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1.
异担子菌属Heterobasidion种类是北半球针叶树最严重的森林病原菌,在世界范围内能侵染27种针叶树,对欧洲和北美洲的经营林己造成重大损失.基于传统形态学研究,认为异担子菌属有2个种,即多年异担子菌H.annosum和岛生异担子菌H.insulare,然而单孢交配实验研究证明2个种为复合种.分子系统发育分析研究表... 相似文献
2.
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( R2/3、 R2/4、 R2/5、 R3/4、 R3/5、 R4/5)。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 R2/3、 R2/4、 R2/5、 R3/4、 R3/5和右侧 R2/3、 R2/4、 R2/5高于汉族男性( P<0.05);畲族女性指长比左侧的 R2/3、 R2/4、 R2/5和右侧 R2/3、 R2/4高于畲族男性( P<0.05);畲族男性指长比左、右侧 R2/3、 R2/4、 R2/5、 R3/5、 R4/5高于汉族男性( P<0.05);畲族女性指长比左侧 R2/3、 R2/4和右侧 R2/3、 R2/4、 R2/5、 R4/5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
3.
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
4.
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 GA 9 and GA 20 can not induce growth. In contrast application of GA, and GA 4 induced shoot elongation. The results indicate that 3β-hydroxylation of GA 9 to GA 4 and of GA 20 to GA 1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA 1, GA 3, GA 4, GA 7, GA 9, GA 12, GA 15, GA 15, GA 20, GA 29, GA 34 and GA 51 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 GA 9, GA 4 and GA 1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA 3, GA 12, and GA 20 between the different photoperiods. The lack of accumulation of GA 9 and GA 20 under short days is discussed. 相似文献
5.
Gibberellin biosynthesis pathways were investigated using isotopically-labelled C 19- and C 20-gibberellins and cell-free preparations from immature seed of Phaseous coccineus cv. Prizewinner. The initial steps in an early 13-hydroxylation pathway involved the conversion gibberellin A 12-aldehyde (GA 12-aldehyde) to GA 12 which was 13-hydroxylated to yield GA 53, Metabolism of GA 53 yielded GA 44. In contrast to other cell-free systems, GA 44 was not further converted, either as a δ-lactone or an open-lactone structure, to the C-20 aldehyde GA 19. GA 19 was, however, metabolised to GA 20, GA 5 and GA 1. GA 20 represented a branch point in the pathway as it was converted both to GA 1, which was an end product, and GA 5 which was further converted to GA 6. Like GA 1, GA 6 was also an end-product of the early 13-hydroxylation pathway. A non-13-hydroxylation pathway involving GA 4, GA 15, GA 24 GA 37 and GA 36 also originated from GA 12. The terminal product of this pathway was the 3β-hydroxy C 19-gibberellin, GA 4. 相似文献
6.
In higher plant cells, there are some enzymes capable of utilizing pyrophosphate (PP i) as an energy donor. Among these, membrane-bound proton pumping pyrophosphatases (H +-PP iase) have been identified. In addition to the well-known vacuolar H +-PP iase (V-PP iase), there is evidence for the presence of a mitochondrial H +-PP iase. This enzyme is localized on the inner surface of the inner membrane and catalyzes the specific hydrolysis of PP i, coupled to proton transport, with a H +/PP i stoichiometry of ca 2. This activity is Mg 2+-requiring, is stimulated by monovalent cations, and is inhibited by Ca 2+, F − and diphosphonates. The H +-PP iase contains a catalytic head which is constituted by a 35-kDa protein which is loosely bound to the inner membrane. This protein exhibits a PP iase activity, stimulated by phospholipids, with characteristics very similar to the membrane-bound enzyme. The mitochondrial PP iase is distinct from the V-PP iase, because an antibody raised against the 35-kDa protein does not react with tonoplast membranes. The mitochondrial H +-PP iase seems to have an F-type structure, similar to the F-ATP synthase and the membrane-bound PP iases from mammalian and yeast mitochondria. It is suggested that, beside synthesizing PP i, this enzyme may act as a buffer for the electrochemical proton gradient, by hydrolyzing PP i, during conditions of oxygen deprivation. 相似文献
7.
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PUEa、PUEgs和WUEgs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PUEa、PUEgs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, PUEa和PUEgs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PUEa和PUEgs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PUEa、PUEgs和WUEgs分别与AP、GSP和ETgs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
8.
