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This study has been conducted to investigate the temperature dependence and mass transfer kinetics of a microbial time–temperature integrator (TTI) developed by using emulsification/internal ionotropic gelation method. We report the effect of the Na-alginate concentrations (0.5%, 2.0%, 4.0% and 6.0% w/v) and temperature (8, 15, 20, 25 and 30 °C) on the TTI responses (changes in pH and titratable acidity [TA]). Results revealed that Ca-alginate microbeads (Ca-AMs) prepared from 2.0% Na-alginate were more uniform and smaller, with a narrow size distribution, in comparison with the other Ca-AMs. For microbeads with above 2.0% Na-alginate, the TTI response rates decreased because of the lower diffusion efficiency. Linearity in the TA was greatest for the 2.0% Ca-AMs. Therefore, the mass transfer and TTI response kinetics data demonstrated that 2.0% Na-alginate was optimal for producing Ca-AMs from which an ideal microbial TTI could be developed to monitor food spoilage processes with accuracy and precision.

In New Zealand, over 87% of the population currently resides in cities. Urban trees can face a myriad of complex challenges including loss of green space, public health issues, and harm to the existence of urban dwellers and trees, along with domestic greenhouse gas (GHG) and air pollutant emissions. Despite New Zealand being a biodiversity hotspot in terms of natural environments, there is a lack of knowledge about native tree species’ regulating service (i.e., tree development and eco-physiological responses to low air quality, GHG, rising air temperatures, and drought) and how they grow in built-up environments such as cities. Therefore, we argue for the value of these native species in terms of ecosystem services and insist that they need to be viewed in relation to how they will respond to urban abiotic extremes and climate change. We propose to diversify planted forests for several reasons: (1) to improve awareness of the benefits of diverse planted urban forests; (2) to foster native tree research in urban environments, finding new keystone species; and (3) to improve the evidence of urban ecosystem resilience based on New Zealand native trees’ regulating services. This article aims to re-evaluate our understanding of whether New Zealand’s native trees can deal with environmental stress conditions similarly to more commonly planted alien species.

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

Air pollutants are emitted from various anthropogenic sources into the atmosphere. Especially, ozone (O3) has become a critical problem since the average O3 concentration is increasing every year by about 0.5–2% across the world. O3 in the air affects plant growth because it mainly passes through the stomata of leaves into plants. This experiment was designed to identify the physiological, morphological, and biochemical responses of plants to O3. For the purposes of this study, eggplant (Solanum melongena L.), which is one of the most well-known crops produced in the world, was used. Eggplants were continuously subjected to 110 nmol mol−1 for 25 days using the phytotron. Following O3 treatment, the growth and biomass of the eggplant were reduced, and the photosynthetic rates were lower than those of the controls. In contrast, water use efficiency increased progressively on the leaves of the eggplant. Initial visible injures were observed at 15 days after O3 treatment. Stomatal density was reduced in response to the O3 treatment. With regard to biochemical responses, malondialdehyde content and relative ion leakage were higher than those of the control. Superoxide and hydrogen peroxide accumulation was observed on the leaf surface after 25 days of O3 treatment. These observations indicate that treatment with 110 nmol mol−1 O3 had negative effects on the physiological, morphological, and biochemical activities of eggplant. Further studies investigating the damage caused by exposure to different concentrations of O3 and for different periods of time are required.

Plants are affected by the features of their surrounding environment, such as climate change and air pollution caused by anthropogenic activities. In particular, agricultural production is highly sensitive to environmental characteristics. Since no environmental factor is independent, the interactive effects of these factors on plants are essential for agricultural production. In this context, the interactive effects of ozone (O3) and supraoptimal temperatures remain unclear. Here, we investigated the physiological and stomatal characteristics of leaf mustard (Brassica juncea L.) in the presence of charcoal-filtered (target concentration, 10 ppb) and elevated (target concentration, 120 ppb) O3 concentrations and/or optimal (22/20 °C day/night) and supraoptimal temperatures (27/25 °C). Regarding physiological characteristics, the maximum rate of electron transport and triose phosphate use significantly decreased in the presence of elevated O3 at a supraoptimal temperature (OT conditions) compared with those in the presence of elevated O3 at an optimal temperature (O conditions). Total chlorophyll content was also significantly affected by supraoptimal temperature and elevated O3. The chlorophyll a/b ratio significantly reduced under OT conditions compared to C condition at 7 days after the beginning of exposure (DAE). Regarding stomatal characteristics, there was no significant difference in stomatal pore area between O and OT conditions, but stomatal density under OT conditions was significantly increased compared with that under O conditions. At 14 DAE, the levels of superoxide (O2-), which is a reactive oxygen species, were significantly increased under OT conditions compared with those under O conditions. Furthermore, leaf weight was significantly reduced under OT conditions compared with that under O conditions. Collectively, these results indicate that temperature is a key driver of the O3 response of B. juncea via changes in leaf physiological and stomatal characteristics.

