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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   

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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已造成重大损失。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明:异担子菌属包括15个种,其中5个种为森林病原菌[冷杉异担子菌H. abietinum、多年异担子菌(狭义)H. annosum s. str.、变孔异担子菌H. irregulare、西方异担子菌H. occidentale和小孔异担子菌H. parviporum];10个种为腐生菌(淀粉孢异担子菌H. amyloideum、南洋杉异担子菌H. araucariae、阿曼德异担子菌H. armandii、南方异担子菌H. australe、岛生异担子菌H. insulare、林芝异担子菌H. linzhiense、东方异担子菌H. orientale、拟岛生异担子菌H. subinsulare、拟小孔异担子菌H. subparviporum和西藏异担子菌H. tibeticum)。多年异担子菌(狭义)H. annosum s. str.、小孔异担子菌H. parviporum和冷杉异担子菌H. abietinum分布于欧洲,分别是松属、云杉属和冷杉属林木的病原菌。变孔异担子菌H. irregulare和西方异担子菌H. occidentale分布于北美洲,前者侵染松属和柏属树木,后者侵染冷杉属、铁杉属、黄杉属和巨杉属树木。虽然广义的多年异担子菌H. annosum sensu lato曾在我国报道,但基于目前研究结果表明该种为拟小孔异担子菌H. subparviporum。目前世界上最具侵染力的5种病原菌即狭义的多年异担子菌H. annosum s. str.、小孔异担子菌H. parviporum、冷杉异担子菌H. abietinum、变孔异担子菌H. irregulare和西方异担子菌H. occidentale还未在我国发现,也未列为对外检疫对象,因此建议将其列为进境植物检疫性有害生物。RNA聚合酶II大亚基序列(RPB1)在异担子菌属种类鉴定中敏感性和特异性最高,研究证明该分子方法可应用于鉴别不同异担子菌种类的有效基因标记,在海关部门进行原木和木质产品的检疫中可运用该分子标记进行林木病原异担子菌的检测。  相似文献   

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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   

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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   

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Addition of small amounts of Fe2+, Zn2+, Cu2+ and thiamine-HCl to the culture medium was required for promoting the galacto-oligosaccharide (Gal-OS)-producing activity of Sterigmatomyces elviae CBS8119, when the concentration of yeast extract in the medium was lowered to 0·1 g l−1. Galacto-oligosaccharide production using a recycling cell culture was performed in a medium containing 360 mg ml−1 of lactose supplemented with optimal concentrations of Fe2+ (1·5 mg l−1 of FeSO4.7H2O), Zn2+ (15 mg l−1 of ZnSO4.7H2O), Cu2+ (0·5 mg l−1 of CuSO4.5H2O) and thiamine-HCl (1 mg l−1 ) . Galacto-oligosaccharide production was maintained at high levels during six cycles of production, with the amount of Gal-OS produced in each cycle being more than 216 mg ml−1 (weight yield of more than 60%).  相似文献   

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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   

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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   

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