小叶杨原生质体培养中的激素和氨含量变化

以小叶杨（Ｐｏｐｕｌｕｓｓｉｍｏｎｉｉｃａｒｒ．）原生质体培养的愈伤组织为供试材料，用高压波相色谱法（ＨＰＬＣ），测定它们在四种不同分化培养基上四大类内源激素（ＩＡＡ，ＧＡ３，ＣＴＫ，ＡＢＡ）的含量变化，并检定有关Ｎ的生化反应。结果表明，不同分化培养基上的愈伤组织中内源激素含量和种类差异很大。导致细胞分裂素（ＣＴＫ）含量高，种类多以及细胞分裂素与生长素的比值（ＣＴＫ／ＩＡＡ）高的处理，有利于愈伤组织分化；但若愈伤组织中含有内源脱落酸（ＡＢＡ），则抑制分化。测定结果还表明，小叶杨原生质体培养的愈伤组织分化过程中，其硝酸还原酶活力与氨基态Ｎ含量互为消长。分化频率高的愈伤组织中，硝酸还原酶活力低，而氨基态Ｎ含量高．     

小叶杨原生质体培养中的激素和氮含量变化

以小叶杨原生质体培养的愈伤组织为供试材料，用高压液相色谱法（ＨＰＬＣ），测定它们在四种不同分化培养基上四大类内源激素（ＩＡＡ，ＧＡ３，ＣＴＫ，ＡＢＡ）的含量变化，并检定有关Ｎ的生化反应，结果表明，不同分化培养基上愈伤组织中内源激素含量和种类差异很大，导致细胞分裂素（ＣＴＫ）含量高，种类多以细胞分裂素与主长素的比值（ＣＴＫ／ＬＡＡ）高的处理，有利于愈伤组织分化；但若愈伤组织中含有内源脱落酸（ＡＢＡ）     

大小年毛竹林中内源激素节律变化特征的研究

运用酶联免疫测定法（ＥＬＩＳＡ）,对大小年毛竹林一个大小年生长发育周期中,不同生长发育时期竹叶、竹秆、竹鞭、鞭梢中内源激素（ＩＡＡ、ＧＡ_３、ＡＢＡ）含量进行了测定和分析,结果表明：（１）大小年毛竹林鞭竹系统中任一器官中ＩＡＡ、ＧＡ_３含量的变化趋势一致,ＡＢＡ含量的变化趋势与ＩＡＡ、ＧＡ_３的相背。（２）立竹的内源激素节律变化,具相对独立性,竹叶、竹秆中内源激素含量的变化具同步性,ＩＡＡ、ＧＡ_３、ＡＢＡ含量各出现两个峰值和两个低值;ＩＡＡ、ＧＡ_３大小年年均含量大年高小年低,ＡＢＡ则相反。（３）鞭梢中ＩＡＡ、ＧＡ_３、ＡＢＡ含量变化也具相对独立性,出现二个峰值和二个低值;ＩＡＡ、ＧＡ_３、ＡＢＡ大小年年均含量基本相当。（４）竹鞭中内源激素的节律变化具整体性,分别是四个峰值和四个低值;ＩＡＡ、ＧＡ_３、ＡＢＡ大小年年均含量基本相当。毛竹大小年的形成是由毛竹林鞭竹系统的整体性结构和立竹个体的生长节律及植物内源激素的调控作用共同决定的。     

枣果生长发育期内源激素变化规律研究

应用高效液相色谱测定法测定了枣花期和果实生长发育期内源生长素（ＩＡＡ）、赤霉素（ＧＡ）和脱落酸（ＡＢＡ）在枣叶、枣果和枣落果中的含量,分析了这些内源激素含量变化对枣果生长发育的影响．在果实生长发育期,枣果中ＧＡ含量高于同期枣叶和落果中的含量,保证果实生长和碳同化物向果实转移,随ＧＡ含量迅速提高,枣果开始快速生长．枣果发育期内ＩＡＡ含量有两次低谷期,枣花受精后,幼果中ＩＡＡ含量开始下降,５月２０日前后为其第一个低谷期,含量为１．７１μｇ／１０ｇＦＷ,其后含量开始回升,６月２０日前后为其第二个低谷期,含量为２．５８μｇ／１０ｇＦＷ,此时与叶片中ＩＡＡ含量差异最大．ＡＢＡ含量在枣叶和枣果中含量很低,因此枣座果后,幼果中低含量的ＩＡＡ和ＡＢＡ不利于枣胚的发育,导致胚早期败育,造成大量落果,７月１０日后,枣果中较高的ＡＢＡ有利于果实中物质转化和碳水化合物的积累．内源ＩＡＡ、ＧＡ和ＡＢＡ的平衡作用有利于枣果的生长发育．     

