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Due to the different responses to air pollutants, plants could be used as the bio-monitors to estimate the air pollution. The air pollution tolerance index, calculated by ascorbic acid content, relative water content, leaf extract pH and total leaf chlorophyll content, is a very important tool to select the sensitive species as bio-indicator of air pollution. In the present study, the air pollution tolerance indexes of four evergreen tree species collected from different polluted areas in Xi'an city were evaluated to determine the sensitivity degrees of trees to air pollutants and their performance in urban areas. Moreover, the anticipated performance index was calculated by combining the air pollution tolerance index values with some relevant socioeconomic and biological characteristics. The results showed that the highest air pollution tolerance indexes were Cedrus deodara and Sabina chinensis, and it was determined that the species with very good performance was Cedrus deodara. On the other hand, the species with the most sensitive and poor performance were Ligustrum lucidum and Euonymus japonicas. All the results exhibited that Ligustrum lucidum and Euonymus japonicas could be effectively used as bio-indicators of air pollution, and Cedrus deodara was the appropriate tree species for green belt development in Xi'an, China. [ABSTRACT FROM AUTHOR]

In order to screen out evergreen tree species with outstanding winter ecological benefits in northern cities, to alleviate atmospheric CO and dust particulate pollution, and to provide scientific support for the garden application of these tree species, this article selects 12 evergreen tree species that are widely used in landscaping in Zhengzhou City, Using the LI-6400 portable photosynthesis analyzer and the elution-quality difference method, and its photosynthetic characteristics and dust retention ability were measured, and its photosynthetic parameters (the net photosynthetic rate of the leaves (P.) and transpiration rate (T) were calculated. ), stomatal conductance (G) intercellular CO concentration (C)) and dust retention parameters (dust retention per unit leaf area, single leaf dust retention, unit crown dust retention per unit area), and cluster analysis was performed respectively, and the results The results showed that: (1) The PTG values ​​of leaves of Ligustrum lucidum, Boxwood, Pittosporum vulgare, and Loquat were significantly higher than those of other tree species (P<0.01); C value of leaves of Cinnamomum camphora, Silverwood, Boxwood, and Loquat were significantly higher than others. Tree species (P<0.01), Ligustrum lucidum, Pittospora and Photinia mesophyll cells maintain high photosynthetic activity, while Cinnamomum camphora and Silverwood leaves have weaker photosynthetic activity, and low temperature inhibition is obvious (2) 7d and 14 after washing 3. The dust retention parameters of loquat, magnolia and osmanthus are significantly higher than other tree species (P<0.01). 