Tamara Jakovljević

Imidiazolium based ionic liquids: Effects of different anions and alkyl chains lengths on the barley seedlings

We studied the effects of five imidiazolium based ionic liquids with different anions and length of alkyl chains linked to imidazolium ring on the early development of barley (Hordeum vulgare). The inhibitory effect depends on the ionic liquids concentration and chemical structure, whereby the most toxic one was [C10mim][Br], followed by [C7mim][Br], [C4mim][Br], [C4mim][CH3CO2] and [C4mim][BF4]. Both anion and cation structures affected the toxicity of ionic liquid indicating that selection of more biocompatible anions such as [CH3CO2] does not necessarily indicate lower toxicity. Alternation in the extent of oxidative stress and antioxidant enzymes activities were found in barley plants due to ionic liquid treatments. When seedlings were exposed to higher concentrations of ionic liquids, antioxidant system could not effectively remove reactive oxidative species, leading to lipid peroxidation and damage of the photosynthetic system. However, overall data indicated that the performance of barley seedling was improved when all measured enzymes involved in scavenging of reactive oxygen species (ROS) were increased with special emphasis on GPX activities. Since there are no studies about ionic liquid (IL) toxicity in plants, that simultaneously evaluates the antioxidative enzyme system in response to different ILs, this work is valuable for gaining knowledge about the protection mechanism of plants from oxidative stress caused by IL exposure.

Balance of glucosinolates content under Cd stress in two Brassica species

We designed a pot experiment to study the changes of growth parameters, accumulation of Cd in cabbage and kale, during a prolonged exposure period with two harvests (after 45 and 75 days of plant growth). Simultaneously, we monitored changes of total S and GSL contents in different plant organs. Both Brassica species showed tolerance to Cd, since no obvious symptoms of metal toxicity were displayed and no significantly reduced plant biomass were recorded. Moreover, a trend of root biomass enhancement was noticed. In general, the Cd concentration in roots was higher than in other organs. Data indicate that the transport system from roots to shoots was already saturated after the first growing period, while root continued to accumulate Cd during the second growing period. Regardless of differences in the GSL content between cabbage and kale, both Brassica species had a similar response to Cd exposure, indicating that the Brassicacea plant family could have unique features for the regulation of GSL content in order to balance the roles of GSLs as defence compounds and as S reservoirs. During the first growing period, GSLs in leaves and root could be more involved in ameliorating S deficiency rather than plant defence. After long-term Cd exposure, we found differences between GSL patterns in leaves and root. Furthermore, we found increased total GSL levels in the stem during whole experiment which indicates that stem could serve as a GSLs storage organ under Cd stress. This paper provides new insight into the possible roles of GSL in Cd stress.