Morphological, biochemical and physiological responses of Indian cress (Tropaeolum majus) to elevated UV-B radiation

Background and Purpose: UV-B radiation is an important environmental factor for many plants with remarkable influence on defence-related secondary metabolite biosynthesis. Possible consequences of UV-B radiation on plants have been widely reported, but its effect on secondary plant metabolites in ornamental and medicinal plants is poorly understood. The aim of the present research was to establish whether it is feasible to cultivate Tropaeolum majus under conditions of enhanced UV-B radiation to alter the content of total phenolic compounds in leaves and flowers and whether UV-B treatment affect plant physiological response. Material and Method: An outdoor study was conducted to examine the effect of different levels of UV-B radiation on the morphological (specific leaf area and length of internodes and petiole), biochemical (photosynthetic pigments, UV absorbing compounds) and physiological characteristics (photosynthesis, photochemical yield of PSII, transpiration rate, water use efficiency) of the widely cultivated annual herb Indian cress ( T. majus L.). Results and Conclusions: Enhanced UV-B radiation induced increased synthesis of total phenolic compounds in leaves, but not in flowers. Photosynthesis and photochemical yield of PSII were mostly unaffected by UV-B. Transpiration rate was higher at elevated UV-B levels in the beginning and peak of the season. Specific leaf area and length of internodes and petiole were unaffected. UV-B treated specimens of T. majus possessed enhanced amounts of total phenolic compounds, which are important for utilisation of T. majus herbs for human health. Enhanced UV-B treatment affected flowering of T. majus at the end of the growing season, which may have an important negative implication for success of this species in elevated UV-B radiation environments

Development of a River Macrophyte Index (RMI) for assessing river ecological status

AbstractWe present the process of developing a macrophyte based index (River Macrophyte Index – RMI) for assessing river ecological status, that would be applicable for rivers with moderate to high water alkalinity, flowing over low slope terrain. A reference value and boundary values were determined for five ecological classes. The relation between the developed index and two existing indices, the Reference Index (RI) and the Trophic Index of Macrophytes (TIM), and selected environmental variables was established. The RMI is based on species composition and abundance from 208 sampling sites being in reference or good hydromorphological conditions and differing in the catchment land use. The percentage of natural areas in the sub-catchment was used for classifying macrophyte taxa into 5 ecological groups. 65 plant taxa, of which 47 were identified as indicator taxa, were included in the analysis. To assess the ecological status of a river site, the presence of at least 3 indicator taxa is necessary, otherwise the assessment is considered inconclusive. RMI is expected to indicate multiple pressures on the river, including trophic level. The developed index and RI and TIM indices differed in relation to slope, distance to source and catchment size

Selenium uptake and Se compounds in Se-treated buckwheat

In field experiments, tartary buckwheat and hybrid buckwheat were foliarly sprayed with an aqueous solution of sodium selenate (20 mg Se L–1). In treated plants, the selenium content was significantly higher than in controls, irrespective of the plant part and taxon of buckwheat. The highest average Se concentrations in hybrid and tartary buckwheat were found in seeds. The main Se species found in seeds was Se methionine. Selenium-sprayed plants had higher photochemical efficiency of photosystem II in both taxa and higher electron transport system activity in hybrid buckwheat, suggesting a positive effect of Se on physiological characteristics. Because of the concentration of Se in both buckwheat taxa and selenomethionine as the dominant species of Se, Se-enriched buckwheat is a potential source of dietary Se for animals and humans

The usage of silicon fertilisation in order to mitigate the oxidative stress and to improve the resilience of barley subjected to drought

Drought causes huge agricultural and economic losses worldwide. Silicon (Si) is considered abeneficial element for plants. It mitigates stress caused by salinity, drought, and high and low temperaturesby promoting antioxidant production. However, the underlying mechanisms are still notelucidated. We investigated Si fertilisation effect on photosynthetic parameters, trichome number,leaf optical properties, as well as profiles of amino acids and polyphenols in barley exposed towater shortage. Silicon was applied in three growth stages: (i) before the flag leaf emergence;(ii) prior to the grain filling phase; (iii) at the grain filling phase start. Drought negatively impactsphotochemical efficiency, stomatal conductance, photosynthetic pigment content, and leaf reflectiveand transmissive properties. Si application between flag leaf emergence and grain fillinghad the strongest effect on light reflectance. Among all analyzed phenolics, saponarin was themost abundant in all samples, irrespective of water regime and Si supply. Caffeoyl ester was theonly hydroxycinnamic acid showing significant accumulation with the latest applied Si comparedto no added Si upon drought. The major amino acids in barley leaves were glutamate, glutamine,aspartate, asparagine, and serine. Aspartate content was the highest in leaves exposed to droughtwithout Si addition, while lysine was the most accumulated in the leaves supplemented by Si atthe grain filling phase start. Proline was 2.5 times more abundant in the leaves exposed to droughtregardless of Si treatment. Taken together, although Si did not mitigate drought stress effects, itseffect was dependent on the barley growth phase prior to supplementation.Book of Abstracts / 4th International Conference on Plant Biology [and] 23rd SPPS Meeting, 6-8 October 2022, Belgrad

The importance and direction of current and future plant-UV research : break-out session discussions at the UV4Plants Network Meeting in Bled (April 15th -18th , 2018)

During the 2nd Network Meeting of UV4Plants at Bled (14th–18th April, 2018) the delegates engaged in a group discussion of prescient questions concerning the future of in plant-UV research. The discussion group was tasked to identify the most valuable directions for plant UV research to take, and to create a coherent framework for how to move the field forward. Here, the outcome of these discussions is summarised in sections that follow the composition of discussion groups as ideas taken from a molecular, biochemical and physiological perspective followed by those from an ecological and plant production perspective. In each case, first basic research questions are considered and then applications and methodological considerations are put forward. Finally, some common ground bringing the two perspectives together is discussed, with the aim of solving scaling problems and ways in which the UV4Plants network might be put to good use.Peer reviewe

<scp>ReSurveyEurope</scp>: A database of resurveyed vegetation plots in Europe

AbstractAimsWe introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.ResultsReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.ConclusionsReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.</jats:sec