14 days after washing, the dust retention per unit area of ​​loquat, magnolia and osmanthus is 6.65 gm-2, crown-1 and above, strong dust retention ability; heather, silverwood, privet, French holly, boxwood, the dust retention per unit area of ​​the crown is above 3.99g, m-2, and crown-1. (3) Clustering The analysis results show that the photosynthetic characteristics of boxwood, Ligustrum lucidum and Pittosporum vulgare have obvious advantages, followed by French holly, Guangyulan, loquat, heather, and Ledong pseudo-partosexual magnolia; Guangyulan, osmanthus, and loquat have the strongest dust-retaining ability, followed by They are Ligustrum lucidum, French holly, heather and silver wood. In summary, Ligustrum lucidum, Magnolia grandiflora, loquat, French holly, boxwood, and heather have important contributions to improving the winter air quality and dust retention in northern cities. With strong ecological regulation ability, it can be used as a priority for landscaping tree species. [ABSTRACT FROM AUTHOR]

Urban air pollution has received increasing attention in recent years. To investigate the interaction between several heavy metal elements and the degree of atmospheric pollution, the leaves of three evergreen tree species—Chinese juniper (Juniperus chinensis L.), dragon juniper (Juniperus chinensis L. 'Kaizuca'), and cedar (Cedrus deodara (Roxb. ex D.Don) G.Don)—were collected from main road intersections in the urban area of Tianjin, China. Two different treatments—water washing (WW) and ethanol washing (EW)—were used, and the contents of Cu, Mn, Cd, and Zn were measured in both washed and unwashed (UW) leaves. It was found that the heavy metal contents within Chinese juniper and dragon juniper were ranked as Mn > Zn > Cu > Cd, and the metal accumulation index (MAI) value was higher for dragon juniper. For the three plants, water washed off 5.36% to 58.58% of the total heavy metals in the needles, while ethanol washed off 16.08% to 71.60% of the total. Both washes were more effective for Cu, Zn, and Cd, and especially for the element Cd. Ethanol could clean off 38.64% to 71.60% of the total Cd from the leaves. Ethanol had a better elution effect compared to water, and the trend of the Cd content in the leaves of the three plants showed a change after the use of different washing methods, which suggests that the water washing may have masked the real difference. [ABSTRACT FROM AUTHOR]

Ｇｒｅｅｎｉｎｇ ｔｒｅｅ ｃｏｍｍｕｎｉｔｉｅｓ ｉｎ ｆｉｆｔｅｅｎ ｃｏｍｐｒｅｈｅｎｓｉｖｅ ｐａｒｋｓ ｉｎ Ｃｈｏｎｇｑｉｎｇ ｗｅｒｅ ｉｎｖｅｓｔｉｇａｔｅｄ ｔｏ ａｎａｌｙｚｅ ｔｈｅ ｉｍ￣ ｐａｃｔ ｏｆ ｐａｒｋ ａｇｅ ｏｎ ｔｈｅ ｄｉｖｅｒｓｉｔｙ ａｎｄ ｃｏｍｐｏｓｉｔｉｏｎꎬ ａｎｄ ｈｏｍｏｇｅｎｅｉｔｙ ａｍｏｎｇ ｐａｒｋｓ. Ｐａｒｋ ａｇｅ ｗａｓ ｄｉｖｉｄｅｄ ｉｎｔｏ ｔｈｒｅｅ ｓｔａｇｅｓ ｉｎｃｌｕｄｉｎｇ ｂｅｆｏｒｅ ｌｉｂｅｒａｔｉｏｎ (ｂｅｆｏｒｅ １９４９)ꎬ ｂｅｆｏｒｅ ｔｈｅ ｍｕｎｉｃｉｐａｌｉｔｙ ｐｅｒｉｏｄ (１９５０－１９９８) ａｎｄ ａｆｔｅｒ ｔｈｅ ｍｕｎｉｃｉｐａｌｉｔｙ ｐｅｒｉｏｄ (ａｆｔｅｒ １９９９). Ｔｈｅ ｒｅｓｕｌｔｓ ｗｅｒｅ ａｓ ｆｏｌｌｏｗｓ: (１) Ｔｈｅｒｅ ｗｅｒｅ ５９ ｔｒｅｅ ｓｐｅｃｉｅｓꎬ ｂｅｌｏｎｇｉｎｇ ｔｏ ２８ ｆａｍｉｌｉｅｓ ａｎｄ ４８ ｇｅｎｅ￣ ｒａꎬ ａｍｏｎｇ ｗｈｉｃｈ ｎａｔｉｖｅ ｔｒｅｅ ｓｐｅｃｉｅｓ ａｃｃｏｕｎｔｅｄ ｆｏｒ ８１.３６％ꎬ ｅｘｏｔｉｃ ｔｒｅｅ ｓｐｅｃｉｅｓ ａｃｃｏｕｎｔｅｄ ｆｏｒ １８.６４％. (２) Ｔｈｅｒｅ ｗａｓ ｎｏ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅｓ ｉｎ ｔｈｅ ｒｉｃｈｎｅｓｓ ｏｆ ｐａｒｋ ｔｒｅｅｓ ａｍｏｎｇ ｔｈｅ ｔｈｒｅｅ ｓｔａｇｅｓꎬ ｂｕｔ ｔｈｅ ｔｒｅｅ ａｂｕｎｄａｎｃｅｓ ｉｎ ｔｈｅ ｐａｒｋ ａｆｔｅｒ ｌｉｂｅｒａｔｉｏｎ ａｎｄ ａｆｔｅｒ ｔｈｅ ｍｕｎｉｃｉｐａｌｉｔｙ ｐｅｒｉｏｄ ｗｅｒｅ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｔｈａｎ ｔｈａｔ ｂｅｆｏｒｅ ｌｉｂｅｒａｔｉｏｎꎻ Ｔｈｅ ｐｒｏｐｏｒｔｉｏｎ ｏｆ ａｌｉｅｎ ｔｒｅｅ ｓｐｅｃｉｅｓ ｉｎ ｃｏｍｍｕｎｉｔｙ ｗａｓ ｎｏ ｓｉｇｎｉｆｉｃａｎｔ ｄｉｆｆｅｒｅｎｃｅｓ ａｍｏｎｇ ｔｈｅ ｔｈｒｅｅ ｓｔａｇｅｓꎻ Ｔｈｅ ａｐｐｌｉｃａｔｉｏｎ ｏｆ Ｆｉｃｕｓ ｖｉｒｅｎｓꎬ Ｆ. ｃｏｎ￣ ｃｉｎｎａꎬ ａｎｄ Ｋｏｅｌｒｅｕｔｅｒｉａ ｂｉｐｉｎｎａｔａ ｉｎ ｔｈｅ ｐａｒｋ ｗａｓ ｄｅｃｒｅａｓｉｎｇꎬ ｗｈｉｌｅ ｔｈｅ ａｐｐｌｉｃａｔｉｏｎ ｏｆ Ｃｅｒａｓｕｓ ｓｅｒｒｕｌａｔａꎬ Ｍａｇｎｏｌｉａ ｇｒａｎ￣ ｄｉｆｌｏｒａꎬ Ｏｓｍａｎｔｈｕｓ ｆｒａｇｒａｎｓꎬ ａｎｄ Ｍｉｃｈｅｌｉａ ｃｈａｍｐａｃａ ｗａｓ ｉｎｃｒｅａｓｉｎｇ.(３) Ｔｈｅ ｄｅｇｒｅｅ ｏｆ ｈｏｍｏｇｅｎｅｉｔｙ ｂｅｔｗｅｅｎ ｐａｒｋｓ ｏｆ ｄｉｆｆｅｒｅｎｔ ａｇｅｓ ｗａｓ ｌｏｗꎬ ｂｕｔ ｔｈｅ Ｊａｃｃａｒｄ ｓｉｍｉｌａｒｉｔｙ ｉｎｄｅｘ ｂｅｔｗｅｅｎ ｐｌａｎｔ ｃｏｍｍｕｎｉｔｉｅｓ ｉｎ ｔｈｅ ｐａｒｋｓ ｂｅｆｏｒｅ ｌｉｂｅｒａｔｉｏｎ ｗａｓ ｓｉｇ￣ ｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｔｈａｎ ｔｈａｔ ｉｎ ｔｈｅ ｏｔｈｅｒ ｔｗｏ ｓｔａｇｅｓ. Ｔｈｅｒｅ ｗａｓ ｎｏ ｓｉｇｎｉｆｉｃａｎｔ ｒｅｌａｔｉｏｎｓｈｉｐｓ ｂｅｔｗｅｅｎ ｔｈｅ Ｊａｃｃａｒｄ ｓｉｍｉｌａｒｉｔｙ ｉｎｄｅｘ ａｎｄ ｔｈｅ ａｇｅ ｏｆ ｐａｒｋ. Ｔｈｅ ｈｉｓｔｏｒｉｃａｌ ｆａｃｔｏｒｓꎬ ｇａｒｄｅｎ ｃｕｌｔｕｒｅ ａｎｄ ｍｏｄｅｒｎ ｕｒｂａｎ ｇｒｅｅｎｉｎｇ ｒｅｇｕｌａｔｉｏｎｓ ｍａｙ ｂｅ ｔｈｅ ｌｉｍｉｔ￣ ｉｎｇ ｆａｃｔｏｒｓ ｆｏｒ ｔｈｅ ｕｓｅ ｏｆ ａｌｉｅｎ ｓｐｅｃｉｅｓ ａｎｄ ｍａｙ ｌｅａｄ ｔｏ ａ ｌｏｗ ｄｅｇｒｅｅ ｏｆ ｈｏｍｏｇｅｎｅｉｔｙ ｏｆ ｓｍａｌｌ￣ｓｃａｌｅ ｐｌａｎｔ ｃｏｍｍｕｎｉｔｉｅｓ. [ABSTRACT FROM AUTHOR]

