[The effects of climate change on isoprene emission rate from leaves of Pleioblastus amarus in different regions.][Pubmed: 29974714]

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[Response of fine root decomposition to simulated nitrogen deposition in Pleioblastus amarus plantation, rainy area of West China].[Pubmed: 25509065]

As an important contributor to carbon (C) flux in the global C cycle, fine root litter decomposition in forests has the potential to be affected by the elevated nitrogen (N) deposition observed globally. From November 2007 to January 2013, a field experiment involving monthly simulated deposition of N in a Pleioblastus amarus plantation was conducted in the Rainy Area of West China. Four levels of nitrogen deposition were included as control (0 g N x m(-2) x a(-1)), low nitrogen (5 g N x m(-2) x a(-1)), medium nitrogen (15 g N x m(-2) x a(-1)) and high nitrogen (30 g N x m(-2) x a(-1)). After 3 years of simulated N deposition experiment (January 2011) , a two-year fine root decomposition experiment was conducted in the simulated N deposition plots using litterbag method, under monthly experimental N deposition. The decomposition rates of fine roots were fast first and then slow. Mass loss of fine roots in the first year of decomposition was up to 60%, and the change of the remaining mass was very slow in the second year. The time of 50% and 95% mass loss of fine roots was 1.20 and 5.17 years, respectively, under the conditions of no addition N input. In general, decomposition rates were underestimated using negative exponential model. Simulated N deposition significantly inhibited the decomposition of fine roots. The remaining mass in the high nitrogen treatment was 51.0% higher than that in the control, after two years of decomposition. Simulated N deposition increased C, P and K contents in the remaining mass of litter. Compared with the control, soil pH decreased significantly in the medium and high nitrogen treatments, soil organic C, total N, ammonium and nitrate contents and fine root biomass of P. amarus increased significantly in the high nitrogen treatment after simulated N deposition for 4. 5 years. Key words: nitrogen deposition; fine root decomposition; Pleioblastus amarus.

Two new compounds from the dry leaves of Pleioblastus amarus (Keng) keng f.[Pubmed: 25253092]

Two new compounds, xylitol 1-O-(6'-O-p-hydroxylbenzoyl)-glucopyranoside (1) and bambulignan B (2), together with three known ones gastrodin (3), glucovanillin (4), and rel-(7S,7'R,8R,8'S)-4,4'-dihydroxy-3,3',5,5'-tetramethoxy-7,7'-epoxyligna-9,9'-diol-9(or)9'-O-β-glucopyranoside (5), were isolated from the 95% EtOH extract of the dry leaves of Pleioblastus amarus (Keng) keng f. Their structures were determined by UV, IR, HR-ESI-MS, CD, and 1D and 2D NMR data analyses as well as GC experiments.

[Characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in rainy area of West China].[Pubmed: 22586950]

To understand the characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in the Rainy Area of West China, a one-year periodic monitoring was conducted in a fixed plot of the plantation from February 2010 to January 2011. In the plantation, the mean annual soil respiration rate was 1.13 micromol x m(-2) x s(-1), and the soil respiration presented a clear seasonal pattern, with the maximum rate in mid-summer and the minimum rate in late winter. The contribution rates of the respiration of litter layer, root-free soil, and root to the total soil respiration of the plantation accounted for 30.9%, 20.8% and 48.3%, respectively, and the respiration of the components had a similar seasonal pattern to the total soil respiration, being related to temperature and litterfall. The annual CO2 efflux from the total soil respiration, litter layer CO2 release, root-free soil CO2 release, and root respiration was 4.27, 1.32, 0.87 and 2.08 Mg C x hm(-2) x a(-1), respectively. The total soil respiration and its components had significant positive linear correlations with litterfall, and significant positive exponential correlations with air temperature and the soil temperature at depth 10 cm. The Q10 values of total soil respiration, litter layer CO2 release, root-free soil CO2 release, and root respiration calculated based on the soil temperature were 2.90, 2.28, 3.09 and 3.19, respectively, suggesting that the temperature sensitivity of litter layer CO2 release was significantly lower than that of the total soil respiration and of its other components.

