Helena Gawrońska

Plant species differences in particulate matter accumulation on leaf surfaces

Particulate matter (PM) accumulation on leaves of 22 trees and 25 shrubs was examined in test fields in Norway and Poland. Leaf PM in different particle size fractions (PM(10), PM(2.5), PM(0.2)) differed among the species, by 10- to 15-folds at both test sites. Pinus mugo and Pinus sylvestris, Taxus media and Taxus baccata, Stephanandra incisa and Betula pendula were efficient species in capturing PM. Less efficient species were Acer platanoides, Prunus avium and Tilia cordata. Differences among species within the same genus were also observed. Important traits for PM accumulation were leaf properties such as hair and wax cover. The ranking presented in terms of capturing PM can be used to select species for air pollution removal in urban areas. Efficient plant species and planting designs that can shield vulnerable areas in urban settings from polluting traffic etc. can be used to decrease human exposure to anthropogenic pollutants.

Deposition of particulate matter of different size fractions on leaf surfaces and in waxes of urban forest species.

Particulate matter (PM) is an air contaminant in urban and industrial areas that often exceeds limit values, creating serious problems due to its harmful effects on health. Planting trees and shrubs as air filters is a way to improve air quality in these areas. However, further knowledge on species effectiveness in air purification is essential. This study compared four species of tree (Acer campestre L., Fraxinus excelsior L., Platanus × hispanica Mill. ex Muenchh. ‘Acerifolia’, Tilia cordata Mill.), three species of shrub (Forsythia × intermedia Zabel, Physocarpus opulifolius (L.) Maxim., Spiraea japonica L.), and one climber species (Hedera helix L.) that are commonly cultivated along streets in Poland to capture fine, coarse and larger particles from air. Separate gravimetric analyses were performed to quantify PM deposited on surfaces and trapped in waxes. Significant differences were found between the plant species tested. The distribution of different particle size fractions differed between and within species and also between leaf surfaces and in waxes.

Particulate matter on foliage of 13 woody species: deposition on surfaces and phytostabilisation in waxes--a 3-year study.

Particulate matter (PM) as an air pollutant can be harmful for human health through allergic, mutagenic and carcinogenic effects. Although the main focus is on decreasing air pollution, after PM has been emitted to the atmosphere, one of the realistic options to decrease its concentrations in urbanized area will be phytoremediation. This study compared the capacity to capture PM from air of seven tree species commonly cultivated in Poland (Catalpa bignonioides Walter, Corylus colurna L., Fraxinus pennsylvanica Marsh., Ginkgo biloba L., Platanus × hispanica Mill. ex Muenchh., Quercus rubra L., Tilia tomentosa Moench ‘Brabant’) and six shrub species (Acer tataricum subsp. ginnala (Maxim.) Wesm., Sambucus nigra L., Sorbaria sorbifolia (L.) A.Br., Spiraea japonica L.f., Syringa meyeri C.K. Schneid. ‘Palibin’, Viburnum lantana L.). Significant differences were found between species in mass of total PM accumulation for two PM categories and three size fractions determined and in amount of waxes. A positive correlation was found between in-wax PM of diameter 2.5–10 μm and amount of waxes, but not between amount of waxes and amount of total PM or of any size fraction.

Investigation of Pb(II) binding to pectin in Arabidopsis thaliana

Phytochelatins and glutathione are known as the most common peptides responsible for binding with toxic metals in plants, but recently the role of other bioligands, such as proteins, organic acids, flavonoids and oligosaccharides, has received renewed attention. Size-exclusion chromatography (SEC) coupled to ICP-MS and electrospray MS were applied for the analysis of lead species synthesised by Arabidopsis thaliana, a model genetic plant. Lead was found to be accumulated mainly in roots (9.6 ± 0.1 μg of Pb per g of the dry mass) and showed good affinity to galacturonic acid, the main component of two pectin domains homogalacturonan and rhamnogalacturonan I. The results demonstrate the potential application of SEC-ICP-MS and SEC-ESI-MS as a complementary and efficient approach to study toxic heavy metals in biological systems.

Effect of sucrose concentration on photosynthetic activity of in vitro cultures Gentiana kurroo (Royle) germlings

In this work, the effect of sucrose on photosynthetic activity during in vitro culture was studied. Experiments were carried out using uniform somatic embryo-derived germlings of Gentiana kurroo (Royle) confirmed by chromosome counting and flow cytometry technique. Photosynthetic activity was measured by chlorophyll a fluorescence and gas exchange method. The efficiency of photosynthetic apparatus as measured by the ratio Fv/Fm, Yield and qP (light phase of photosynthesis) was the highest when the medium was supplemented with 0.3% sucrose which well corresponded with plant gas exchange. Taking all data into consideration for the best development of photosynthetic apparatus and the most efficient of net photosynthesis of studied germlings would be medium supplemented with 0.2–0.4% of sucrose.

The Role of Plant–Microbe Interactions and Their Exploitation for Phytoremediation of Air Pollutants

Since air pollution has been linked to a plethora of human health problems, strategies to improve air quality are indispensable. Despite the complexity in composition of air pollution, phytoremediation was shown to be effective in cleaning air. Plants are known to scavenge significant amounts of air pollutants on their aboveground plant parts. Leaf fall and runoff lead to transfer of (part of) the adsorbed pollutants to the soil and rhizosphere below. After uptake in the roots and leaves, plants can metabolize, sequestrate and/or excrete air pollutants. In addition, plant-associated microorganisms play an important role by degrading, detoxifying or sequestrating the pollutants and by promoting plant growth. In this review, an overview of the available knowledge about the role and potential of plant–microbe interactions to improve indoor and outdoor air quality is provided. Most importantly, common air pollutants (particulate matter, volatile organic compounds and inorganic air pollutants) and their toxicity are described. For each of these pollutant types, a concise overview of the specific contributions of the plant and its microbiome is presented. To conclude, the state of the art and its related future challenges are presented.

