安徽省北部大豆根瘤菌的分离,血清学分析及田间自然结瘤调查

对安徽省北部分离的２７株快生大豆根瘤菌和３８株慢生大豆根瘤菌的血清学分析及田间自然结瘤的血清学调查表明：００５血清型系安徽北部夏大豆产区占据优势的血清型，１８组样品和再现频率为１００％；３６株分离物中２６株属００５血清型，占总分离物的７２．５％。２０４８血清型出现频率为８３．３％；在３组样品中占瘤率达４１－５１。６％。２１７血清型占瘤率普遍低于１６％。讨论了自然结瘤调查中采样地点，大豆品种和土壤类     

广西相思树病害的调查与防治

对广西6种外来相思(马占相思、直干相思、纹荚相思、厚荚相思、杂交相思和黑木相思)的病害进行调查,发现主要病害有4种,次要病害3种,并提出防治方法。相思炭疽病病原为胶孢炭疽菌(Col-letotrichum gloeosporioides),在马占相思、直干相思、纹荚相思、厚荚相思和杂交相思的叶状柄上只产生病原菌的无性阶段,而在厚荚相思叶状柄上可同时出现无性阶段和有性阶段;相思白粉病病原为白粉菌(Oidi-umsp.),为害马占相思、厚荚相思和杂交相思的叶状柄和嫩枝,其中杂交相思白粉病发生普遍而严重,发病期多在3~5月;黑木相思叶状柄尖枯病病原为异色拟盘多毛孢(Pestalotiopsis versicolor),一年四季均可发病;马占相思心腐病,主要发生在树干基部,造成木材的大量损失,病原尚未得到确定。     

抗春雷霉素大豆根瘤菌突变株的诱变及其生物固氮特性的分析

根瘤菌与豆科植物共生可以固定大量的氮。根瘤菌剂接种豆科作物是一项普遍推广应用、有效的农业技术。但由于大量土著根瘤菌的存在，产生竞争障碍，降低了接种菌剂的占瘤率。大多数的土著根瘤菌对春雷霉素敏感，因此接种抗春雷霉素的高效结瘤固氮根瘤菌，并用春雷霉素处理种子，可抑制土著根瘤菌，提高接种菌剂的占瘤率，从而达到高结瘤、高固氮和提高产量的目的。本文将探讨诱变对根瘤菌抗春雷霉素突变的作用，并对获得的抗性突变株的生物固氮特性进行分析。     

马占相思木材物理力学性质的研究

对采自广西高峰林场9．5年生马占相思木材的主要物理力学性质进行测定和分析。结果表明：马占相思木材的气干密度、基本密度和全干密度分别为0．5636，0．4839和0．5333g／cm^3，其径向、弦向和体积干缩系数分别为0．0908％，0．2703％和0．3824％，其顺纹抗压强度为60．40MPa，径面和弦面的顺纹抗剪强度分别为10．89和12．01MPa，径面和弦面的顺纹抗劈强度分别为194．3和208．5N／mm，端面、径面和弦面的硬度分别为82．99，64．58和56．99MPa，冲击韧性为66．90kJ／m^2，抗弯强度和抗弯弹性模量分别为184．0MPa和13．944GPa。除了冲击韧性较小外，马占相思木材的主要力学强度均属于中上水平，可作为承重结构和高中档家具用材。     

甘肃省白龙江流域豆科植物根瘤菌共生固氮研究

对甘肃省白龙江流域甘南、陇南的大部分地区豆科植物——根瘤菌资源进行了调查 ,共采集 2 1属45种豆科植物 6 9份根瘤样品。从 6 9份样品中获 6 3株根瘤菌 ,对其中 44株根瘤以 13种寄主进行了回接试验 ,31株结瘤 ,结瘤率 70 .5 %。该区根瘤一般带有粉红色 ,形态比较规则。乙炔还原活力测定结果表明 ,88.5 %为有效根瘤。不同种根瘤固氮活性相差不大 ,但高于甘肃省其它地区。对豆科植物在蓄水保土 ,改良土壤状况中的地位进行了讨论。     

甘宁黄土高原地区重要水土保持植物共生固氮资源及特性研究

甘肃省黄土高原区不同生态条件下栽培和野生豆科植物根瘤菌资源及共生固氮特性的调查结果表明 ,从 112份 2 4属 5 3种根瘤样品中分离获得 87株根瘤菌。它们与豆科植物共生结瘤 6 3 .5 %为有效根瘤。不同种根瘤固氮活性差异较大 ,一般比较低 ,小于 1μmol/(g·h)占 35 %。大于 10 μmol/(g·h)仅占6 %。根据研究结果对这些豆科植物在水土保持中的作用及意义进行了讨论。     

