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1.
本文旨在研究福建闽南地区汉族和畲族指长比(R)的特点。随机选择福建闽南地区汉族506例(男性173例,女性333例),畲族450例(男性231例,女性219例),采用体质测量法,测量并计算左右侧6项指长比(R2/3R2/4R2/5R3/4R3/5R4/5)。福建闽南地区汉族和畲族左、右侧指长比均呈R2/3<R2/4<R3/4<R2/5<R4/5<R3/5的趋势;汉族女性指长比左侧R2/3R2/4R2/5R3/4R3/5和右侧R2/3R2/4R2/5高于汉族男性(P<0.05);畲族女性指长比左侧的R2/3R2/4R2/5和右侧R2/3R2/4高于畲族男性(P<0.05);畲族男性指长比左、右侧R2/3R2/4R2/5R3/5R4/5高于汉族男性(P<0.05);畲族女性指长比左侧R2/3R2/4和右侧R2/3R2/4R2/5R4/5高于汉族女性(P<0.05)。同民族不同性别两侧R2/4百分比分布差异有统计学意义,不同民族同性别右侧R2/4百分比分布差异有统计学意义。福建闽南地区汉族和畲族指长比存在性别、侧别的不同,与其他地区、族群也存在差异。  相似文献   

2.
Abstract. Net NO3 uptake by NO3 deficient Chara cells was used to calculate [NO3]c assuming that the cytoplasm occupies 10% total volume and that nitrate reduction and storage are negligible (i.e. maximum [NO3]c was calculated). A linear relationship was found between NO3 efflux and [NO3]c. There was an initial burst of NO3 efflux when NH+4 was added, followed by a slower efflux rate which matched influx rate such that net NO3 uptake was zero. Over 50% of NO3 that had been taken up in 2 h was lost within the first 5 min of NH+4 addition. The Nernst equation was used to predict the direction of the electrochemical driving force for NO3 entry. Under the experimental conditions used NO3 efflux is actively transported. The differential involvement of both NO3 influx and NO3 efflux in the regulation of NO3 uptake is discussed and a model is proposed to account for these results which envisages discrete NO3 influx and NO3 efflux carriers.  相似文献   

3.
Abstract The utilization of NO3, NO2 and NH+4 was studied in whole filaments and isolated heterocysts of Anabaena 7120 (ATCC27893). NO3- and NO2-uptake were detectable in whole filaments but not in heterocysts, whereas NH+4-uptake was detectable in both. Activity of NO3-reductase was present in cell-free extracts of whole filaments but not of heterocysts, whereas activities of NO2-reductase and glutamine synthetase were present in both. NO3-uptake and reductase activities could not be induced in heterocysts even after prolonged incubation in NO3 medium. It is suggested that NO3-metabolism in heterocysts is impaired due to a selective and irreversible loss of NO3-uptake and reductase systems resulting in the abolition of competition for molybdenum cofactor (Mo-Co) and reductant between nitrogenase and NO3-reductase, and an increase in glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase levels.  相似文献   

4.
刘晴  王芬  徐方旭  徐岩岩  董彩虹 《菌物学报》2021,40(11):2962-2980
蛹虫草规模化栽培过程中,真菌病害普遍发生且危害严重。本研究对人工栽培蛹虫草中真菌病害进行调研,对病原真菌进行分离、纯化、鉴定及致病性检验,并分析病害发生的特点。结果发现引起蛹虫草病害的病原真菌主要有虫草生齿梗孢、产扁虫菌素单端孢、镰刀菌、裂褶菌、哈茨木霉、淡紫拟青霉、稻绿核菌、粉红枝穗霉、卵孢单端孢、扩展青霉、黄曲霉和黑曲霉。其中虫草生齿梗孢为引起蛹虫草侵染性病害的主要病原真菌。虫草生齿梗孢、产扁虫菌素单端孢、镰刀菌、裂褶菌和哈茨木霉主要为害蛹虫草子实体;淡紫拟青霉、稻绿核菌、粉红枝穗霉、卵孢单端孢、扩展青霉、黄曲霉和黑曲霉主要为害栽培料与蛹虫草菌丝体。镰刀菌、裂褶菌、哈茨木霉、淡紫拟青霉、稻绿核菌和粉红枝穗霉为引起蛹虫草病害的首次报道。本研究为蛹虫草病害防控奠定基础,以促进产业健康发展。  相似文献   

