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1.
A cutting of Phaseolus mungoproduced about 4 adventitious rootsat the basal 1 mm region when the basal part of the cuttingwas dipped in water. Rootlets became visible after a 36 hr lagperiod in untreated cuttings. Treatment with 2-thiouracil or5-bromodeoxyuridine increased the number of roots formed onthe cutting and prolonged the lag period. Effects of 2-thiouraciland 5-bromodeoxyuridine were reversed by simultaneously applieduracil and thymidine. The number of roots decreased and thelength of lag period was shortened. The increases in the numberof roots by 2-thiouracil or 5-bromodeoxyuridine was reducedby gibberellic acid, which did not cause a decrease in the numberof roots to be formed on control cuttings. Roots formed at thebasal region seem to suppress further root formation at theupper part of the hypocotyl. Inhibitors used here probably workby blocking the formation of these bottommost roots. (Received April 30, 1971; )  相似文献   
2.
EFFECT OF LIGHT ON AUXIN TRANSPORT AND ELONGATION OF AVENA MESOCOTYL   总被引:1,自引:0,他引:1  
The present work was undertaken to find if there are relations between light and auxin action on elongation of coleoptilar node and mesocotyl with Avena seedlings. Red light inhibited the elongation of mesocotyl and simultaneously decreased the rate of transport of diffusible auxin through the node. Red light also inhibited the transport of exogenously given IAA through the nodal region. The light inhibition of IAA transport was closely related to the increase of IAA immobilization. As the age proceeds, the ability of IAA immobilization increased with the decrease in the rate of mesocotyl elongation, even if the seedling was grown in complete darkness. The nature of radioactive substances found in the IAA-C14 treated tissue was examined by paper chromatography. The above results strongly suggested that the increase of IAA immobilization might result in the inhibition of mesocotyl elongation.  相似文献   
3.
NAD-independent, mitochondrial -glycerophosphate dehydrogenaseof baker's yeast, Saccharomyces cerevisiae, was liberated fromcells and its nature was examined. Hydrogen acceptors, pH optimaand reaction rates with substrate and hydrogen acceptor of theenzyme were determined. A naturally occurring phenolic pigmentextracted from yeast cells was also found to function as aneffective hydrogen acceptor for the enzyme. Addition of FMNor FAD to the -glycerophosphate oxidation system largely acceleratedenzymatic activity, whereas the enzyme system was strongly blockedby SH-reagents. This suggests that the SH-group functions atan essential site. Clear-cut inhibition by antimycin A of electrontransfer to cytochrome c suggests the intermediation of cytochromeb. (Received December 13, 1968; )  相似文献   
4.
Single-celled protonemata of the fern Adiantum capillus-veneris, kept under continuous red light, grew with a very low rate of cell division, and the cell cycle was arrested in the early G1 phase. Cell division was induced by transferring the protonemata to the dark after various light treatments, and the duration of component phases in the cell cycle was determined by a continuous-labelling technique with 3H-thymidine. Blue light irradiation greatly reduced the duration of the G1 phase but did not affect that of other phases. The greater the fluence of blue light, the shorter was the duration of G1 phase was observed. In contrast, a brief exposure of red-light-grown protonemata to far-red light given immediately before the dark incubation showed no effect on the duration of G1 S and M phases but significantly extended that of the G2 phase. The effect of far-red light on the G2 phase was reversed by red light, and the effects of red and far-red light were repeatedly reversible. The progression in the M phase was shown by means of a time-lapse video system to be not at all influenced by any pre-irradiation described above.  相似文献   
5.
Cytochrome oxidase and succinate dehydrogenase activities increasedduring aging of sliced tissue for sweet potato root after respectivelag phases of about 8 and 10 hr. The increase in the formerwas stepwise. On the other hand, malate dehydrogenase activityincreased slowly without a lag phase. Spectrophotometric determinationof heme contents in mitochondria indicated that the hemes increasedafter a lag phase for at least 8 hr during aging Treatment of tissue slices with cycloheximide at a concentrationof 10–6 M prior to aging resulted in an extension of thelag phase in the increase of cytochrome oxidaseactivity andin complete inhibition of the increase of malate dehydrogenaseactivity. The antibiotic, at a concentration of 10–5 M,completely suppressed the increases. Chloramphenicol (6 ? 10–3M) also blocked the increases, except for that in malate dehydrogenaseactivity at an early stage of aging (Received December 22, 1970; )  相似文献   
6.