Caragana microphylla is a leguminosae plant and grows mainly in semi-arid areas of northwest China and Mongolia. However, the lack of studies on C. microphylla reference genes limits the accurate understanding of the molecular biology mechanisms in this crop under abiotic stresses. In this study, we selected nine candidate genes from salt-treated C. microphylla transcriptome data and evaluated their stability by using geNorm, NormFinder, BestKeeper, and RefFinder in salt and drought conditions. In addition, the relative expressions of Delta 1-pyrroline-5-carboxylate synthase 2 (P5CS2) and Catalase 2 (CAT2) were examined to confirm the stability of the candidate reference genes. As a results, glyceraldehyde-3-phosphate dehydrogenase C2 (GAPC2) and 26S proteasome regulatory subunit (RPN5) were the most stable in both salt and drought treatments. The relative expression of P5CS2 and CAT2 also showed more stable levels in normalization by GAPC2 and RPN5 than the most unstable gene, Ubiquitin 4 (UBQ4). Therefore, it is believed that these candidate reference genes selected and validated in our study could be used to study the molecular biological study of response to salt and drought stress in C. microphylla. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12298-020-00874-3) contains supplementary material, which is available to authorized users.

We evaluated surface-based analysis for assessing the possible relationship between the microstructural properties and particulate matter (i.e., two size fractions of PM2.5 and PM10) adsorption efficiencies of their leaf surfaces on ten woody species. We focused on the effect of PM adsorption capacity between micro-morphological features on leaf surfaces using a scanning electron microscope and a non-contact surface profiler as an example. The species with higher adsorption of PM10 on leaf surfaces were Korean boxwood (Buxus koreana Nakai ex Chung &amp, al.) and evergreen spindle (Euonymus japonicus Thunb.), followed by yulan magnolia (Magnolia denudata Desr.), Japanese yew (Taxus cuspidata Siebold &amp, Zucc.), Japanese horse chestnut (Aesculus turbinata Blume), retusa fringetree (Chionanthus retusus Lindl. &amp, Paxton), maidenhair tree (Ginkgo biloba L.), and royal azalea (Rhododendron schlippenbachii Maxim.). There was a higher capacity for the adsorption of PM2.5 on the leaf surfaces of B. koreana and T. cuspidata, followed by A. turbinata, C. retusus, E. japonicus, G. biloba, and M. denudata. In wax layer tests, T. cuspidata, A. turbinata, R. schlippenbachii, and C. retusus showed a statistically higher PM2.5 capturing capacity than the other species. Different types of trichomes were distributed on the adaxial and abaxial leaves of A. turbinata, C. retusus, M. denudata, pagoda tree (Styphnolobium japonicum (L.) Schott), B. koreana, and R. schlippenbachii, however, these trichomes were absent on both sides of the leaves of G. biloba, tuliptree (Liriodendron tulipifera L.), E. japonicus, and T. cuspidata. Importantly, leaf surfaces of G. biloba and S. japonicum with dense or thick epicuticular leaf waxes and deeper roughness revealed lower PM adsorption. Based on the overall performance of airborne PM capture efficiency, evergreen species such as B. koreana, T. cuspidata, and E. japonicus showed the best results, whereas S. japonicum and L. tulipifera had the lowest capture. In particular, evergreen shrub species showed higher PM2.5 depositions inside the inner wall of stomata or the periphery of guard cells. Therefore, in leaf microstructural factors, stomatal size may be related to notably high PM2.5 holding capacities on leaf surfaces, but stomatal density, trichome density, and roughness had a limited effect on PM adsorption. Finally, our findings indicate that surface-based microstructures are necessarily not a correlation for corresponding estimates with leaf PM adsorption.