5.
Short photoperiod induces growth cessation in seedlings of Norway spruce ( Picea abies (L.] Karst.). Application of different gibberellins (GAS) to seedlings growing under a short photoperiod show that GA9 and GA20 can not induce growth. In contrast application of GA, and GA4 induced shoot elongation. The results indicate that 3β-hydroxylation of GA9 to GA4 and of GA20 to GA1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA1, GA3, GA4, GA7, GA9, GA12, GA15, GA15, GA20, GA29, GA34 and GA51 were identified by combined gas chromatography-mass spectrometry in shoots of Norway spruce seedlings. The effect of photoperiod on GA levels was determined by using deuterated and 14C-labelled GAs as intermal standards. In short days, the amounts of GA9, GA4 and GA1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA3, GA12, and GA20 between the different photoperiods. The lack of accumulation of GA9 and GA20 under short days is discussed.  相似文献   

6.
We evaluate onshore-offshore trends in age-frequency distributions and trophic transfer efficiencies using 11 modern death assemblages off the Texas coast. Trophic transfer efficiencies within trophic levels offer little insight over that achieved by a size-frequency distribution. Production/biomass ratios will always be 1 in the fossil record. Within trophic-level estimates of paleogrowth efficiency, the ratio of paleoproduction to paleoingestion (Piglt/Iilt where i indicates the ith trophic level and lt indicates the time-averaged value) follow the expected ecological trend precisely in that paleogrowth efficiency is consistently higher in primary consumers than in predators in all 11 death assemblages. Paleoutilization efficiency, the ratio of predator paleoingestion to prey paleoproduction, I2lt°/P1glt°, may provide information on the degree of bias in the preservation of primary (1 °) and secondary (2 °) consumer trophic groups. I2lt°/P1glt° fell below 0.1 in most cold-seep and bay assemblages, indicating a large surplus of primary consumers. In sharp contrast, I2lt°/P1glt°  相似文献   

7.
Net fluxes of NH4+ and NO3 along adventitious roots of rice ( Oryza sativa L.) and the primary seminal root of maize ( Zea mays L.) were investigated under nonperturbing conditions using ion-selective microelectrodes. The roots of rice contained a layer of sclerenchymatous fibres on the external side of the cortex, whereas this structure was absent in maize. Net uptake of NH4+ was faster than that of NO3 at 1 mm behind the apex of both rice and maize roots when these ions were supplied together, each at 0·1 mol m–3. In rice, NH4+ net uptake declined in the more basal regions, whereas NO3 net uptake increased to a maximum at 21 mm behind the apex and then it also declined. Similar patterns of net uptake were observed when NH4+ or NO3 was the sole nitrogen source, although the rates of NO3 net uptake were faster in the absence of NH4+. In contrast to rice, rates of NH4+ and NO3 net uptake in the more basal regions of maize roots were similar to those near the root apex. Hence, the layer of sclerenchymatous fibres may have limited ion absorption in the older regions of rice roots.  相似文献   

8.
Abstract: We studied the action of H2O2 on the exocytosis of glutamate by cerebrocortical synaptosomes. The treatment of synaptosomes with H2O2 (50–150 µ M ) for a few minutes results in a long-lasting depression of the Ca2+-dependent exocytosis of glutamate, induced by KCl or by the K+-channel inhibitor 4-aminopyridine. The energy state of synaptosomes, as judged by the level of phosphocreatine and the ATP/ADP ratio, was not affected by H2O2, although a transient decrease was observed after the treatment. H2O2 did not promote peroxidation, as judged by the formation of malondialdehyde. In indo-1-loaded synaptosomes, the treatment with H2O2 did not modify significantly the KCl-induced increase of [Ca2+]i. H2O2 inhibited exocytosis also when the latter was induced by increasing [Ca2+]i with the Ca2+ ionophore ionomycin. The effects of H2O2 were unchanged in the presence of superoxide dismutase and the presence of the Fe3+ chelator deferoxamine. These results appear to indicate that H2O2, apparently without damaging the synaptosomes, induces a long-lasting inhibition of the exocytosis of glutamate by acting directly on the exocytotic process.  相似文献   

