Effects of Low Temperature Stress on Physiological and Biochemical Characteristics of Podocarpus nagi

[Objective] The paper was to study the effect of low temperature stress on physiological and biochemical characteristics of Podocarpus nagi. [Method] Through the determination of physiological indices such as plasma membrane permeability, free proline content, soluble sugar content, malondialdehyde （MDA） content and chlorophyll content, the change law of these indices of P. nagi seedlings under natural conditions and artificially controlled low temperature conditions within the continuous 5 d was studied. [Result] The soluble sugar content, free proline content, MDA content and plasma membrane permeability of P. nagi seedlings were slightly in- creased compared with control; the chlorophyll content gradually decreased with the prolongation of low temperature stress. P. nagi seedlings produced active response to low temperature stress, so the low temperature injury P. nagi seedlings suffered was reduced. [Conclusion] The study provided theoretical basis for winter management in P. nagi cultivation in Hanjiang plain area.

Study on Development of the Leaf Structure of Podocarpus macrophyllus var. maki Endl.

The leaf development of Podocarpus macrophyllus var.maki Endl.started from the leaf primordium formed by the cell division in shoot apical meristem.During the leaf development,three resin canals from the inferior part of vascular bundles firstly began to differentiate,then protoxylem in vascular bundles differentiated from adaxial side to abaxial side.Meanwhile,a layer of parenchyma cells from the inferior part of protoderm developed into the sclerenchyma,which played an important role in supporting young leaves.When xylem became mature basically,transfusion tissue,phloem and accessory transfusion tissue began to differentiate,so mesophyll tissue finally differentiated into developmental palisade cells and sponge cells.The thicker cuticle was formed in the lateral side of epidermal cells at the same time of differentiation and development for the inner structure of leaves.Therefore,the developmental palisade cells and the cuticle in the leaf structure of Podocarpus macrophyllus var.maki Endl.is greatly significant for photosynthesis and transpiration when it grows in arid and cold regions.

Conducting Tissue of Leaves in Nageia and Podocarpus

The conducting tissue structure of transverse and longitudinal sections was observed on leaves of Podocarpus and Nageia.Results showed:in Podocarpus leaves,there is only one midrib,the xylem tracheid of midrib vascular bundle is multi-form,transfusion tissue belongs to Cycas-type and transfusion tracheids are isodiametric,the accessory transfusion tracheids between palisade tissue and sponge tissue are developed;in Nageia leaves,there are plenty of parallel leaves,the xylem tracheids of each vein are relatively simple,transfusion tissue belongs to Taxus-type and transfusion tracheids are longer in longitudinal section than that in transverse section,the accessory transfusion tissue between palisade tissue and sponge tissue is absent.Considering other differences that in leaves of Podocarpus there are three resin ducts under vascular bundle of midrib,mesophyll cells are differentiated into palisade tissue and sponge tissue;in leaves of Nageia,there is only one resin duct under vascular bundle in each vein and no obvious differentiation in mesophyll cells,palisade tissue can be found on both sides,and sclereids can also be found in mesophyll tissue.The anatomical differences of leaf veins and mesophylls between Nageia and Podocarpus mentioned above support the viewpoint that Nageia and Podocarpus are two independent genera.

Podocarpus milanjianus Rendle的化学成分研究(英文)

目的:对PodocarpusmilanjianusRendle的根进行化学成分研究。方法:采用层析手段和波谱方法及相关物理常数对照进行化学成分的分离和结构鉴定。结果:得到9个化合物分别鉴定为:竹柏内酯D (1) ,竹柏内酯G(2 ) ,竹柏内酯F(3) ,罗汉内酯C(4) ,陶塔酚(5 ) ,19 羟基陶塔酚(6 ) ,β- 谷甾醇(7) ,胡萝卜苷(8) ,豆甾醇(9)。结论:化合物1,2 ,7,8,9为该属中首次发现。

Does nitrogen fertilization impact nonstructural carbohydrate storage in evergreen Podocarpus macrophyllus saplings?

Nonstructural carbon(NSC),which represents the relationship between the carbon source and carbon sink,is an important factor that reflects the functions and performance of a tree.However,little is known regarding the timeseries responses of NSC storage in evergreen species to different nitrogen(N)fertilization regimes.This study,which was based on a pot experiment,examined the response of the NSC(soluble sugars and starch storage to different N addition intensities[light N addition(LN):6.5 g N m^(-2)a^(-1);moderate N addition(MN):13.0 g N m^(-2)a^(-1);and heavy N addition(HN):26.0 g N m^(-2)a^(-1))]in saplings of the evergreen species Podocarpus macrophyllus.Our results showed that the net photosynthetic rate(P_(n))under MN was significantly higher than that under LN,but was comparable to that under HN.Moreover,saplings subject to MN had a significant higher leaf biomass than that to LN and HN.These results indicated that the C supply via photosynthesis under MN was greater than that under LN and HN.The NSCs reserve under MN was considerable with that under LN,which suggested that saplings in MN group consumed higher and stored lower properties of NSCs than those in LN group.However,saplings under HN stored higher properties of NSCs than those under MN considering that no difference in NSCs pools was found between the two treatments.The leaf N concentrations were found in the increasing sequence of LN<MN<HN,whilst the leaf chlorophyll concentration under HN was obviously lower than that under MN.The growth rate under MN was higher than that under LN and HN.We concluded that the NSCs allocation between con-sumption and reserve in P.macrophyllus saplings depended on soil N availability,and an excessive N addition to soil favors the storage rather than the consumption of NSCs by plants.

