首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 15 毫秒
1.
1983年总目录     
昆虫的卵····,·························……夏邦颖动物界的一个新门—扁盘动物门简介…… ......·.··..························……吴宝铃海参的形态结构和生活习性······……许慈荣娱蛤和马陆···············……张崇洲张福祥略淡软体动物的齿舌·····一陈德牛高家祥弓l‘植物学部分,矛2,哎少.12,J,‘6 6 60曰,8,1 04︸6曰,3廿0 93润翻,.﹄12,‘,勺,‘22,‘,几22,且.几,几,‘,‘,j,jJ,4︼,︼勺巴」 作者世界著名观赏树种—琪碉······……林…  相似文献   

2.
胡杨异形叶叶绿素荧光特性对高温的响应   总被引:4,自引:0,他引:4  
王海珍  韩路  徐雅丽  王琳  贾文锁 《生态学报》2011,31(9):2444-2453
胡杨(Populus euphratica Oliv)是塔里木极端干旱荒漠区优势乔木树种,由于其生长在荒漠环境中,极端高温远高于其它地区,因此研究胡杨对高温胁迫的响应特征对于解释胡杨的抗逆机理与生态适应策略具有极为重要的意义。以胡杨3种典型的异形叶为材料,研究不同温度对其叶绿素荧光特性和能量分配的影响。结果表明,25-45 ℃温度下胡杨异形叶的F0FmFv/FmFv/F0变化不大,尤其Fv/Fm仍能保持在0.78左右,光合反应正常;高温胁迫下(>45 ℃)FmFv/F0Fv/FmF'v/F'mqPΦPSⅡ、P和ETR均大幅降低;F0qNE显著上升,而D先上升后下降,说明高温抑制了PSⅡ的功能,使PSⅡ反应中心活性下降,QA-的还原速率加快,光化学电子传递速率降低,某些能量耗散途径受阻,影响了PSⅠ和PSⅡ激发能的平衡分配,最终导致光合机构受损、光合速率降低。胡杨3种异形叶的叶绿素荧光参数随温度升高变幅不同,高温处理下锯齿阔卵形叶各参数均高于卵形叶与条形叶,表明锯齿阔卵形叶比卵形叶和条形叶具有更强的高温耐受能力。用模糊数学的隶属度函数对胡杨3种异形叶的耐热性进行综合评价,锯齿阔卵形叶的耐热性最强。  相似文献   

3.
We studied the peculiarities of permeability with respect to the main extracellular cations, Na+ and Ca2+, of cloned low-threshold calcium channels (LTCCs) of three subtypes, Cav3.1 (α1G), Cav3.2 (α 1H), and Cav3.3 (α1I), functionally expressed in Xenopus oocytes. In a calcium-free solution containing 100 mM Na+ and 5 mM calcium-chelating EGTA buffer (to eliminate residual concentrations of Ca2+) we observed considerable integral currents possessing the kinetics of inactivation typical of LTCCs and characterized by reversion potentials of −10 ± 1, −12 ± 1, and −18 ± 2 mV, respectively, for Cav3.1, Cav3.2, and Cav3.3 channels. The presence of Ca2+ in the extracellular solution exerted an ambiguous effect on the examined currents. On the one hand, Ca2+ effectively blocked the current of monovalent cations through cloned LTCCs (K d = 2, 10, and 18 μM for currents through channels Cav3.1, Cav3.2, and Cav3.3, respectively). On the other hand, at the concentration of 1 to 100 mM, Ca2+ itself functioned as a carrier of the inward current. Despite the fact that the calcium current reached the level of saturation in the presence of 5 mM Ca2+ in the external solution, extracellular Na+ influenced the permeability of these channels even in the presence of 10 mM Ca2+. The Cav3.3 channels were more permeable with respect to Na+ (P Ca/P Na ∼ 21) than Cav3.1 and Cav3.2 (P Ca/P Na ∼ 66). As a whole, our data indicate that cloned LTCCs form multi-ion Ca2+-selective pores, as these ions possess a high affinity for certain binding sites. Monovalent cations present together with Ca2+ in the external solution modulate the calcium permeability of these channels. Among the above-mentioned subtypes, Cav3.3 channels show the minimum selectivity with respect to Ca2+ and are most permeable for monovalent cations. Neirofiziologiya/Neurophysiology, Vol. 38, No. 3, pp. 183–192, May–June, 2006.  相似文献   

