麻楝扦插生根进程中内源激素和营养物质含量的变化

【目的】研究麻楝扦插生根进程中形态、内源激素和营养物质含量的变化,揭示麻楝插穗内源激素和营养物质含量对其扦插生根的影响。【方法】以麻楝6个月生半木质化枝条为材料进行扦插,在扦插后每隔10 d取一次样,记录插穗生根情况,及测定基部内源激素和营养物质含量。【结果】观测证实麻楝嫩枝插穗生根类型主要为皮部生根型,少量为愈伤组织生根型和中间生根型;其生根进程大致分为3个时期:皮孔萌动根原基诱导期(0～20 d)、不定根表达发生期(20～40 d)和不定根伸长发育期(40 d以后)。外源激素处理组麻楝插穗生根进程研究发现,内源激素IAA含量、IAA/ABA值、IAA/ZR值呈"上升-下降-上升"的变化趋势,ABA含量呈"上升-下降"趋势,GA和ZR含量的变化相似,均为"上升-下降-上升-下降"。营养物质含量变化研究中,处理组可溶性糖与淀粉含量均呈"下降-上升-下降"的变化趋势,可溶性蛋白含量变化表现为先下降而后缓慢上升。【结论】麻楝插穗生根过程中,外源激素IBA的施用可在一定程度上提高插穗内源激素IAA、GA、ZR的含量及IAA/ABA、IAA/ZR的比值,降低ABA的含量。较高浓度的IAA和较为稳定的低浓度ZR有利于插穗不定根的发生;低浓度的ABA有利于不定根的形成与伸长;同时较低水平的IAA和GA对插穗根系伸长生长有益。较高比值的IAA/ZR和IAA/ABA有利于麻楝嫩枝插穗生根。外源激素处理加快了麻楝插穗内各营养物质的代谢进程,对插穗生根有利;各处理可溶性糖和淀粉含量显著高于可溶性蛋白含量,变化幅度也较可溶性蛋白含量大,与麻楝插穗生根的联系更为紧密。     

黑果枸杞扦插生根过程中内源激素的动态变化

为探讨黑果枸杞扦插中内源激素对插穗生根的作用,采用酶联免疫吸附法(ELISA)测定了黑果枸杞硬枝插穗生根过程中韧皮部吲哚乙酸(IAA)、脱落酸(ABA)及玉米素(ZR) 3种植物内源激素的含量变化。结果表明:生根初期,插穗有1个衰老过程,插穗生根部位的IAA、ZR和IAA/ABA比值均迅速降低,ABA变化不明显。IAA生根中的含量变化规律与ABA的大致相同,对生根不起主要作用,只是起到协同作用。与对照相比,萘乙酸(NAA)处理插穗对ABA影响不显著,但插穗生根部位IAA含量、IAA/ABA比值得到提高,同时ZR含量下降。低浓度的ZR有利于愈伤组织形成。插穗内源激素的动态平衡,共同调控不定根的发生。IAA/ABA比值可以作为生根能力的判断标准之一。     

枫杨硬枝扦插生根的研究

为了研究不同的处理方法对枫杨硬枝扦插生根的影响及扦插生根与插穗内营养物质含量之间的关系,以1年生枫杨实生苗为实验材料,从基质种类、插穗部位、长度及粗度、ABT、IBA及NAA浓度等方面研究了不同处理对生根的影响,同时测定了枫杨生根过程中可溶性糖和蛋白质两种营养物质的含量,以及GA_3、IAA/ABA、IAA/ZR的动态变化。结果表明:泥炭土与珍珠岩体积1:1混合基质中插穗生根率最高,达93. 9%;选用1年生实生苗基部插穗的生根率最高,为93.3%;粗度为0.6～0.9 cm、长度为10.0～15.0 cm的插穗,生根效果更好。质量浓度为150 mg/L的IBA处理插穗效果最好,生根率达88.4%,并且苗高与地径显著大于对照。枫杨硬枝扦插以皮部生根为主。生根过程中插穗基部的蛋白质含量呈下降—升高—下降—升高,可溶性糖含量呈急剧下降后升高再下降,内源激素GA_3呈升高—下降,IAA/ABA比值呈下降—升高—下降、IAA/ZR比值呈下降—升高—下降—升高。     

