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The aim of this work was to study the changes in the BVOCs emission rates and physiological mechanistic response of Pinus massoniana saplings in response to drought stress. Drought stress significantly reduced the emission rates of total BVOCs, monoterpenes, and sesquiterpenes, but had no significant effect on the emission rate of isoprene, which slightly increased under drought stress. A significant negative relationship was observed between the emission rates of total BVOCs, monoterpenes, and sesquiterpenes and the content of chlorophylls, starch, and NSCs, and a positive relationship was observed between the isoprene emission rate and the content of chlorophylls, starch, and NSCs, indicating different control mechanism over the emission of the different components of BVOCs. Under drought stress, the emission trade-off between isoprene and other BVOCs components may be driven by the content of chlorophylls, starch, and NSCs. Considering the inconsistent responses of the different components of BVOCs to drought stress for different plant species, close attention should be paid to the effect of drought stress and global change on plant BVOCs emissions in the future.

Diclofenac potassium was synthesized from aniline and chloroacetyl chloride. The reaction of diclofenac potassium with calcium sulphate dihydrate and ammonium sulphate yielded diclofenac calcium and diclofenac ammonium, respectively. After diclofenac potassium was acidized with hydrochloride, the esterification of attained diclofenac with absolute methanol and absolute ethanol yielded compounds diclofenac methyl ester and diclofenac ethyl ester, respectively. Among the five compounds, diclofenac calcium and diclofenac ammonium are new compounds, and their synthetic methods have not been reported in the world. Every synthesized compound and intermediate were measured their 1H-NMR, 13C-NMR spectra. Analgesic activity of the target compounds was screened using acetic acid writhing test of mice and anti-inflammatory activity of the compounds was tested by xylene-induced ear swelling of mice. The results showed that all the 5 compounds had strong analgesic activity and anti-inflammatory activity. Among them, diclofenac methyl ester is the strongest, its analgesic and anti-inflammatory effects were stronger than the clinical use of diclofenac potassium.

Forest bathing is receiving increased attention due to its health benefits for humans. However, knowledge is scarce about the adjunctive therapeutic effects of forest bathing in different seasons on geriatric hypertension. The aim of the current study was to evaluate the antihypertensive effects of forest bathing in a Cinnamomum camphora (C. camphora) forest environment in four seasons. One group of participants with geriatric hypertension was sent to a C. camphora forest to experience a 3 day trip, while, as a control, another group was sent to the urban center. The participants’ blood pressure, blood routine, and blood biochemistry were assessed. The profile of the mood states (POMS) of the participants was assessed before and after the experiment. The air quality, atmospheric environment, and content of volatile organic compounds (VOCs) at the two experimental sites were monitored during the experiment. This experiment was repeated across four seasons. The advantages of the urban forest groups over the control groups were mainly represented by reductions in diastolic blood pressure (DBP), systolic blood pressure (SBP), and heart rate (HR), as well as increased oxygen saturation (SpO2). The antihypertensive effects of forest bathing in the C. camphora forest environment changed with the seasons. Compared with the baseline level, SBP and DBP declined after forest bathing across the whole year, except during winter, whereas SpO2 increased. The effect of forest bathing on lowering blood pressure was particularly pronounced during summer and autumn. The antihypertensive effects of forest bathing in the four seasons were highly consistent with the seasonal dynamics of VOCs and negative air ions (NAIs), which implies that the effect of forest bathing may be attributed to alterations of the atmospheric environment. The antihypertensive effects of C. camphora forest were confirmed in our study, and the results can provide a reference for scheduling bathing trips.

Plant fine-root decomposition is an important pathway for the reentry of nutrients into the soil. Studies have mainly focused on the loss of fine-root mass and the release characteristics of major elements, including, C, N, and P, but there are few reports on trace elements. In this study

We estimated canopy structure and transmitted radiation using hemispherical photography in four monitoring years (2008-2010, 2016) following the 2008 huge ice storm in a subtropical forest in south China, so as to assess changes in canopy biophysical parameters during forest recovery from natural disturbance. Significant decrease in canopy openness (CO), transmitted direct radiation (TransDir), and transmitted diffuse radiation (TransDif), as well as significant increase in leaf area index (LAI), were found in the disturbed forest stand in the subsequent years following the ice storm, indicating rapid canopy recovery. In contrast, these biophysical parameters of the undisturbed forest stand were quite stable during the monitoring years. The strength of relationships between CO and other canopy biophysical parameters decreased in the disturbed stand along the monitoring years. The disturbed stand had common slopes for the CO-TransDir and CO-TransDif models in the first two monitoring years, but different slopes for the CO-LAI model between the first and the subsequent monitoring years, while the undisturbed stand had common slopes for all the regression models in the first three monitoring years following the huge ice storm. These results showed that stronger correlations of LAI or TransDir with CO were characteristic of less complex canopies, such as those damaged by disturbance; the sensitivity of transmitted radiation in response to CO decreased with canopy recovery. Our findings demonstrated that forests with different canopy structure varied in biophysical parameters, which can be quantified by hemispherical photography.

In order to reveal how transmitted solar radiation affects understory plant diversity patterns, we carried out plant census in a subtropical forest in south China. We determined canopy structure and understory gap light regimes using hemispherical photography. The results showed that a total of 206 species and 14489 individuals occur in the understory vegetation of the 2-ha sampling plots. Canopy openness was found to be a good predictor for transmitted direct radiation, diffuse radiation, and total radiation. Indicator species analysis detected a number of indicators to varying canopy openness. Six of these indicator species with significant indicator values are tree seedlings, shrubs, or vine, which are shade-intolerant, or frequently occur in habitats with the greatest canopy openness. Our results demonstrated that understory plant species composition and diversity are affected by transmitted gap light and different species may have varying response to the radiation gradient, which will have implications for using plants from the natural environment in landscaping.