Fractal root system of Melica przewalskyi along different aspect in degraded grassland

Aims Fractal root system is phenotypic plasticity result of plant root architecture to respond to environmental heterogeneity, may reflect the growth strategy of plants to adapt to environmental conditions. Our objective was to explore the relationship between root fractal dimension and fractal abundance of fractal root system of Melica przewalskyi population in response to aspect variation in the northwest of China. Methods The study site was located in a degraded alpine grassland on the northern slope in Qilian Mountains, Gansu Province, China. Survey and sampling were carried out at 40 plots which were set up along four slope aspects transects with 20 m distance between adjacent plots. Handheld GPS was used to determine the elevation, longitude and latitude of each plot. ArcGIS was used to set up digital elevation model (DEM). Community traits were investigated and six individuals roots of M. przewalskyi were collected randomly at each plot. The samples were cleaned and divided into different organs, then scanning the root with the Win-RHIZO for measurements of fractal dimension and fractal abundance in laboratory, and their biomass were then measured after being dried at 80 °C in an oven. Important findings With the slope aspect turned from north to east, west, and south, the density, height and soil moisture content of the plant community displayed a pattern of initial decline, the height, density, root fractal abundance of M. przewalskyi increased and the root fractal dimension decreased. The root fractal dimension was negatively associated with the fractal abundance in all aspects, but the relationship varied along the slope aspects gradient; there was a highly significant negative correlation (p < 0.01) between the root fractal dimension and fractal abundance at north slope and south slope aspect, whereas the correlation only reached a significant level (p < 0.05) at the east slope aspect and west slope aspect; indicating that there is a trade-off between the root fractal dimension and fractal abundance. In addition, when the slope aspect changed from north to east, west and south, the standardized major axis (SMA) slope of the regression equation in the scaling relationships between root fractal dimension and fractal abundance increased (p < 0.05), indicating that the roots of M. przewalskyi at the droughty southern slope have less branch and more sparse in the same soil volume of root exploitation and utilization. Consequently, the resource allocation pattern on reasonable trade-off between root fractal dimension and fractal abundance in different slope aspect of M. przewalskyi, reflects the relationship between the income and the cost of construction of plant root architecture.     

广西种子植物小资料

几年来,我所在中草药资源调查工作中,发现一些我国及广西未曾记录过的植物,现整理成文,以供有关部门参考。本文引用的标本均收藏在广西中医药研究所植物标本室(GXMI)。 山椒子水番挑(博白)番落技科Annonaceae Uvar花a grandiflora Roxb.in FI.Ind.2:665.1524;李秉滔,植物分类学报14(1):98.2976,蒋英,李秉滔,中国植物志30(2):26,图版10. 1979。 广西东南部:博白县,浪平公社,水库边1971年5月9日,王鉴均2247外北流县,隆盛公社,天堂,坡地疏林中,1977年9月26日北流调查队8一44口7。 分布:广东南部,广西东南部;印度、缅甸、泰国、越南、马来…     

黄山北草核的核型和G带带型研究

本文研究了北草晰的核型和G带带型,结果表明,北草蝴的染色体数2。二38,由18对常染色休和 1对性染色休组成．常染色体可分成三组：1组有2对染色体;11组包括15对染色体;而川组仅含 1对微小染色体。性染色体为ZW型．这个种的染色体均为端部着丝粒,其AN二38包括1对Z染色 体）,从核型特征上看,可能是晰蝎类中较原始的种。从G带显示结果可见,北草晰的各染色体对均有 其特有的带型,容易辨别。     

红豆草组织培养物的超低温保存及其超微结构的观察

红豆草(Onobrychis viciaefolia Scop.)组织培养物在5%DMSO+10%甘油+8%蔗糖的冰冻保护剂及以1℃/分钟的速度降温到-35—-40℃,停留2小时后,投入液氮,40℃水浴快速化冻等条件下,存活率达60—70%,并保持了高的分化能力。电子显微镜的观察结果表明,快速冰冻和1℃/分钟慢速冰冻至-35℃—40℃不停留,对细胞结构造成严重的致死性破坏;-35℃停留30分钟对细胞结构的损伤是可逆性的;停留2小时的其超微结构基本上与对照材料无明显差别。     

草蛉科纳草蛉属研究（Ⅱ）—六新种记述（脉翅目：草蛉科）

本文是纳草蛉属Navasius研究续报(研究Ⅰ见“动物分类学报”第15卷第3期)。报道了纳草蛉属6新种:跃纳草蛉N.igneus sp.nov.,冠纳草蛉N.lophophorus sp.nov.,黑角纳草蛉N.nigricornutus sp.nov.显沟纳草蛉N.phantosulcus sp.nov.康纳草蛉N.sanus sp.nov.及三齿纳草蛉N.tridentatus sp.nov.。     

广西植物一新种和二新变种

<正> 1.百色黄精新种 图2(百合科) Polygonatum longistylum Y. Wan ex C. Z. Gao,sp.nov. (Liliaceae) Haec species P. cathcartii Baker affinis, sed laminis foliorum apice circinatis,filamentis apice non sacciformibus,stylo ovario fere(?)-plo longiore facile differt.     

金雀花碱的植物生长调节活性

应用植物激素生物试法测定了金雀花碱（cytisine)的某些植物生长调节活性,实验结果表明：金雀花碱抑制小麦芽鞘切段的伸长,但促进黑暗中（26℃）培养的离体黄瓜子叶鲜重的增加;能明显促进黑暗中（25℃）培养的离体黄瓜子叶的生根作用和根的生长。能显著提高离体黄瓜子叶中吲哚乙酸氧化酶的活性,这些现象说明,金雀花碱具有明显的植物生长调节活性。     

盐泽螺旋藻(Spirulina subsalsa)藻胆体的分离和特性

采用一种简便而快速的方法分离了盐泽螺旋藻的藻胆体。藻胆体的最大吸收波长位于618 nm,室温下荧光反射峰位于677～678 nm。利用7～15％SDS—聚丙烯酸胺梯度凝胶板状电泳,可分出三条有色多肽,其中藻蓝蛋白的α亚单位与别藻蓝蛋白的α亚单位几乎重叠,不易区分;另有分子量为117,99,53,49,27,24.5和14kD的七条无色多肽。117和 99kD多肽可能联结藻胆体和类囊体,并作为末端能量受体,而14kD多肽多为“核”亚结构的组分,其余的可能为“棒”亚结构内和“核”“棒”亚结构间的联结蛋白。