In recent decades, airborne allergens for allergic respiratory diseases have been found to increase significantly by a process of converting coniferous forests into broad-leaved forests in Korea. This study was conducted to evaluate factors, including airborne pollen counts, micromorphology, and flowering phenology, that can affect oak pollen-related allergic symptoms. The catkin of Mongolian oak (Quercus mongolica Fisch. ex Ledeb.) showed the most rapidly blooming catkin on Julian day 104 in flower development. Among six species, the last flowering was observed on Julian day 119 in Korean oak (Quercus dentata Thunb.). The pollen dispersal was persisted for about 32 days from Julian day 104 to Julian day 136. Airborne pollen was observed about 2 weeks after flowering phase H, the senescence phase. Pollen size varied by species, with the largest from Q. mongolica (polar axis length, PL = 31.72 &micro, m, equatorial axis length, EL = 39.05 &micro, m) and the smallest from Jolcham oak (Quercus serrata Murray) (PL = 26.47 &micro, m, EL = 32.32 &micro, m). Regarding pollen wall structure, endexine of Q. dentata was coarsely laminated or fragmented. The endexine thicknesses of Sawtooth oak (Quercus acutissima Carruth.) and Q. serrata were thick and stable, whereas Galcham oak (Quercus aliena Blume), Q. mongolica, and Oriental cork oak (Quercus variabilis Blume) had thinner endexines. The area occupied by pollenkitt of Q. variabilis was significantly larger than that of Q. acutissima. Importantly, Q. variabilis had a distinctly thick 17 kDa protein band, a presumed major allergen. Oak species differ in pollen protein composition, and thus there is a possibility that the allergenic activity of pollen proteins vary depending on oak species. This study highlights the fact that native oak species in Korea differ in flowering pattern of male flowers, pollen morphology, and pollen chemical constituents. These discrepancies in flowering and pollen properties imply variable allergic responses to oak pollen from different species.

Global warming and ozone (O3) pose serious threats to crop yield and ecosystem health. Although neither of these factors will act individually in reality, most studies have focused on the responses of plants to air pollution or climate change. Interactive effects of these remain poorly studied. Therefore, this study was conducted to assess the effects of optimal (22/20 &deg, C day/night) and elevated temperature (27/25 &deg, C) and/or ambient (10 &plusmn, 10 nL L&minus, 1) and elevated O3 concentrations (100 &plusmn, 1) on the growth, physiology, and reactive oxygen species (ROS) accumulation of leaf mustard (Brassica juncea L.). The aim was to examine whether elevated temperature increase the O3 damage due to increasing stomatal conductance, and thus, O3 flux into the leaf. Significant reductions in photosynthetic rates occurred under O (elevated O3 with optimal temperatures) and OT (elevated O3 and temperature) conditions compared to C (controls). Stomatal conductance was significantly higher under T than in the C at 7 DAE. Under OT conditions, O3 flux significantly increased compared to that in O conditions at 7 days after exposure (DAE). Significant reductions in total fresh and dry weight were observed under OT conditions compared to those under O. Furthermore, significant reductions in levels of carotenoids and ascorbic acid were observed under OT conditions compared to O. Lipid peroxidation and accumulation of ROS such as hydroxyl radical, hydrogen peroxide, and superoxide radical were higher under O and OT conditions than in C conditions at 7 and 14 DAE. As a result of O3 stress, the results of the present study indicated that the plant injury index significantly increased under OT compared to O conditions. This result suggested that elevated temperature (+5 &deg, C) may enhance O3 damage to B. juncea by increasing stomatal conductance and O3 flux into leaves.

This study aimed to determine the effects of plant growth-promoting rhizobacteria Bacillus subtilis JS on the growth and physiological changes of Populus euramericana and Populus deltoides × P. nigra. Poplar seedlings were treated with B. subtilis JS and their growth was monitored for up to 120 d. Three different types of treatments [control, B1 (B. subtilis:double-distilled water, 1:100, v/v), and B2 (1:50)] were established. B. subtilis JS enhanced seedling height by 62% and total biomass by 37% after 120 d. Physiologically, the photosynthetic rate increased by 54%, and the total chlorophyll (Chl) content, foliage nitrogen and phosphate content were significantly higher after treatment with B2 than that of the control. These results suggest that the total Chl content is directly related to not only the photosynthetic capacity of the foliage but also to the nitrogen content, indicating that the strain JS may promote the growth of poplar.