红松种子层积催芽处理和萌发过程中内源GA_S和IAA含量的变化

采用高效液相色谱纯化、气质联用仪定性定量分析的方法，研究了红松种子在萌发过程中ＧＡＳ和ＩＡＡ含量的变化，并与萌发率相比较。结果表明：低温层积过程中ＩＡＡ、ＧＡ１、３、９含量均先下降后升高，呈“Ｖ”字型变化曲线，其中层积１１周ＧＡ１、３的含量超过层积０周的水平。室温干藏过程中，ＧＡ１、３、９含量均呈下降趋势。低温层积后萌发过程中，ＧＡ３、９、４呈上升势态，ＩＡＡ在萌发第５天有一个极大的上升高峰。室温干藏后萌发过程中ＩＡＡ、ＧＡ１、３、４、７、９含量均呈下降势态。     

中国沙棘休眠枝条中ABA和IAA含量消长对生根的影响

对中国沙棘１２月至翌年３月休眠枝条中ＡＢＡ和ＩＡＡ含量的消长对生根的影响进行研究的结果表明，从１２月至２月枝条中ＡＢＡ含量增加，而ＩＡＡ含量下降；至３月ＡＢＡ下降，ＩＡＡ则上升，ＩＡＡ含量的消长与插穗生根成正相关，而ＡＢＡ与插穗生根成负相关。     

中国沙棘休眠枝条中ABA和IAA含量消长对生根的影响

对中国沙棘１２月至翌年３月休眠枝条中ＡＢＡ和ＩＡＡ含量的消长对生根的影响进行研究的结果表明，从１２月至２月枝条中ＡＢＡ含量增加，而ＩＡＡ含量下降，至３月ＡＢＡ下降，ＩＡＡ则上升，ＩＡＡ含量的消长与插穗生根成正相关而ＡＢＡ与插穗生根成负相关。     

红松种子层积催芽处理和荫发过程中内源GAs和IAA含量的变化

采用高效液相色谱纯法、气质联用仪定性定量分析的方法，研究了红松种子在萌发过程中ＧＡｓ和ＩＡＡ含量的变化，并与萌发率相比较。结果表明：低温层积过程中ＩＡＡ、ＧＡ、１、３、９含量均先下降后升高，呈“Ｖ”字型变化曲线，其中层积１１周ＧＡ１、３的含量超过层积０周的水平。室温干藏过程中，ＧＡ１、３、９含量均呈下降趋势。低温层积后萌发过程中，ＧＡ３、９、４呈直升势态，ＩＡＡ在萌发第５天有一个极大的上升高峰。室     

用于林区和边境防火线的化学除草剂

经１６年经验筛选出林区和边境防火线的化学除草剂以草甘膦＋２，４－Ｄ丁酯、草甘膦＋威尔柏等混剂配方为好，除草效果达９５％以上，室内试验表明，草甘膦具有解偶联剂作用，抑制膜上ＡＴＰ酶活性。     

草甘膦的作用机理及部位

研究结果表明，草甘膦除抑制芳香氨基酸的生物合成外还抑制莽草酸的生物合成，作用部位在磷酸烯醇丙酮酸到莽草酸中间；同时还抑制胡萝卜素、叶黄素的生物合成，作用部位在丙酮酸之后的乙酰辅酶Ａ到类胡萝卜素中间；抑制叶绿素的生成作用部位在琥珀酰ＣＯＡ与σ－氨基ｒ－酮戊酸中间；此外草甘膦还抑制光合磷酸化，作用部位为抑制ＡＴＰ酶的活性。草甘膦高效的杀草能力，应当是它多种作用的综合结果     