4.
Trypanosomes were isolated from Atlantic cod Gadus morhua L. collected from several fjords in western Norway. Morphological studies showed that the 12 infections studied represented a single species, identified as Trypanosoma pleuronectidium Robertson, 1906 which is resurrected and redescribed. This species is characterised by its body length (57.9 ± 5.4 μm), nearly central nucleus (NI = 1.05 ± 0.12) and relatively short post-kinetoplastic (PK) region (3.2 ± 0.8 μm). T. pleuronectidium is transmitted by the leech Calliobdella nodulifera (Malm). T. murmanense Nikitin, 1927 (emend.) is delimited to a species transmitted by the leech Johanssonia arctica (Johansson). This species is separated from T. pleuronectidium by its attained body length, more anterior nucleus, presence of cytoplasmic refractive granules, adnuclear vacuoles and by a longer PK region. Partial SSU rDNA sequences of T. pleuronectidium and T. murmanense from Norway (1980 nt) diverged by 1.9%. The nominal North Atlantic and Mediterranean trypanosome species are reviewed, and T. flesi Lebailly, 1904, T. bothi Lebailly, 1905 and T. limandae Brumpt & Lebailly, 1904 are considered synonyms of T. platessae Lebailly, 1904. T. triglae senegalensis Ranque, 1973 is not considered conspecific with T. triglae Neumann, 1909, and consequently raised to species status as T. senegalense Ranque, 1973. Some other likely synonymies are discussed. In addition to T. pleuronectidium and T. murmanense, the following marine teleost trypanosomes are provisionally listed as valid species pending further study: T. callionymi Brumpt & Lebailly, 1904; T. cotti Brumpt & Lebailly, 1904; T. delagei Brumpt & Lebailly, 1904; T. dorhni Yakimov, 1911; T. gobii Brumpt & Lebailly, 1904; T. laternae Lebailly, 1904; T. myoxocephali Fantham, Porter & Richardson, 1942; T. platessae Lebailly, 1904; T. scorpaenae Neumann, 1909; T. soleae Laveran & Mesnil, 1901; T. triglae Neumann, 1909; and T. yakimovi Yakimov, 1911.  相似文献   

5.
《生物技术通讯》2003,14(6):582-586
(第14卷,总第55~60期)研究报告 遗传修饰小鼠胚胎干细胞种系嵌合体小鼠的研制·································……程董,周江,谭晓红,等(l) 新型纳米转染试剂转染PNP自杀基因体外杀伤实验···························……杜芝燕,黄伟,李峰生,等(4) 犬2型腺病毒E3区表达载体的构建················································……邱薇,夏咸柱,范泉水,等(8) 间隔臂和探针长度与寡核昔酸芯片重复性相关性研究····…  相似文献   

6.
Annual gross primary productivity in mesotrophic Shahidullah Hall pond (Dhaka, Bangladesh) was 1383.35 g C m−2 y−1 (arithmetic mean). Daily primary productivity (between 1.6 and 6.8 g C m−2 d−1 was correlated with chlorophylla, day length and dissolved silica. Chlorophylla related significantly withk, incident light, SRP, alkalinity and conductivity. A negative correlation existed between biomass and rainfall. Productivity, biomass, conductivity, alkalinity, and SRP increased after mid-winter.k, I k andZ eu varied according seasonally.P max related directly with temperature. Seasonal variation of ∝ B was 0.0049–0.0258 mg C (mg chla mmol PAR)−1 m−2. Q10 was 2.12, community respiration 1334.99 g C m−2 y−1, and the underwater light climate 186.43μE m−2 s−1.  相似文献   