Urban air pollution has received increasing attention in recent years. To investigate the interaction between several heavy metal elements and the degree of atmospheric pollution, the leaves of three evergreen tree species—Chinese juniper (Juniperus chinensis L.), dragon juniper (Juniperus chinensis L. ‘Kaizuca’), and cedar (Cedrus deodara (Roxb. ex D.Don) G.Don)—were collected from main road intersections in the urban area of Tianjin, China. Two different treatments—water washing (WW) and ethanol washing (EW)—were used, and the contents of Cu, Mn, Cd, and Zn were measured in both washed and unwashed (UW) leaves. It was found that the heavy metal contents within Chinese juniper and dragon juniper were ranked as Mn > Zn > Cu > Cd, and the metal accumulation index (MAI) value was higher for dragon juniper. For the three plants, water washed off 5.36% to 58.58% of the total heavy metals in the needles, while ethanol washed off 16.08% to 71.60% of the total. Both washes were more effective for Cu, Zn, and Cd, and especially for the element Cd. Ethanol could clean off 38.64% to 71.60% of the total Cd from the leaves. Ethanol had a better elution effect compared to water, and the trend of the Cd content in the leaves of the three plants showed a change after the use of different washing methods, which suggests that the water washing may have masked the real difference.

Numerous studies have documented the negative effects of ozone (O 3 ) on tree species in growing season, however, little is done in non-growing season. Three evergreen tree species, Phoebe bournei (Hemsl.) Yang ( P. bournei ), Machilus pauhoi Kanehira ( M. pauhoi ) and Taxus chinensis (Pilger) Rehd ( T. chinensis ), were exposed to non-filtered air, 100 nmol mol −1 O 3 air (E1) and 150 nmol mol −1 O 3 air (E2) in open-top chambers in subtropical China. In the entire period of experiment, O 3 fumigation decreased net photosynthesis rate (Pn) through stomatal limitation during the transition period from growing to non-growing season (TGN), and through non-stomatal limitation during the period of non-growing season (NGS) in all species tested. Meanwhile, O 3 fumigation reduced and delayed the resilience of Pn in all species tested during the transition period from non-growing to growing season (TNG). O 3 fumigation significantly decreased chlorophyll contents during NGS, whereas no obvious injury symptoms were observed till the end of experiment. O 3 fumigation induced increases in levels of malondialdehyde, superoxide dismutase, total phenolics and reduced ascorbic acid, and changes in four plant endogenous hormones as well in all species tested during NGS. During NGS, E1 and E2 reduced Pn by an average of 80.11% in P. bournei , 94.56% in M. pauhoi and 12.57% in T. chinensis , indicating that the O 3 sensitivity was in an order of M. pauhoi > P. bournei > T. chinensis . Overall, O 3 fumigation inhibited carbon fixation in all species tested during NGS. Furthermore, O 3 -induced physiological activities also consumed the dry matter. All these suggested that elevated O 3 , which is likely to come true during NGS in the future, will adversely affect the accumulation of dry matter and the resilience of Pn during TNG in evergreen tree species, and further inhibit their growth and development in the upcoming growing season. [ABSTRACT FROM AUTHOR]

