Characters and Species Diversity of Torreya fargesii Franch. Community in the Jinfo Mountains

This paper aims to study characteristics and biodiversity of the Torreya fargesii community in the Jinfo Mountains to provide baseline information related to the protection of T. fargesii. The results indicated that among the 5 plots(100 m2 each) set along an altitudinal gradient, 176 species of vascular plants, 136 genera and 64 families were recorded. These included 7 species of pteridophytes, 6 genera and 4 families, 3 species of gymnosperms, 3 genera and 2 families, and 166 species of angiosperms, 127 genera and 58 families. The community physiognomy was mainly dominated by phanerophytes with medium-sized herbaceous and simple leaves. The proportions of phanerophytes among the fl oristic spectrum, frequency spectrum and vegetational spectrum are 68.75%, 73.13% and 67.48% respectively. The vertical structure can be divided into the shrub and herb layers in this community. The dominant species in shrub layer were T. fargesii, Zanthoxylum ovalifolium, Rubus coreanus, Kerria japonica, Cotoneaster horizontalis etc.. The dominant herbs included Miscanthus sinensis, Carex gibba, Artemisia lactifl ora, Pteridium aquilinum var. latiusculum, Pilea notata, Aster ageratoides etc.. Species richness(S) and the Simpson(D), Shannon-Wiener(H') and Pielou evenness(Jsw) indices of shrub layer species richness are higher than those of the herb layer; the distribution of the species in the community is obviously uneven. The species richness and diversity indices increase with the rising altitude.

Allelopathic Effects of Aqueous Extract of Torreya fargesii Aril on Seed Germination and Seedling Growth of Radish, Mustard and Cabbage

[Objective] This study aimed to investigate the allelopathic effects of Torreya fargesii aril. [Method] By indoor bioassay, the effects of different con-centrations （10, 20,40, 80 g/L） of aqueous extract of T. fargesii aril on seed germination rate, seedling root length, seedling height, fresh weight, chlorophyll content, malondialdehyde （MDA） content and anti oxidative enzyme activities of radish, mustard and cabbage were analyzed and compared. [ Result] Different concentrations of aqueous extract of T. fargesii aril inhibited seed germination and seedling growth of three crops, and the inhibitory effects were enhanced with the increase of concentration. Seedling height and fresh weight of three crops were improved by low concentrations of aqueous extract of T. fargesii aril and inhibited by high concentrations of aqueous extract. Overall, aqueous extract of T. fargesii aril exhibited allelopathic inhibitory effects on three crops, and the level of allelopath-ic inhibitory effects demonstrated a descending order of radish 〉 mustard 〉 cabbage. Compared with the control group, 80 g/L aqueous extract of T. fargesii aril almost significantly reduced seed germination rate, seedling root length, seedling height, fresh weight and chlorophyll content, and significantly improved MDA con-tent and antioxidative enzyme （SOD, CAT, POD） activities of radish, mustard and cabbage （P 〈 0 .0 5 ） . [ Conclusion] Aqueous extract of T. fargesii aril exhibited remarkable allelopathic inhibitory effects on seed germination of radish, mustard and cabbage, which indicated that there might be dormancy-associated germination in-hibiting allelochemicals in T. fargesii aril. This study provided theoretical basis for subsequent clarification of the mechanism of seed dormancy of T. fargesii.

Responses of Leaf Functional Traits of Torreya fargesii to the Altitudinal Variation