The time course of aerobic photobleaching of various chlorophyll-protein complexes in vivo at high light intensities was studied with isolated Aspidistra elatior chloroplasts. 1. 1. Ca680 bleaching starts with the onset of irradiation and, initially, proceeds linearly with time. Washing the chloroplasts causes a nearly constant increase of the bleaching rate throughout the experiment. 2. 2. Ca670 does not appreciably, if at all, bleach initially; subsequently, bleaching proceeds linearly with time and at a slightly higher rate than that for Ca680. Washing makes Ca670 bleach concomitantly with the onset of illumination, and at a nearly constant rate. 3. 3. Bleaching at 665 nm is likely to start only after a relatively long period of illumination. Washing shows no effects during this period. Once bleaching has started, washing causes its rate to increase. 4. 4. No indication of the occurrence of “short-wave” chlorophyll a forms other than Ca670 and Ca665 was obtained. 5. 5. Cb bleaching starts concomitantly with illumination at a low rate. The rate increases more or less exponentially with time. Washing enhances bleaching in two steps. 6. 6. The importance of the results is discussed.
Abbreviations: Ca700,Ca695, Ca680, Ca670, Ca665, chlorophyll a-protein complexes in vivo with absorption maxima around 700, 695, 680, 670, and 665 nm, respectively; Cb; chlorophyll b-protein complex in vivo Abbreviations: DCIP, 2,6-dichlorophenolindophenol 相似文献
9.
探究不同沙地樟子松混交林土壤碳氮磷化学计量变化规律,为其混交经营提供科学依据.以沙地樟子松纯林为对照,在沙地樟子松×榆树及沙地樟子松×怀槐带状混交林中,沿沙地樟子松和伴生树种两个方向在距离混交中心0、1、2、3和4 m处的不同土层采集土样,分析土壤有机C、全N、全P、速效N、速效P含量及其计量比的特征.结果表明: 沙地樟子松混交林土壤有机C、全N和速效N含量高于纯林, 沙地樟子松与榆树混交主要增加了深层土壤有机C和全N含量,以及C/N和C/P, 沙地樟子松与怀槐混交提高了土壤N含量, 降低了P含量.随着远离混交林中心,沙地樟子松×榆树混交林中沙地樟子松林带的土壤C/N先升高后降低,全P和速效P含量下降,N/P增加;榆树林带土壤C/N下降,速效P含量先升高后降低.沙地樟子松×怀槐混交林土壤全N含量在沙地樟子松林带先降低后升高,在怀槐林带先升高后降低.沙地樟子松混交林提高了土壤C、N储量,沙地樟子松应与榆树行间混交,与怀槐间隔2行混交. 相似文献
10.
本试验采用发光二极管(LED)精准调控光源环境,以‘改良大龙茄’为试材,在前期探明红/蓝组合光(R/B)=3/1有利于培育茄子壮苗基础上,以R/B=3/1(9/3,CK 1)和LED白光(W,CK 2)为对照,分别设定LED红蓝白组合光为: R/B/W=3/1/1(9/3/3,T 1)、R/B/W=9/3/8(T 2)、R/B/W=3/1/6(9/3/18,T 3)和R/B/W=3/1/16(9/3/48,T 4),研究其对茄子幼苗生长、根系发育及定植后茄子产量和品质的影响,以期为茄子集约化高效育苗和设施生产补光提供理论依据和技术指导.结果表明: R/B/W=9/3/8组合光处理下,茄子幼苗株高、茎粗、壮苗指数、地上部干重、根干重、根系发育,以及定植后茄皮花青素、类黄酮含量和前期产量均较高;R/B/W=3/1/1组合光处理下,幼苗根冠比、定植后茄皮总酚和果肉中可溶性糖含量较高;而R/B/W=3/1/6组合光处理下,全株叶面积及定植后茄子果肉中游离氨基酸含量较高;R/B/W=3/1/16组合光处理下,定植后茄子果肉中可溶性蛋白含量较高.不同红蓝白组合光可不同程度提高茄子幼苗质量及定植后茄子前期产量和品质,以R/B/W=9/3/8组合光效果最显著. 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 Ca 2+ and Mg 2+. In the presence of Ca 2+ and Mg 2+, 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 Ca 2+ and Mg 2+, 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.
