Abstract Nutrition is one of the most important factors influencing quantitative and qualitative plant yield. This study examined the effect of manganese (Mn) in nutrient solution on photosynthetic activity parameters, and the relations between photosynthetic activity parameters, yield and plant nutrient status in tomato (Solanum lycoper-sicum L.). Mn supplementation significantly modified the nutrient content of leaves. Macronutrient content var-ied less than micronutrient content. The optimal Mn concentration differed between the studied cultivars. Both Mn deficit and Mn excess caused a decrease of tomato yield. Gas exchange parameters, relative water content (RWC) and specific leaf area (SLA) were measured in fully expanded tomato leaves. Certain levels of Mn were found to be needed for proper plant function and future yield, and toxic effects of excess Mn were noted. Changes in PN (net photosynthetic rate) were found to be the first signal of plant response to higher Mn supply, while yield was as for optimal Mn concentrations. Under Mn treatment, uptake of some nutrients increased. A higher level of absorbed Mg led to a higher photosynthesis rate and increased stomatal opening. PN and gs (stomatal con-ductance) also increased, while Ci (intercellular CO2 concentration) decreased, indicating proper CO2 consumption during the assimilation process.
Tropospheric ozone is one of the most reactive air pollutants, which causes visible injuries, as well as biomass and yield losses. The negative effect of ozone is cumulative during the growing season; hence crops are the most sensitive plants. Visible symptoms and biomass losses can cause economic losses. Tobacco plants have been recognized as one of the best bioindicators, but data on the cumulative effect of ozone on this species are limited. Results of an experiment with ozone-sensitive tobacco plants grown on sites varying in ozone concentration are presented in this paper. Two indices were used for data presentation of visible leaf injury degree. Higher solar radiation was the main cause of higher ozone concentration at the rural site. Higher tropospheric ozone concentrations were noted in 2010 in comparison to 2011, which was reflected in visible leaf injury. Canonical variate analysis did not reveal highly significant differences between sites, however, differences were observed in certain investigation periods. Moreover, higher leaf injury was noted at the rural site at the end of the experiment in both experimental years. This indicates the cumulative effect of ozone during the growing season. However, higher injury variability was noted at the urban site, even though lower ozone concentrations were noted there. Lower variability of injury at the rural site might suggest lack of influence of particulate matter and occurrence of higher injury even though lower ozone concentrations occurred. Better detection of ozone injury was shown by the first index based on three mean values.
The major aim of the study was to identify the relationships of photosynthetic pigments with elemental contents of plants exposed to various ambient air conditions. Lolium multiflorum L. plants were exposed at five sites varying in environmental characteristics, including potential air pollution levels. The effect of air pollution by trace elements on plants was examined. Selected trace elements (Pb, Cd, As, Ni, Cr), some macro-elements as well as chlorophyll content were measured after each of four series. The graphical visualization revealed groups of sites with similar response of elements and chlorophyll contents. Sites located outside the city were grouped into one, and two urban sites were grouped into another. The trace element contents were relatively low and, excluding Ni and As, did not reach toxic levels in dry mass of leaves. However, some relations could be noted, which indicates the sensitivity of the photosynthetic process even at low levels of trace elements in ambient air. Chlorophyll b was found to be more sensitive to most of the analyzed trace elements than chlorophyll a. The results revealed chlorophylls, K and Na as indicators of plant stress caused by trace elements present in ambient air, even at relatively low levels.