9.
水分利用效率是深入理解生态系统碳、水循环间耦合关系的重要指标。以前研究青藏高原的水分利用效率多基于年降水量(AP)来分析, 但植物对水分的利用主要在生长季。该研究采用以AP、生长季降水量(GSP)和生长季蒸散量(ETgs)分别计算的年降水利用效率(PUEa)、生长季降水利用效率(PUEgs)和生长季水分利用效率(WUEgs), 分析了2000-2010年间青藏高原两种主要植被类型高寒草甸和高寒草原PUEaPUEgsWUEgs的差异及其与降水量、蒸散量和气温的关系。结果表明: (1)高寒草甸的PUEaPUEgs均大于高寒草原, 但两种草地类型的WUEgs无显著差别, 这说明两种草地类型可能存在相似的内在的水分利用效率。(2)从年际动态来看, PUEaPUEgs的波动范围相似, 而WUEgs的波动范围更大, 说明以蒸散为依据的WUEgs可能比PUEaPUEgs更敏感, 因而可能更好地反映生态系统的水分利用能力。(3)高寒草甸和高寒草原的PUEaPUEgsWUEgs分别与APGSPETgs呈单调递减趋势, 表明3种水分利用效率均随降水量或蒸散量的增加而降低。高寒草原的3种水分利用效率中仅WUEgs随着气温的增加而增加, 而高寒草甸的3种水分利用效率均与气温无显著关系, 这说明相比高寒草甸, 高寒草原的水分利用效率对气温更加敏感。  相似文献   

10.
ABSTRACT. We examined the effects of surfactant protein A (SP-A), a collectin, on the interaction of Pneumocystis murina with its host at the beginning, early to middle, and late stages of infection. Pneumocystis murina from SP-A wild-type (WT) mice inoculated intractracheally into WT mice (WTS-WTR) adhered well to alveolar macrophages, whereas organisms from SP-A knockout (KO) mice inoculated into KO mice (KOS-KOR) did not. Substitution of WT mice as the source of organisms (WTS-KOR) or recipient host macrophages (KOS-WTR) restored adherence to that found with WTS-WTR mice. In contrast, when immunosuppressed KO and WT mice were inoculated with P. murina from a homologous source (KOS-KOR, WTS-WTR) or heterologous source (WTS-KOR, KOS-WTR) and followed sequentially, WTS-KOR mice had the highest levels of infection at weeks 3 and 4; these mice also had the highest levels of the chemokine macrophage inflammatory protein-2 and neutrophils in lavage fluid at week 3. Surfactant protein-A administered to immunosuppressed KOS-KOR mice with Pneumocystis pneumonia for 8 wk as a therapeutic agent failed to lower the organism burden. We conclude that SP-A can correct the host immune defect in the beginning of P. murina infection, but not in the middle or late stages of the infection.  相似文献   

11.
Low-K+, high-Na+ cells of strain RL21a of Neurospora crassa , in steady state with 25 m M Na+, were used to study K+/Na+ exchanges in the presence or absence of Ca2+ and Mg2+. In the presence of Ca2+ and Mg2+, a low concentration of K+ (0.3 m M ) triggered a rapid exchange, but in the absence of the divalents, a high K+ concentration (30 m M ) was required to initiate the exchange at a rapid rate. In the absence of Ca2+ and Mg2+, K+ uptake did not occur at low K+ concentration, internal K+ did not regulate Na+ influx in the presence of external K+, and the efflux of Na+ proceeded at maximum activity at very low-K+ contents.  相似文献   

12.
Cessation of shoot elongation in seedlings of Salix pentandra L. is induced by short photoperiod. Gibbereliin A9 (GA9) applied either to the apical bud or injected into a mature leaf, induced shoot elongation under a short photoperiod of 12 h, and GA9 could completely substitute for a transfer to a long photoperiod. When [3H]GA9 or [2H2]GA9 was injected into a leaf, no [3H]GA9 was detected in the elongating apex and only traces of [3H]GA9 were found in the shoot above the treated leaf. By the use of gas chromatography-mass spectrometry (GC-MS), [2H2]GA20 was identified as the main metabolite of [2H2]GA9 in both the shoot and the treated leaf. In addition, [2H2]GA1 and [2H2]GA29 were also identified as metabolites of [2H2]GA9. These results are consistent with the hypothesis that exogenous GA, promotes shoot elongation in Salix through its metabolism to GA20 and GA,.  相似文献   

13.
Abstract A consortium was enriched from a humisol incubated with 3.6 kPa CH4 and NH4+. This consortium oxidized NH4+ to NO2 and NO3 (NO3/NO2 ratio about 20) with smaller amounts of N2O. This oxidation stopped in the stationary phase after depletion of CH4. CH3OH or CO2 did not support oxidation. Growth and resting cell experiments suggested that nitrification was associated with methanotrophic activity and that chemoautotrophic nitrifiers were absent.  相似文献   

