保水剂在城市草坪建设中的应用试验

保水剂是一种高分子化合物,独特的网形结构使其具有良好的保水性,运用于城市草坪建设中,可有效缓解城市水资源短缺与草坪种植、养护需水量大的矛盾。试验表明:保水剂施用量以50g/m2最为合理,施用保水剂的草坪可节约灌溉用水50%～60%,同时可促进草坪地下生物量生长,提高草坪的抗逆性。     

不同形态氮肥处理对樱桃植株生长发育影响的研究

利用盆栽植株研究了不同形态氮肥处理对樱桃生长发育的影响。结果表明,3种形态氮肥均能促进根系生长,其中以硫酸铵效果最显著,但3种氮肥对细根中不同养分的含量影响效应不同;施用尿素对植株地上部分营养生长的促进效应好于硫酸铵和硝酸钾处理,而施用硝酸钾对植株地上部分生殖发育的促进效应好于尿素和硫酸铵处理。     

水翁幼苗生长规律研究

对水翁Cleistocalyx operculatus幼苗的生长过程进行研究。结果表明,水翁幼苗的株高、地径生长具有阶段性的特点,利用Logistic曲线拟合了水翁幼苗株高与地径的生长模型,决定系数均在0.95以上;其生长进程可划分为4个阶段,即出苗期、生长前期、速生期和生长后期;根冠比总体呈下降趋势,生长重心逐渐由地下部分向地上部分转移;叶面积比与叶根比呈先下降后上升的趋势;地径与主根长、单株总叶面积等形态指标以及地上生物量、地下生物量以及单株总生物量等生物量指标之间均存在较强的正相关关系(r0.92,P0.01);根冠比与株高、地径、单株总叶面积、主根长、地上生物量、地下生物量、单株总生物量均存在负相关关系;地上生物量、地下生物量、单株总生物量之间均存在极显著的正相关关系(r0.97,P0.01)。     

云南松苗期不同器官生物量相关性及异速生长关系

为给云南松（Pinus yunnanensis）良种培育提供理论基础，以2年生云南松实生苗为材料，测定其苗高、地径及各组分生物量，采用相关性分析法及异速生长分析法分析各器官生物量，建立各器官生物量异速生长数学模型，研究各器官生物量分配及异速生长关系，反应云南松2年生时的生长状况及各器官的生长发育情况。结果表明，2个生长性状指标和5个生物量指标间均呈显著或极显著正相关；叶的生物量最大，叶在各器官中的生长速度也最快，说明2年生云南松苗木更倾向地上部分的生长。各指标间均存在密切联系，可用于云南松苗期生物量估测，也可通过对某一性状进行培育，提高云南松整体指标，满足生产需求，培育更多优良的云南松苗木。     

中幼龄闽楠生长及生物量分配特征研究

对不同造林地不同林龄的闽楠生长及生物量分配特征进行研究,研究结果表明:随着树龄的增大,闽楠叶生物量显著增大,但占总生物量的比例显著下降;闽楠主干生物量占总生物量的比例随着树龄的增长而显著上升,造林26a后,树干生物量比例占62.8%;闽楠根生物量随着树龄的增大显著上升,但占总生物量的比例反而显著下降,这些数据说明闽楠生物量累积优势不断转向地上部分。闽楠在整个生长过程前8a叶、枝、根生长速度及总生物量积累速度均比8~26a快,但干的生物量积累则是在8~26a速度加快,本研究的结论表明闽楠是适合培养大径材的珍贵用材树种,其径材培育周期远超过26a,研究结果可为闽楠人工林高效培育与经营管理提供理论依据。     