Questions Mosaics of evergreen and deciduous trees that are characteristic of evergreen broad-leaved forests ( EBLF) are thought to arise from habitat heterogeneity, but empirical evidence for this is limited. We test this assertion asking: (1) whether environmental heterogeneity explains the distribution of deciduous and evergreen trees; (2) which are the most important environmental variables; and (3) does their importance change with scale? Location Tiantong National Forest Park, Ningbo, Zhejiang, China. Methods We used data from a 20-ha individual-mapped EBLF in spatial point-pattern analyses testing the scale of aggregation within, and segregation between, the two life forms. We used a heterogeneous Poisson process model to remove the effects of environmental heterogeneity, predicting segregation would disappear if the mosaic was due to habitat heterogeneity alone. Finally, we tested the relative importance of theoretically important environmental variables using multivariate regression trees at three spatial scales (10, 20 and 50 m grid cells). Results We found evergreen and deciduous trees were aggregated at scales below 125 m and 60 m, respectively, and mutually exclusive at scales <120 m. Evidence of any spatial segregation between the life forms was removed at all scales after controlling for environmental heterogeneity. Only soil phosphorus concentrations contributed to spatial patterns at all scales, with values >0.27-0.30 g·kg−1 favouring deciduous species. Conclusions Our study is consistent with habitat heterogeneity creating the observed mosaics of evergreen and deciduous tree species, but micro-habitat heterogeneity contributed even at scales <20 m. Soil phosphorus availability appears to be the major environmental variable maintaining these mosaic patterns at hillslope scales in EBLF. [ABSTRACT FROM AUTHOR]

It is unclear how or even if phosphorus (P) input alters the influence of nitrogen (N) deposition in a forest. In theory, nutrients in leaves and twigs differing in age may show different responses to elevated nutrient input. To test this possibility, we selected Chinese fir (Cunninghamia lanceolata) for a series of N and P addition experiments using treatments of +N1 - P (50 kg N ha-1 year-1), +N2 - P (100 kg N ha-1 year-1), -N + P (50 kg P ha-1 year-1), +N1 + P, +N2 + P and -N - P (without N and P addition). Soil samples were analyzed for mineral N and available P concentrations. Leaves and twigs in summer and their litters in winter were classified as and sorted into young and old components to measure N and P concentrations. Soil mineral N and available P increased with N and P additions, respectively. Nitrogen addition increased leaf and twig N concentrations in the second year, but not in the first year; P addition increased leaf and twig P concentrations in both years and enhanced young but not old leaf and twig N accumulations. Nitrogen and P resorption proficiencies in litters increased in response to N and P additions, but N and P resorption efficiencies were not significantly altered. Nitrogen resorption efficiency was generally higher in leaves than in twigs and in young vs old leaves and twigs. Phosphorus resorption efficiency showed a minimal variation from 26.6 to 47.0%. Therefore, P input intensified leaf and twig N enrichment with N addition, leaf and twig nutrients were both gradually resorbed with aging, and organ and age effects depended on the extent of nutrient limitation. [ABSTRACT FROM AUTHOR]

