中国顶丝藻科新记录

继续报导中国顶丝藻科新记录６种。渐尖旋体藻Ａｕｄｏｕｉｎｅｌａａｔｅｎｕａｔａ,球状旋体藻Ａ．ｇｌｏｂｏｓａ,纤细旋体藻Ａ．ｇｒａｃｉｌｉｓ,无柄旋体藻Ａ．ｈｙｐｎｅａｅ,偏枝旋体藻Ａ．ｓｅｃｕｎｄａｔａ,连续旋体藻Ａ．ｓｅｒｉａｔａ。     

塔里木河流域胡杨和灰叶胡杨克隆分株空间分布格局

以叶尔羌河下游阿瓦提县天然胡杨和灰叶胡杨混交林、塔里木河上游农一师16团天然灰叶胡杨林和塔里木河中游轮台县天然胡杨林为对象,研究胡杨和灰叶胡杨克隆分株种群的空间分布格局.结果表明: 8种不同取样尺度(5 m×5 m、5 m×10 m、5 m×15 m、10 m×10 m、10 m×15 m、15 m×15 m、15 m×20 m、20 m×20 m)下,3个研究区2物种克隆分株种群的空间分布格局均表现为集群分布,表明集群分布是研究区胡杨和灰叶胡杨克隆分株种群空间分布格局的基本属性;在5 m×5 m尺度上,3个研究区2物种克隆分株种群均表现出负二项参数最小、Cassie指标和聚块性指标最大、聚集强度最大的分布特征.     

莎车巴旦姆物候期对气象条件的响应及花期预测模型

利用莎车县农业气象试验站2008—2013年巴旦姆物候期和同期气象观测资料,分析了巴旦姆物候期的变化特征以及气温、日照时数对物候期的影响.结果表明：巴旦姆花期之前的物候期始日之间均呈正相关,与花期之后的物候期始日的相关性大多较小,花芽膨大早迟与休眠期、生长期天数分别呈极显著的正相关和负相关.以果实成熟期为界,气温对之前、之后物候期间隔日数的影响分别为负相关和正相关,日照时数与物候期间隔日数大多为正相关.果实成熟 叶变色始期间隔日数对平均最高气温以及花序出现 开花末期、叶变色始期 落叶末期间隔日数对日照时数存在明显的响应.当巴旦姆休眠期符合日平均气温-3.0～-7.5 ℃的天数满30 d后,经过17～28 d将进入花芽萌动期.花芽萌动期、开花始期、叶变色始期和落叶末期的始日分别与首个候平均气温≥4 ℃且候平均最高气温≥12 ℃、春季侯平均气温≥14 ℃且侯平均最高气温≥22 ℃、秋季首个侯平均气温≤10 ℃且侯平均最高气温≤18 ℃和冬季首个侯平均气温≤1.9 ℃的候序一一对应.利用偏最小二乘法回归分析,建立巴旦姆盛花期始日预测模型,经过检验模型效果较好.     

Motor Responses to Polarized Light and Gravity Sensing in Euglena gracilis*†

SYNOPSIS. Euglena gracilis strain Z has a motor response which results in orientation with respect to the polarization of a light stimulus. Cells swim preferentially in a direction perpendicular to the plane of polarization of the stimulus. If 2 polarized stimuli are given from opposite directions, the preferred direction is, under certain circumstances, at right angles to the directions of both stimuli. Euglena also preferentially assumes an orientation that is at right angles to the force of gravity. The relationships between these responses and phototactic movements oriented with respect to the direction of the stimulus are discussed.     

Hydrolytic Enzymes of Euglena gracilis: Characterization and Activity as a Function of Culture Age and Carbon Deprivation*†

SYNOPSIS. Optimal assay conditions are described for 8 hydrolases of Euglena gracilis var. bacillaris, SM-L1 (streptomycinbleached) strain, 7 of which have an acid pH-optimum. Acid phosphatase, β-galactosidase, β-glucosidase, β-fucosidase, cathepsin D, RNase, DNase, and an esterase are active in cell homogenates. Amylase has very low activity, and β-glucuronidase, arylsulfatase, β, N-acetyl-glucosaminidase, α-fucosidase, and α- and β-mannosidase are inactive. Hydrolase activity increases as a culture proceeds from the midexponential to the late stationary-phase of growth, being most pronounced in the case of β-glucosidase. In cultures deprived of a utilizable carbon source, the specific activities of the hydrolases (per mg total protein or dry weight) increase. When expressed on a per cell basis, however, the activities of DNase decrease while those of β-galactosidase, cathepsin D, and RNase increase. The hydrolases appear to be involved in the adaptation of Euglena to the metabolic demands imposed by different conditions of growth.     