~(60)Co-γ对海州常山扦插过程内源激素含量的变化影响

以海州常山(Clerodendrum trichotomum Thumb)1年生休眠枝条为材料,采用60Co-γ射线(剂量15Gy)处理扦插插穗,未经辐射处理为对照。于扦插后40d、47d、54d、64d、74d、84d和104d从辐射与对照处理插穗基部皮部取样,测定生根过程中内源激素生长素(IAA)、赤霉素(GA3)、脱落酸(ABA)和玉米素(ZR)含量的动态变化。结果显示:60Co-γ射线抑制海州常山扦插生根。与对照相比,15Gy的60Co-γ射线辐射处理组的内源IAA含量、ABA含量和ZR含量均在不定根诱导和形成期间多上升,GA3含量、IAA/ABA,GA3/ABA,ZR/ABA比值含量降低,IAA和ZR含量谷值推后到来。60Co-γ辐射处理提高不定根形成期内源ABA含量,从而IAA/ABA,GA3/ABA,ZR/ABA比值降低,这是插穗生根推迟的主要原因。     

南京椴嫩枝扦插生根过程中植物激素的变化

以南京椴嫩枝插穗为研究对象,采用1 000 mg·kg-1 IBA粉剂处理插穗基部,对扦插生根过程中插穗皮部生长素IAA、玉米素核苷ZR、赤霉素GA3、脱落酸ABA含量以及IAA/ABA和IAA/ZR比值进行动态测定,探究嫩枝扦插生根过程中植物激素变化特点及其对生根的影响。结果表明:1)IBA处理可以显著促进南京椴嫩枝插穗生根,生根率接近67%;其生根过程可划分为愈伤组织形成期、根原基诱导期、不定根形成期和不定根生长期,各自对应时间约为10 d。2)IBA处理可以提高嫩枝插穗中IAA含量,IAA对于根原基的诱导和不定根的发生具有较为直接的影响作用,其含量升高有利于生根;GA3含量增加有利于根原基形成,而低水平GA3则更有利于不定根的生长;ABA和ZR含量升高不利于插穗生根,对于根原基的诱导和不定根的发生具有抑制作用;IAA、ABA在插穗根原基诱导和不定根形成过程中具有相互协调作用,IAA/ABA可作为衡量南京椴嫩枝扦插生根能力的指标。3)外源IBA处理可以促进插穗内IAA含量升高,调节ABA、ZR、GA3含量降低,促使IAA/ABA在诱导生根期快速增大,通过相关激素的调控,使插穗向有利于促进生根的生理状态转变。     

金叶银杏硬枝扦插繁殖生根过程及其生根机制研究

【目的】研究不同生长调节剂处理对金叶银杏硬枝扦插生根率和成活率的影响,探讨金叶银杏的生根机制,为金叶银杏苗木扦插快繁技术体系的建立提供技术支持和理论指导。【方法】通过NAA和IBA处理金叶银杏硬枝插穗,检测它们对插穗的生根状态、生根指标及IBA对扦插过程中插穗皮部可溶性糖、抗氧化酶、激素含量的影响,探究金叶银杏硬枝扦插繁殖技术和生根机理。【结果】1)金叶银杏插穗愈伤组织诱导期和形成期、不定根发生期和形成期分别在插后的20~26、26~42、42~53、53~79 d。2)800 mg·L^-1 IBA和400 mg·L^-1 NAA+400 mg·L^-1IBA(混合)处理的插穗愈伤组织和不定根出现期及生根率与根数都较其他相应处理的效果好,其中生根率分别达64.4%和51.1%;不定根数分别达8.6条和9.3条。3)插穗生根过程中(500 mg·L^-1 IBA处理)基部韧皮部的SOD、PPO活性在插后40、60 d达到高峰,均比对照提前20 d达到峰值;插穗的POD活性出现上升-下降-升高的趋势,插穗可溶性糖也出现升高-下降-升高的趋势,但时间点不一致;而淀粉的含量出现下降-上升的趋势。4)生根期间插穗基部韧皮部的IAA含量出现了2个峰值和一个谷值;而ZR含量在第40天达到峰值后下降;GA含量先下降后上升;ABA含量在插后的前期高后期低,且值都低于同期对照。IAA/ABA比值在插后的第40天(愈伤组织形成期)达到谷底,后又上升(不定根形成期)。IAA/GA在插后的40~60 d内快速上升,80 d后又开始大幅下降;IAA/ZR值在扦插愈伤组织形成期(40 d)呈下降趋势,到60 d时(不定根发生期)又急剧上升到峰值。【结论】高活性的SOD和POD有利于插穗初期愈伤组织的形成(40 d),高活性的POD与PPO有利于不定根的形成(60 d)。较高的IAA含量是保证愈伤组织形成(20~40 d)的必要条件,不定根形成期(60 d)需要较高的IAA/ZR、IAA/ABA、IAA/GA比值。本研究为金叶银杏扦插繁殖技术和生根机理的研究及金叶银杏苗木的快速繁殖生产提供技术支持。     

