半天然杉木阔叶树混交林生长效果研究

以福建省永安国有林场11.5 a林龄人工杉木、木荷与10.5 a林龄天然檫树、南酸枣混生的半天然杉阔混交林为研究对象,分析树种组成分别为9杉1阔、8杉2阔、7杉3阔、5杉5阔等4种林分的生长效果。8杉2阔的林分蓄积最高,总蓄积297.73 m^(3)/hm^(2),其中杉木平均胸径13.28 cm、树高11.52 m、蓄积226.56 m^(3)/hm^(2)、年均生长19.70 m^(3)/hm^(2),达到福建省杉木最适宜区速生丰产林立地等级Ⅰ级的大径材生长量指标,可供科学培育半天然杉阔混交林参考。9杉1阔的林分次之,总蓄积252.04 m^(3)/hm^(2),其中杉木平均胸径11.96 cm、树高9.34 m、蓄积189.46 m^(3)/hm^(2)。7杉3阔的林分最差,总蓄积182.79 m^(3)/hm^(2),其中杉木58.31 m^(3)/hm^(2),檫树91.83 m^(3)/hm^(2)。5杉5阔的林分,檫树生长最优,10.5 a林龄保存密度775株/hm^(2),平均胸径16.79 cm、树高14.32 m、蓄积131.60 m^(3)/hm^(2),总蓄积207.37m^(3)/hm^(2),森林演替成天然檫树为主的混交林,可逐步疏伐改造为檫树母树林。

人工-天然杉阔混交林种群生态位及竞争研究

对人工 -天然杉阔混交林中 4个主要种群进行生态位研究 ,定量测定混交林中主要种群生态位宽度、生态位相似比例、生态位重叠 ,并分析了各种群生态位的生态学意义 ;同时采用Lotka_Volterra竞争方程研究混交林中主要种群。结果表明 :通过定量的生态位分析 ,结果与自然规律相符合。平衡时 ,杉木和米槠相对优势度分别为87 4 5 %和 12 5 5 % ,即人工 -天然杉阔混交林仍将由杉木、米槠两种种群共优组成 ,杉木种群支配整个群落。

半天然杉阔混交林优势种群的增长规律

采用有限空间种群增长的逻辑斯谛模型,研究半天然杉阔混交林群落中主要种群（杉木、米储）的底面积增长规律,指出杉木、米槠在不同类型群落中的底面积的最大增长速度的径级范围。

闽西北天然杉阔混交林杉木及其伴生树种种群动态研究

采用立木级存活数据、存活曲线以及数量动态等方法对闽西北天然杉阀混交林杉木及其伴生树种木荷和丝栗栲的种群动态进行研究。结果表明,木荷和丝栗栲种群立木级结构齐全,属于成熟种群,林下幼苗和幼树较多,属于增长种群;杉木种群立木级结构齐全,属于成熟种群,林下幼苗和小树数量较少,属于衰退种群。

梅花山自然保护区不同海拔段天然杉阔混交林物种组成

梅花山国家级自然保护区内不同海拔段杉阔混交林中,杉木(Cunninghamia laceolata)、毛竹(Phyllostachys pubescens)、木荷(Schima superba)、上杭锥(Castanopsis lamontiivar.shanghangensis)、厚叶厚皮香(Ternstroemia kwangtungensis)和黄山松(Pinus taiwanensis)是主要建群种。在不同海拔段的群落中各建群种的优势变化明显。随海拔升高,乔木层中杉木、毛竹、木荷的优势下降明显,厚叶厚皮香、黄山松和上杭锥则随海拔升高其重要值增大。在下木层中,这些树种的优势明显下降,仅厚叶厚皮香在950-1250m的海拔段其重要值的排序进入前10位。在地被层中,部分树种幼苗的重要值有所提高,表明这些建群种有一定的更新潜力。

云南高黎贡山自然保护区贡山天然台湾杉生境植物群落结构研究

高黎贡山处于云南与缅甸的交界之处,北边与高原相连,南边与半岛相接,其在气象与生物学方面存在由南到北的过渡性,是森林系统当中由热带向温带过渡的唯一地区。正由于高黎贡山所处的独特地理位置,因此成为了台湾杉的良好生长场所,然而由于山脉的地区环境差异,台湾杉的群落结构与其他树木相比也存在较大的差别。本文将对高黎贡山保护区的台湾杉木的群落特征进行进一步地研究。

