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1.
This paper covers major events of the early history of chlorophyll research in the Russian Empire and the Soviet Union from 1771 until 1952, when the modern period of studies on photosynthesis began in full swing. Short biographical sketches of key scientists, reviews of their major research contributions and some selected photographs are included. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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A new orchid genus, Ypsilorchis Z. J. Liu, S. C. Chen & L. J. Chen, is established based on Ypsilor-chis fissipetala (Finet) Z. J. Liu, S. C. Chen & L. J. Chen (basionym: Liparis fissipetala Finet). The new genus differs from Liparis and its allies by having two granular-waxy pollinia each with a somewhat elastic caudicle, deeply bilobed petals and strongly crisped-margined leaves with an apical awn to 1 mm long. These features are an indication of its distant relation to the members of the subtribe Liparidinae, and thus a new subtribe, Ypsilor-chidinae Z. J. Liu, S. C. Chen & L. J. Chen, is proposed.  相似文献   

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The effects of adding lysine, arginine and ammonia to gluten on the self-selection of protein and energy by the weanling rat simultaneously offered a choice of two diets differing only in gluten concentration (15 and 55%) were tested. Previous studies have shown that while lysine (6 g/100 g) additions to gluten decreased the amount of gluten selected by the rat from 40 to 20 g per 100 g of food eaten, selection was not related to the nutritional quality of the gluten. When graded levels of arginine (1.8, 3.6 or 7.2 g/100 g) were added to the gluten with or without lysine (0 or 6 g/100 g) the dietary protein selection was unaffected. The addition of ammonia (1.4 g/100 g as NH4Cl) to gluten had initially the same effect as lysine (6 g/100 g) but with time protein intake returned to control levels. This effect of ammonia was unaltered by arginine additions. It is concluded that the mechanisms which lead to decreases in gluten selection caused by lysine or ammonia are not similar, and that the effects of lysine on gluten selection are not caused by an increased arginine requirement for urea cycle activity.  相似文献   

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基于丫瓣兰Ypsilorchis fissipetala (Finet)Z.J.Liu,S.C.Chen &L.J.Chen(基名为裂瓣羊耳蒜Liparis fissipetala Finet)建立了兰科新属--丫瓣兰属Ypsilorchis Z.J.Liu,S.C.Chen&.J.Chen.新属与羊耳蒜属Liparis的区别点为:新属有两个粉蜡质花粉团:每个花粉团具1个多少有弹性的花粉团柄;花瓣二深裂;叶具强烈波状的边缘,其先端有一个长达1 mm的芒尖.这些特征表明了其与羊耳蒜亚族Liparidinae有明显的差别,为此,建立了一个新的亚族--丫瓣兰亚族Ypsilorchidinae Z.J.Liu,S.C.Chen &L.J.Chert.  相似文献   

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应用石蜡切片法、荧光显微镜和紫外分光光度法,对不同年生巴戟天根组织结构的变化进行了观察、对蒽醌类化合物在根中的分布场所及其积累动态进行了研究。结果表明:巴戟天根的结构类似一般多年生草本植物,薄壁细胞是巴戟天根中蒽醌类化合物的分布储存场所,蒽醌类化合物含量随着根生长年限的增加而增加。由以上研究总结出巴戟天以四年或四年以上采收为好,并以根皮厚、木心细者为上品。  相似文献   

7.
Endogenous gibberellins (GAs) were extracted and purified from apical buds of Eucalyptus nitens (Deane and Maid.) Maid. and the cambial region of E. globulus (Labill.). then analysed by capillary gas chromatography-mass spectrometry. GA1 GA19 GA20 and GA29 were identified by full scan mass spectra. Kovats retention indices and high resolution selected ion monitoring. Using deuterated internal standards. GA1. GA19. GA20 and putative GA29 and GA53 were quantified in the apical buds, while GA4. GA8. GA9 and GA44 were shown to be either absent or present at very low levels. From the cambial region. GA1 and GA20 were quantified at levels of 0.30 ng (g fresh weight)-1 and 8.8 ng (g fresh weight)-1 respectively. These data suggest that the early 13-hydroxylation pathway is the dominant pathway for GA biosynthesis in Eucalyptus .  相似文献   

