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141.
ABSTRACT. This report deals with a group of ciliated protozoa with short ciliary bands found mainly in the cecum of black rhinoceros, Diceros bicornis (Linnaeus, 1758), and white rhinoceros, Ceratotherium simum (Burchell, 1817) from southern Africa. A new genus, Rhinozeta , based on the sum total of the characteristics of seven new related species is described. The species described are R. rhinozeta n. sp., R. triciliata n. sp., R. caecalis n. sp., R. addoensis n. sp., R. cristata n. sp., R. multiplatus n. sp., and R. unilaminatus n. sp. The specific features of the new genus make it incompatible with any of the known families of the Order Entodiniomorphida containing the ciliates present in the digestive tract of herbivorous mammals. This merits the creation of a new family, the Rhinozetidae.  相似文献   
142.
L. C. HO   《Annals of botany》1979,43(4):437-448
Simultaneous measurement of export from leaves and import tofruits were made on tomato plants reduced to one fully expandedleaf and one fruit. Experimental leaves were exposed to sixlight flux densities (0.5–100 W m–2) for 24 h whilerapidly growing fruits were kept in the dark at 22 °C. The rates of export of assimilate from these leaves varied from70 to 120 mg C leaf–1 day–1 corresponding with ratesof carbon fixation from 3 to 290 mg C leaf–1 day–1.Export from leaves with the lowest carbon fixation rates weremaintained by a loss of up to one-sixth of their initial carbon.In contrast, leaves with the highest carbon fixation rates exportedonly half the newly fixed carbon. The rates of import of assimilate to similar-sized fruits (c.16 cm3) were between 80 and 110 mg C fr–1 day–1but differed from the export rates of the source leaves. Thespecific growth rates and the specific respiration rates ofthe fruits were related to their initial carbon content at thebeginning of the experiment. Thus, over 24 h, the rate of importwas predetermined by the developmental stage of the fruit unalteredby the rate of current carbon fixation in the source leaf. Translocationof assimilate was regulated by sink demand under both source-and sink-limiting conditions in this short-term situation. The dynamic relationship between assimilate production in leavesand its utilization in fruits is discussed together with therole of sucrose concentration in these organs in regulatingtransport. Lycopersicon esculentumL, tomato assimilate translocation, source-sink relationships  相似文献   
143.
长江大堤上黑翅土白蚁的地面活动与其巢位的关系   总被引:2,自引:1,他引:1  
根据1961年3—4月在长江大堤上观察黑翅土白蚁的地面活动与地下蚁巢位置的关系,知道蚁巢上方地面,一般具有一块直径3米大的白蚁活动区域,在春季以每半个月调查一次,连续四次调查中,至少有三次发现白蚁在此区域内活动,可称为“常现区”。这种“常现区”,常与地下巢位十分接近;给黑翅土白蚁巢位判断上提供了便利的目标。白蚁的一个单独活动点(泥被、泥线),一般不能作为巢位判断的根据。  相似文献   
144.
The performance of Aphis fabae on an artificial diet was assessed by comparing the aphid's excretion rate on the diet with that on bean plants to investigate the possibility of using this diet in toxicological studies. No significant difference was found in the rates of honeydew excretion, but the diet-fed aphids were noticeably smaller than those fed on beans.  相似文献   
145.
146.
Seven new taxa, including one new section, three new species and three new varieties, are described; one new name, Ligularia pojarkovana S. W. Liu et T. N. Ho, and one new combination, Ligularia liatroides (C. Winkl.) Hand.-Mazz. var. shifangensis (G. H. Chen et W. J. Zhang) S. W. Liu et T. N. Ho are made; five species are mentioned as new records. The seven new taxa are Youngia sect. Cyanoglossa S. W. Liu et T. N. Ho, Youngia zhenduoi S. W. Liu et T. N. Ho, Y. cyanea S. W. Liu et T. N. Ho, Mulgedium qinghaicum S. W. Liu et T. N. Ho, Cremanthodium campanulatum (Franch.) Diels var. flavidum S. W. Liu et T. N. Ho, Ligularia amplexicaulis DC. var. nepalensis S. W. Liu et T. N. Ho, and L. paradoxa Hand. Mazz. var.palmatifida S. W. Liu et T. N. Ho.  相似文献   
147.
