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11.
Estimating the rate of photorespiration in leaves 总被引:20,自引:1,他引:19
Thomas D. Sharkey 《Physiologia plantarum》1988,73(1):147-152
The influence of Li+ on the circumnutations of hypocotyls of Helianthus annuus L . cv. Californicus was investigated. LiCl at concentration levels from 0 to 40 m M (lethal) was added to intact hypocotyls grown in liquid nutrient medium. The Li+ concentration in the hypocotyls was measured by flame photometry. The growth of the hypocotyls was not affected by the LiCl.
Amplitude and frequency of the circumnutations were determined by correlation analysis. The oscillatory pattern of the movements became less regular at concentrations above 10 m M LiCl. The amplitude of the movements was reduced for concentrations above 7 m M LiCl. The frequency of the movements was reduced when LiCl was increased from 0 to 10 m M . Above 10 m M LiCl the frequency of the circumnutations was higher than for control plants. The results showed that circumnutations of sunflower hypocotyls can be added to the group of oscillators in biological organisms that are affected by Li+ . 相似文献
Amplitude and frequency of the circumnutations were determined by correlation analysis. The oscillatory pattern of the movements became less regular at concentrations above 10 m M LiCl. The amplitude of the movements was reduced for concentrations above 7 m M LiCl. The frequency of the movements was reduced when LiCl was increased from 0 to 10 m M . Above 10 m M LiCl the frequency of the circumnutations was higher than for control plants. The results showed that circumnutations of sunflower hypocotyls can be added to the group of oscillators in biological organisms that are affected by Li
12.
Francisco J. Acosta Jose M. Serrano Jesus M. Barandica Francisco Lopez 《Journal of Insect Behavior》1992,5(3):337-346
The focal-animal technique assumes the continuous recording of the behavior of an individual during a certain time interval. The length of this interval (sampling unit) can be problematic when estimating the duration of behavioral acts. Two acts from the behavioral repertoire of the ant Leptothorax fuenteiwere focused on in this work at different ranges of temporal scales. Analyzing these acts we show the possibility of existence of a sampling artifact, in such a way that the estimates of the durations of the acts would be forced to depend upon the length of the sampling unit that is being used. 相似文献
13.
Berend Aukema 《Oecologia》1991,87(1):118-126
Summary In two successive years the fecundity of the carabid beetles Calathus (Neocalathus) cinctus, C. (N.) melanocephalus and C. (N.) mollis was studied in relation to wing-morph and temperature. Differences were found between the three species in both egg production and timing and length of the oviposition period. In all species the fecundity of laboratory bred beetles was significantly higher than that of females collected in the field. Long-winged females of both cinctus and melanocephalus had significantly higher egg production than short-winged females, and they also tended to produce eggs over a longer period. In mollis only the fecundity of the long-winged morph was established. The observed lower relative fitness of the short-winged morph in both cinctus and melanocephalus contradicts the supposed increase of the frequency of this morph in ageing, more or less isolated, populations of these species. The loss of long-winged genotypes, resulting from flight activities, is considered the most plausible cause of the increase of short-winged beetles in ageing populations. The higher fecundity of macropterous females makes them especially suited for (re)establishing populations.Communication No. 429 of the Biological Station WijsterPresent address and address for offprint requests: Kortenburg 31, NL-6871 ND Rentum 相似文献
14.
立地性日照长短与甜橙生长发育的相关性 总被引:1,自引:0,他引:1
甜橙[Citrus sinensis(L.)Osbesk,本文中均指雪柑(Citrus sinensis var.sekkan)]对日照的需要量,比温州蜜柑(Citrus reticulata var.unshiu)等桔类要少些,即温州蜜柑比甜橙和杂柑类的耐荫性稍弱。然而,究竟可少到什么临界值呢?同一果园,同一管理水平,同一树龄,由于坡向、地形等的不同,而 相似文献
15.
W. Puchalski G. R. Lynch 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,169(2):185-189
Summary Djungarian hamsters (Phodopus sungorus), were exposed to constant light with increasing intensities (20, 60, 350 lux), and wheel running activity was recorded. With increasing light intensity the percentage of hamsters showing a split in their daily activity pattern increased and the free running period was lengthened for both the unsplit and the split state. The fact that the free running period of both states depended on the light intensity together with the observation that the highest incidence of acircadian activity occurred under 350 lux, provoked the idea that the emergence of splitting or acircadian rhythmicity is a direct consequence of the light induced lengthening of the free running period. However, analysis of the data failed to support the idea that emergence of a split or acircadian activity is a threshold phenomenon with respect to the free running period.Due to differences in circadian function some Djungarian hamsters do not exhibit photoinduction following short day exposure. In these individuals splitting also occurred but required exposure to a higher light intensity than in photo-responsive hamsters. This observation is in accordance with the idea that the two phenotypes differ in the interaction of the two component oscillators underlying circadian rhythmicity.Abbreviations
LD
long day photoperiod
-
LL
constant light
-
SD
short day photoperiod
-
free running period 相似文献
16.
