A new dilactone from the seeds of Gaultheria yunnanensis

Gaultheriadiolide (1), a new compound, together with the known dauosterol (2), ginkgetin (3), myricetin (4), 6-ethyl-5-hydroxy-2,7-dimethoxy-1,4-naphthoquinone (5), ursolic acid (6), methyl salicylate 2-O-β-d-xylosyl(1→6)β-d-glucopyranoside (7), and methyl salicylate 2-O-β-d-glucopyranoside (8) were isolated from Gaultheria yunnanensis. The structure was elucidated on the basic of spectral analysis, especially 1D and 2D NMR. Primary bioassays showed that compound 1 had medium cytotoxic activity against HEp-2 and HepG2 Cells, with IC₅₀ of 23.337 μM and 29.4497 μM, respectively.     

Comparative study of the discriminating capacity and effectiveness of AFLP, STMS and EST markers in assessing genetic relationships among evergreen azaleas

The application of amplified fragment length polymorphism (AFLP), sequence tagged microsatellite site (STMS) and expressed sequence tag (EST) markers to study the genetic relationships in an evergreen azalea gene pool was investigated. STMS and EST markers revealed a higher genetic distance detection capacity than AFLPs, which, nevertheless, were the most efficient marker system due to their highest polymorphism detection capacity. Similarity matrices showed weak, yet significant, correlations when Mantel's test was applied. To assess the usefulness of the overall information provided by these marker data for establishing phylogenetic relationships and horticultural classification, cluster analysis was performed. The joint AFLP, STMS and EST data were demonstrated to be remarkably effective for group discrimination and phylogenetic studies. The use of these polymerase chain reaction marker systems is discussed in terms of the choice of appropriate marker techniques for different aspects of evergreen azalea germplasm evaluation.     

Evaluating Bearberry Nitrogen Nutrition Using Hydroponic Cultures: Establishing Preliminary DRIS Norms

Abstract

This study was designed to explore nitrogen (N) nutrition in bearberry plants (Arctostaphylos uva‐ursi L.) using a hydroponic culture system. Two experiments were performed in which the total N concentration (34, 52, and 73 mg L^?1) and N‐NO₃ ^?:N‐NH₄ ⁺ ratio (50/50, 60/40, and 70/30 in %) in the nutrient solution were varied and effects on nutrient uptake [N, phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] and foliar composition determined. Highest‐quality plants were yielded using a N level of 73 mg L^?1 and a N‐NO₃ ^?:N‐NH₄ ⁺ ratio of 50/50. Standard nutrient values for foliar tissue were obtained for bearberry plants growing in these hydroponic cultures for their use as preliminary norms in the diagnosis and recommendation integrated system (DRIS). In a subsequent complementary experiment, these norms were used in the DRIS procedure and applied to plants growing in solutions of varying K concentrations. It was found that the DRIS norms established in the hydroponic experiments were able to account for changes in nutrient limiting factors produced in response to the varying K concentrations in the nutrient solution. The results obtained will be useful for the nutritional diagnosis of bearberry plants.     

Rapid uptake of N-ammonium and glycine-C, N by arbuscular and ericoid mycorrhizal plants native to a Northern California coastal pygmy forest

While it is well established that plants are able to acquire nitrogen in inorganic form, there is less information on their ability to ‘short circuit’ the N cycle, compete with microbes, and acquire nitrogen in organic form. Mycorrhizal fungi, known to enhance nutrient uptake by plants, may play a role in organic N uptake, particularly ericoid mycorrhizas. We asked the question—Can mycorrhizal fungi increase the ability of plants to take up organic N, compared to inorganic N? Here, we report on the abilities of three plant species, ericoid mycorrhizal Rhododendron macrophyllum and Vaccinium ovatum and arbuscular mycorrhizal Cupressus goveniana ssp. pigmaea, to acquire C and/or N from an organic and an inorganic N source. All three species are native to a California coastal pygmy forest growing in acidic, low-fertility, highly organic soils. In a pot study, glycine-α¹³C, ¹⁵N and ¹⁵N-ammonium were applied to pygmy forest soil for 17 or 44 h. Ericoid mycorrhizal species did not demonstrate a preference for either inorganic or organic sources of N while Cupressus acquired more NH₄-N than glycine-N. For all species, glycine-N uptake did not increase after 17 h suggesting glycine uptake and glycine immobilization occurred rapidly. Both glycine-N and glycine-C were recovered in shoots and in roots suggesting that all species acquired some N in organic form. Regression analyses of glycine-N and glycine-C recovery in root tissue indicate that much of the glycine was taken up intact and that the minimum proportion of glycine-N recovered in organic form was 85% (Cupressus) and 70% (Rhododendron). Regressions were non-significant for Vaccinium. For all species, glycine-N remained predominantly in roots while glycine-C was transferred to shoots. In contrast, NH₄-N remained in roots of ericoid plants but was transferred to shoots of arbuscular mycorrhizal Cupressus. Since net N mineralization rates in pygmy forest soils are low, our results suggest that organic N may be an important N source for plants in this temperate coniferous ecosystem regardless of mycorrhizal type. Acquisition of amino acid C by these species also may partially offset the carbon cost to plants of hosting mycorrhizal fungi.     

