干旱胁迫对真桦根系形态及生物量分配的影响

通过人工控水土培方法,研究了干旱胁迫对真桦的根系形态、分级特征、苗高生长以及生物量分配的影响。结果表明,干旱胁迫显著影响真桦根系形态及构型,随着土壤含水量的降低,真桦根系质量和平均直径降低。轻度和中度干旱使真桦根系总长度、根系表面积、比根长降低;重度干旱下,直径小于0.5 mm的细根比例显著提高,根系总长度、根系表面积、比根长显著提高。随着土壤含水量的降低,真桦苗木的高生长受到抑制,生物量降低,根冠比明显提高。     

扁担木生物量及纤维形态的测定

对扁担木生物量、木纤维含率及其长度、宽度的测定结果表明：（１）单株生物量、木纤维含率与株龄呈正相关；（２）株龄对木纤维含率、纤维形态没有明显影响，但土地条件对纤维形态影响比较显著，而产地没有影响；（３）扁担水木纤维与韧皮纤维含率及形态有显著变化，韧皮纤维含率４５．１８％，纤维均长８９１、６ｕｍ，长宽比５６．８１；木纤维含率５８．１１％，纤维均长７４８．９ｕｍ，长宽比５０．７０。扁担木是优质纤维经济灌木树种，应深入进行其开发利用的研究。     

3种海拔对团竹生物量分配和克隆形态特征的影响

通过对四川省北川县片口自然保护区不同海拔梯度下（2700 m、2800 m与2900 m）团竹分株种群特征进行调查,研究其生物量分配格局和克隆形态特征。结果表明,（1）分株及构件生物量随海拔增加而增加;在不同海拔条件下,地下茎生物量分配有显著差异,其他构件生物量分配无明显差异;秆在构件生物量分配比值中最大,为38％;（2）地上构件形态特征随海拔升高而变化显著;地下构件中根的数量、地下茎基茎、地下茎长度和分蘖强度都随海拔升高呈现出先增加后减少的趋势,且在海拔2800 m时达到最大值,因此宜选择海拔2800 m地带的团竹苗用于人工种植。团竹在不同海拔环境中具有生物量分配和克隆形态的可塑性,有利于其种群对水分、光资源等的有效利用。     

基质配方对油茶容器苗根系生物量及形态的影响

【目的】了解不同基质配方对油茶容器苗根系生长的影响,揭示油茶容器苗根系生长规律,筛选最适合油茶容器苗生长的基质配方,提高油茶容器苗的品质。【方法】以1年生油茶芽苗砧嫁接容器苗为材料,设置5种基质配方(黄心土、松林表土、菇渣、泥炭、粪土按不同体积比混合制成)和对照(园土)6个处理,选择10 cm×10 cm的聚乙烯袋为育苗容器,进行油茶芽苗砧嫁接容器育苗试验,对容器苗根系生物量和形态指标进行测定分析,采用隶属函数法对各配方促进根系生长的效果进行模糊综合评价。【结果】各基质对油茶容器苗根系茎叶干质量、根系干质量、苗木干质量、根冠比的影响存在极显著差异,其中Ⅳ基质配方处理的根系生物量最大,茎叶干质量为1.48 g,根系干质量为1.19 g,苗木干质量为2.67 g,根冠比为0.80,分别是CK的1.34、1.83、1.50、1.29倍。各基质对油茶苗根系长度、表面积、体积和直径的影响存在极显著差异,其中Ⅳ基质配方处理的各根系形态指标最好,根系长度为280.32 cm,表面积为106.72 cm²,体积为8.71 cm³,直径为1.316 mm,分别...     

土壤水分对大红袍花椒生物量与耗水特性的影响

通过盆栽试验,对不同土壤水分条件下（土壤含水量分别为田间持水量的80%、60%、45%、35%）1年生大红袍花椒生长及蒸腾耗水特性进行了研究。结果表明：不同土壤水分条件下,大红袍花椒耗水量差异很大,土壤含水量为田间持水量的80%、60%、45%、35%时,5~8月份花椒幼苗的耗水量分别为10.05、5.97、5.39、3.37 kg;土壤水分供应充足有利于花椒地上部分的生长,干旱胁迫则有利于花椒根系的生长。     

采伐强度对杉阔混交人工林细根生物量及形态特征影响

[目的]比较杉阔混交人工林在不同采伐强度下细根生物量及形态特征的差异,探究林木细根生长与采伐强度的关系,以期为区域杉阔混交人工林科学经营提供基础数据和理论参考.[方法]以闽北杉阔混交人工林为研究对象,2011年8月实施4种不同采伐强度(按蓄积量计算分别为中度择伐34.6％、强度择伐48.6％、极强度择伐67.6％和皆伐...     

