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Chromatin modification contributes to the expression divergence of three TaGS2 homoeologs in hexaploid wheat
No full textPlastic glutamine synthetase (GS2) is responsible for ammonium assimilation. The reason that TaGS2 homoeologs in hexaploid wheat experience different selection pressures in the breeding process remains unclear. TaGS2 were minimally expressed in roots but predominantly expressed in leaves, and TaGS2-B had higher expression than TaGS2-A and TaGS2-D. ChIP assays revealed that the activation of TaGS2-B expression in leaves was correlated with increased H3K4 trimethylation. The transcriptional silencing of TaGS2 in roots was correlated with greater cytosine methylation and less H3K4 trimethylation. Micrococcal nuclease and DNase I accessibility experiments indicated that the promoter region was more resistant to digestion in roots than leaves, which indicated that the closed nucleosome conformation of the promoter region was important to the transcription initiation for the spatial-temporal expression of TaGS2. In contrast, the transcribed regions possess different nuclease accessibilities of three TaGS2 homoeologs in the same tissue, suggesting that nucleosome conformation of the transcribed region was part of the fine adjustment of TaGS2 homoeologs. This study provides evidence that histone modification, DNA methylation and nuclease accessibility coordinated the control of the transcription of TaGS2 homoeologs. Our results provided important evidence that TaGS2-B experienced the strongest selection pressures during the breeding process
Three new species of the fern genus Pteridrys (Tectariaceae) from Vietnam
No full textThe fern genus Pteridrys is characterized by having free veins and a tooth on each sinus between two pinna or pinnule lobes. This genus is currently known from nine to ten species. Here we add three new species of Pteridrys from northern Vietnam found in an expedition in 2013
Fine roots branch orders of Abies faxoniana respond differentially to warming in a subalpine coniferous forest ecosystem
No full textRoot is an important plant organ and has high heterogeneity. Global warming could change root and affect belowground ecological processes. There is little information on how fine roots branch orders responds to global change. This study examined the growth, morphological and physiological responses of fine roots of a subalpine coniferous species to warming. We investigated biomass, average diameter, specific root length (SRL), triphenyltetrazolium chloride (TTC) reducing capacity, carbon (C), total non-structural carbon (TNC) and fractions of the primal five branch order roots of Abies faxoniana in April, August, October and December. The decrease in total fine roots biomass after a growing season was significantly greater under warming treatment compared to control, suggesting that warming could accelerate the carbon input from root to soil, but the increment depended on tree species. Warming did not affect average diameter and SRL. Responses of biomass, TTC reducing capacity, C, TNC and fractions to warming significantly differed with root order and month. Significant warming effects were only observed in C and starch concentration of the first order and also TNC and soluble sugar concentration of the first three orders. The results indicated that the lower order roots (the first three orders) were more sensitive to warming, probably because they had more frequent, intense interactions with soil and low defense capability. Thus, global warming may dramatically alter root functions such as nutrients and water uptake as well as the cycle of C and nutrients at the whole subalpine coniferous forest ecosystem
Spinulum lioui, a new species referred as to Lycopodium neopungens (Lycopodiopsida: Lycopodiaceae) in China
No full textOne earlier known species of Lycopodium from China, "L. neopungens H.S. Kung & Li Bing Zhang", is described as Spinulum lioui Li Bing Zhang & H.He (sp. nov.)
The `plant economic spectrum' in bryophytes, a comparative study in subalpine forest(1)