Seedlings of Pterocarpus indicus were grown in both well-watered and drought stress conditions in phytotron. Seedlings grown under well-watered and drought stress conditions were exposed to either combined or without ozone of 200 ppb for one month. First, the physiological responses to elevated ozone levels indicated a decreased biomass. The seedlings grown in arid soil and exposed to ozone showed less biomass than those grown in arid soil but not exposed to ozone. Moreover, all the seedlings except the well-watered and unexposed ones showed a significantly lower photosynthetic rate (PN) over time. However, with the accumulation of ozone injuries, the antioxidant enzyme activities increased overall. In the study results, when exposed to ozone, the well-watered seedlings exhibited more antioxidative enzyme activity than did the seedlings grown in arid soil. Generally, P. indicus in arid soil suffered less damage from elevated ozone than did the well-watered plants.

The present study was conducted to examine the response of Pterocarpus indicus to elevated ozone by comparing the effects between well-watered and soil drought treatments. The ozone concentration was 200 ppb and the exposure was conducted for a month with well-watered and soil drought treatments in chamber environmental conditions. Elevated ozone-induced visible injuries to P. indicus varied among the well-watered environmental conditions, with the appearance of light green chlorosis in the SWO seedlings over time. However, in the SDO seedlings, no difference was visible between drought and drought with ozone treatment. Shriveled leaves were evident because of the water deficiency. Moreover, elevated ozone induced leaf stomata injury and a harsh abaxial surface, whereas drought stress induced less injured stomata because of stomata closing. In addition, the palisade tissues exhibited smaller chloroplasts, damaged thylakoid, increased plastoglobuli, decreased starch grain and thinner cell walls on the upper leaf surface. Thus, the SDO seedlings were less influenced by elevated ozone stress than SWO seedlings due to the reduced ozone absorption which caused by stomata closing to prevent water loss.

Oak pollen is a major respiratory allergen in Korea, and the distribution of oak trees is expected to increase by ecological succession and climate change. One of the drivers of climate change is increasing CO2, which is also known to amplify the allergy risk of weed pollen by inducing elevated allergenic protein content. However, the impact of CO2 concentration on tree pollen is not clearly understood due to the experimental difficulties in carrying out extended CO2 treatment. To study the response of pollen production of sawtooth oak trees (Quercus acutissima) to elevated levels of ambient CO2, three open-top chambers at the National Institute of Forest Science in Suwon, Korea were utilized with daytime (8 am–6 pm) CO2 concentrations of ambient (× 1.0, ~ 400 ppm), × 1.4 (~ 560 ppm), and × 1.8 (~ 720 ppm) treatments. Each chamber had three sawtooth oak trees planted in September 2009. One or two trees per chamber matured to bloom in 2016. Five to six catkins were selected per tree and polyethylene bags were attached to collect pollen grains. The total number of catkins per tree was counted and the number and weight of pollen grains per catkin were measured. Oak allergen—Que a 1 (Allergon Co., Uppsala, Sweden)—was extracted and purified to make an ELISA kit by which the antigen levels in the pollen samples were quantified. Total pollen counts per tree of the × 1.4 and × 1.8 treatments showed significant increase of 353 and 1299%, respectively, from the × 1.0 treatment (p

Air pollutants are emitted from various sources into the atmosphere. During winter, greenhouses are heated by the burning of fuel in heating systems, which creates sulfur dioxide (SO2) that can be detrimental to plant growth and human health. However, there is a poor understanding of the comprehensive effects of SO2 on crops in a greenhouse environment. Therefore, this review aimed to summarize the impacts of greenhouse heating system-derived SO2 on the physiological, morphological, and biochemical responses of plants. In general, plant SO2 exposure has a negative effect on these processes. An initial decline in physiological activities appears several days following SO2 exposure. Morphological and biochemical activities are also negatively affected by extensive SO2 exposure. However, since sulfur is an essential nutrient for plant growth, low-level SO2 exposure has a positive impact on plants. Atmospheric SO2 is taken up by the plant via the stomata, after which it is assimilated and used to synthesize sulfur-containing amino acids, such as methionine and cysteine. Sulfur-containing compounds are crucial for plant growth, and various physiological and biochemical processes. It was concluded that SO2 is a significant greenhouse pollutant, especially for crops.

