants varied in a similar way. The short-term variations of element concentrations in roots and leaves of the plants were also rather large. In many cases, a decrease of element concentration in roots correlated with an increase of its concentration in leaves. Although the plants were collected simultaneously and from the same site, mean concentrations of many elements in different plant species were statistically significantly different. This can be due to the fact that the plants belong to different clades. The differences between concentrations of most part of elements in roots and leaves of the plants were also statistically significant. The concentrations of many trace elements were higher in roots than in leaves, while the concentrations of essential plant nutrients were often higher in leaves compared to roots. | |
| Biography: Affiliation and work address: Institute of Earth Sciences, St. Petersburg State University, Universitetskaya nab., 7/9, St. Petersburg 199034 Russia, Tel: 007 812 687-61-22, E-mail: shtangeeva@gmail.com Career/Employment: 2014 – senior researcher,InstituteofEarth Sciences,St. PetersburgUniversity 2006 – 2014 senior researcher, Chemical Department,St. PetersburgUniversity 1999 - 2006 - senior researcher,InterdisciplinaryCenter,St. PetersburgUniversity 1991 -1999 - senior researcher,InstituteofEarth Crust,St. PetersburgUniversity 1983 -1991 - researcher,InstituteofEarth Crust,St. PetersburgUniversity 1979 -1983 - junior research scientist,InstituteofEarth Crust,St. PetersburgUniversity 1978 -1979 - engineer,InstituteofEarth Crust,St. PetersburgUniversity Main scientific interests: Ecology, biogeochemistry, multivariate statistics and modelling, modern analytical techniques | |