防风固沙林带对沙丘形态结构的影响

通过不同结构防风固沙林带对沙丘形态结构影响的试验研究，结果表明：对高大沙丘无论是迎风坡角度的缩小值，坡长度的增长值还是高度的降低值，都是稀疏林带的在于紧密结构林带，但对中等沙丘，迎风坡角度的缩小值，稀疏结构林带比紧密结构林带要小。     

湖桑一龄萌条材生物量及纤维形态的研究

研究结果表明:(1)在超短期(1年生)集约栽培条件下,湖桑-龄萌条材年均hm~2生物量30013kg,最高达40006kg;1—5年生桩龄与其上-龄萌条材生物量成正相关规律;(2)湖桑-龄萌条材木纤维平均长度803.6μm,平均宽度13.75μm,长宽比58.4;其树皮纤维平均长3630.1μm,平均宽度17.20μm,长宽比211.05;其萌条材规格与纤维长度和宽度无明显规律。是制造优质纸张品种的优质原料之一。     

北镇新立湖湿地水深对芦苇香蒲共生关系影响的研究

芦苇和香蒲为辽宁省湿地1.0 m水深浅水区域优势物种,研究其共生关系对湿地保护与恢复具有重要意义。该文以北镇新立湖湿地内的芦苇和香蒲作为对象,通过对93个样方调查,分析不同水深对芦苇和香蒲生长及对其共生关系的影响。结果表明:水深显著影响芦苇和香蒲的生长,且对芦苇的影响大于对香蒲的影响。两种水生植物在共生竞争时均采用逃避策略,芦苇趋于向浅水区扩展,香蒲趋于向深水区扩展。     

不同水淹条件下芦苇立枯体的分解及营养动态

以东太湖芦苇湿地的芦苇立枯体为研究对象,研究了不同水淹条件下芦苇立枯体的分解及营养动态。实验表明,在分解初期的30天内,水淹对于分解速率的影响并不明显,60天后差异性显著(p<0.01)。在分解过程中,C释放与总重量的消减基本同步。在完全水淹条件下,P元素出现了净释放,而N元素却有一定的积累。无水淹条件下,芦苇立枯体的分解速率与C/N和C/P的相关性并不明显;部分水淹条件下,分解速率只与C/N呈显著正相关(p<0.01);完全水淹条件下,分解速率与C/N和C/P也无显著相关。实验表明,一定的水淹对于枯落物的分解有促进作用,但是过量水淹又会降低氧气的可利用性,抑制立枯体的分解。     

中国芦苇研究现状与趋势

芦苇Phragmites australis为多年生高大草本植物,是世界广布的重要湿地物种,具有广泛的适应性及形态变异,并有极高的生态学和社会经济学价值。本文通过对近10年来中国各地对于芦苇研究的成果文献进行统计分析,揭示出我国芦苇研究的现状与趋势。     

黄河三角洲柽柳与芦苇光合特性比较

选取黄河三角洲典型植被优势种柽柳(Tamarix chinensis)和芦苇(Phragmites australis),以全天自然光的日变化为光照梯度,研究两者对光强的响应规律,比较它们的光合荧光特性。结果显示,柽柳具有较高的光补偿点和光饱和点,在高光强时蒸腾依然旺盛,并且气孔调节能力较强,以反应中心状态转换和可逆失活进行能量调节,最大可能减少无谓的能量散失,光系统有效量子产量高,从而保证了较高的电子传递速率;芦苇气孔调节和光能利用能力较柽柳低,在高光强时出现净光合速率和蒸腾速率的降低及电子传递饱和现象,随光照增加,光系统有效量子产量下降较大,采取热耗散的方式散失过剩光能以避免光损伤。本次光响应研究的尝试证明其具有一定的合理性,但仍有待进一步验证。     

芦苇植株再生体系优化

在前人工作基础上利用禾本科芦苇成熟种子为外植体建立了植株再生体系。芦苇成熟种子经2%洗涤灵溶液洗涤,70%乙醇处理30s,20%＂84＂消毒液处理25min后接种到MS＋4%蔗糖（pH 5.5）的种子萌发培养基中培养,种子萌发率为62%。萌发种子继代至MS＋1mg/L 6-BA＋0.1mg/L 2,4-D＋0.5mg/LNAA＋4%蔗糖（pH 5.5）培养基进行不定芽诱导,不定芽发生率为95%。无根丛生芽继代到不定根诱导培养基1/2MS＋0.5mg/L IBA＋0.5mg/L NAA＋4%蔗糖（pH 5.5）,不定根发生率为90%。     

Influence of rain water harvesting and conservation practices on growth and biomass production of Azadirachta indica in the Indian desert