Isolation of the photoreceptor (paraflagellar body) of the phototactic flagellate Euglena gracilis

We have described a procedure for isolating photoreceptors (paraflagellar bodies) from the unicellular phototactic alga Euglena gracilis. This procedure elicited the evagination of the reservoir membrane, and the detachment of the flagellar apparatus due to the very high concentration of CaCl₂ in the isolation solution that caused a frenetical acceleration of the flagellar beating.     

发根农杆菌转化大豆的研究

本文利用发根农杆菌感染大豆不同外植体,在成熟胚靠近子叶节部位诱导产生毛状根。经冠瘿碱检测表明,毛状根及由此产生的愈伤组织均有甘露碱存在,说明Ri质粒的T-DNA已整合到大豆的转化根及愈伤组织中。转化根再生实验表明,在含NAA和IAA8mg/L的MS培养基上得到不定根的分化,MS和B_3培养基及6％蔗糖对转化丛生芽的诱导有利。转化的丛生芽在MS基本培养基上进一步长成小植株。     

Effects of simulated grazing on different genotypes of Bouteloua gracilis: how important is morphology?

Populations of grasses exposed to grazing by vertebrates often exhibit reduced stature, increased tillering, reduced flowering, and other morphological differences which distinguish them from ungrazed populations. These differences frequently are interpreted as an adaptive response that reduces grazing damage; however, there are few experimental tests of this hypothesis. This paper describes a field experiment designed to determine whether morphological variation among genotypes of the grass Bouteloua gracilis is related to variation in their responses to grazing. Eleven genotypes differing in morphological and reproductive characters were transplanted into a shortgrass steppe community near Fort Collins, Colorado. Replicates of each genotype were subjected to clipping treatments intended to realistically simulate three grazing intensities. After two growing seasons, different genotypes still maintained significant differences in a wide range of morphological and demographic characters. However, there were few significant effects of grazing treatment, and no significant genotype×treatment interactions. These results suggest that for B. gracilis clipped in simulation of natural grazing, defoliation has few short-term effects on fitness components, and intrapopulation morphological variation has few consequences for defoliation resistance. Received: 22 March 1999 / Accepted: 26 October 1999     

甘肃景电灌区不同栽植年限枸杞生物量分配特征

枸杞(Lycium barbarum L.)常作为我国干旱区盐渍化土地开发利用中的首选灌木型经济林,研究枸杞各构件及根系生物量的分配特征可以为提高枸杞生产力及资源的持续利用提供理论依据.在甘肃景电灌区选择栽植4年、7年和11年的构杞,研究构杞枝条、果实、叶片生物量在垂直空间上的分布特征,并按地下根系径级的大小,研究了根系生物量在各径级的分配规律.结果表明:构杞栽植初期植株间高度、冠幅差异较小,栽植7年进入生长旺盛期后差异较大,而栽植11年个体间形态指标差异又减小.栽植4年、7年、11年的构杞总生物量及枝条生物量在50 ～ 100 cm空间最大,而栽植4年的果实及叶片生物量最大值在50～100 cm空间,栽植7年时果实及叶片生物量最大值在100 ～ 150 cm空间.4年生与7年生构杞粗根和细根生物量所占的比例均比较大,11年生时细根的生物量比例明显减小,而粗根的比例则超过了50％.果实与叶片以及中根与粗根的生物量均随栽植年限的增加而增加,但枝条以及细根和极细根的生物量为7年生＞11年生＞4年生.用二次函数可以较好地预测该区域枸杞叶片及地下根系各径级生物量与生长年限之间的关系.     

快速城市化区域不同生境类型的蝴蝶多样性

2011年5—10月,在重庆两江新区选取人工次生林、人工草地、苗圃地、荒草地、农田、天然次生林6种不同生境类型,进行蝴蝶调查。共采集蝴蝶1547只,隶属6科27属37种。结果表明:菜粉蝶(Pieris rapae)、东方菜粉蝶(P.canidia)、酢浆灰蝶(Pseudozizeeria maha)和点玄灰蝶(Tongeia filicaudis)是研究区域的优势种;沿城市化梯度,不同采样断面蝴蝶多样性指数变化趋势明显,即城市化水平越高,多样性指数越低;同时生境类型和人为干扰对蝴蝶多样性影响明显;蝴蝶群落多样性特征可以作为生境质量和环境变化的指标。最后提出:在快速城市化区域中,应根据不同城市化水平、不同生境类型采取有差异的管理措施,保护和提高城市生物多样性。