1,10-Phenanthroline-5,6-dione (C 12H 6N 2O 2 (1)) reacts with V(η 6-mesitylene) 2 and Ti(η 6-toluene) 2 affording coordination compounds of general formula M( O, O′---C 12H 6N 2O 2) 3 (M=Ti (2); M=V (3)) which further react with TiCl 4 or TiCp 2(CO) 2 yielding the tetrametallic species M( O, O′---C 12H 6N 2O 2--- N, N′) 3(M′L n) 3 (M=V, M′L n=TiCl 4 (4); M=Ti, M′L n=TiCp 2 (5); M=V, M′L n=TiCp 2 (6)). The complex salt [Fe( N, N′---C 12H 6N 2O 2) 3][PF 6] 2 (7) has been obtained from iron(II) chloride tetrahydrate and 1 in the presence of NH 4PF 6. The reaction of 7 with TiCp 2(CO) 2 affords the tetrametallic derivative [Fe( N, N′---C 12H 6N 2O 2--- O, O′) 3(TiCp 2) 3][PF 6] 2 (8). TiCl 2(THF) 2 reacts with MCp 2( O, O′---C 12H 6N 2O 2) to give MCp 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 2 (M=Ti (9); M=V (10)). By reaction of TiCp 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 2 (9) with C 12H 6N 2O 2, the bimetallic derivative TiCp 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 2( O, O′---C 12H 6N 2O 2) (11) has been prepared, which readily adds to TiCl 4, to give the trimetallic titanium derivative TiCp 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 4 (12). VCp 2( O, O′---C 12H 6N 2O 2--- N, N′)TiCl 2 (10) reacts with the tris-chelate iron(II) cation 7 affording the heptametallic cationic complex [Fe( N, N′---C 12H 6N 2O 2--- O, O′)TiCl 2( N, N′---C 12H 6N 2O 2--- O, O′)VCp 2] 3 +2 isolated as the hexafluorophosphate 13. 相似文献
13.
The haemolytic reagent allowing direct serological detection of He homozygous pigs was obtained by the immunization of a Landrace sow. Another monospecific reagent prepared from immune serum of a Miniature pig made possible the evidence for a new factor of the H system - He. This factor is genetically controlled by the allele H be. Its frequency in Miniature pigs was 0.099. The H system with alleles H 1=H a, H 2= H b, H 3= H ab, H 4=H cd, H 5= H bd, H 6=H be and H 7= H- continues to be a genetically open system. 相似文献
14.
Ratios of ammonium (NH 4+) to nitrate (NO 3–) in soils are known to increase during forest succession. Using evidence from several previous studies, we hypothesize that a malfunction in NH 4+ transport at the membrane level might limit the persistence of early successional tree species in later seral stages. In those studies, 13N radiotracing was used to determine unidirectional fluxes and pool sizes of NH 4+ and NO 3– in seedlings of the late-successional species white spruce ( Picea glauca ) and in the early successional species Douglas-fir ( Pseudotsuga menziesii var. glauca ) and trembling aspen ( Populus tremuloides ). At high external NH 4+, the two early successional species accumulated excessive NH 4+ in the root cytosol, and exhibited high-velocity, low-efficiency (15% to 22%), membrane fluxes of NH 4+. In sharp contrast, white spruce had low cytosolic NH 4+ accumulation, and lower-velocity but much higher-efficiency (65%), NH 4+ fluxes. Because these divergent responses parallel known differences in tolerance and toxicity to NH 4+ amongst these species, we propose that they constitute a significant driving force in forest succession, complementing the discrimination against NO 3– documented in white spruce (Kronzucker et al. 1997). 相似文献
15.
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 (WT S-WT R) adhered well to alveolar macrophages, whereas organisms from SP-A knockout (KO) mice inoculated into KO mice (KO S-KO R) did not. Substitution of WT mice as the source of organisms (WT S-KO R) or recipient host macrophages (KO S-WT R) restored adherence to that found with WT S-WT R mice. In contrast, when immunosuppressed KO and WT mice were inoculated with P. murina from a homologous source (KO S-KO R, WT S-WT R) or heterologous source (WT S-KO R, KO S-WT R) and followed sequentially, WT S-KO R 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 KO S-KO R 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
16.
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
17.