Study on tracheid variation of Picea koraiensis (nakai) in natural stand and plantation

Tracheid characteristics ofPicea koraiensis from natural stand in Liangshui area and plantation in Mao'ershan area were studied. The results of variance analysis showed that the tracheid length, diameter, and thickness of tracheid wall were significant differences between the growth rings. All those characteristics tend to increase from heart-center to bark. In natural stand, it has positive correlation between the characteristics. In plantation, the tracheid length has positive correlation with the trachied diameter, while both the trachied length and the trachied diameter has negative correlation with the thickness of trachied wall. The tracheid length and diameter have no significant difference in growth between natural stand and plantations. The thickness of tracheid wall from the plantation is a little thicker than that from the natural stand before 15 years.

Microbial biomass in subtropical forest soils： effect of conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation

Conversion of natural secondary broad-leaved forest to Cunninghamia lanceolata plantation is a common management practice in subtropical China. In this study, we compared soil physico-chemical properties, microbial biomass in one natural secondary broad-leaved forest and two C. lanceolata plantation sites to estimate the effects of forest conversion on soil microbial biomass at the Huitong Experimental Station of Forestry Ecology, Chinese Academy of Sciences. Concentrations of soil organic carbon, total nitrogen, NH4^＋-N and microbial biomass carbon and nitrogen were much lower under C. lanceolata plantations as compared to natural secondary broad-leaved forest. Soil microbial biomass C in the first and second rotation of C. lanceolata plantations was only 53%, 46% of that in natural secondary broad-leaved forest, and microbial biomass N was 97% and 79%, respectively. The contribution of microbial biomass C to soil organic C was also lower in the plantation sites. However, the contribution of microbial N to total nitrogen and NH4^＋-N was greater in the C. lanceolata plantation sites. Therefore, conversion of natural secondary broad-leaved forest to C. lanceolata plantation and continuous planting of C. lanceolata led to the decline in soil microbial biomass and the degradation of forest soil in subtropical China.

A New Method for Isolating and Purifying Natural Drug Taxol

A pharmacological interaction target (PIT) method for solving the difficult problem in the separation of taxol from cephalonmanine was proposed. A two-phase extraction technique was used to carry out the PIT separation process. The effects of buffer, temperature and protein on the separation were investigated. Feasible disassembly conditions were also discussed. The final purity of taxol can reach 95% or higher.

天然二萜类衍生物DS2抑制胃癌细胞增殖及迁移

目的探讨合成的对映．贝壳杉烷型二萜类衍生物DS2抗胃癌细胞增殖及迁移的作用及其可能机制。方法采用四甲基偶氮唑蓝法、平板克隆实验和流式细胞术检测DS2对胃癌细胞增殖的影响，采用划痕实验和Transwell实验检测DS2对胃癌细胞MGC．803迁移的抑制作用，采用Westernblot检测DS2对细胞迁移相关蛋白表达的影响。结果DS2可抑制胃癌细胞增殖。6．25μmol／LDS2作用MGC．803、SGC-7901和HGC-27胃癌细胞24h后，细胞的生存率分别为（53．87±3．05）％、（55．91±6．97）％和（32．41±2．64）％；DS2对胃癌细胞的抑制活性呈剂量依赖性，而对正常胃黏膜细胞GES-1影响不大，其生存率为（83．47±1．77）％。DS2可将胃癌细胞MGC-803周期阻滞在G2／M期，同时诱导其凋亡，DS2以阻滞细胞周期和诱导凋亡的方式抑制胃癌细胞的生长增殖。DS2对MGC-803细胞的单克隆形成及迁移能力均有明显的抑制作用，并呈现剂量依赖性：DS2作用于MGC-803后可上调E-cadherin的表达，下调β-catenin和N-cadherin蛋白的表达。结论新化合物DS2具有强烈的抗胃癌活性，为设计合成更多、更有效的二萜类抗肿瘤衍生物奠定基础。