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In view of the recent demonstrations that Neuropeptide Y (NPY) and adrenergic transmitters coexist in neurons of the rat brain, we have compared the effects of intraventricular (Ivt) injections of NPY and catecholamines on LH release and food intake in intact male rats. Of the three catecholamines, dopamine (DA), norepinephrine (NE) and epinephrine (E), only E (5.3 micrograms or 15.9 micrograms/rat) significantly stimulated LH release, although NE and E (5.3 micrograms/rat) were equally effective in eliciting food intake in satiated rats. Ivt administration of 10 micrograms NPY significantly stimulated LH release, whereas either lower (0.5 or 2 micrograms/rat) or higher (25 micrograms/rat) doses were ineffective. In contrast, NPY at doses of 0.5 - 10 micrograms/rat increased cumulative food intake in a dose-related fashion. These findings present preliminary evidence of the physiological correlates of the neuronal coexistence of adrenergic transmitters and NPY in the brain and raise the possibility that NPY may normally act either independently, in concert with or via adrenergic systems to evoke LH release and feeding responses in the rat.  相似文献   

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A method is described for counting the number of macrophages which develop from a sample of human venous blood. Because the macrophages are nondividing cells under these conditions of culture, it is possible to use the count to describe the size of a population of macrophage precursors in the blood. Counts on 43 healthy individuals show that on average there are some 200,000/ml of blood, which is 5–6% of the total white cell count. The precursor cells are mononuclear and the majority of them will adhere to plastic. These characteristics suggest that monocytes are the precursor cells.  相似文献   

12.
Singchia Z. J. Liu & L. J. Chen, a new orchid genus, is established based on the new species S. malipoensis Z. J. Liu & L. J. Chen found in southeast Yunnan, China. The new genus is related to Pteroceras, from which it differs by having a lip with its basal margins immovably adnate to the lower part of the pendent column foot, a thin-walled spur, and very unequally and deeply split pollinia, each with a distinct caudicle. In addition to a discussion on Ascocentrum pusillum, a species of questionable placement, another new genus, namely Gunnaria S. C. Chen ex Z. J. Liu & L. J. Chen, is set up and a new combination, namely G. pusilla (Aver.) Z. J. Liu & L. J. Chen, is made. The new genus Gunnaria differs from its allyAscocentrum by having a cross-shaped pollinarium, sulcate or split pollinia, each with a distinct caudicle attached to a common linear stipe much longer than either pollinia or viscidium, and strongly incurved side lobes of the lip.  相似文献   

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It was believed for a long time that the first Old World crops were introduced to the northwest of Argentina in a.d. 1550 during the foundation of Barco, and that the indigenous people incorporated them into their subsistence almost passively. However, since wheat, barley, and peach have been recovered from El Shincal, an Inka (Inca) administrative centre, new questions have arisen about who first brought these crops to the study region, as well as about where they were grown for the first time and which routes they followed after that. This paper will try to solve these questions during a period ranging from the 16th to the 18th century. This time span, although arbitrary, is consistent with the major damage to the original social structure caused by the Spaniards to the local indigenous populations. Our approach includes the comparison of ethnohistorical with archaeobotanical evidence. It is concluded that the first Old World crops were brought from Chile to Santiago del Estero by Spanish soldiers in a.d. 1556, and to Londres in a.d. 1558. These crops were taken up by local indigenous people during the period of the encomenderos and used to carry out a pachamanca ceremony at El Shincal during a Diaguita rebellion. Electronic Supplementary Material Supplementary material is available in the online version of this article at  相似文献   