The cork oak (Quercus suber L.) is a prevalent tree species in the Mediterranean climate zones of western Europe and north Africa with a quite narrow geographical range of distribution, as compared with the other Mediterranean evergreen oak species such as Quercus calliprinos (holly oak) and Quercus ilex (holm oak). This species offers the ecological, economic and social importance, including their biodiversity and sustainable forest production in these areas. The increase of mean annual temperature and rainfall extremes during recent decades follows the trends predicted by present climate change models projecting a higher frequency of droughts and intense rain events in the Mediterranean climate areas. Nevertheless, various biotic and abiotic factors, including climate change (increased frequency and rigor of high temperature and drought) and related physiological decline of trees, increases in the outbreaks of disease, and an excessive development of forest resources has been recognized as main factors to induce a cork oak forest decline. In general, sustainable cork oak forest management and proper agroforestry activity that can generate income for local people through local community participation would be the ways to prevent cork oak forest decline in northern Tunisia.

This study was conducted in Elsen tasarkhai, an arid region in Mongolia, to investigate the physiological response of Populus sibirica to different irrigation regimes and to suggest optimal irrigation intervals for successful reforestation in Mongolia. Two-year-old P. sibirica seedlings were planted, and three different irrigation regimes (well-watered (WW), irrigation every 2 days; moderate drought (MD), irrigation every 5 days; severe drought (SD), irrigation every 7 days) were applied. Although the survival rate was unaffected by the applied water deficit intensity, the relative growth rate was significantly reduced in SD in accordance with a decline in carbon assimilation. Although the total chlorophyll content also decreased as the water deficit increased, the chlorophyll b (Chl b) and total carotenoid (Car T) levels increased to dissipate the excess energy. Increased quantum efficiencies in the SD condition were caused by the enlargement of the reaction center (RC) antenne, indicating increased of excess energy dissipation. Therefore, P. sibirica showed resistance to a certain degree of water deficit intensity (MD and SD). The irrigation regime of SD appeared to be adequate for P. sibirica based on survival rate and physiological traits. These results might enlighten the development of effective irrigation systems in arid area.

To counter the threat of drought, which is expected to increase in the future, we analyzed the combined effects of elevated carbon dioxide (CO2) concentration and drought on the photosynthetic apparatus and morphological traits in seedlings of yellow poplar (Liriodendron tulipifera). The plants were grown for four months in a phytotron under different CO2 concentrations [ambient CO2, 430 ppm, AC) and elevated CO2, 640 ppm, EC] and water treatment [field capacity, FC and 50% of field capacity, FC50]. FC50 was sufficient for inducing a reduction in the photosynthetic rate of L. tulipifera. However, under FC50 combined with EC, we observed an increase in photosynthetic rate with increased photopigment content, photochemistry efficiency, and light harvesting ability. Further, decreased specific leaf area and increased wax coverage in EC suggested that EC contributed to protect chloroplasts and reduce water loss. In conclusion, functional improvements of the photosynthetic apparatus with changes in morphological traits were observed under FC50 combined with EC and EC ameliorated the adverse effect of FC50 on the seedlings of L. tulipifera.

We introduced a simple methodology to determine basin-wide marine export production ratios during spring phytoplankton bloom periods by combining monthly varying mixed layer depths (MLD) derived from observed temperature depth profiles, satellite time series of chlorophyll-a (Chl-a) concentrations, and hypothetical critical depth. The MLD-Chl-a based approach yielded monthly export ratios reflecting seasonal variability of net community production in correlation with the MLD variations. Regional averages of export ratio in the spring for the southern part of the East Sea (36–39°N, 130–134°E), North Pacific Ocean (42–45°N, 151–155°E), and North Atlantic Ocean (57–60°N, 17–21°W) are 0.44 ± 0.22, 0.42 ± 0.16, and 0.73 ± 0.29, respectively, which compare favorably with prior field data. This suggests that the approach enables estimation of export production ratios with high spatial and temporal resolutions, complementing the methods that rely on extrapolation of limited field measurements to larger space and time scales.