光下最大荧光( Fm′)是植物生理生态研究中的重要参数,一般采用饱和脉冲(RF)方案来估计.然而,光系统Ⅱ(PSⅡ)受体库的反馈调节会影响RF方案对 Fm′估计的准确性.为消除PSⅡ受体库反馈调节的影响,根据光脉冲强度( Q′)与叶绿素荧光( F′)的线性关系提出多相脉冲(MPF)方案,估算 Q′无穷大时的 F′(即 Fm′).本研究采用MPF和RF方案分别对苦槠、青冈和乌桕3个树种叶片的叶绿素荧光和气体交换数据进行同步测量,并对两种方案估计的 Fm′及其计算参数PSⅡ光化学效率( ΦPSII)、PSⅡ的电子传递速率( J)、最大电子传递速率( Jmax)、叶肉导度( gm)和叶绿体内CO 2浓度( Cc)等光合参数进行比较,分析两种方案对3个树种叶片6个光合参数的影响.结果表明: 当光合有效辐射(PAR)<200 μmol·m -2·s -1时,两种方案对苦槠、青冈和乌桕叶片 Fm′、 ΦPSII和 J的估计无显著影响;当PAR>200 μmol·m -2·s -1时,采用MPF方案获得的苦槠、青冈和乌桕的 Fm′分别比RF方案获得的 Fm′高3.5%~5.2%、11.7%~18.0%和3.2%~7.1%;当PAR>200 μmol·m -2·s -1时,采用MPF方案获得的 ΦPSII、 J和 Jmax分别不同程度地大于RF方案获得的参数, gm和 Cc分别不同程度地小于RF方案获得的参数.说明当PAR较低(<200μmol·m -2·s -1)时,MPF与RF方案对植物叶片 Fm′、 ΦPSII、 J的估计没有显著影响;当PAR较高(≥200μmol·m -2·s -1)时,MPF与RF方案对植物叶片 Fm′、 ΦPSII、 J、 Jmax、 gm和 Cc的估计有显著影响,且RF方案对植物叶片的 Fm′、 ΦPSII、 J和 Jmax比MPF方案分别有不同程度的低估,对 gm和 Cc则有不同程度的高估. 相似文献
18.
To elucidate how excess light energy is dissipated during water deficit, net photosynthesis (P N), stomatal conductance (g s), intercellular CO 2 concentration (c i) and Chl a fluorescence were investigated in control and drought-stressed tomato plants ( Lycopersicon esculentum ). Gross O 2 evolution (E o) and gross O 2 uptake (U o) were determined by a mass spectrometric 16O/ 18O 2 isotope technique. Under drought stress P N, g s, c i and U o decline. While photochemical fluorescence quenching decreases under water deficit, non-photochemical quenching rises. The maximal efficiency of PSII measured in the dark is not affected by drought; however, in the light, E o decreases under water deficit. The ratio P N/E o falls under stress while the ratio U o/E o increases. We conclude that tomato plants follow a double strategy to avoid photodamage under drought stress conditions: (1) a substantial portion of light energy is emitted as heat and PSII activity is downregulated. This results in a decrease in E o as well as P N and U o. Despite reduced charge separation at PSII, the decline of CO 2 assimilation because of lowered stomatal conductance and metabolic changes results in the need of degrading excessive photosynthetic electrons. (2) Oxygen is used as an alternative electron acceptor in photorespiration or Mehler reaction and U o rises relative to E o. 相似文献
19.
Abstract: We studied the action of H 2O 2 on the exocytosis of glutamate by cerebrocortical synaptosomes. The treatment of synaptosomes with H 2O 2 (50–150 µ M ) for a few minutes results in a long-lasting depression of the Ca 2+-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 H 2O 2, although a transient decrease was observed after the treatment. H 2O 2 did not promote peroxidation, as judged by the formation of malondialdehyde. In indo-1-loaded synaptosomes, the treatment with H 2O 2 did not modify significantly the KCl-induced increase of [Ca 2+] i. H 2O 2 inhibited exocytosis also when the latter was induced by increasing [Ca 2+] i with the Ca 2+ ionophore ionomycin. The effects of H 2O 2 were unchanged in the presence of superoxide dismutase and the presence of the Fe 3+ chelator deferoxamine. These results appear to indicate that H 2O 2, 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
20.
Abstract. An increase in egg size with embryonic development in stoneflies is believed to result from the uptake of water by osmosis. The present study aims to investigate whether a selective ion transport through egg membranes exists before hatching, and whether ions are released after hatching. Viable and nonviable egg masses are incubated in Petri dishes filled with water, and the concentrations of the ions F −, Cl −, SO 42−, NO 3−, Na +, K −, Mg 2+ and Ca 2+ in the water are determined. The ion transport of an egg mass before and after hatching and a nonviable egg mass is then calculated. Before hatching, Cl −, SO 42−, NO 3−, Na +, Mg 2+ and Ca 2+ are taken up from the surrounding water into the inner egg. These ions are selectively taken into the egg. After hatching, Cl −, SO 42−, Na +, Mg 2+ and Ca 2+ are released into the surrounding water. The amount of these ions released after hatching is lower than the amount taken up before hatching. Ions that are not released after hatching are considered to be used in embryonic development. 相似文献
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