14.
Na+ influx and efflux in Neurospora crassa RL21a can be studied separately to calculate net Na+ movements. In the absence of external K+, Na+ influx was independent of the K+ content of the cells, but when K+ was present, the inhibition of Na+ influx by external K+ was higher the higher the K+ content. Efflux depended on the K+ and Na+ content, and on the history of the cells. Efflux was higher the higher the Na+ and K+ contents, and, in low-K+ cells, the efflux was also higher in cells grown in the presence of Na+ than when Na+ was given to cells grown in the absence of Na+. Addition of K+ to cells in steady state with external Na+ resulted in a net Na+-loss. In cells grown without Na+ this loss was a consequence of the inhibition of Na+ influx. In Na+-grown cells, addition of K+ inhibited Na+ influx and increased Na+ efflux.  相似文献   

15.
Shoot activity has been reported to affect rates of ion uptake by plant roots in other ways than merely through supply of assimilates. To elucidate the mechanisms by which a signal from the upper part of the plant controls the rate of K+ and NO3 uptake by roots, both uptake of K+ and NO3 and secretion into the xylem of young sunflower plants ( Helianthus annuus L.) were measured after changes in light intensity.
No close correlation was observed between the uptake of NO3 and that of K+; an increase in light intensity produced a much greater stimulation of NO3 uptake than of K+ uptake. On the other hand, secretion of NO3 into the xylem was tightly coupled to that of K+, and this coupling was strongly disturbed by excision of the root. The results suggest the involvement of the K2-malate shuttle on the regulation by the shoot of K+ and NO3 secretion in the xylem, which is linked to NO3 uptake, while K+ uptake is independent of this regulation mechanism.  相似文献   

16.
Understanding the classification and biosystematics of species in Triticeae Dumort., an economically important tribe in the grass family (Poaceae), is not an easy task, particularly for some perennial species. Does genomic analysis facilitate the understanding of evolutionary relationships of these Triticeae species? We reviewed literature published after 1984 to address questions concerning: (1) genome relationships among the monogenomic diploid species; (2) progenitors of the unknown Y genome in Elymus polyploids, X genome in Thinopyrum intermedium, and Xm genome in Leymus; and (3) genome constitutions of some perennial Triticeae species that were unknown or misidentified. A majority of publications have substantiated the close affinity of the Eb and Ee genomes in Th. bessarabicumand Th. elongatum, supporting the use of a common basic genome symbol. The E genome is close to the St genome of Pseudoroegneria and ABD genomes ofTriticum/Aegilops complex, providing an explanation for transferring genes from the E to ABD genomes with relative ease. Although the solid proof is still lacking, theW, P, and especially Xp genomes are possible origins for the Y genome of polyploid Elymus. The absence of the E genome and the allopolyploidy nature of tetraploidLeymus species have been unequivocally confirmed by both cytogenetic and molecular studies. However, the donor of the Xm genomes of Leymus was only speculated to be related to the P genome of Agropyron and F genome of Eremopyrum. Intermediate wheatgrass (Th. intermedium) has been extensively studied. The presence of the St (as the previously designated X) genome in Th. intermedium is now unequivocal. Its two more closely related E1 and E2 genomes are shown to be older versions of the E genome rather than the current Eb and Ee genomes. Speciation of Th. intermedium was similar to that of Triticum aestivum, in which the Js/Es(like B) genomes had the greatest differentiation from the current J (Eb) genome owning to repetitive sequences of the V genome, whereas its St (like D) had the least differentiation from the current St genome. Species with unknown or misidentified genomes have been correctly designated, including those with the ESt, StP, StPY,StWY, EStP, HW, StYHW, and NsXm genomes. Some of those species have been transferred to and renamed in appropriate genera.  相似文献   

17.
It has long been assumed that Al3+ is an important rhizotoxic ion in acid soils around the world, but the toxicity of Al3+ relative to mononuclear hydroxy-Al [AlOH2+ and Al(OH)+2] has been examined in detail only for an Al-sensitive wheat variety ( Triticum aestivum L. cv. Tyler). That plant appears to be sensitive to Al3+ but not to AlOH2+ and Al(OH)+2. New experiments, and reanalyses of previously published experiments, provide evidence that dicotyledonous species may be sensitive to mononuclear hydroxy-Al and that Al3+ may be nontoxic, or less toxic, to those plants. Despite these consistently measured differences between wheat and the dicotyledons, the determination of relative toxicities (Al3+ vs mononuclear hydroxy-Al) may be an intractable problem. Because of hydrolysis equilibria, (AlOH2+) and (Al(OH)+2) are equivalent to (Al3+)k1(H+)−1 and (l3+)k2(H+)−2, respectively, in which k1 and k2 are the first and second hydrolysis constants (braces denote activities). Thus, any expression of root elongation as a function of mononuclear hydroxy-Al can be alternatively expressed as a function of (Al3+) and (H+). Toxicity attributed to mononuclear hydroxy-Al may actually be Al3+ toxicity that increases as pH rises (i.e. Al3+ toxicity ameliorated by H+).  相似文献   