Environmental pollution is an important issue in metropolitan areas, and roadside trees are directly affected by various sources of pollution to which they exhibit numerous responses. The aim of the present study was to identify morpho-physio-biochemical attributes of maidenhair tree (Ginkgo biloba L.) and American sycamore (Platanus occidentalis L.) growing under two different air quality conditions (roadside with high air pollution, RH and roadside with low air pollution, RL) and to assess the possibility of using their physiological and biochemical parameters as biomonitoring tools in urban areas. The results showed that the photosynthetic rate, photosynthetic nitrogen-use efficiencies, and photochromic contents were generally low in RH in both G. biloba and P. occidentalis. However, water-use efficiency and leaf temperature showed high values in RH trees. Among biochemical parameters, in G. biloba, the lipid peroxide content was higher in RH than in RL trees, but in P. occidentalis, this content was lower in RH than in RL trees. In both species, physiological activities were low in trees planted in areas with high levels of air pollution, whereas their biochemical and morphological variables showed different responses to air pollution. Thus, we concluded that it is possible to determine species-specific physiological variables affected by regional differences of air pollution in urban areas, and these findings may be helpful for monitoring air quality and environmental health using trees.

Carbon sequestration in agroforestry systems plays an important role for climate change regulation. Policy makers make use of growth models for carbon estimations of the large scale projects in designing regulation. This study revealed the aboveground carbon sequestration potentials and established allometric growth models of four species in agroforestry. Based on the results, the aboveground carbon storages of Morinda tinctoria Roxb., Terminalia oliveri Brandis., Rhus paniculata Wall. and Emblica officinalis Gaertn. were 6.88, 6.59, 4.34 and 3.53 kg C tree−1, respectively. In comparison between two types of agroforestry, a mixture of M. tinctoria and E. officinalis had a higher carbon sequestration potential (1331 kg C ha−1) than a mixture of R. paniculata and T. oliveri (1151.40 kg C ha−1). A hyperbolic growth model and a basic quadratic model were the best-fit models for R. paniculata and E. officinalis, respectively, while a basic logarithmic model was the best fit for both M. tinctoria and T. oliveri. This study highlighted that both Akaike Information Criterion, Furnival index and coefficient of determination should be taken into consideration for model selection, as opposed to only considering the coefficient of determination. The study also pointed out that a mixture of M. tinctoria and T. oliveri should be considered as a tentative model for agroforestry plantations to enhance the carbon storage in semi-arid area in the future.

In the present study, photosynthetic traits and chlorophyll (Chl) fluorescence parameters of Populus sibirica grown under different irrigation regimes were investigated to estimate seedling growth and vitality for reforestation of a desertification area. According to our results, photosynthesis and Chl fluorescence were significantly affected by water deficit only under severe drought conditions.

The Republic of Tunisia, located in northern Africa, faces various environmental challenges caused by anthropogenic practices such as overgrazing, deforestation, and desertification. The conversion of natural ecosystems is the major cause of plant biodiversity loss. Tunisia can be divided into three main climatic zones as follows: a northern Mediterranean climate zone, a central steppe climate zone, and a southern desert climate zone. Because of this great environmental diversity, there are distinctive vegetation and various genetic resources in Tunisia. This research was conducted to investigate plant biodiversity within the various bioclimatic zones and to characterize useful plant resources in Tunisia. We investigated native, medicinal and aromatic, desert, and soil erosion control plant species.

It is important to manage sustainable short-rotation coppices (SRCs), having an important role in carbon sink and bioenergy output, because most of SRCs in South Korea were established on reclaimed land. However, during the last three years, the growth pattern of the SRCs was remarkably changed with soil condition. This study aimed to identify the sustainability of SRCs used for carbon storage, biomass and fuel pellet production, monitoring the neighboring vegetation of SRCs by land-use exchange, examine physiological changes of poplar in a seasonal trend, and to evaluate whether poplar is suitable for making wood pellets over time. The calculated biomass yield per area of poplar grown was 103.07 Mg per total area (55.6 ha), and volumes of carbon dioxide absorption were estimated to be 329.72 Mg CO2. Wood pellet quality based on the criteria scored third grade, indicating that poplar is appropriate to be manufactured as fuel pellets. Moreover, monitoring of the flora distribution in SRCs revealed changes in species composition. As halophyte was increased during drought, soil organic matter, net growth and total chlorophyll of poplar were significantly decreased. These findings indicate that physiological changes and growth pattern of SRCs may be negatively affected by microclimate and provide better understanding for the effective management of SRCs amid environmental changes.

