Simple method of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> cultivation in liquid nutrient medium

Simple method of Arabidopsis thaliana w.t. cv. Columbia (L.) Heynh. cultivation in liquid nutrient medium is presented. After 5 weeks of growth in soil, the plants were transferred to modified Hoagland nutrient medium. This allowed us to cultivate Arabidopsis in conditions comparable to all other hydroponically grown higher plants used in plant physiology and plant stress physiology experiments. Absence of agar in growth medium and free access to whole root system makes this method useful also in experiments concerning root physiology.     

Entrepreneurs, Elites, and Exclusion in Maasailand: Trends in Wildlife Conservation and Pastoralist Development

Maasai pastoralists in Kenya are rapidly diversifying. Maasai may now derive their main livelihoods (and sometimes considerable income) from farming, wildlife tourism, and/or the leasing of land for large-scale cereal cultivation. The spread of large-scale commercial cultivation competes with wildlife for grazing land, and wildlife populations around protected areas are rapidly declining as a result. This paper presents new data to analyse the way returns from different land uses, and the social structures affecting their distribution, influence the land-use choices being made by Maasai around the Mara National Reserve in Kenya. Returns to different interest groups from livestock, cultivation, and wildlife enterprises, seen in the light of current social, economic, and political trajectories, can help to clarify likely future land-use trends in the Mara. In particular, community conservation initiatives that seek to make conservation worthwhile to reserve-adjacent dwellers inevitably have a strong economic dimension. However, the choices made by Maasai landowners are not a simple function of the economic returns potentially accruing from a particular enterprise. They are as much or more influenced by who is able to control the different flows of returns from these different types of enterprise. These findings are relevant not only for the wider Serengeti-Mara Ecosystem, but also for pastoral livelihoods and wildlife conservation elsewhere in sub-Saharan Africa.     

盐碱地种植麻黄试验研究

麻黄在干旱区硫酸盐,氯化物盐碱地中种植,其土壤0-30cm土层含盐量1.2%以下生长良好,初步化验分析,麻黄在盐碱地中种植其麻黄碱含量有所提高,同时可获得较大的社会、生态、经济效益。     

低浓度蒽对两种海洋微藻生长的兴奋效应

以两种海洋微藻金藻 870 1(Isochrysisgalbana 870 1)和骨条藻 (Skeletonemacostatum )为材料 ,研究了低浓度蒽 (1 5～ 6 μg·L-1)对两种海洋微藻生长的影响 .结果表明 ,在一定浓度蒽作用下 ,两种微藻的生长均呈现出较明显的“兴奋效应” ,细胞密度有所增加 ,但达到最佳刺激作用的浓度与时间有所不同 .在刺激浓度作用下 ,两种微藻体内的蛋白质、叶绿素a(chla .)、类胡萝卜素 (car.)含量都有所增加 ,其变化趋势与细胞密度的变化类似 .在整个实验过程中 ,微藻体内清除活性氧的关键性酶超氧化物歧化酶 (SOD)始终处于较高水平 ,其变化趋势类似于细胞密度的变化     

黄土丘陵区藓结皮人工培养方法试验研究

以陕北黄土丘陵区自然发育的藓结皮为繁殖材料,通过室内人工培养研究了藓类植物孢子繁殖法(孢子法)、植物碎片营养繁殖(断茎法)以及生物结皮团块粉碎(碎皮法)接种等不同方法对藓结皮形成发育的影响,并对不同培养温度和土壤含水量条件下的藓结皮生长发育进行比较分析.结果表明,(1)相同培养条件下,碎皮法接种有利于藓结皮盖度的形成,在20℃、光照5 230 lx、光周期12 h/d条件下,经80 d培养,藓结皮盖度、密度分别达到76%和59株/cm2,且显著高于其他方法.(2)不同的接种量对藓结皮形成发育影响显著,采用碎皮法,接种量在500～750 g/m2水平下藓结皮的盖度和藓类植物的密度生长较高.(3)温度显著影响藓结皮的形成和发育,在试验条件下,17℃有利于藓结皮盖度、藓类植株密度和株高的生长.(4)土壤含水量只有>60%田间持水量时才有藓结皮形成,当土壤含水量达到超饱和含水量,并在近地面处有水汽存在时则更有利于藓结皮的形成和发育.     

