Particulate Matter in an Urban–Industrial Environment: Comparing Data of Dispersion Modeling with Tree Leaves Deposition

Particulate matter represents a serious hazard to human health, and air quality models contribute to the understanding of its dispersion. This study describes particulate matter with a ≤10 μm diameter (PM10) dynamics in an urban–industrial area, through the comparison of three datasets: modeled (TAPM—The Air Pollution Model), measured concentration (environmental control stations—ECS), and leaf deposition values. Results showed a good agreement between ECS and TAPM data. A steel plant area was used as a PM10 emissions reference source, in relation to the four sampling areas, and a distance/wind-based factor was introduced (Steel Factor, SF). Through SF, the three datasets were compared. The SF was able to describe the PM10 dispersion values for ECS and leaf deposition (r2 = 0.61–0.94 for ECS; r2 = 0.45–0.70 for leaf); no relationship was found for TAPM results. Differences between measured and modeled data can be due to discrepancies in one district and explained by a lack of PM10 inventory for the steel plant emissions. The study suggests the use of TAPM as a suitable tool for PM10 modeling at the urban scale. Moreover, tree leaves are a low-cost tool to evaluate the urban environmental quality, by providing information on whether and when data from leaf deposition can be used as a proxy for air pollution concentration. Further studies to include the re-suspension of particles as a PM10 source within emission inventories are suggested.

Characterization and Chemical Composition Analysis of Tea Tree (Meleuca alternifolia) Leaf Hydrosols Growing on Lombok Island

Tea tree is an essential oil-producing plant from Australia which is also found growing in several parts of Indonesia, including the island of Lombok. So far, tea tree essential oil producers on the island of Lombok do not utilize by-products in the form of hydrosol (distilled water) produced in the process of making essential oils. In this study, the characterization and analysis of the chemical composition of the hydrosol of tea tree leaves growing on the island of Lombok was carried out. The characteristic aroma of hydrosol is similar to that of tea tree essential oil. The results of the GC-MS analysis also showed that the hydrosol of tea tree leaves also had similarities with the essential oil, composed of major compounds in the form of trans-caryophyllene (28.58%), limonene (13.98%) and terpinen-4-ol (16.27%). Other compounds detected were -pinene (4.14%), -pinene (6.50%), -myrcene (8.09%), -terpineol (10.10%) and -terpinene (5.77%).

Endophytic bacterial communities are associated with leaf mimicry in the vine Boquila trifoliolata

The mechanisms behind the unique capacity of the vine Boquila trifoliolata to mimic the leaves of several tree species remain unknown. A hypothesis in the original leaf mimicry report considered that microbial vectors from trees could carry genes or epigenetic factors that would alter the expression of leaf traits in Boquila. Here we evaluated whether leaf endophytic bacterial communities are associated with the mimicry pattern. Using 16S rRNA gene sequencing, we compared the endophytic bacterial communities in three groups of leaves collected in a temperate rainforest: (1) leaves from the model tree Rhaphithamnus spinosus (RS), (2) Boquila leaves mimicking the tree leaves (BR), and (3) Boquila leaves from the same individual vine but not mimicking the tree leaves (BT). We hypothesized that bacterial communities would be more similar in the BR–RS comparison than in the BT–RS comparison. We found significant differences in the endophytic bacterial communities among the three groups, verifying the hypothesis. Whereas non-mimetic Boquila leaves and tree leaves (BT–RS) showed clearly different bacterial communities, mimetic Boquila leaves and tree leaves (BR–RS) showed an overlap concerning their bacterial communities. The role of bacteria in this unique case of leaf mimicry should be studied further.

First report of Anthracnose on Cinnamomun burmannii Caused by Colletotrichum scovillei in China