马占相思营养袋育苗技术探讨

通过对马占相思种子育苗生产观察调查研究,探讨了马占相思种子营养袋育苗问题,包括苗期管理、病虫害防治、苗木生长情况、苗木出圃及包装运输,总结出一套马占相思营养袋育苗技术,以供参考。     

山西省费氏中华根瘤菌数量分布及特性探析

费氏中华根瘤菌(Sinorhzobium fredii)的区域分布与抗逆特性比较明显,在山西省石灰性土壤环境条件下,其数量分布达5100~5100000个/g(土),约占土著大豆根瘤菌的99.4%。该菌群与当地晋豆品种的自然结瘤率达80%以上,是山西省高感土著大豆根瘤菌的主要类群和资源优势,而与美国大豆“Osumi”等品种不亲和,几乎不结瘤。供试高效费氏中华根瘤菌株与当地“晋豆19”与“晋豆20”等主栽品种具有较好的结瘤固N效果。费氏中华根瘤菌的产酸性能有利于在山西省碱性土壤中生存,其活化根际养分效应与结瘤固N效果可能同等重要。     

高效紫云英根瘤菌的选育

通过分离鉴定、回接及盆栽试验,筛选出能高效结瘤、具有高效固氮酶活性,能有效提高紫云英生物量的紫云英根瘤菌作为目标菌株,制备液体菌剂应用于田间试验并测定其效果。结果表明,本试验筛选出的3株目标菌株均发挥了根瘤菌优越的生物固氮作用,增加了根瘤菌数量,提高了紫云英的生物学产量,并以GL-L-6菌株表现为最优。     

不同森林类型林冠截留效应研究

本文研究了7种不同森林类型林冠截留的月动态变化情况及林冠截留的水文生态效应。在一个观测期内林冠截留量随季节的变化而出现相应的变化,在雨季林冠截留量明显增大,7种不同森林类型林冠截留量的变幅从大到小的排序为：麻竹〉马占相思〉桉树〉勃氏甜龙竹〉混交林〉毛竹〉红竹。林冠截留量最大的是麻竹,最小的是毛竹,从大到小的排序为：麻竹（100．5ram）〉马占相思（62．4mm）〉勃氏甜龙竹（48．4ram）〉混交林（48．3mm）〉红竹（26．4mm）〉桉树（23．Omm）〉毛竹（10．1mm）。林冠截留率从大到小依次排序为麻竹（18．70％）〉马占相思（11．80％）〉桉树（8．56％）〉勃氏甜龙竹（8．41％）〉混交林（8．07％）〉毛竹（7．42％）〉红竹（4．10％）。结果表明：林冠层作为截留降水的第一作用层,对阻挡雨水侵蚀,减小雨滴的溅蚀,发挥了巨大的作用。     

施氮对镉胁迫下杂交相思树生长及镉吸收分配的影响

【目的】研究不同水平氮的供应对木本固氮植物杂交相思树适应镉环境胁迫及其生物修复能力的影响,可为有目的地进行相思树栽培提供施肥依据。【方法】以杂交相思树 (Acacia mangium × Acacia auriculiformis) 为试材进行了盆栽试验。Cd2+ 设3个水平(0、30、60 mg/kg),在Cd2+ 30 mg/kg的基础上设施尿素2个水平(0.4、0.8 g/kg) ,共5个处理。研究了杂交相思幼苗的干物质、氮(N)、磷(P)、钾(K)、镉(Cd)的积累和分配规律。【结果】Cd2+ 胁迫显著抑制了杂交相思幼苗根、茎、叶和总干物质的积累,限制了N、P、K等元素的吸收和积累;杂交相思Cd转移系数为0.044～0.224,根Cd含量明显高于茎和叶,并且根部Cd累积能力要大于地上部;但Cd2+ 60 mg/kg胁迫下,杂交相思通过向地上部分转移Cd以更好地适应强胁迫环境。Cd2+ 30 mg/kg胁迫下,高氮 (0.8 g/kg) 较低氮 (0.4 g/kg) 更显著地促进了茎、叶和植株总的P、K积累,而低氮更有效地增加了根的N、P、K积累量;高氮较低氮更显著地提高了茎、叶干重以及干物质在茎叶中的分配比例,低氮则提高了根干重以及干物质在根中的分配比例和根冠比;Cd2+ 胁迫下施氮显著促进了杂交相思对Cd的吸收和积累,提高了Cd转移系数;低氮更显著地促进了根、叶和总Cd的积累,高氮更显著地促进了茎Cd的积累及Cd在茎、叶中的分配比例。【结论】Cd2+ 胁迫下杂交相思通过改变干物质及N、P、K、Cd积累和分配规律以及提高N、P和K利用率的方式,保证根系生长,以更好地适应胁迫环境。低Cd2+ 胁迫下 (30 mg/kg),施氮可缓解杂交相思由镉胁迫所引起的对N、K吸收的抑制,促进杂交相思各器官干物质以及N、P、K、Cd的积累。低施氮量 (尿素 0.4 g/kg) 促进相思树生长的效果更佳,高施氮量 (尿素 0.8 g/kg) 促进Cd向地上部的运转,提高其对Cd生物修复能力。     