培养方式对盐藻生长和积累β-胡萝卜素的影响

盐藻细胞生长和积累β-胡萝卜素的最佳条件存在差异,通过正交实验获得盐藻生长最适浓度C、N、P的分别为15、2．0、0．2mmol／L,累积β-胡萝卜素最适浓度分别为15、1．0,0．1mmol／L。比较了一次添加型、分次添加型、不完全更换型和完全更换型4种培养方法对生长和累积β-胡萝卜素的影响,发现完全更换型培养方式有利于β-胡萝卜素的积累。中途补给10mmol／L NaHCO3也有利于藻细胞积累β-胡萝卜素。在实验最佳条件下藻液中的β-胡萝卜素含量是对照的1．43倍。可采用先快速培养盐藻细胞、后更换培养基、添加NaHCO3分段培养方式以促进细胞大量合成β-胡萝卜素。     

中药大蒜素体外抗弓形虫效应及其机制的研究

目的 观察大蒜提取物体外抗弓形虫的作用效果及其机制.方法 将弓形虫RH株速殖子与兔肾细胞共同培养,加入不同浓度的大蒜素(实验组)和磺胺嘧啶(阳性对照组),培养不同时间后取出细胞,固定染色后观察细胞感染率及每个纳虫泡中弓形虫速殖子的数量;采用MTT比色法观察大蒜素对弓形虫速殖子侵袭细胞及其正常细胞增殖的影响;采用台盼兰着色法观察大蒜素对弓形虫速殖子活性的影响;采用TUNEL末端标记法检测弓形虫速殖子凋亡率,对药物的效应和机制进行探讨.结果 (1)10～80 μg/ml的大蒜素能抗弓形虫的感染,呈现剂量依赖性,与时间无明显的相关性.(2)40 μg/ml、80 μg/ml的大蒜素不能抑制细胞的增殖,对细胞无明显的毒副作用;160 μg/ml的大蒜素对细胞有明显的毒副作用.(3)大蒜素80 μg/ml时,台盼兰着色率最高,弓形虫的活力最低.(4)大蒜素80 μg/ml的浓度时,弓形虫速殖子凋亡率最高.结论 大蒜素可以抑制弓形虫速殖子的活力、对宿主细胞的感染力、在细胞内的增殖,无明显的毒副作用,最适宜浓度为80 μg/ml.大蒜素是一种良好的抗弓形虫药物,诱导弓形虫速殖子凋亡是其抗弓形虫机制之一.     

蔓荆子野生品及不同采收期栽培品氨基酸成分分析

目的比较蔓荆子野生品及不同采收期栽培品中氨基酸成分及含量。方法色谱柱3μm×4.6 mm×60 mm,缓冲液流量0.4 m1.min-1,茚三酮流量0.3 m1.min-1,分析时间30 min。结果蔓荆子生药材中检出17种氨基酸,野生与栽培蔓荆子中氨基酸总量分别为32.5 g.kg-1和46.5 g.kg-1,8月下旬、10月中旬、12月中旬3个采收期栽培蔓荆子中氨基酸总量分别为44.7 g.kg-1、47.5 g.kg-1和47.2 g.kg-1。结论蔓荆子中氨基酸总量与其生长环境及方式有关,栽培品质量优于野生品;不同采收期蔓荆子中氨基酸总量无明显差异。     

Effects of repeated cultivation of transgenic Bt cotton on functional bacterial populations in rhizosphere soil

The impact of multiple-year (0–5 years) cultivation of transgenic Bacillus thuringiensis (Bt) cotton on the functional bacterial populations in rhizosphere soil was investigated. The transgenic Bt + CpTI cotton line SGK321 and a non-Bt cotton line Shiyuan321 were planted in four fields in which Bt cotton had been continuously cultivated for 0, 1, 3, and 5 years. Rhizosphere soil samples were collected at the seedling, squaring, flower and boll, and boll-opening stages of cotton. Numbers of bacteria involved in nitrogen-fixing, organic phosphate-dissolving, inorganic phosphate-dissolving, and potassium-dissolving were measured with cultivation-dependent approaches. The data presented here showed no consistent statistically significant differences in the numbers of different groups of functional bacteria between rhizosphere soil of Bt and non-Bt cotton in the same field, and no obvious trends in the numbers of the various group of functional bacteria with the increasing duration of Bt cotton cultivation. These studies suggest that multiple-year cultivation of transgenic Bt cotton may not affect the functional bacterial populations in rhizosphere soil.     

生物破乳剂产生菌混合培养及其发酵条件的优化

【目的】对菌株L1和XH1的混合发酵条件进行优化,为混合菌发酵生物破乳剂的实际生产和应用提供理论依据。【方法】利用响应面实验(RSM)的中心组合旋转设计方法(CCRD)针对混合菌的发酵条件进行优化,通过对模型乳状液进行破乳实验,以排油率作为发酵液破乳效能的评价标准。【结果】经模型的分析与验证,确定最佳发酵条件为：种子液比例(L1:XH1)为3:2,葡萄糖投加时间为第4天,投加葡萄糖后再培养21 h,液体石蜡含量3.6% (体积比)。【结论】与破乳菌XH1和L1单独培养相比,经混合培养后获得复合生物破乳剂具有投加量少、破乳接触时间短的优势。同时双株破乳菌复配培养有效地提高了培养基中主要营养物质的利用率,减少了对底物的浪费。