15.
Prostacyclin (PGI2) induced a dose-dependent decrease in blood pressure with slight increases in heart rate and body temperature, when administered at the doses of 0.1–100 μg into the lateral cerebral ventricle (i.c.v.) of the urethane-anaesthetised rat. When the same doses were administered intravenously, both the blood pressure and heart rate decreased. Central pretreatment with sodium meclofenamate (1 mg/rat i.c.v.) antagonised the central hypotensive effect of PGI2 but i.c.v. pretreatment of the rats with indomethacin (1 mg/rat) failed to affect the PGO2-induced hypotension. Central pretreatment with two histamine H2-receptor antagonists, cimetidine (500 μg/rat i.c.v.) or metiamide (488 μg/rat i.c.v.), antagonised the blood pressure lowering effect of 0.1 μg dose of PGI2 but failed to affect the hypotension induced by higher PGI2 doses. Therefore the main central hypotensive effect of PGI2 seems not to be associated with the stimulation of histamine H2 -receptors in the brain.The hypotensive effect of i.c.v. administered PGI2 appears to be due to an action upon the central nervous system rather than to a leakage into the peripheral circulation. This assumption is supported by the fact that sodium meclofenamate i.c.v. antagonished the effect of PGI2. In addition, the chronotropic response to i.c.v. PGI2 was opposite to that induced by intravenous administration. The results also suggest that there may be differences in the mode of action between sodium meclofenamate and indomethacin.  相似文献   

16.
根据对乐都锦鸡儿Caragana leduensis Y.Z.Zhao,Y.H.Wu&L.Q.Zhao和玉树锦鸡儿CtanguticaMaxim.ex Kom.var.yushuensis Y.H.Wu模式标本的观察及对国内标本馆大量标本的研究,将它们分别处理为青甘锦鸡儿C.tangutica Maxim.ex Kom.和沧江锦鸡儿C.kozlowi Kom.的新异名,并对二者的地理分布范围进行了讨论。  相似文献   

17.
Eighteen mature estrous cycling beef cows and 9 prepuberal heifers were stratified by breed, age and weight to determine the effect of ovary-transplantation to a proximal site (right uterine horn) (U) and distal site (parotid region) (P) upon ovarian activity. Active ovaries (AO), ovaries with the corpus luteum (CL), were autotransplanted to the myometrium of the U in 3 cows and to the muscles of the P in 2 cows and their inactive ovaries (IO), ovaries without a CL, remained. Active ovaries of 6 cows were removed and heterotransplanted to 6 prepuberal heifers and their 10 were heterotransplanted to the U or the parotid (3). Six heifers received either a mature AO in the U or in the parotid. Three heifers were ovariectomized and their ovaries were heterotransplanted to 6 cows, 3 per site. Cows and heifers were slaughtered randomly 2 months after surgery and their ovaries were collected for microscopic and histological analysis. The transplants were successfully accomplished in 94% of the cows and in 83% of the heifers. Both of the unsuccessful heterotransplantations were located in the uterus. More estrous activity was found (P<.025) in cows than in heifers with their own ovaries in situ . All prepuberal ovaries in situ showed follicular development when mature AO were transplanted to either the U or parotid. The same trend was found in prepuberal ovaries transplanted to mature cycling cows. Cows with an IO in situ and AO transplanted to either site had more estrous activity than did ovariectomized cows with an IO transplanted to either site. Pregnancy rates in mature cycling cows with an least one ovary in situ were higher (P<.005) in cows with an ovary in the parotid region than cows with an ovary transplanted to the uterus.  相似文献   

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We have investigated the actions of beta-ecdysone and fat body on wing disks of Plodia interpunctella in a series of sequential incubations in vitro. These experiments revealed that extended treatment times of beta-ecdysone at concentrations of 0·5 μg/ml or greater inhibited development of disks, and confirm that the presence of a fat body factor in the culture medium prevents this inhibition.  相似文献   

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