17.
Human cells deficient in rate of excision repair of DNA damage induced by UV-radiation, i.e., xeroderma pigmentosum (XP) cells, are much more sensitive to the mutagenic effect of UV than are cells from normal persons. The lower frequency of mutants in the latter cells has been attributed to the fact that, unlike XP cells, they excise most of the potentially mutagenic lesions before these can be converted into mutations. If semi-conservative DNA synthesis on a template still containing unexcised lesions is responsible for introducing mutations and if replication of the gene of interest, e.g., hypoxanthine (guanine)phosphoribosyltransferase (HPRT) for thioguanine resistance or the elongation factor 2 (EF-2) for diphtheria toxin resistance, occurs at a particular time during S-phase, it should be possible to shorten the time available for such repair by synchronizing cells and irradiating them just as the gene is to be replicated. The predicted result would be a much higher frequency of mutants at one part in the S-phase than at other times. To test this, cells were synchronized using the alpha-polymerase inhibitor aphidicolin, which blocks cells at the G1/S border. Autoradiography, cytofluorimetry, and incorporation of tritiated thymidine studies showed that DNA synthesis started immediately after release from aphidicolin and was completed in 8-10 h. Cells irradiated with 6 J/m2 at various times post-release were assayed for survival and mutations. The frequency of thioguanine- or diphtheria toxin-resistant cells in the population was highest in cells irradiated during the first fifth of the S-phase, i.e., 0-1.5 h post-release. It was significantly lower in cells irradiated at later times. In contrast, UV-induced cytotoxicity showed no significant time dependence during S-phase. These data suggest that the HPRT and EF-2 genes are replicated early in S-phase. 相似文献
18.
Haruki Ochi 《Environmental Biology of Fishes》1985,12(2):155-160
Synopsis Reproductive behavior of the temperate damselfish, Chromis notata, was investigated on the island of Mukaishima, Japan, almost daily during the breeding season in 1982. Both males and females
repeated reproductive cycles many times during the breeding season. Females had a strong tendency to spawn a whole clutch
on one nest during a few hours. The average number of eggs which a male gained per reproductive cycle was estimated at 38560
(480–131100 eggs). Males ordinarily cared for eggs until just prior to hatching, but abandoned more than half of the nests
with the eggs numbering less than 11568.
Contribution 207 from the Mukaishima Marine Biological Station. 相似文献
19.
在自然呼吸和窦性节律下,用浮置式玻璃微电极引导在体单个左心室肌纤维动作电位,作为兴奋的指标,以其 0相触发产生期前的试验刺激,测定有效不应期(ERP)。38只家兔的测定结果表明,在R-R间期为205—330ms的范围内,随着心率加快(R-R间期缩短),ERP减小,而 ERP/RR 间期增大,说明 ERP 与心率直接有关。并且,在较快的心率时,ERP 相对延长。通过相关与回归分析,制出了能够删除心率影响的校正公式。静脉注射酒石酸锑钾(50mg/kg)发现,在窦性和起搏节律下,酒石酸锑钾均能轻度延长 ERP(P<0.001)。窦性节律下的校正后值与起搏节律的测定结果完全一致。证明校正后值能够用来比较处理前后不同心率条件下,各种药物、离子及其它因素对ERP 的影响。 本文的校正公式虽然只适用于同种动物和方法,但此校正公式的制作原理也可以广泛应用到其它多种动物。 相似文献
20.
温度对粘虫产生和释放性信息素规律的影响 总被引:1,自引:1,他引:0
在21℃饲养的粘虫雌蛾腺体提取物中Zll-16:Aid含量峰值时间是羽化后第8~9天;25℃是羽化后第4~5天,27℃是羽化后第3~4天。低温不仅推迟了粘虫雌蛾求偶和释放性信息素的时间,而且降低了腺体中性信息素的滴度。在27℃,粘虫雌蛾腺体中Zll-16:Ald峰值的平均值达15ng;在25℃时为10ng,而在21℃时,只有5ng。由此可见,低温环境明显抑制粘虫雌蛾的性发育,延缓了性成熟。 相似文献