7.
The angiotensin Ⅱ type 1 receptor and receptor-associated proteins   总被引:1,自引:0,他引:1  
INTRODUCTIONThe renin-angiotensin system (RAS) is consid-ered to be the major regulator of blood pressure)electrolyte balance and renal, neuronal as well as en-docrine functions related to cardiovascular control.The RAS is the key factor in most cases essential hy-pertension, as indicated by successes in treatment ofhypertensive patients with various angiotensin I con-verting enzyme (ACE) inhibitors and receptor block-ers. Renin was a central subject of intense investigation because of…  相似文献   
8.
In the sporulation of Alternaria tomato, conidiophores are induced by near ultraviolet irradiation but not by darkness, and the conidia develop only when the irradiation is followed by a period of darkness. Conidial development is suppressed by a short exposure to blue light at a definite time during the dark period following the inductive irradiation. The suppression of conidial development by blue light can be reversed by exposure to near ultraviolet light immediately following the blue light irradiation. This reversion is reversibly suppressed by a further exposure to blue light immediately following near ultraviolet irradiation. Thus, at least two stages are involved in the sporulation of A. tomato, the first being a photochemical stage necessary for the induction of conidiophores, and the second essential for the conidial development which proceeds only in the absence of exposure to the blue region of the spectrum. Moreover, conidial development can be controlled by alternating doses of blue and near ultraviolet light, and the subsequent response depends upon the last kind of radiation given. It is concluded that a new pigment system, which we have named “Mycochrome”, is involved in the blue and near ultraviolet reversible photoreaction, and that this compound plays an important role in the photocontrol of conidial development in this fungus.  相似文献   
9.
A brief red irradiation caused an immediate rise of NADPH level and an immediate drop of NADP level in coleoptilar node of etiolated Avena seedling. With the duration of the dark incubation after the red irradiation, the level of NADPH gradually fell, and the NADP level rose higher than in non-irradiated materials. Such NADP-dependent dehydrogenases as glucose-6-phosphate, isocitrate and 6-phosphogluconate dehydrogenases were activated immediately after the red irradiation.  相似文献   
10.
An examination was made of the effects of ethanol at 0.2–6.0%(v/v) on the germination, under aerobic conditions, of intactand dehusked seeds of indica rice (cv. Assam IV), which hadbeen harvested 14, 21 and 28 d after anthesis, and of the japonicarice (cv. Sasanishiki), which had been harvested 30 and 60 dafter anthesis. The inhibition of germination caused by dehuskingjaponica rice was overcome by 0.5–5% ethanol, with maximumgermination (frequently 100%) achieved at 3–5% (30 d afteranthesis) or 1–4.5% (60 d after anthesis) ethanol. Furtherincreases in the ethanol concentration reduced germination.The germination of dehusked indica rice was slightly inhibitedat 0.5 and 1% ethanol, whilst the promotion of germination by2% ethanol increased as the seeds matured. At all harvests germinationwas greatest at 3% ethanol, and at 5–6% ethanol germinationfell to 0%. Inhibition, no effect, or minimal stimulation ofthe germination of intact seeds of both japonica and indicarice by ethanol was observed at the concentrations examined.The absence of oxygen stimulated germination of dehusked japonicarice, but this germination was inhibited by ethanol. In contrastethanol had little or no effect on the failure of dehusked indicaseeds to germinate in anaerobic conditions. Thus ethanol treatmentmay help break the strong dormancy of dehusked seeds of indicaand japonica rice. The possible role of ethanol in stimulatinggermination in rice is discussed. Rice; Oryza sativa L.; seed germination; dehusking treatment; ethanol; indica; japonica; oxygen; dormancy; germination inhibition; seed formation  相似文献   
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