PCR–DGGE method for in planta detection and identification of Phytophthora species

We have developed a method to detect multiple species of Phytophthora directly in infected plant tissues. The method is based on the polymerase chain reaction and uses Phytopththora‐specific primers and denaturing gradient gel electrophoresis (PCR–DGGE). The method distinguished most of the 16 Phytophthora species tested. Very closely related species might not, however, be identified using the method. The detection efficiency was high and successful in eight different plant tissues tested. The PCR–DGGE detection tool developed here will be a fast and inexpensive method suitable for pathogen surveys and research programmes.     

Vascular cambial sucrose metabolism and growth in loblolly pine (Pinus taeda L.) in relation to transplanting stress

Sucrose synthase (SS) was the dominant enzyme of sucrose metabolism in both stem and root vascular cambial zone tissues of nursery-grown loblolly pine (Pinus taeda L.) seedlings. Acid invertase (AI) and neutral invertase (NT) activities were generally less than 10% of the SS activity in both tissues. In both cambial tissues, seasonal patterns of enzyme activity were observed for SS but not for AI or NI. The seasonal patterns of SS activity in stem and root cambia paralleled the periodic growth of stems and roots. Stems had high SS activity and growth during summer and early fall. Roots had substantial SS activity and growth during summer and fall, but SS activity and growth were even higher in winter. When seedlings were transplanted, about eight months elapsed before stem and root cambia resumed rates of growth and sucrose metabolism similar to those in control nontransplanted seedlings. Two months after transplanting, root SS was at its lowest, whereas AI activity in transplants was 50% higher than in control nontransplanted seedlings. In stems, SS activity decreased in response to transplanting, whereas AI and NI activities did not change appreciably. In loblolly pine tissues, SS was specific for uridylates, whereas the nucleotide triphosphate-dependent phosphofructokinase (NTP-PFK) had similar activity with either UTP or ATP. Except in winter, the NTP-PFK was less active than the pyrophosphate-dependent phosphofructokinase (PPi-PFK) during all seasons. The PPi-dependent PFK activity in nontransplanted seedlings followed similar seasonal and spatial patterns to those of SS activity. In actively growing tissues, such as stem cambial tissues in summer and root cambial tissues in winter, the measured total PFK to SS ratio ranged between 1.5/1 and 3/1. In contrast, in less actively growing tissues or transplanted seedlings, a greater decrease occurred in SS than in PFK activity, hence the ratio rose to as high as 12/1. It was concluded that: (1) SS was the dominant enzyme for sucrose metabolism in root and stem cambial tissues of loblolly pine seedlings; (2) both SS and PPi-PFK in the cambial tissues can be used as biochemical indicators of growth sink strength in stems and roots; and (3) both enzymes can be used as indicators of seedling stress caused by events such as transplanting and winter freezing.     

Temperature effect on Chalara fraxinea: heat treatment of saplings as a possible disease control method

Ash dieback is an emerging disease caused by the fungus Chalara fraxinea that severely affects Fraxinus excelsior and F. angustifolia stands in Europe. Previous studies have shown that this pathogen prefers temperatures around 20°C, while its growth in pure cultures at 30°C proved to be very limited. The purpose of this study was to determine the effects of temperature on the development and growth of C. fraxinea in pure cultures and in plant tissues, as well as to test the heat tolerance of F. excelsior saplings. The sensitivity of fungus to heat in ash tissues was higher than in pure cultures. Low isolation success rate from diseased ash tissue after a five‐hour hot water treatment at 36°C and the relatively high survival rate of ash saplings after hot water treatments at 36°C and 40°C indicate possibilities for the development of a C. fraxinea eradication method in ash saplings. Field monitoring showed that in hot weather periods, thermal conditions inside the ash tissues can be extreme enough to markedly decrease the viability of C. fraxinea in infected plant tissues.     

