Soil stoichiometric imbalances constrain microbial-driven C and N dynamics in grassland.

Grassland restoration leads to excessive soils with carbon (C) and nitrogen (N) contents that are inadequate to fulfill the requirements of microorganisms. The differences in the stoichiometric ratios of these elements could limit the activity of microorganisms, which ultimately affects the microbial C, N use efficiencies (CUE, NUE) and the dynamics of soil C and N. The present study was aimed at quantifying the soil microbial nutrient limitation and exploring the mechanisms underlying microbial-induced C and N dynamics in chrono-sequence of restored grasslands. It was revealed that grassland restoration increased microbial C, N content, microbial C, N uptake, and microbial CUE and NUE, while the threshold elemental ratio (the C:N ratio) decreased, which is mainly due to the synergistic effect of the microbial biomass and enzymatic stoichiometry imbalance after grassland restoration. Finally, we present a framework for the nutrient limitation strategies that stoichiometric imbalances constrain microbial-driven C and N dynamics. These results are the direct evidence of causal relations between stoichiometric ratios, microbial responses, and soil C, N cycling.

Association of medicinal plant consumption with all-cause mortality and cognitive impairment in older adult: A large prospective cohort study.

BACKGROUND: Panax ginseng and other medicinal plants have long been believed to have beneficial effects on health, and there is substantial evidence supporting their mechanisms of action. However, the extent of the health benefits derived from consuming these medicinal plants lacks substantial evidence from large-scale longitudinal population studies. The purpose of this study was to analyze the effect of consuming these medicinal plants on all-cause mortality and cognitive impairment. METHODS: A population-based cohort study was conducted using the Chinese Longitudinal Healthy Longevity Survey (CLHLS), which was established in 1998 and has been followed up till now. The main exposure was the frequency of eating medicinal plants, including Panax ginseng, Astragalus membranaceus, Lycium barbarum, Angelica sinensis, etc. According to the consumption patterns of medicinal plants, the participants were divided into three groups: frequent use, occasional use, and rarely or never use group. The participants were individually tracked to determine their mortality and cognitive impairment status during the period from 2008 to 2018. Cox proportional hazards regression and competing risk model were used to calculate the hazard ratio (HR) for the association between the use of medicinal plants and the all-cause mortality and cognitive impairment. RESULTS: Among 13,918 participants, the average age was 87.2 ± 11.3 years old, and 70.1% (9,754/13,918) of the participants died during follow-up. The proportion of those frequently using, occasionally using, and rarely using medicinal plants was 8.4%, 20.7%, and 70.8%, respectively. Compared with the rarely or never use group, the occasional and frequent use groups demonstrated significantly lower risks for all-cause mortality, with HR of 0.75 (95% CI: 0.71 - 0.79) and 0.53 (95% CI: 0.49 - 0.58), respectively. The protective effect of medicinal plants against all-cause mortality decreased with increasing age in the subgroup analysis. Additionally, frequent use of medicinal plants reduced the risk of cognitive impairment in the competing risk model (HR = 0.73, 95% CI: 0.60 - 0.87). However, there was no protective effect on cognitive function for those who occasional use medicinal plants. CONCLUSION: In elderly individuals, occasional and frequent use of medicinal plants was associated with reductions in risk of all-cause mortality, and frequent use of medicinal plants could reduce the risk of cognitive impairment.

Association of Drinking Herbal Tea with Activities of Daily Living among Elderly: A Latent Class Analysis.

The aim of this study was to explore whether drinking herbal tea and tea would positively benefit activities of daily living (ADL) in the elderly. We used data from the Chinese longitudinal healthy longevity survey (CLHLS) to explore the association. Drinking herbal tea and drinking tea were divided into three groups using latent class analysis (LCA): frequently, occasionally, and rarely. ADL disability was measured by the ADL score. Multivariate COX proportional hazards models with competing risks were used to explore the impact of drinking herbal tea and tea on ADL disability, statistically adjusted for a range of potential confounders. A total of 7441 participants (mean age 81.8 years) were included in this study. The proportions of frequently and occasionally drinking herbal tea were 12.0% and 25.7%, respectively. Additionally, 29.6% and 28.2% of participants reported drinking tea, respectively. Multivariate COX regression showed that compared with rarely drinking, frequently drinking herbal tea could effectively reduce the incidence of ADL disability (HR = 0.85, 95% CI = 0.77-0.93, p = 0.005), whereas tea drinking had a relatively weaker effect (HR = 0.92, 95% CI = 0.83-0.99, p = 0.040). Subgroup analysis found that frequently drinking herbal tea was more protective for males under 80 years old (HR = 0.74 and 0.79, respectively), while frequently drinking tea was somewhat protective for women (HR = 0.92). The results indicate that drinking herbal tea and tea may be associated with a lower incidence of ADL disability. However, the risks associated with using Chinese herb plants still deserve attention.