[Effects of simulated nitrogen deposition on the fine root characteristics and soil respiration in a Pleioblastus amarus plantation in rainy area of West China].[Pubmed: 21328931]

Fine root is critical in the belowground carbon (C) cycling in forest ecosystem. Aimed to understand the effects of nitrogen (N) deposition on the fine root characteristics and soil respiration in Pleioblastus amarus plantation, a two-year field experiment was conducted in the Rainy Area of West China. Four treatments with different levels of N deposition were installed, i. e., CK (0 g N x m(-2) x a(-1)), low N (5 g N x m(-2) x a(-1)), medium N (15 g N x m(-2) x a(-1)), and high N (30 g N x m(-2) x a(-1)). There were great differences in the biomass and element contents of <1 mm and 1-2 mm fine roots among the treatments. Comparing with < 1 mm fine roots, 1-2 mm fine roots had higher contents of lignin, P, and Mg, but lower contents of cellulose and Ca. Nitrogen deposition increased the biomass of < 2mm fine roots significantly, with the values being (533 +/- 89) g x m(-2) in CK, and (630 +/- 140), (632 +/- 168), and (820 +/- 161) g x m(-2) in treatments low N, medium N, and high N, respectively. The N, K, and Mg contents of <2 mm fine roots also had an obvious increase under N deposition. The annual soil respiration rate in treatments CK, low N, medium N, and high N was (5.85 +/- 0.43), (6.48 +/- 0.71), (6.84 +/- 0.57), and (7.62 +/- 0.55) t C x hm(-2) x a(-1), respectively, indicating that N deposition had obvious promotion effects on soil respiration. There were significant linear relationships between the annual soil respiration rate and the biomass and N content of <2 mm fine roots. N deposition increased the fine root biomass and promoted the root metabolism, and stimulated the rhizospheric soil respiration rate via promoting microbial activities.

[Soil enzyme activities in a Pleioblastus amurus plantation in Rainy Area of West China under simulated nitrogen deposition].[Pubmed: 20353060]

From November 2007 to May 2009, a simulation test was conducted in a Pleioblastus amarus plantation in Rainy Area of West China to study the effects of nitrogen deposition on the activities of soil enzymes. Four treatments were installed, i.e., control (0 g N x m(-2) x a(-1)), low nitrogen (5 g N x m(-2) x a(-1)), medium nitrogen (15 g N x m(-2) x a(-1)), and high nitrogen (30 g N x m(-2) x a(-1)). Half year after N deposition, 0-20 cm soil samples were collected monthly, and the activities of peroxidase, polyphenol oxidase, cellulase, sucrase, urease, and acid phosphatase were determined. All test enzyme activities had apparent, seasonal variation, with the peak of cellulase, suerase, and acid phosphatase activities in spring, of urease activity in autumn, and of peroxidase and polyphenol oxidase activities in winter. Nitrogen deposition stimulated the activities of polyphenol oxidase, sucrase, urease, and acid phosphatase, inhibited cellulase activity, but had no significant effects on peroxidase activity. The test P. amurus plantation ecosystem was N-limited, and nitrogen deposition stimulated the decomposition of soil organic matter by microbe-enzyme system.

Flavone glucosides with immunomodulatory activity from the leaves of Pleioblastus amarus.[Pubmed: 15081303]

Three flavone glucosides, pleiosides A-C, were isolated from the leaves of Pleioblastus amarus, along with two known flavones: tricin and tricetin 3,5-dimethoxy-7-O-beta-d-glucopyranoside. Their structures were elucidated by extensive spectral studies. Pleiosides A-C were found to inhibit the proliferation of murine T and significantly stimulate the proliferation of murine B lymphocytes in vitro.