[Objective] To reveal the leaf functional traits and adaptive strategy of Torreya fargesii at different altitude gradients.[Method] Leaves of T. fargesii were selected from the altitudes of 1 570, 1 700, 1 900, 2 125 and 2 360 m in Jiajinshan forest area of Sichuan Baoxing County, and the altitudes of 1 000, 1 200, 1 450, and 1 700 m in Hua'eshan Mountain Nature Reserve of Sichuan Wanyuan County as the research materials. Leaf blade traits such as leaf length, leaf width, leaf girth, leaf area and leaf dry weight were determined, and the influence of altitude on each index and correlation between characters were analyzed. [Result] For the leaves from both Baoxing County and Wanyuan County, leaf length, leaf width, leaf girth, leaf aspect ratio and leaf area decreased with the increase of altitude. There was no significant difference in the changes of leaf width, leaf girth and leaf aspect ratio among different altitudes(P>0.05), while the difference was significant in leaf length between high altitude and low attitude(P<0.05), and the difference was also significant in leaf area for the leaves from Baoxing County between high altitude and low altitude. However, there was no obvious correlation between leaf width and altitude, which could be considered as a relatively stable parameter. Leaf thickness and leaf dry weight increased first and then decreased with altitude,while the specific leaf area decreased first and then increased. In leaf length, leaf girth, leaf width and leaf area parameters, except for leaf width and leaf area for the T. fargesii from Wanyuan County, any two parameters reached significant or very significant positive correlation level(P<0.01). Leaf dry weight and leaf thickness had significant or very significant positive correlation, leaf dry weight and leaf area had a certain positive correlation but not significant. There existed no significant positive correlation between specific leaf area and leaf area, while specific leaf area was in negative correlation with leaf dry weight, and the negative correlation of specific leaf area with leaf area of T. fargesii from Wanyuan County reached the significant level.[Conclusion] T. fargesii adapted to different altitudes by changing leaf dry weight, leaf area and leaf area ratio, and the most suitable altitudes for the growth of T. fargesii were 1 900 and 1 450 m in Baoxing and Wanyuan area respectively.

阔叶榧总DNA的提取及其RAPD反应条件的研究

在阔叶榧新鲜针叶DNA提取过程中 ,应用 pH值较低 ,无机盐浓度较高的提取缓冲液可沉淀蛋白质 ,其中加入 2 %的 β 巯基乙醇可有效地防止次生代谢物质使DNA变色 .提取出的DNA样品产率在 83.7～ 197.5ng/mg .f.,DNA质量和纯度较高 ,2 6 0nm/ 2 80nm光密度比值在 1.8～ 1.9之间 .所得DNA可直接用于限制性内切酶酶切 ,并可用于随机引物PCR扩增 .在优化RAPD各种反应条件研究中 ,确定了阔叶榧最佳RAPD反应体系为 :15 μL反应体系中含有 5 0mmol/LKCl、10mmol/LTris HCl (pH 9.0 )、0 .1%Triton 10 0、3nmol/ μLMgCl2 、0 .6nmol/ μLdNTPs、6 μg/ μLBSA、1UTaq酶、6 0ng引物、5 0～ 10 0ng左右的阔叶榧DNA .

巴山榧树枝和叶提取物的抗氧化能力、抑菌活性与挥发性成分

探究巴山榧树枝和叶提取物的抗氧化能力、抑菌活性和枝叶挥发性成分,为开发利用巴山榧树的食用或药用价值提供科学依据。利用90%乙醇超声提取巴山榧树枝和叶,采用自由基清除率测定抗氧化能力,牛津杯法分析抑菌活性,顶空固相微萃取-气相色谱质谱联用法检测枝叶挥发性成分及其相对含量。结果发现,巴山榧树枝和叶的提取物对DPPH、ABTS^(+)和羟基自由基有不同程度的清除作用,以开州区的巴山榧树枝提取物对DPPH和ABTS^(+)自由基清除率最高,分别达到39.9%和95.3%;开州区巴山榧树叶提取物的羟基自由基清除率最高,达到69.8%。巴山榧树枝和叶的提取物显著抑制大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌的生长和繁殖,以开州区巴山榧树枝提取物对枯草芽孢杆菌的抑菌活性最强,抑菌圈直径达到26.9 mm。巴山榧树枝和叶的挥发性成分中98%以上为萜烯类化合物,以单萜和倍半萜为主。巴山榧树枝和叶提取物具有较强的抗氧化能力与抑菌活性,其枝叶挥发性成分主要为单萜和倍半萜。