Zygotic and somatic embryos of cucumber (Cucumis sativus L.) substantially differ in their levels of abscisic acid

In this work we studied the changes in the level of abscisic acid (ABA) in the somatic embryos (SE) and in the diploid and triploid zygotic embryos (ZE) of the same cucumber line during embryogenesis and seed maturation. Different stages of seed development were selected according to days after pollination (DAP): 21, 24, 28, 35, 42 and 42 plus 14 days of storage for diploid ZE and 35 and 42 plus 14 days of storage for triploid ZE. SE were collected at five growth stages from globular to late cotyledonary. Quantitative analysis of ABA was performed using an enzyme linked immunosorbent assay (ELISA) test. Both types of embryos - somatic and zygotic - essentially differed in their levels of ABA, always being the highest for 2n ZE and lowest for SE. Although the concentration of ABA in ZE of the triploid line was higher when compared with the same DAP, when the comparison was based on embryo development, both the concentration and content of ABA was higher in the diploid line. The pattern of developmental changes in the level of ABA in the diploid ZE was consistent with that known for other species. An increase was observed during embryo development with a peak (51.1 µg g(-1) FW or 0.95 µg per embryo) at the final stage of embryo formation between 21 and 24 DAP. A sharp decrease in the ABA level then took place (more than 3-fold within 4 days) and was followed by a further reduction as the seed matured. The maximal and minimal values for ABA concentration differed about 35-fold. SE differed substantially from their zygotic counterparts not only in that the concentration of ABA was extremely low (0.005-0.011 µg g(-1) FW) but also that no significant changes occurred during embryo development and no peak of ABA concentration was observed. Other tissues of the ovule and ovary also contained ABA and could be a source of ABA for the embryo.

Effect of the carmine spider mite (Acarida: Tetranychidae) infestation and mechanical injury on the level of ABA in tomato plants

The aim of this study was to determine the changes in the abscisic acid (ABA) content in tomato leaves infested by the carmine spider mite (CSM) (Tetranychus cinnabarinus Boidsuval) and in leaves that were mechanically injured. It was also investigated whether signalling from stressed to non-stressed organs occurred.Tomato plants (Lycopersicon esculentum Mill.) cvs. Romatos and Slonka (with various susceptibility to CSM) were stressed at the stage of first cluster flowering by either CSM feeding (72 hours) or by mechanical puncturing simulated feeding injury by CSM (18 hours).It was found that under control condition the level of ABA differed significantly between cultivars, being always higher in plants of the susceptible cv. Romatos.In response to CSM feeding, the content of ABA in infested organs of the more tolerant plant (cv. Slonka) increased by 95 % but in the susceptible one by 11 % only. ABA content in the organs non-stressed by CSM feeding either increased (Slonka cv.) or decreased (Romatos cv.).In response to mechanical wounding, ABA content in directly injured organs increased but to a lower degree (49 %) and only in Slonka cv.. The same was true for ABA content in non-injured organs of damaged plants of this cultivar. Observed changes in ABA level in non-stressed organs are probably the results of signalling from stressed organs. Plant response measured by changes in ABA level to the stress generated by CSM feeding, was much stronger than merely by mechanical injury.

The effect of drought hardening and chilling on ABA content in xylem sap and ABA - delivery rate from root of tomato plant

This paper is a continuation of our studies related to the response of two tomato cultivars: Robin and New Yorker to chilling: the later is more tolerant to chilling than the former one (Starck et al. 1994). The concentration of ABA in the xylem sap and ABA delivery rate (calculated as the amount of ABA exuded in 2h from the cut stump, following shoot removal) were estimated by ELISA. The relative water content (RWC) of the leaf blades and stomatal resistance (RS) were also measured. Tomato plants were grown in a greenhouse, under noncontrolled conditions. Before chilling some of the plants were drought hardened for 10 days (H). As an consequence of water deficit only New Yorker growth slightly decreased. Plants were chilled to 2–5 °C during three consecutive, 16-h nights, preceded by warm days, which caused a decrease in the RWC of leaf blades. Chilling did not decreased leaf blade hydration significantly, but drastically increased the concentration of ABA in the xylem sap in more chilling tolerant cv. New Yorker only. The delivery rate of ABA was markedly enhanced in both cultivars, but much more in New Yorker. Drought hardening increased ABA delivery rate in cv. Robin only, especially after chilling. The lack of correlation between changes in the RWC of leaf blades after low temperature treatment and the concentration of ABA in the xylem sap as well as its delivery rate suggest, that in both tomato cultivars chilling increased ABA level directly, not as an secondery effect of temperature-induced water deficit.

The Level of Particulate Matter on Foliage Depends on the Distance from the Source of Emission

One of the most dangerous inhaled pollutants is particulate matter (PM). PM in inhaled air have a negative impact on human wellbeing and health, and may even cause deaths. Where pollutants have been emitted into the outdoor atmosphere, the only possible method for cleaning the air is through phytoremediation, a form of environmental biotechnology, where plants act as biological filters for pollutants. This study compared PM levels on the leaves of Tilia cordata Mill. trees growing in locations at increasing distances from the source of the PM emission. Significant differences between individual trees growing at a distance of between 3 m and 500 m from the road edge were found in: (i) the mass of PM that accumulated on leaves (total, surface, in-wax and the three determined size fractions) and (ii) the amount of waxes deposited on leaves.