苹果属无融合生殖SERK1基因的克隆与生物信息学分析

[目的]为探讨苹果属植物无融合生殖分子机制。[方法]以苹果属平邑甜茶及杂种后代33#为试材,以苹果基因组CDS序列设计引物,通过PCR扩增技术克隆出SERK同源基因的cDNA全长序列,命名为MhSERK1和MhdSERK1(GenBank登录号JQ231273和JQ231272),利用实时定量RTqPCR的方法检测了这两个基因在平邑甜茶和杂种后代各组织和器官中的表达模式。[结果]序列分析显示MhSERK1和MhdSERK1编码区序列全长为1 899 bp和1 881 bp,分别编码632和626个氨基酸,其氨基酸序列与其他植物的SERK1同源基因所编码的氨基酸同源性都在80%以上,特别是与葡萄科龙眼品种同源性最高,高达92.56%,与模式植物拟南芥、烟草等植物的SERK同源基因都具有很高的同源性。实时定量PCR结果表明,在平邑甜茶和杂种后代不同组织、花器官中SERK1基因的表达量存在差异,其中在子房中的表达量最高,在营养生长的组织中表达量很低,在平邑甜茶花蕾期的子房中表达量最高。[结论]推测该基因在平邑甜茶和杂种后代的生殖发育过程中可能发挥重要作用。     

Transient gene expression in western white pine using agroinfiltration

A method for transient gene expression was developed for western white pine(WWP, Pinus monticola Dougl. ex D.Don) using reporter gene uid A encoding bglucuronidase(GUS). GUS was transiently expressed in cross sections of primary and secondary needles, cotyledons, and current and second year stems of WWP via vacuum-infiltration with Agrobacterium tumefaciens. Histochemical assays of cross sections of secondary needles showed stronger blue color indicating GUS expression at day 1 and 2 than on other days post agroinfiltration(dpa).GUS activity expressed inside WWP cells was confirmed using light microscopy. In fluorometric assays, GUS expression was high at 1 dpa and lasted until 4 dpa in detached secondary needles, while similarly high expression levels only lasted until 2 dpa in attached secondary needles then dropped significantly. Although the length of GUS-staining zones varied among different WWP organs and between growth and dormant seasons, all tested WWP tissues using the protocol had high levels of transient GUS expression. Thus, heterologous candidate genes or endogenous silencing can be expressed in various WWP tissues or organs using this agroinfiltration approach. The current protocol for efficient transient gene expression willaid functional genomics study of WWP and its pathogens and related conifer species.     

Photosynthate distribution patterns in cherrybark oak seedling sprouts

We used 14C tracers to determine photosynthate distribution in cherrybark oak (Quercus pagoda Raf.) seedling sprouts following release from competing mid-story vegetation. Fall acquisition of labeled photosynthates by seedlings followed expected source-sink patterns, with root and basal stem tissues serving as the primary sinks. Four months after the seedlings had been labeled with 14C, they were clipped to induce sprouting. First-flush stem and leaf tissues of the resulting seedling sprouts were the primary sinks for labeled photosynthates stored in root tissues. Second-flush stem and leaf tissues, and first-flush stem and leaf tissues the following growing season, were not primary sinks for labeled photosynthates stored in root tissues despite the high radioactivity in root tissues. Root tissues appeared to deposit photosynthates in a layering process whereby the last photosynthates stored in new xylem were the first to be depleted during the initiation of a growth flush the following spring. There were more labeled photosynthates in roots of released seedling sprouts compared with non-released seedling sprouts, indicating increased vigor of released seedling sprouts in response to greater light availability. In contrast, stem and source leaf tissues of non-released seedling sprouts contained greater percentages of labeled photosynthates compared with released seedling sprouts, indicating either greater sink strength or poorly developed xylem and phloem pathways that created inefficiencies in distribution to root tissues. The 14C distribution coefficients confirmed the distribution patterns and provided additional information on the important sinks in released and non-released cherrybark oak seedling sprouts.     