Potentials of tree species as biofilters depend on appropriate selection based on their tolerance to air pollution, which is usually evaluated by the air pollution tolerance index (APTI) and anticipated performance index (API). Thus, these index values need as a means of scientific understanding to assess the role of urban trees for better greenspace planning/management to mitigate impacts of gaseous air pollution such as ozone (O3) and sulfur dioxide (SO2). O3 exposure to Chionanthus retusus, Pinus densiflora, and Ginkgo biloba showed higher stomatal O3 flux than the others, finally resulting in both favoring stomatal movement and maintaining carbon fixation. In contrast, despite the whole tree enhanced SO2 uptake under excess SO2 exposure, the carbon assimilation capacity was only found in Taxus cuspidata and Zelkova serrata as a consequence of no stomatal sluggishness. On the basis of API, P. densiflora and Prunus &times, yedoensis were good performers for developing greenspace, while Z. serrata and G. biloba were moderate performers, however, C. retusus and T. cuspidata were estimated to be poor and very poor performers, respectively, for reducing the air quality injury caused by air pollutants. The present study suggests that an integration of both APTI and API based on stomatal absorption flux is needed for selecting sound tree-species in greenspace planning/construction to control gaseous air pollutions.

Plants can undergo external fluctuations in the natural light and dark cycle. The photosynthetic apparatus needs to operate in an appropriate manner to fluctuating environmental factors, especially in light. Yellow-poplar seedlings were exposed to nighttime artificial high-pressure sodium (HPS) lighting to evaluate night light-adaptation strategies for photosynthetic apparatus fitness relative to pigment contents, photosystem II photochemistry, photosynthetic parameters, histochemical analysis of reactive oxygen species, and plant biomass. As a result, seedlings exhibited dynamic changes including the enhancement of accessory pigments, the reduction of photosystem II photochemistry, increased stomatal limitation, downregulation of photosynthesis, and the decreased aboveground and belowground biomass under artificial night lighting. Histochemical analysis with 3,3′-diaminobenzidine (DAB) and nitroblue tetrazolium (NBT) staining indicates the accumulation of in situ superoxide radicals (O2−) and hydrogen peroxide (H2O2) in leaves exposed to the lowest level of artificial night lighting compared to control. Moreover, these leaves exposed to artificial night lighting had a lower nighttime respiration rate. These results indicated that HPS lighting during the night may act as a major factor as repressors of the fitness of photosynthesis and growth patterns, via a modification of the photosynthetic light harvesting apparatus.

Specific bacterial strains that promote plant growth have been investigated extensively and are characterized as plant growth-promoting rhizobacteria (PGPR). To identify the series of genes involved in PGPR-mediated enhanced plant growth, suppression subtractive hybridization was performed using cDNA from tobacco plants exposed to the PGPR strain, Bacillus subtilis strain JS. After hybridization, forward and reverse subtraction cDNA libraries containing 580 clones were obtained. Blastx search detected 170 single genes. These were classified into 14 functional categories, including metabolic processes and cellular processes implicated in growth promotion. Of the 36 responsive genes confirmed by RT-PCR, expression of 24 genes was up-regulated and 12 were down-regulated by treatment with B. subtilis JS volatile compounds. Photosynthesis pathway related genes encoding chlorophyll a/b binding protein, chloroplast sedoheptulose-1,7-bisphosphatase, and the photosynthate transport related gene were up-regulated, perhaps accounting for the volatile compound-mediated enhanced plant growth. Reactive oxygen species scavenging enzyme encoding genes as well as glutathione S-transferase and methionine-R-sulfoxide reductase were down-regulated.

The present study revealed that Ginkgo biloba and Platanus occidentalis, the most abundant roadside trees in Seoul, grown under polluted environmental conditions, displayed lower contents of total chlorophyll (Chl), carotenoids (Car), and ascorbic acid (AsA) compared to the trees grown under clean conditions. The reduction in Chl, Car, and AsA contents was 59, 53, and 50%, respectively, in G. biloba, contrary to 26, 23, and 24%, respectively, in P. occidentalis. Furthermore, relative ion leakage and leaf temperature was higher in the trees grown under polluted conditions than in those grown under clean conditions. The increase in relative ion leakage and leaf temperature was 58 and 3% for G. biloba and 17 and 4% for P. occidentalis, respectively. Our results, therefore, highlighted the negative impact of urban environmental pollution on the physiological and biochemical parameters in roadside trees.