Mycorrhizal synthesis between Pisolithus arhizus and adult clones of Arbutus unedo in vitro and in nursery

Arbutoid mycorrhizae were synthesized between adult se-lected clones of Arbutus unedo L. and Pisolithus arhizus. Two micro-propagated clones were tested:AL1, in vitro and C1 (acclimatized plants) in nu...     

Inhibition of viral adsorption and penetration by an aqueous extract from Rhododendron ferrugineum L. as antiviral principle against herpes simplex virus type-1

The polyphenol-enriched aqueous extract RF from the aerial parts of Rhododendron ferrugineum exhibited strong antiviral activity against herpes simplex virus type-1 while adenovirus 3 was not affected. RF exhibited an IC₅₀ of 7.4 μg/mL and a selectivity index of 64 when added to the virus inoculum prior to infection. RF abolished virus entry into the host cell by blocking attachment to the cell surface. When added after attachment at a concentration of > 25 μg/mL, RF inhibited also penetration of HSV-1 into the host cell. RF directly interacts with viral envelope proteins as demonstrated for the viral glycoprotein gD.     

内蒙古大兴安岭地区杜鹃花科植物资源的研究

杜鹃花科(Ericaceae)中,有很多种具有重要的经济作用。内蒙古大兴安岭地区分布有该科植物5属9种,其中兴安杜鹃(Rhododendron dauricum)、小叶杜鹃(Rh. parvifolium)、杜香(Ledum palustre)、笃斯越桔(Vaccinium uliginosum)、越桔(V. vitis-idaea)5种广泛分布于整个地区且蕴藏量极为丰富。其每种的总蕴藏量(鲜重)为:兴安杜鹃933430.90t;小叶杜鹃118776.80t;杜香9479423.00t;笃斯越桔373929.60t;越桔965720.60t。这五种都有多种经济用途:它们均具观赏价值;其中除笃斯越桔外均有药用价值;杜香为东北著名的芳香油植物;越桔、笃斯越桔是东北著名的野生浆果植物。根据全区各林业局杜鹃花科植物的蕴藏量,将内蒙古大兴安岭地区划分为两个亚区:Ⅰ.北部亚区;Ⅱ.南部亚区。充分开发利用这些植物,对于本区经济建设具有重要意义。     

青藏高原东缘杜鹃花科藏药植物资源调查

青藏高原东缘生态环境复杂,植物种类多样,杜鹃花科藏药植物资源丰富,据统计,共有1属7种.为此对青藏高原东缘杜鹃花科藏药植物的属种组成、区系成分及药用价值等进行了分析研究,并对其开发利用提出了相关建议.     

我国杜鹃花科植物菌根及其真菌多样性研究现状

我国是杜鹃花科植物资源较为丰富的国家,分布于全国各地,主产地在西南部山区。杜鹃花科植物分布广泛,而且大多生境条件恶劣,与其共生菌根真菌有着举足轻重的关系。菌根对杜鹃花类植物的营养吸收、增强对逆境因子的抗性等方面具有重要的作用。本文从杜鹃花科植物菌根的多样性、杜鹃花科植物菌根真菌的物种多样性等方面,对我国杜鹃花类菌根的研究现状进行了综述。