The Summerwood: Springwood Ratio in Conifers: How it arises, varies, and affects end use for timber, board, and paper

A theoretical discussion of variation in summerwood and springwoodcontents among conifers. Three methods of measuring these, bycross-sectional area of logs, by dryweight fibre percentage,and by nominal specific gravity, are compared. High-summerwood tissues have a nominal specific gravity of 0?45or over; low-summerwood tissues have a specific gravity below0?45. All conifers have a low summerwood content in their juvenilewood or core wood formed towards their stem-tips. In Pinus,Larix, and Pseudotsuga the summerwood percentage increases markedlywith age, but only in the outer layers towards the butt; inPicea, Abies, and Tsuga similar increases occur, but high-summerwoodtissues are seldom found. Within any species, and for any particulargrowth rate, low-summerwood tissues are characteristic of regionsof high relative humidity where summer water deficits rarelyoccur, such as high altitudes, far northern latitudes, and themaritime climate of western Britain. High-summerwood tissuesdevelop where summer temperatures are high, with associatedstrong sunshine, low relative humidity, and frequent summerwater deficits. High-summerwood tissues have greater strength in compressionand bending, relative to volume; but low-summerwood tissueshave greater strength relative to their weight. Low-summerwoodmaterial has proved satisfactory for most structural purposes,and for the manufacture of several kinds of artificial board.Its technical properties for the making of many types of paperare excellent, provided high resistance to tearing is not required.Likely summerwood content should guide planting programmes andmarketing policies.     

Aeroponic production of Acacia mangium saplings inoculated with AM fungi for reforestation in the tropics

Aeroponics, a soilless plant culture method, was used to produce Acacia mangium saplings associated with arbuscular mycorrhiza (AM) fungi. A. mangium seedlings were first grown in multipots and inoculated with Endorize, a commercial AM fungal inoculum. They were then, either transferred to aeroponic systems or to soil. Aeroponics was found to be a better system than soil, allowing the production of tree saplings twice as high as those grown in soil. Moreover, compared to plants grown in soil, aeroponically grown saplings inoculated with AM fungal inoculum exhibited significantly different rates of mycorrhization, resulting in an increase in phosphorus and chlorophyll in plant tissues. Our results suggest that the aeroponic system is an innovative and appropriate technology which has the potential to produce in large quantities, tree saplings associated with soil micro-organisms, such as AM fungi, for reforestation of degraded land in the humid tropics.     

Main Anatomy Characteristics in Cell Wall and Lignin Distribution of Bamboo Culms(Pseudosasa amabilis)

The anatomy characteristics of cell wall and lignin distribution in different anatomical regions for 12-month-old bamboo species Pseudosasa amabilis was investigated.The lignin distribution was studied by means of optical microscope and confocal laser scanning microscope and the color reaction. In addition,the distribution of lignin in different tissues(fiber,parenchyma and vessel) was investigated by visible-light microspectrophotometry coupled with the Wiesner and Maule reaction.The cell walls of different tissues were all lignified and the lignin was widely distributed in different tissues, in which there was a difference between tissues and anatomical regions in lignin content.Guaiacyl lignin and syringyl lignin unit could be found in cell wall of fiber,parenchyma and vessel through Wiesner and Maule reaction and the absorbance peak of spectrum. There was no regular variation in lignin content with different radial location of culms and different location in fiber strands.The lamellation of the fiber cell wall was generally had as alternating broad and narrow layers with alternating low and high concentration of lignin.     

茶秆竹细胞壁解剖特性以及木质素微区分布

对12个月的茶秆竹进行细胞壁解剖特性和木质素微区分布的研究,运用光学显微镜、激光共聚焦扫描显微镜以及颜色反应鉴定木质素的存在,利用组织化学染色方法及其可见光显微分光光度计半定量测定竹材纤维、薄壁组织和导管细胞壁各微区的木质素含量。12个月时细胞壁全部木质化,木质素在各组织中均有分布,其含量因组织类型及其细胞壁微区不同而有差异。从组织化学染色及可见光吸收光谱图的吸收峰值,说明细胞壁各微区中存在愈创木基(G)和紫丁香基(S)2种木质素组成单元。竹壁径向和纤维帽不同位置的木质素含量未有明显的规律性变化。纤维次生壁具有薄厚层交替的多层结构,薄层木质素含量大于厚层。