A field experiment was conducted to investigate the influence of various rain water harvesting and conservation techniques on soil moisture storage, growth and biomass production of Azadirachta indica (neem) in the Indian desert. The treatments were as follows: control; weed removal; weed removal plus soil working; saucers of 1.0 m diameter; saucers of 1.5 m diameter; saucers of 1.5 m diameter covered with mulch around the trees; bunding around each tree in a checkerboard design; inter-row slopes of 20%. The treatment with inter-row slopes of 20% produced the highest amount of soil moisture storage, a four times increase in total biomass of a 26-month-old neem plantation (from 1.69 to 6.39 t ha⁻¹), a 4.5 times increase in root mass (from 0.43 to 1.92 t ha⁻¹) and a 70% increase in tree height, as well as an appreciable enhancement in all the growth parameters. The treatment with larger saucers (1.5 m diameter) combined with a surface mulch was equally effective. Growth increases owing to the other water harvesting treatments were lower, though significantly better when compared with the control. The various treatments significantly improved the water use efficiency of neem.     

扎龙湿地芦苇恢复与生态补水分析

芦苇是珍稀水禽的栖息地，具有调节气候、涵养水源、降低风速等生态效应。文章介绍了扎龙湿地植被的类型、影响芦苇生长的主要因子。资料表明，严重缺水使芦苇退化，生物量显著降低，而水量过多又造成芦苇生长受限，只有适量的生态补水才能促进芦苇的生长。     

沿海地区水杉林带生物产量的时空结构特征

根据江苏沿海地区水杉林带中３３ 株标准木生物量的测定资料,分析了不同立地类型、不同林龄阶段水杉林带生物产量的结构特征。结果表明：旱作田水杉林带总生物产量稍高于水旱轮作田,但旱作田水杉林带的干量相对分配率小于水旱轮作田,而根量、枝量和叶量的相对分配率则大于水旱轮作田;随着林龄的增长,两立地类型水杉林带的干量相对分配率相应增大,根量、枝量和叶量的相对分配率相应减少;旱作田水杉林带生物生产力高于水旱轮作田,旱作田年平均净生产量由６ ａ 生的３－３６１ ｔ／（ｈｍ２·ａ） 增至１９ ａ 生的１７－５９２ ｔ／（ｈｍ２·ａ） ,水旱轮作田则由５ ａ 生的２－４９１ ｔ／（ｈｍ２·ａ） 增至１５ ａ 生的１０－６２２ｔ／（ｈｍ２·ａ） 。     

Cost structure of and competition for forest-based biomass

Abstract

Biomass has become a popular alternative to satisfy expanding energy demand and as a substitute for fossil fuels and phased-out nuclear energy in Europe. The European Union White Paper stipulates that the utilization of biomass shall increase to 1566 TWh by 2010. However it is often overlooked that the forest resources are already, to a large extent, used by the forest industries. When promoting biomass for energy generation the consequences for the forest industries also need to be considered. Sweden is an excellent case study, as there are vast quantities of forest resources, nuclear power is starting to be phased out, there are restrictions on expanding hydropower and the political desire exists to “set an example” with respect to carbon dioxide emissions. This paper attempts to estimate and analyse the supply of two types of forest resource, namely, roundwood and harvesting residues derived from final harvesting and commercial thinnings. Two separate supply curves are estimated: one for roundwood and one for harvesting residues. The cost structure is based on an economic-engineering approach where the separate cost components are constructed from the lowest cost element into aggregates for labour, capital, materials and overhead costs for each forest resource. The results indicate an unutilized economic supply of 12 TWh of harvesting residues in Sweden. However, after these 12 TWh have been recovered it becomes more profitable to use roundwood for energy purposes than to continue extracting further amounts of harvesting residues.     

Growth dynamics and biomass accumulation of 8-year-old hybrid poplar clones in a short-rotation plantation on a clayey-sandy mining substrate with respect to plant nutrition and water budget

In 1995 a short-rotation plantation (2.5 ha) was established in the mining region Welzow-Süd in Brandenburg, Germany, on a clayey-sandy, lignite- and pyrite-free substrate in order to study the biomass potentials of fast-growing tree species (hybrid poplar clones). In this study, special emphasis was placed on yield aspects as well as on the interaction between soil and plants, especially with regard to the plant nutrition and soil–water relationships. So far, the results indicate that the cultivation of hybrid poplar clones in a short-rotation plantation is an adequate tool for establishing alternative land-use systems in the post-mining landscape as a potential source of biomass energy. Aboveground biomass production ranged from 24–49 t dry matter (DM) per hectare at age 8. In particular during this period of investigation, nitrogen nutrition of the clones decreased to below a threshold of 20 mg g^–1 DM in the year 2002. Investigations of the water budget of low- and high-yielding clones indicated that differences in the biomass accumulation seemed to be accompanied by different water-use efficiencies.