No full textPREMISE OF THE STUDY: Tradeoffs among functional traits of vascular plants are starting to be better understood, but it is unclear whether bryophytes possess similar tradeoffs or how trait relationships, or the `economic spectrum', differ between the two groups. METHODS: We determined functional-trait values [ including shoot mass per area (SMA), light-saturated assimilation rate (A(mass)), dark respiration rate (Rd(mass)), N and P concentrations (N-mass and P-mass), and photosynthetic N and P use efficiency (PNUE and PPUE)] and their bivariate relationships for 28 bryophytes growing in a subalpine old-growth fir forest on the eastern Tibetan Plateau. Trait values and scaling relationships of these bryophytes were compared with data for vascular plant leaves from the Global Plant Trait Network (GLOPNET) dataset. KEY RESULTS: We found that the A(mass), N-mass, N: P, PNUE and PPUE of bryophyte shoots were lower than those of vascular plant leaves. In contrast, bryophytes possessed higher P mass and the two groups had similar values of SMA and Rd(mass). The N-mass and P-mass were closely associated with A(mass) and Rd(mass), and these traits were all significantly negatively related to SMA. Metabolic rates increased faster with nutrient concentrations in bryophytes than in vascular plants. CONCLUSIONS: Our research indicates that bryophytes have similar trait relationships as vascular plant leaves, although the slopes of the relationships differ for most trait combinations. This study confirms a functional-trait tradeoff in bryophytes, and reveals that bryophytes allocate greater proportions of N and P into the metabolic pools
Chemical Composition, Antioxidant and Anti-bacterial Potential of Essential Oil of Medicinal plant Isodon rugosus
No full textIsodon rugosus is a medicinally valuable herb containing a variety of important secondary metabolites and essential oil with important chemical constituents of pharmaceutical precursors. The active components of volatile oil of I. rugosus were analyzed using GC-MS. Anti-oxidant potential of the oil was assessed with 2, 2-diphenyl-1-picrylhydrazyl (DPPH). Anti-bacterial power of the essential oil accessed disc diffused method. A total of 19 constituents were quantified and identified with different concentrations in essential oil. Among which Caryophyllene oxide was 28.99 %. Limonene oxide cis was 26.52 %, (Z, E)-Farnesol was 17.34 %, followed by 1-erpinen-4-ol 3.33 %, o-Cymene 2.04 while the concentrations of rest of constituents were between 1.11 to 0.2 %. The investigation showed that the essential oil of I. rugosus possessed significant antibacterial and antioxidant potentia
Photoprotective and antioxidative mechanisms against oxidative damage in Fargesia rufa subjected to drought and salinity
No full textDrought and salinity are the two most common and frequently co-occurring abiotic stresses limiting plant productivity worldwide, yet it remains unclear whether bamboo species possess effective mechanisms to protect against oxidative damage caused by drought and salinity, either alone or in combination. In this study, we utilised Fargesia rufa Yi, a species important to forest carbon sequestration and endangered giant pandas, to evaluate physiological, biochemical and ultrastructural responses to drought, salinity and their combination. Under drought alone, F. rufa exhibited reduced water loss from leaves, photochemistry inhibition, pigment degradation, reactive oxygen species accumulation, lipid peroxidation, and damage to organelles compared with salinity and combined stress treatments. The superior performance under drought alone was attributed to greater thermal dissipation and the water-water cycle capacities, increased SOD/AsA-GSH cycle enzymes activities, and a favourable redox balance of antioxidants. Therefore, relative to salinity alone and drought+salinity, F. rufa plants under drought exhibit highly efficient mechanisms to protect against oxidative damage, which most likely allow accelerated recovery of photosynthetic plasticity once the stress is removed
川西次生灌丛和不同类型人工林对土壤养分的影响
No full text为评价不同树种造林对土壤养分循环的影响,以落叶阔叶灌丛为对照,比较研究川西亚高山造林恢复28年后4种人工林(连香树Cercidiphyllum japonicum、油松Pinus tabulaeformis、落叶松Larix kaempferi和华山松Pinus armandii)土壤有机质(SOM)、可溶性有机碳(DOC)、可溶性有机氮(DON)及全氮(TN)、全磷(TP)、土壤铵态氮(NH4+-N)和硝态氮(NO3--N)的含量,结合林地凋落物贮量及细根生物量等参数,试图揭示不同人工林土壤养分差异化的影响因素.结果显示:人工造林影响土壤的养分循环,与落叶灌丛林地相比,除连香树样地TP密度及2015年10-20 cm的SOM、TN密度外,落叶人工林土壤养分基本呈下降趋势.除华山松样地的可溶性有机质(DOC、DON)外,油松及华山松人工林土壤地力的退化趋势更甚于落叶人工林样地,其土壤有机质含量、TN、TP密度、可溶性有机质及速效养分均呈不同程度的下降.不同人工林间土壤养分的差异性与不同树种的凋落物、细根、土壤容重及涵水能力差异化有关.综上所述,人工林林分结构单一导致小气候恶化、凋落物分解缓慢是造成土壤养分循环功能下降的重要原因;选择有利于养分循环的阔叶树种营造针阔混交林以改善林分结构和土壤环境条件,可促进土壤养分的循环
遮光和施氮对暗紫贝母生长和C-N平衡的影响
No full text为了了解暗紫贝母对资源变化的适应策略,本研究通过田间控制试验,研究了遮光和施氮对暗紫贝母生物量、生物量分配,以及叶、根C、N状态的影响。结果表明:遮光和施氮处理后,暗紫贝母生物量均减少;遮光下叶片的生物量分配相对增加,叶根生物量比显著升高(P<0.05),但施氮处理下叶根生物量比的变化不明显;遮光和施氮后,暗紫贝母叶、根N含量均显著升高(P<0.05),叶片和根的C:N显著降低(P<0.05);相关分析显示,叶片N、C:N与暗紫贝母总生物量、叶根生物量比有极显著的相关性(P<0.01)。本研究表明,与生物量分配相比,C-N平衡,尤其是叶片的C:N比能更好的解释暗紫贝母对资源变化的适应
温州种子植物区系统计分析
No full text温州地区位于浙江东南部，地处27°03′~28°36′N，119°37′~121°18′E,独特的地理位置和生态环境令其植物物种多样性较为丰富.基于文献和标本查阅，通过《温州植物志》项目组近6 a的系统调查，编写了《温州野生维管束植物名录》，以此名录为依据对温州种子植物区系进行了统计分析.结果发现：温州地区共有野生种子植物166科，958属，2 460种（不含种下类群），其中裸子植物8科，20属，25种，被子植物158科，938属，2 435种.就科和属所包含的种数而言，寡种科(2~10种)和单种属最多，分别占总科数和总属数的48.2%和53.9%，体现出科、属水平上的多样性.属的分布区可划分为14个类型和24个变型，热带分布的属稍多于温带分布（分别占50.1%和47.4%），以泛热带分布及其变型所占比例最大（19.8%），其次是北温带分布及其变型（17.0%）和东亚分布及其变型（13.2%）.本种子植物区系具有植物种类丰富、地理成分多样、珍稀濒危植物较多、亚热带山地植物区系性质、外来植物入侵风险较大等特征