家兔Bezold—Jarisch反射的血流动力学效应   总被引:1,自引:0,他引:1  
在40只麻醉兔,观察经冠脉内注射尼古丁诱发Bezold-Jarisch反射时的血流动力学变化。反射效应表现为心率减慢、动脉血压和左心室收缩压降低以及左心室内压微分值减小。切断两侧窦神经和减压神经后,上述效应增强;两侧迷走神经切断后,多数动物反射效应消失。 冠脉内注射尼古丁后,心输出量和总外周阻力均下降。人工起搏心脏以防止心率减慢时,对上述效应无明显影响。动物阿托品化并切除两侧星状神经节后,心率减慢基本消失,但动脉血压降低的程度并无明显变化。结果提示,Bezold-Jarisch反射时所表现的动脉血压降低,可归因于心输出量减少和总外周阻力降低,而以后者为主。  相似文献   
148.
在39只乌拉坦麻醉家兔,记录了腺苷作用于颈动脉体时窦神经化学感受性传入单位的放电活动。全部实验中共记录了73个有自发放电的化学感受性单位。所得结果如下:(1)颈动脉内注射腺苷(10ug/kg)时,在55个单位中有51个的放电频率由0.76±0.10增加到1.53±0.23 imp/s(P<0.001),部分实验中有新的单位被激活。(2)在隔离的颈动脉窦灌流液中加入腺苷(0.5,1.0、5.0、10、50和100μg/kg)时,9个单位的放电频率由0.51±0.06分别增加到0.58±0.07、0.78±0.13、0.96±0.15、1.11±0.017、1.34±0.21和1.38±0.18imp/s,有明显的剂量依赖性(P<0.001).(3)9个自发放电频率为1.30±0.40 imp/s 的单位,在颈动脉内注射多巴胺(50μg/kg)后,其放电频率减慢至0.56±0.19imp/s(P<0.001)。在多巴胺作用的基础上再注射腺苷。可使放电频率增加到1.07±0.28imp/s,但与注射多巴胺前的腺苷效应相比,此增值明显减小(P<0.001)。根据以上结果,我们推测腺苷对颈动脉体化学感受器的兴奋作用,可能与其作用于感受器复合体的突触前膜,从而使颈动脉体内抑制性递质多巴胺释放减少,以及腺苷直接兴奋化学感受性神经末梢有关。  相似文献   
149.
何桂铭 《昆虫学报》1963,(3):368-371
在1957年7月,作者在广州市郊夏收后稻田积水,采集库蚊幼虫一批,经隔离培养获得羽化成虫、蛹皮及幼虫皮,另保存四龄幼虫一批,经研究后认为是库蚊属的一新种。现将其中雌蚊10个,雄蚊9个及其幼虫皮,并将幼虫形态描述如下: 一、成虫 雌蚊 头部复盖有淡色至棕色弯窄鳞及直竖叉状鳞片,头顶部两侧有扁平淡色鳞  相似文献   
150.
1. The effector and catalytic proteins of glucocerebrosidase associated in the presence of acidic phospholipid to give active enzyme. 2. At optimum concentrations of acidic phospholipid (about 0.15 mM), the association reached equilibrium instantaneously. 3. From the experimental data, a tentative model of the association was deduced. This involved a two-step complex formation. When the effector concentration was limiting, a simple binary complex was formed between one molecule each of effector and catalytic proteins; the reaction proceeded rapidly to completion. When the effector was in excess, a ternary complex was formed by the addition of another molecule of effector; this reaction did not go to completion and was characterised by a finite equilibrium constant. 4. The experimental data were curve fitted to an equation derived from the model  相似文献   
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