18.
为了探明典型荒漠灌木优势物种黑沙蒿(俗名油蒿, Artemisia ordosica)光合过程能量中分配对环境波动的相对变化及其长期调节机制, 该研究于2018年4-10月在宁夏盐池毛乌素沙地, 同时使用MONITORING-PAM多通道荧光监测仪和LI-6400XT便携式光合测量仪对黑沙蒿叶片的最小荧光产量(Fo)、最大荧光产量(Fm)、稳态荧光产量(Fs)、光下最大荧光产量(Fm′)、净光合速率(Pn)、暗呼吸速率(Rd)、蒸腾速率(E)和叶片气孔导度(gs)进行现场测定, 在实验室内计算比叶面积(SLA)、单位面积氮含量(Narea)、叶绿素含量(CChl)和叶绿素a/b (Chl a/b), 分析黑沙蒿光合过程能量分配中固碳耗能占比(ΦA)、光呼吸耗能占比(ΦPR)、调节性热耗散耗能占比(ΦNPQ)和非调节性热耗散耗能占比(ΦNO)与环境参数和叶性状参数之间的关系以及能量分配各组分之间的相对变化。结果表明, 光化学反应组分(ΦAΦPR)和热耗散组分(ΦNPQΦNO)之间呈负相关竞争关系, 两组分内部呈正相关协同关系, EΦAΦPR正相关, 和ΦNPQΦNO负相关。在低土壤含水量(SWC)和高饱和水汽压差(VPD)环境条件下, 黑沙蒿ΦAΦPRSLA显著降低, ΦNPQΦNO显著增加。研究认为, 在长期干旱或高蒸散条件下, 黑沙蒿通过降低SLA等途径避免水分的过度流失, 同时将部分过剩光能由光呼吸代谢途径转移到热耗散组分进行耗散。波动环境下黑沙蒿形态性状的变异和光合过程能量分配的长期调节机制, 反映了其利用形态与生理的协同可塑性对逆境的适应。  相似文献   

19.
Passive fluxes of K+ (86Rb) into roots of sunflower ( Helianthus annuus L. cv. Uniflorus) were determined at low K+ concentration (0.1 and 1.0 mM K+) in the ambient solution. Metabolic uptake of K+ was inhibited by 10−4M 2,4-dinitrophenol (DNP). K+ (86Rb) fluxes were studied both continuously and by time differentiation of uptake. In high K+ roots passive uptake was directly proportional to the K+ concentration of the uptake solution, indicating free diffusion. This assumption was supported by the fact that passive Rb+ uptake was not affected by high K+ concentrations. In low K+ roots the passive uptake of K+ was higher than in high K+ roots. The increase was possibly due to carrier-mediated K+ transport. As K+ effluxes were quantitatively similar to influxes, it is suggested that passive K+ fluxes represent exchange diffusion without relation to net K+ transport.  相似文献   

20.
The reaction of perrhenate with 2-hydrazinopyrimidine in MeOH–HCl yields [ReCl31-NNC4H3N2H)(η2-HNNC4H3N2)] (1). The analogous reaction with Na2MoO4 yields [MoCl31-NNC4H3N2H)(η2-HNNHC4H3N2)] (1a). The reaction of 1 with pyrimidine-2-thiol and triethylamine produces [Re(η1-C4H3N2S)(η2-C4H3N2S)(η1-NNC4H3N2)(η2-HNNC4H3N2)] (2), while reaction of 1 with the Schiff base HSC6H4N=C(H)C6H4OH provides [Re(η3-SC6H4N=C(H)C6H4O)(η1-NNC4H3N2)(η2-HNNC4H3N2)]·0.6CH2Cl2 (3·0.6CH2Cl2). The analogous hydrazinopyridine complex of the Schiff base, [Re(η3-SC6H4N=C(H)C6H4O)(η1-NNC5H4N)(η2-HNNC5H4N)] (4), was also synthesized by reacting [ReCl31-NNC5H4NH)(η2-HNNC5H4N)] with HSC6H4N=C(H)C6H4OH. The crystal structures of 1–4 have been determined.  相似文献   

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