Water and light are the most important environements for plants’ growth. These environemts are critical factors needed not only for the survival of plants but also their production. When plants are exposed to drought condition, they change in their anatomical, physiological and biochemical properties. Drought affects plants wildly from their cell structure to growth. It causes higher plastoglobuli, lower starch grain, distortion of thylakoids, disrupted grana and swelling of chloroplast. Plants grown under enhanced light, have increased palisade parenchyma, thicker leaf, higher biomass, increased photosynthesis, lower contents of chlorophyll, carotenoid and nitrogen. Keywords: Drought, plant, shade, water

Oak pollen is a major respiratory allergen in Korea, and the distribution of oak trees is expected to increase by ecological succession and climate change. One of the drivers of climate change is increasing CO

An understanding of how species diversity, structural pattern, and species distribution vary across different environmental regions is crucially important for tropical ecology. In this study, we explored how these ecological parameters vary across various rainfall regions in the tropics with annual rainfall levels ranging from 843 to 2035 mm. Diversity, similarity, structure, and forest classification, and their correspondence with rainfall regions were tested. We found that species diversity, site class, and structural complexity increased with rainfall, with differences of 1000 mm having significant effects on diversity. The structure and heterogeneity of forests were higher in the high rainfall regions than the low rainfall regions. The forest structure was significantly correlated with rainfall, and the structure differed substantially where annual rainfall differed among sites by approximately 200 or 400 mm. Forests could be classified into two types according to whether they had high annual rainfall (1411–2035 mm) or low annual rainfall (843–1029 mm). In addition, the dominance of species changed noticeably from high- to low-rainfall regions, with Tectona hamiltoniana and Terminalia oliveri only being abundant in the low rainfall region. Species diversity and richness were significantly correlated with rainfall and average temperature. These findings will provide invaluable information for forest management and ecological phytogeography.

Yellow poplar (Liriodendron tulipifera L.) is a widespread hardwood tree of great ecological and economic value. Light pollution caused by excessive and indiscriminate exposure to artificial night light has emerged as a new risk factor due to its adverse effects related to energy waste, sleep disorders, anthropogenic habitat disturbance, and perceptual disorder of daily and seasonal rhythms in wildlife. However, it remains unknown how associations between artificial night light and stomatal behaviors controlled by internal signals are established. After continuous exposure to artificial light at night over 3 years, leaves in the experimental set-up were measured for stomatal movements, starch turnover, endogenous abscisic acid (ABA) levels, and chloroplast ultrastructure during the growing season. Yellow poplar showed dynamic changes in stomatal movement, starch turnover, and endogenous ABA levels in response to day/artificial night light cycle, resulting in reduction of circadian phase-shifting capacity at both dusk and dawn and normal chloroplast development as compared with natural night. Nighttime light exposure may act as a major factor for disorder of circadian and circannual rhythms as well as physiological and ultrastructural repressor in plants, via a modification of the perceived photoperiod. Our study suggests that these dynamic responses can provide advantageous insights that complement the current knowledge on light pollution.

The aim of the present study was to investigate the interactive effects of expected environmental constraints, specifically elevated CO2 and drought conditions, on the physiological responses of Perilla frutescens var. japonica Arum. Perilla frutescens var. japonica ‘Arum’ was exposed to 700 μmol mol−1 of CO2 under both well-watered and water-stressed conditions. Photosynthetic rate was higher under elevated CO2 conditions. Stomatal resistance increased while transpiration rates declined, which suggests that water-use efficiency rose under elevated CO2 conditions. Under water-stressed conditions, elevated CO2 concentrations induced much higher stomatal resistance than ambient CO2 levels. This result implies that elevated CO2 concentrations might increase plant sensitivity to water stress, thereby providing plants with increased protection against drought. Furthermore, elevated CO2 concentrations alleviated drought-induced photosynthetic decline in the early stages of drought, although this effect was not sustainable. Water stress also elevated ascorbate peroxidase (APX) activity but had little effect on glutathione reductase activity. Water stress-induced APX activity was much lower under elevated CO2 conditions compared to ambient CO2 levels. Therefore, elevated CO2 concentrations might increase plant resistance to water stress. Moreover, there is a possibility that increased ethylene evolution under elevated CO2 conditions could improve the capacity of plants to scavenge reactive oxygen species by enhancing APX activity.