扦插过程中秤锤树插穗内激素含量的变化

采用酶联免疫法测定了秤锤树扦插过程中插穗的内源激素含量的变化。结果表明,2年生母树插穗内的IAA、ZR含量大于10年生母树插穗,利于生根;10年生母树的插穗内ABA含量大于2年生母树的,表现出对生根的抑制作用;在春夏季扦插IAA/ABA呈下降趋势,在生根关键阶段,处理大于对照,表现出促进生根,而ZR/IAA值是对照大于处理,表现出抑制生根的作用。     

糙叶杜鹃扦插生根过程中生理生化分析

以野生糙叶杜鹃半木质化茎段为试材,采用植物生长激素KNAA和KIBA对插穗进行处理,测定不同生根期内源激素IAA,GA3,ZR,ABA,以及茎段扦插过程中可溶性糖、全氮含量和相关抗氧化酶活性变化.结果表明:2 000 mg·L-KNAA+2 000 mg·L-KIBA处理对插条生根具有显著影响,处理后的插穗生根率达到78.65％.在扦插生根过程中,较高浓度的内源IAA含量有利于根原基分化形成,GA3含量上升与插穗愈伤组织的诱导、不定根的形成呈正相关性,低水平的ABA更有利于糙叶杜鹃扦插生根;插穗在根原基分化和愈伤组织形成时期需要消耗一定的内源ZR;在生根过程中IAA/ABA比值较小,这可能是糙叶杜鹃扦插难生根的主要原因之一;插穗在生根过程中可溶性糖含量的增加、氮素含量的降低均有利于插穗不定根的生成.在扦插生根过程中氧化酶活性呈规律性变化,SOD,POD,PPO活性在愈伤组织诱导期上升,愈伤组织形成后略有下降,其中POD,PPO活性在不定根的形成期上升;生根后期糙叶杜鹃的CAT活性维持在较高的水平.     

无患子硬枝扦插进程插穗内源激素和多酚类物质含量变化

为了解无患子硬枝扦插生根机制,以1年生无患子硬枝作为扦插材料,在扦插第0—80天调查愈伤组织发育和根系形成情况,测定插穗的腋芽(嫩叶)以及基部2cm长度的韧皮部内源激素和多酚类物质的含量。结果表明,无患子硬枝扦插第10天开始出现愈伤组织,第50天愈伤率达到最高值83.33%;第40天开始出现生根插穗,生根率为6.67%,随后不定根数量迅速增加,第70天生根率达到86.67%,此时平均有5.33条。之后生根数量不变,根系仍然在生长,且扦插后根系效果指数持续增高。插穗韧皮部内源激素含量变化较复杂。整体来看,高含量赤霉素(GA3)抑制愈伤组织和不定根形成,且在根原基发生期和不定根形成关键期达到峰值,在不定根速生期持续下降;高含量生长素(IAA)促进不定根的形成,且在扦插后第20天,即根原基发生期,达到峰值(92.7μg/g);玉米素核苷(ZR)对无患子硬枝扦插过程的生理作用较复杂,低含量的ZR有利于根原基的发生和不定根速生,但高含量的ZR促进不定根形成。韧皮部ZR/IAA在扦插后第20—40天呈下降趋势,第40—60天快速上升,促进不定根生长;GA3/IAA整体呈现抛物线形下降趋势,特别是在根原基发生期和不定根速生期,下降速率更快,以促进不定根的生长。无患子硬枝插穗生根进程中,多数多酚类物质对愈伤组织形成、根原基发生及不定根形成有极显著抑制作用,没食子酸抑制效果稍弱;插穗内多种激素和多酚类物质的含量均发生了变化,且对插穗生根产生重大影响。总之,插穗根原基发生和不定根形成等关键时期,IAA含量升高,GA3、ZR以及多酚类物质含量降低,植物体内多种内源物质此消彼长,达到动态平衡,共同促进插穗生根。     

青钱柳扦插过程中内源激素变化研究

为了探明青钱柳扦插生根机理,以青钱柳半木质化枝条为插穗,用I系和K系处理插穗,纯净水为对照,研究扦插生根过程中插穗内源激素含量的变化。结果表明:用I系和K系处理插穗能够促使插穗生根,尤其以质量浓度为600 mg/L处理的插穗生根率和生根数最好。经过I系和K系处理后的插穗IAA含量均表现出先升后降再升的规律;ABA的变异规律呈"先降后升"模式;ZR的变异规律呈"先升后降再升再降"模式;GA的变异规律呈"先降后升再趋平稳"模式;IAA/ABA值的变异规律呈"先升后降再升再降"模式。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.