We compared seedling growth, leaf morphology and biomass allocation of ive widely distributed, evergreen species (Elaeocarpus sylvestris, Illicium henryi, Quercus phillyraeoides, Gardenia jasminoides and Ardisia crenata) under varying controlled light conditions using artiicial shade houses. Regardless of species, higher height growth rate was observed at intermediate light levels (33-52% sunlight). Diameter growth rate, however, increased with increasing light level. Morphological variables (mean leaf area, total leaf area per plant, speciic leaf area and leaf area ratio) were signiicantly affected by light, with greater variation occurring in deep shade treatment (6% sunlight). Total biomass increased with light levels for E. sylvestris, Q. phillyraeoides and G. jasminoides but larger biomass was found at intermediate light levels for I. henryi and A. crenata. Biomass allocation patterns displayed small variations in the ive species. Although the ive species differ in their growth strategy across a light gradient, their large plasticity allows them to grow well under a wide range of light environments. As a whole, E. sylvestris, Q. phillyraeoides and G. jasminoides showed their best growth above 52% sunlight. Optimal light condition for I. henryi and A. crenata were from 33 to 52% sunlight. Our indings support the underplanting of these ive evergreen species in order to enrich the biodiversity of subtropical plantation ecosystems. [ABSTRACT FROM AUTHOR]

Abstract: We sought the biological factors determining variations in the methane emission rates from leaves of different plant species under aerobic conditions. Accordingly, we studied relations between the methane emission rate and leaf traits of two Acacia and five Eucalyptus species. We grew seedlings of each species in a glasshouse and measured the methane emission rate of the detached leaves under dark conditions at 30 °C. At the same time we measured the leaf mass per area (LMA), water content, and concentrations of carbon and nitrogen. There was no correlation between the leaf nitrogen concentration and the methane emission rate. This is consistent with previous findings that enzymatic processes do not influence methane emission. We found a significant negative correlation between LMA and the methane emission rate. Our results suggest that leaf structure is primarily responsible for differences in the rates of aerobic methane emission from leaves of different species. [Copyright &y& Elsevier]

Numerous studies have documented the negative effects of ozone (O 3 ) on tree species in growing season, however, little is done in non-growing season. Three evergreen tree species, Phoebe bournei (Hemsl.) Yang (P. bournei), Machilus pauhoi Kanehira (M. pauhoi) and Taxus chinensis (Pilger) Rehd (T. chinensis), were exposed to non-filtered air, 100 nmol mol -1 O 3 air (E1) and 150 nmol mol -1 O 3 air (E2) in open-top chambers in subtropical China. In the entire period of experiment, O 3 fumigation decreased net photosynthesis rate (Pn) through stomatal limitation during the transition period from growing to non-growing season (TGN), and through non-stomatal limitation during the period of non-growing season (NGS) in all species tested. Meanwhile, O 3 fumigation reduced and delayed the resilience of Pn in all species tested during the transition period from non-growing to growing season (TNG). O 3 fumigation significantly decreased chlorophyll contents during NGS, whereas no obvious injury symptoms were observed till the end of experiment. O 