Mei Pian tree belongs to a new physiological type of Cinnamomun burmannii discovered in the eastern part of the Guangdong province in China in 1987 (Chen et al. 2011). Although the external morphology of Mei Pian tree is similar to Cinnamomun burmannii, the leaves of Mei Pian tree, known as an important traditional Chinese medicine, are rich in natural D-borneol, which protects the heart, brain, and other organs, regulates the central nervous system, and promotes the absorption of other drugs (Yang et al. 2020; Fu et al. 2020). In April 2020, we found that the yield and quality of Mei Pian tree leaves were seriously threatened by anthracnose. Approximately, 40 - 60% of trees were infected in Pingyuan County, Meizhou City, Guangdong Province (N24°28'31.13", E115°50'50.02"). Small circular black spots were initially observed on infected leaves, and spots continued to grow and developed chlorotic margins and concentric rings with sunken areas. As the disease progressed, multiple spots were observed on almost all leaves. Four symptomatic leaves were collected and used for pathogen isolation. The areas of symptomatic and healthy-appearing leaf tissues at the margin of spots were surface-sterilized with 0.5% NaClO for 2 minutes and 70% alcohol for 30 seconds. The sterilized leaves were washed three times with sterile water, air dried, plated on potato dextrose agar (PDA) medium, and incubated at 28°C for 4 days in the dark. A total of six single-spored isolates were obtained and named from MPS-1 to MPS-6, respectively. Among those isolates, MPS-2, MPS-5, and MPS-6 were identical when cultured on PDA plate. The colonies were white to pale gray with dense aerial mycelia, and the reverse side of the colonies was light reddish brown. Conidia were cylindrical and measured 9.0 to 14.0 μm in length and 3.0 to 4.5 μm in width (n = 35). For molecular identification, the primers ITS1/ITS4, GDF/GDR , CHS-79F/CHS-345R, ACT-512F/ACT-783R and T1/Bt2b were used to amplify the partial regions of rDNA-ITS, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase(CHS1), actin (ACT) and β-tubulin (TUB2), respectively, from the genomic DNA extracted from fresh mycelia of MPS-2 (Damm et al. 2012). The resulting sequences were deposited in GenBank with accession numbers of MW091490, MW125584, MW125585, MW125586 and MW125587, respectively. The phylogenetic tree was generated by the maximum likelihood method of the MEGA 7 software using a concatenated alignment of ITS, GADPH, CHS1, ACT and TUB2 sequences. According to both morphological and sequence analyses, MPS-2 was identified as Colletotrichum scovillei (Damm et al. 2012, 2020). Pathogenicity tests were performed by inoculating healthy Mei Pian tree leaves with 5 mm PDA plugs containing actively growing mycelium of MPS-2 and wound-inoculated by spraying MPS-2 conidial suspension (106 conidia ml-1). Controls were inoculated only with sterile PDA plugs and ddH2O. All inoculated plants were maintained in a moist chamber (RH greater than 90%) at 25 °C, with an 8-h photoperiod under T5 LED lights. All inoculated leaves developed symptoms similar to those on naturally infected leaves after 5 days, but leaves on control plants remained asymptomatic. The fungus on the inoculated plants was identical in morphology to that found on the original sample collected in the field, thus fulfilling Koch’s postulates. In previous studies, Colletotrichum scovillei also caused anthracnose on banana (Musa spp. AAA group), pepper (Capsicum annuum), and mango (Mangifera indica L.) in China (Zhou et al. 2016; Zhao et al. 2016; Qin et al. 2019). To our knowledge, this is the first report of Colletotrichum scovillei causing anthracnose on Cinnamomun burmannii in China and worldwide. The identification of C. scovillei as the causal agent of the observed anthracnose on C. burmannii is critical to the prevention and control of this disease in the future.

Dye extracted from Bael leaves as a photosensitizer in dye sensitized solar cell

This study has explored a new plant source, Bael tree leaves, as an efficient dye extraction towards green energy harvesting through dye-sensitized solar cells (DSSCs). The photosensitizers, photo-absorption, bandgap, and ionic conductivity characteristics of the extracted dye were determined using thin-layer chromatography (TLC), ultraviolet-visible spectroscopy, Tauc plot, and conductivity meter, respectively. Chlorophyll is the main constituent in the extracted dye confirmed by TLC analysis. An optimum concentration (0.2 g/mL) with ionic conductivity of 455 μS/cm of the dye was used as a photoactive layer in DSSC, demonstrating power densities of 1.345 μW/m2 and 8.078 μW/m2 under the illumination of the LED lamp (1555 lx) and tungsten bulb (1926 lx), respectively. Additional parameters, including fill factor (0.26), ideality factor (1.25), characteristic resistance (309 Ω), series resistance (313 Ω), and shunt resistance (662 Ω) of the fabricated DSSCs under tungsten illumination reveal that the novel Bael tree leaves-based dye can harvest green energy efficiently through DSSCs.

SMOS L-VOD shows that post-fire recovery of dense forests is slower than what is depicted with X- and C-VOD and optical indices

Anthropogenic climate change is now considered to be one of the main factors causing an increase in both frequency and severity of wildfires. These fires are prone to release substantial quantities of CO2 in the atmosphere and to destroy natural ecosystems while reducing biodiversity. Depending on the ecosystem and climate regime, fires have distinct triggering factors and impacts. To better analyse and describe fire impact on different biomes, we investigated pre and post fire vegetation anomalies at global scale. The study was performed using several remotely sensed quantities ranging from optical vegetation indices (the enhanced vegetation index (EVI)) to vegetation opacities obtained at several microwave wavelengths (X-band, C-band, and L-band vegetation optical depth (X-VOD, C-VOD, and L-VOD)), ranging from 2 to 20 cm. It was found that C- and X-VOD are mostly sensitive to fire over low vegetation areas (grass and small bushes) or over tree leaves; while L-VOD depicts better the fire impact on tree trunks and branches. As a consequence, L-VOD is probably a better way of assessing fire impact on biomass. The study shows that L-VOD can be used to monitor fire affected areas as well as post-fire recovery, especially over densely vegetated areas.

Influence of temperature and time of exposure to temperature on the yield of the obtaining process of ethanolic and hydroethanolic extracts from Syzygium malaccense (L.) Merr. & L. M. Perry leaves

The present study aimed to obtain alcoholic and hydroalcoholic (70% v/v) extract of Syzygium malaccense (L.) Merr. & L. M. Perry (red jambo fruit tree) leaves and investigated the influence of temperature and time of exposure to temperature on the extraction yield. It was applied a 2x2 factorial design, considering temperature and time of exposure as independent variables with two levels each: 30 or 60 °C for temperature and 60 or 120 minutes for time. For both ethanolic and hydroethanolic extraction, higher process yields were observed at higher temperature and time (24.26% and 19.00%, respectively), however, no significant difference was noticed when increasing the time of exposure to temperature.