7.
千烟洲红壤丘陵区人工针叶林土壤CH4排放通量   总被引:3,自引:0,他引:3       下载免费PDF全文
 CH4在温室效应中起着重要作用,为估算中亚热带CH4的源汇现状,评价森林生态系统对温室效应的影响,采用静态箱-气相色谱法研究了千烟洲红壤丘陵区人工针叶林的土壤CH4 排放通量特征及水热因子对其的影响。对2004年9月~2005年12月期间的观测结果分析表明 :千烟洲人工针叶林土壤总体表现为大气CH4的吸收汇,原状林地土壤(Forest soil)情况下,CH4通量的变化为7.67~-67.17μg&;#8226;m-2&;#8226;h-1,平均为-15.53μg&;#8226;m-2&;#8226;h-1;无凋落物处理(Litter-free)情况下,CH4通量的变化是9.31~-90.36 μg&;#8226;m-2&;#8226;h-1,平均为-16.53μg&;#8226;m-2&;#8226;h-1。 二者对土壤CH4的吸收表现出明显的季节变化规律,秋>夏>冬>春,但无凋落物处理CH4变化幅度较原状林地土壤大,无凋落物处理吸收高峰出现在10月,最低值出现在翌年3月,原状林地土壤则分别在9月和翌年2月,均提前1个月。对土壤CH4吸收通量与温度和湿度的相关分析表明: 无论是原状林地土壤还是无凋落物处理情况下,土壤CH4通量都与地下5 cm的温度和湿度相关性最高。偏相关分析反映了不同季节水热配置对土壤吸收CH4通量的影响:冬季为12月~翌年2月,温度起主要作用;雨季3~6月,温度作用为主,随着温度的升高而升高,水分作用微弱;7~8月,CH4吸收通量随着湿度的降低而增加,但高温限制了CH4的吸收;秋季(9~11月)水热配置适宜,CH4通量达到高峰值。总之,CH4吸收通量随着温度的升高和 湿度的降低而增大,但温度过高会抑制其吸收。  相似文献   

8.
三画于龙川,韩济生:家兔下丘脑弓状核区参与从伏核到中脑导水管周围灰质的下行镇痛通路,·····”·“········一(1 17)马新亮,减益民,朱妙章,王跃民:肾上腺髓质在急性心肌缺血时血液流变学变化中的作用····一”···……(1 40)马新亮,范家骏,朱妙章,减益民:急性心肌缺血时低切变率下全血粘度变化机理研究·····“··“”······……(289)四西尹丽艳,谢选珠,高晓明,夏振勤,谢翠微,汤健:心钠素在强啡肤降压效应中的作用··········”······……(343)王庆(见李慧麟等)·····“·”·”····…  相似文献   

9.
内蒙古不同类型草地叶面积指数遥感估算   总被引:5,自引:0,他引:5  
叶面积指数(Leaf Area Index,LAI)是重要的植被结构参数,反演LAI是植被遥感的重要研究内容之一。根据在内蒙古呼伦贝尔和锡林浩特草原利用LAI 2000观测的草地LAI,比较了不同植被指数(SR、RSR、EVI、NDVI、SAVIARVI)估算不同类型草地LAI的能力,建立了基于Landsat-5 TM遥感数据的LAI估算模型,并利用LAI观测数据对模型进行了检验,生成了研究区内草地LAI分布图,据此对MODIS LAI产品一致性进行了评价。结果表明,在呼伦贝尔和锡林浩特两个研究区,RSRLAI的相关性最高(R2分别为0.628、0.728,RMSE分别为0.512、0.490),在低密度草地,RSR的优势更为明显;验证表明,根据RSR建立的LAI估算模型的精度可达70%;利用TM数据生成的两个地区的LAI(TM LAI)空间变化明显,锡林浩特草地的LAI值整体上低于呼伦贝尔草地;在呼伦贝尔和锡林浩特,MODIS LAI产品与TM LAI一致性分别为0.566,0.323,MODIS LAI产品高估了呼伦贝尔草地LAI值,而在锡林浩特研究区则存在低估现象。  相似文献   

10.
第1期研究报告假单胞菌XN一1硝基苯降解性质粒的提取及研究························……刘春,周集体,黄丽萍,吕红(1)嗅氨酸降解菌株的分离和特性···································……李莹,蔡宝立,庄源益,丁春丽,杨湘龙(5)富硒姬松茸液体培养条件的研究··,·····························,·····················……杨淑云,刘朝贵,朱凯(9)缺失氨肤酶N的变铅青链霉菌的构建和鉴定········……,’’,,····…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号