3 fumigation induced increases in levels of malondialdehyde, superoxide dismutase, total phenolics and reduced ascorbic acid, and changes in four plant endogenous hormones as well in all species tested during NGS. During NGS, E1 and E2 reduced Pn by an average of 80.11% in P. bournei, 94.56% in M. pauhoi and 12.57% in T. chinensis, indicating that the O 3 sensitivity was in an order of M. pauhoi > P. bournei > T. chinensis. Overall, O 3 fumigation inhibited carbon fixation in all species tested during NGS. Furthermore, O 3 -induced physiological activities also consumed the dry matter. All these suggested that elevated O 3 , which is likely to come true during NGS in the future, will adversely affect the accumulation of dry matter and the resilience of Pn during TNG in evergreen tree species, and further inhibit their growth and development in the upcoming growing season., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The ecophysiological mechanisms underlying the pattern of bimodal elevational distribution of evergreen tree species remain incompletely understood. Here we used leaf economics spectrum (LES) theory to explain such patterns. We measured leaf economic traits and constructed an LES for the co-existing 19 evergreen and 15 deciduous species growing in evergreen broad-leaved forest at low elevation, beech-mixed forest at middle elevation and hemlock-mixed forest at high elevation in Mao'er Mountain, Guangxi, Southern China (25°50'N, 110°49'E). Leaf economic traits presented low but significant phylogenetic signal, suggesting trait similarity between closely related species. After considering the effects of phylogenetic history, deciduous species in general showed a more acquisitive leaf strategy with a higher ratio of leaf water to dry mass, higher leaf nitrogen and phosphorous contents, higher photosynthetic and respiratory rates and greater photosynthetic nitrogen-use efficiency. In contrast, evergreen species exhibited a more conservative leaf strategy with higher leaf mass per area, greater construction costs and longer leaf life span. With the elevation-induced decreases of temperature and soil fertility, both evergreen and deciduous species showed greater resource conservation, suggesting the increasing importance of environmental filtering to community assembly with increasing elevation. We found close inter-specific correlations between leaf economic traits, suggesting that there are strong genetic constraints limiting the independent evolution of LES traits. Phylogenetic signal increased with decreasing evolutionary rate across leaf economic traits, suggesting that genetic constraints are important for the process of trait evolution. We found a significantly positive relationship between primary axis species score (PASS) distance and phylogenetic distance across species pairs and an increasing average PASS distance between evergreen and deciduous species with increasing elevation, implying that the frequency of distantly related evergreen and deciduous pairs with wide spreading of leaf economic values increases with increasing elevation. Our findings thus suggest that elevation acts as an environmental filter to both select the locally adapted evergreen and deciduous species with sufficient phylogenetic variation and regulate their distribution along the elevational gradient based on their coordinated spreading of phylogenetic divergence and leaf economic variation., (Published by Oxford University Press on behalf of the Annals of Botany Company.)