Effect of Isolation of Hainan Island from the Mainland on the Genetic Variation of Podocarpus imbricatus

Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic variation of Podocarpus imbricatus in Hainan Island and Mainland of China. Two populations of Dacrydium pierrei were used as comparison materials. Both Podocarpus imbricatus and Dacrydium pierrei showed a low level of genetic diversity. However, Podocarpus imbricatus showed higher genetic diversity and higher population differentiation than Dacrydium pierrei. The geographic range may affect the genetic diversity of Podocarpus imbricatus and Dacrydium pierrei significantly. The UPGMA cluster tree showed that populations of Podocarpus imbricatus in Hainan Island and Guangxi Zhuang Autonomous Region were closer than those in Yunnan Province, indicating possible gene flow between Hainan Island and Guangxi Zhuang Autonomous Region. The young geological history of Hainan Island and the three times of unification and separation between Hainan Island and the Mainland may give the two species more possibilities of gene flow.

Bioactivity‑Guided Isolation of Totarane‑Derived Diterpenes from Podocarpus neriifolius and Structure Revision of 3‑Deoxy‑2α‑hydroxynagilactone E

Bioactivity-guided phytochemical investigation of Podocarpus neriifolius D.Don.(Podocarpaceae)has led to the isolation of one new(2)and three known(1,3,and 4)B-type podolactones,along with three totarane-type diterpenes(5-7).Their structures were determined by interpretation of High Resolution ElectroSpray Ionization Mass Spectrometry(HRESIMS)and 1D and 2D NMR data,and comparison with the values reported in the literature.The structure of compound 1,previously identifed as 3-deoxy-2α-hydroxynagilactone E(8),was revised as its 2β-epimer,which has been reported recently as a new compound.All of the isolates were evaluated for their antiproliferative activity against a panel of four human cancer cell lines,namely,ovarian(OVCAR3),breast(MDA-MB-231),colon(HT-29),and melanoma(MDA-MB-435),and compounds 1 and 3 were found to be cytotoxic with IC_(50) values in the low micromolar range for most of the cell lines used.The major compound,inumakilactone A(3),was further tested in vivo using the HT-29,MDA-MB-435,and OVCAR3 cells in a murine hollow fber model,for the frst time.

A rhizobia strain isolated from root nodule of gymno-sperm Podocarpus macrophyllus

Symbiotic nitrogen fixation of rhizobia and leguminous plants is considered as the most important biologic nitrogen fixation system on earth. Symbiotic nodulation of gymnosperm Podocarpus macro-phyllus and rhizobia has never been reported. In this study, 11 endophytic bacteria strains were isolated from root nodules of P. macrophyllus and its variation P. macrophyllus var. maki. The plant infection tests on these strains indicated that the isolated strains could be nodulated on P. macrophyllus plants, and weak nitrogenase activity of nodules was found in acetylene reduction method. According to the physiological and biochemical characteristics of the 11 strains, GXLO 02 was selected as the representative strain. 16S rDNA full-length sequence analysis of GXLO 02 confirmed that the representative strain GXLO 02 belongs to Rhizobium sp.

Two New Cyclopeptides from Podocarpus nagi

Two new cyclopeptides, nagitides A and B, were isolated from the stem bark ofPodoearpus nagi. Their struc- tures were elucidated on the basis of NMR experiments including IH-IH COSY, HSQC, HMBC, ROESY, etc. This is the first report of cyclopeptides separated from this plant.

不同泥炭土与蛭石配比的基质盆栽竹柏的比较试验

采用不同配比的泥炭土和蛭石制成4种基质,研究不同配比的基质对竹柏(Podocarpus nagi)植株株高、新叶数、根长及根数的影响。结果表明,泥炭土与蛭石的体积比为2∶1时是最佳方案。

不同产地罗汉松叶总黄酮提取工艺的优化与含量测定

采用回流提取法提取罗汉松[Podocarpus macrophyllus(Thunb.)D.Don]叶总黄酮,通过单因素试验,考察提取方法、提取溶剂体积分数、提取体积、提取时间对药材总黄酮含量的影响,采用正交试验优化提取工艺条件,筛选出罗汉松叶总黄酮的最佳提取工艺。结果表明,罗汉松叶总黄酮的最佳提取工艺为75%乙醇、料液比1∶30(g∶mL)、回流提取时间0.5 h。该方法重复性较好、稳定、可行。

罗汉松茎中总黄酮的提取工艺优化及其含量测定

采用超声提取法提取罗汉松[Podocarpus macrophyllus(Thunb.)D.Don]茎中的总黄酮,通过单因素试验方法考察了提取方法、提取溶剂体积分数、提取溶剂体积、提取时间对总黄酮含量的影响,采用正交试验优化提取工艺条件,筛选出罗汉松茎中总黄酮的最佳提取工艺。结果表明,最佳提取工艺为70%乙醇、超声提取1.0h、料液比1∶20(m/V)。超声提取法提取罗汉松茎中总黄酮含量,该方法重复性较好、稳定、可行。

四种罗汉松属植物茎水力结构特征初步研究

对罗汉松属(Podocarpus)竹柏(P.nagi)、长叶竹柏(P.fleuryi)、罗汉松(P.macrophyllus)和大理罗汉松(P.forrestii)4种植物茎水力结构特征参数进行了测定。结果显示,4种植物平均叶面积和茎端总叶面积均差异明显;4种植物的胡伯尔值(Hv)、边材密度、导水率(Kh)、比导率(Ks)、叶比导率(LSC)没有显著差异,与其平均叶面积也没有显著的相关性,可能是由于4种植物的茎端总叶面积没有显著差异引起的。