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Agroforestry is being promoted as a feasible land use management to improve understory economic benefits. However, there are few studies on species selection and the comprehensive evaluation of soil quality change in rhizoma bletillae (Bletilla striata) agroforestry systems. The soil quality index (SQI) and minimum dataset (MDS) methods can reflect the overall condition and were effective tools for understanding different cultivation systems. In this study, we evaluated the soil quality of four cultivation models (including three agroforestry systems: PeB, moso bamboo (Phyllostachys edulis)–rhizoma bletillae; PoB, plane trees (Platanus orientali)–rhizoma bletillae; CcB, pecan trees (Carya cathayensis)–rhizoma bletillae; and CK, rhizoma bletillae monoculture. The total dataset (TDS) consisted of 15 soil parameters containing physical, chemical, and biological characteristics. The results showed that soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) were finally selected and established as the MDS. Agroforestry could significantly influence soil quality. Compared with CK, the SQI in CcB significantly increased and decreased in PeB and PoB. Soil water content (SWC), nitrate nitrogen (NO3−-N), dissolved organic carbon (DOC), SOC, TN, and TP contents were higher in CcB than in the other cultivation models. Based on various soil indicators and SQI analysis, the CcB was the best in improving soil quality. These findings showed that the soil quality index based on the MDS can be used as an effective indicator for agroforestry systems selection. It provides theoretical guidance for the practice of bionic cultivation and the sustainable management of rhizoma bletillae. [ABSTRACT FROM AUTHOR]

Torreya grandis (T. grandis, Taxaceae) is a well-known nut tree species. Its fruit aril and leaves possess a unique aroma, making it an ideal natural raw material for extracting essential oils (EOs). This study aims to comprehensively compare the composition, biological activities, and pharmacological mechanism of EOs extracted from the arils (AEO) and leaves (LEO) of T. grandis. The results revealed that the chemical composition of the two EOs was highly consistent, with α-pinene and D-limonene as the main components. Both EOs significantly reduced cellular melanin production and inhibited tyrosinase activity in α-MSH-stimulated B16 cells (p < 0.05). AEO and LEO suppressed inflammatory responses in LPS-stimulated RAW 264.7 macrophages, significantly inhibiting cellular NO production and proinflammatory cytokines such as TNF-α and IL-6 (p < 0.05). A network pharmacology analysis reveals that AEO and LEO share similar molecular mechanisms and pharmacological pathways for treating skin pigmentation and inflammation. Regulating inflammatory cytokines may be a critical pathway for AEO and LEO in treating skin pigmentation. These findings suggest that AEO and LEO have potential for cosmetic applications. The leaves of T. grandis could be a valuable source of supplementary materials for producing T. grandis aril EO. [ABSTRACT FROM AUTHOR]

Shading and drought are considered crucial abiotic stress factors that limit the normal growth of plants. Under natural conditions, the quality of Bletilla striata pseudobulbs (BP), a Chinese traditional medicinal crop, is often affected by the dual stresses of shading and drought. However, the relationship and mechanism of the interaction between the two stress factors in B. striata remain unclear. In this study, we examined the changes in photosynthetic properties and active ingredients of B. striata under shading (L), drought (W), and shading-drought dual stresses (LW). We aimed to explore the metabolite mechanism that led to these changes using GC-MS-based non-targeted metabolomics techniques. The results indicated a significant reduction in the polysaccharide content of BP under W and LW treatments compared to the control (CK). The total phenol content was significantly reduced under L treatment, while the total flavonoid content did not change significantly under the three stresses. The significant increase in militarine content under all three stresses implies that B. striata may modulate its biosynthesis in response to different environmental stresses. Transpiration rate and stomatal conductance were reduced, amino acid expression was up-regulated, and carbohydrate expression was down-regulated in B. striata under L treatment. The net photosynthesis rate, stomatal conductance, and transpiration rate exhibited significant reductions, and the tuber metabolic disorder marker Homocysteine increased and organic acid content as well under W treatment. The net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency of B. striata were further reduced under LW compared with single stress, which is in agreement with the "trade-off theory". Pseudobulb metabolite changes, in combination with the results of the two single stresses, showed an up-regulation of amino acids and disaccharide compounds and a down-regulation of monosaccharide compounds. A support vector machine model (SVM) was used to screen 10 marker metabolites and accurately predict the changes in active ingredient content through an artificial neural network model (ANN). The results suggest that an appropriate stress environment can enhance the content of the target active ingredients based on cultivation goals. [ABSTRACT FROM AUTHOR]

Agroforestry has great potential for improving the ecological environment and raising the ecosystem productivity. This study is aim to evaluate the soil quality of bamboo forest and identify the main site factor that influencing the yield of Polygonatum tubers following the agroforestry practices. Four intercropping modes with different culm densities were conducted in Anhui, East China. The minimum data set method (MDS) was applied to evaluate soil quality index (SQI). Based on principal component analysis (PCA), microbial biomass carbon (MBC), available potassium (AK), altitude, and pH were selected as the MDS. The results showed that intercropping significantly increased SQI compared with moso bamboo monoculture. The mode M1(1750 culms/ha) was significantly better than other modes in improving soil fertility and increasing the yield of Polygonatum tubers. Results from random forest and structural equation model (SEM) showed the direct path coefficient of density on Polygonatum tubers yield was the largest, which was −0.83. Altitude, soil organic carbon (SOC) and nitrate nitrogen (NO3−-N) had a small impact, with direct path coefficient of 0.16, 0.10, and 0.15 (p < 0.05), respectively. Our findings provide a theoretical basis for managing the moso bamboo and P. cyrtonema agroforestry system in a more effective manner. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have drastically increased nitrogen (N) deposition, resulting in increased N availability. The continuous increase of N availability may exacerbate phosphorus (P) deficiency, which would limit forest productivity in subtropical forests. Effects of long-time N and N + P additions on SOC turnover in subtropical forests is therefore crucial for understanding the global carbon (C) cycle. The argument of whether N and N + P addition accelerates or slows SOC turnover has been under debate, particularly in P-limited subtropical forests. This study mainly aims to confirm this argument. A ten-year field experiment was conducted in a subtropical evergreen broad-leaved forest in southern Anhui, China. We measured the soil δ13CSOC contents and physicochemical properties under N (100 kg N·ha−1·a−1), N + P (100 kg N ha−1·a−1 + 50 kg P ha−1·a−1) additions, and the control (CK, no N and P additions). We also estimated the β value, which represents the soil organic carbon (SOC) turnover rate, from the slope of the regression between the log10-transformed SOC content and δ13CSOC in soil depth profiles. Our findings revealed that N addition significantly affected soil δ13CSOC compared to CK on both mid-slope and flat ridge sites. The β values responded differently to various treatments and sites. On the mid-slope, the β values did not show significant change with N and N + P additions. On the flat ridge, however, the β value decreased significantly in N and N + P additions, implying an increased SOC turnover rate. In addition, analysis of soil C–N–P stoichiometric ratios and physicochemical properties showed that N and N + P additions could affect β values by modifying soil nutrient content and composition. In general, our findings indicate that N and N + P additions could accelerate the SOC turnover in subtropical forest ecosystems, albeit with close dependence on site-specific factors. [ABSTRACT FROM AUTHOR]