马占相思近熟林养分循环研究

研究了广西高峰林场11年生（近熟林）马占相思人工林10种营养元素生物循环的特点。结果表明：（1）马占相思不同器官营养元素含量以树叶（叶状柄）为最高,树干最低;各器官中大量营养元素含量以N最高,其次是Ca或K,然后是Mg,P最低;微量元素含量则以Mn和Fe最高,其次是Zn和B,Cu最低;（2）林分营养元素贮存量为2609．28kg／hm^2,乔木层、灌木层、草本层和凋落物层分别占83．95％、4．43％、1．71％和9．91％,林木中不同器官营养元素贮存量排序为干材〉树枝〉树根〉干皮〉树叶．（3）林分年吸收量、归还量、存留量分别为388．47、195．51和192．96kg／（hm^2·a）,10种元素的循环系数为0．39～0．78,循环速率依次为Mn〉Zn〉Mg〉P〉Ca〉Fe〉N〉Cu〉K〉B。     

不同林分土壤养分、微生物与酶活性的研究

研究了尾叶桉、马占相思、柚木、落羽杉纯林及黎蒴栲和湿地松、红荷和湿地松、黎蒴栲和加勒比松针阔混交林的土壤养分含量、微生物数量和酶活性。结果表明 :与马尾松纯林相比 ,马占相思、柚木、落羽杉纯林及针阔混交林能显著增加有机质和土壤养分 ,而尾叶桉纯林的效果随养分种类而异。黎蒴栲×湿地松混交林地及尾叶桉林地的微生物数量小于马尾松纯林地 ,其余林地的微生物数量大于后者。除了尾叶桉林地和马占相思林地外 ,其他林地的酶活性大于马尾松纯林地。总的来看 ,尾叶桉纯林改良土壤效果不佳 ,其他 6种人工林可以提高土壤肥力 ,防止地力衰退。     

越南和平水电站库区不同农林复合模式的环境效益比较

为了找出最适宜于越南中部山区、预期综合环境效益最佳的、更利于生态平衡的农林复合模式,该研究以越南和平水电站库区4种主要农林复合模式：马占相思树（Acacia mangium）-玉米（Zea mays）、马占相思树-木薯（Manihot esculenta crantz）、赤桉树（Eucalyptus camandulensis）-旱稻（Oraza sativa）和马占相思树-木薯-玉米为研究对象,采用盖度、土壤理化性质、土壤蓄水能力、水土保持能力等指标进行环境效益的比较,最后得出的结论为：在4种农林复合模式中,马占相思树-木薯-玉米复合模式具有最高的水土保持效益和综合环境效益;赤桉树-旱稻复合模式的水土保持效益和综合环境效益均最低;实践中应该增加前者的种植面积,限制和减小后者的种植面积。在马占相思树-木薯-玉米复合模式的基础上加以改进,提出了预期综合环境效益更好的马占相思树-木薯-玉米-肉桂（Cinnamomum cassia）复合模式,为农林复合系统在和平水电站库区的应用提供更好的选择,同时也为世界上有类似气候环境条件的地区农林复合模式的采用提供参考。     

Differentiation between two sub-species of <Emphasis Type="Italic">Acacia senegal</Emphasis> complex: <Emphasis Type="Italic">Acacia senegal</Emphasis> (L.) Willd. and <Emphasis Type="Italic">Acacia dudgeoni</Emphasis> Craib ex Holland using morphological traits and molecular markers

The Acacia senegal complex is formed by closely related species of Acacia senegal (L.) Willd. These species share several botanical characters, so from a morphological point of view, there is no clear discontinuity between some of them. A. dudgeoni Craib ex Holland is one species of the A. senegal complex that was formerly described as A. senegal ssp. senegalensis var. samoryana (A. Chev.) Rob. In order to differentiate Acacia senegal from A. dudgeoni, we analyzed a range of morphological traits such as tree height and diameter in natural stands, and, at the nursery stage, seedling height, number of branches, main root depth, biomass dry weight and leaf characteristics. Within addition, molecular polymorphism analyses were conducted using 11 microsatellite markers. Leaf characteristics and molecular markers appear to be the most effective tools to distinguish A. senegal from A. dudgeoni. These tools can improve our understanding of the relationship between two species belonging to the same species complex.     

Characterization of two Acacia gums and their fractions using a langmuir film balance

The mechanical properties of monolayers from two Acacia gums [Acacia senegal (L.) Willd. and Acacia seyal Del.] and their three fractions isolated by hydrophobic interaction chromatography were studied with a Langmuir film balance to obtain a more complete understanding of their action mode. The analysis of compression isotherms revealed that A. senegal gums globally exhibit better interfacial properties than A. seyal ones. The behavior of the whole gums appeared to be strongly influenced by their arabinogalactan-protein complex.     

华南典型人工林的土壤物理性质及其水源涵养功能

对杉木、马尾松、湿地松、尾叶桉和马占相思林的土壤物理性质、凋落物持水量以及土壤贮水性能进行了研究。5种林分土壤的毛管孔隙度、非毛管孔隙度和总孔隙度均为上层大于下层,而土壤容重为上层小于下层。总体来看,5种林分中杉木和马占相思林土壤疏松、孔隙度大;尾叶桉林土壤紧实、孔隙度小,马尾松林和湿地松的土壤孔隙度中等。凋落物最大持水量呈现杉木林(18thm-2)>马占相思林(15thm-2)>尾叶桉林(14thm-2)>马尾松林(11thm-2)>湿地松林(10thm-2)。土壤是森林涵养水源的主体,其最大持水量占林地最大持水量的99%以上,顺序为杉木林地和马占相思林(2064和2061thm-2)>湿地松林(2041thm-2)>马尾松林(2032thm-2)>尾叶桉林(1941thm-2)。林地最大持水量的顺序为杉木林地(2082thm-2)>马占相思林地(2076thm-2)>湿地松林地(2051thm-2)>马尾松林地(2043thm-2)>尾叶桉林地(1955thm-2)。     

Chemical composition and structural features of the macromolecular components of plantation Acacia mangium wood

The wood of Acacia mangium, a prominent fast-growing plantation species used in the pulp-and-paper industry and, so far, poorly investigated for its chemical structure, was submitted to a detailed characterization of its main macromolecular components. Lignin (28% wood weight) isolated by mild acidolysis and characterized by permanganate oxidation, 1H and 13C NMR, and GPC, showed a very low content of syringylpropane-derived units (S:G:H of 48:49:3), a high degree of condensation, a low content of beta-O-4 ( approximately 0.40-0.43 per C6) structures, and a Mw of 2230. Glucuronoxylan (14% wood weight) isolated by alkaline (KOH) or by dimethyl sulfoxide extraction was characterized by methylation analysis, 1H NMR, and GPC. About 10% of the xylopyranose (Xylp) units constituting the linear backbone were substituted at O-2 with 4-O-methylglucuronic acid residues. Almost half of the Xylp units (45%) were O-2 (18%), O-3 (24%) or O-2,3 (3%) acetylated. X-ray diffraction analysis of cellulose (46% wood weight), isolated according to the Kürschner-Hoffer method, showed a degree of crystallinity of 67.6%.     

Nodulation status of native woody legumes and phenotypic characteristics of associated rhizobia in soils of southern Ethiopia

The nodulation of provenances of Acacia seyal, Acacia tortilis and Faidherbia albida, and other indigenous multipurpose tree species were tested in 14 different soil samples collected from diverse agro-ecological zones in southern Ethiopia. Associated rhizobia were isolated from these and from excavated nodules of field standing mature trees, and phenotypically characterized. Indigenous rhizobia capable of eliciting nodules on at least one or more of the woody legume species tested were present in most of the soils. Tree species were markedly different in nodulation in the different site soils. Sesbania sesban and Acacia abyssinica showed higher nodulation ability across the different sites indicating widespread occurrence of compatible rhizobia in the soils. The nodulation patterns of the different provenances of Acacia spp. suggested the existence of intraspecific provenance variations in rhizobial affinity which can be exploited to improve N fixation through tree selection. Altogether, 241 isolates were recovered from the root nodules of trap host species and from excavated nodules. Isolates were differentiated by growth rate and colony morphology and there were very fast-, fast-, slow-, and very slow-growing rhizobia. The bulk of them (68.5%) were fast-growing acid-producing rhizobia while 25.3% were slow-growing alkali-producing types. Fast-growing alkali-producing (2.9%) and slow-growing acid-producing strains (3.3%) were isolated from trap host species and excavated nodules, respectively. All isolates fell into four colony types: watery translucent, white translucent, dull glistering and milky (curdled) type. The diversity of indigenous rhizobia in growth rate and colony morphology suggested that the collection probably includes several rhizobial genera.