种子处理方式对欧洲垂枝桦发芽率及苗木生长的影响

以引进的俄罗斯欧洲垂枝桦种子为材料,研究了冷藏、沙藏和雪藏3种种子处理对欧洲垂枝桦场圃发芽率及苗木生长的影响。结果表明:不同种子处理的场圃发芽率、苗高、地径、地上生物量、地下生物量和全株生物量存在显著差异,种子雪藏处理的场圃发芽率、苗高、地径、地上生物量、地下生物量和全株生物量等指标均优于其他处理,其场圃发芽率、生长量和生物量最高。     

基于生物量分配格局的植物生长策略研究进展

由于植物的生物量是其获取外界资源的基础,生物量分配是植物对资源利用最大化的一种生长策略,探讨了不同环境下的生长策略有助于预测未来环境变化下植物的生长和分布趋势.分别从自然环境和人为干扰两种因素下综述了植物在不同生态条件下生物量的分配格局,总结了在不同生长条件下植物各构件生物量分配差异,阐述了植物通过改变地上与地下部分,...     

根系分布不同的两种共存草原植物对降水格局的响应差异

为研究降水格局改变对内蒙古草原两种优势种植物生长的影响,以内蒙古新巴尔虎右旗草原优势植物种多根葱和克氏针茅为研究对象,采取试验设置模拟小、中、大3个降雨量,并设置与之对应的3个降雨时间间隔,来研究其对降水格局的响应差异。结果表明:①降雨量和降雨间隔时间对两种草原植物的生长都有不同的影响,但降雨量对其生长的影响更显著;②在相同降雨量处理下,增加降雨间隔时间有利于克氏针茅幼苗各器官生物量的积累;③在相同降雨时间,降雨量的增加,混播克氏针茅地上、地下生物量显著减少,混播多根葱在模拟降中雨条件下根系地下生物量大于地上生物量,根冠比值为最大;④该两种草原优势种植物幼苗地上生物量、地下生物量、总生物量和根冠比的变化主要由各时间段内降雨量不同而引起的。     

基于异速生长和理论生长方程的广东省木荷生物量动态预测

【目的】将异速生长方程与理论生长方程相结合,预测广东省木荷生物量动态,为广东省木荷林碳汇计量提供模型和方法,为其他树种碳汇计量提供可借鉴的方法学支持。【方法】基于实测样木生物量调查数据,包括40株树干解析资料,构建由胸径和年龄的理论生长方程以及地上生物量和胸径的异速生长方程组成的模型系,利用非线性度量误差联立方程组,在胸径生长速度分级情况下拟合模型参数;基于3期森林资源连续清查固定样地样木数据,对广东省木荷生物量动态进行预测。采用决定系数( R 2)和均方根误差(RMSE)评价模型拟合效果,通过生物量存量估计误差和增量估计误差判断模型预测效果。【结果】在胸径生长速度分级情况下,理论生长方程中年龄对胸径的解释率达0.95以上,比不分级提高0.166 3,均方根误差下降到1.97 cm,降低2.16 cm以上,预测胸径对地上生物量的解释率提高到近0.82;接近独立异速生物量模型中实测胸径对地上生物量的解释率达0.88以上,比不分级提高近0.30,均方根误差下降到51 kg左右,下降30 kg以上。在胸径生长速度不分级情况下,各期生物量存量估计误差变动幅度在-46.31%~77.45%之间,而分级情况下下降到-16.13%~7.06%;在尺度上,分级与不分级均呈相同规律,即单木误差小于林分误差、林分误差小于区域误差。不分级时,单木水平和区域尺度间的误差不大于10%,而分级时小于8%。不同间隔期生物量增量估计误差,不分级时估计值普遍偏大,在32.57%~115.45%之间,而分级时下降到-6.57%~15.77%之间,在单木尺度上不超过±10%;随着尺度增大,增量估计误差不断增加,不分级时单木水平和区域尺度间的误差介于10%~15%之间,分级时稳定在8%左右。【结论】对于理论生长方程和异速生长方程组成的模型系,分级可极大提高模型精度,减小预测估计误差;生长速度不分级时,仅利用胸径或年龄数据,分级时,则可利用2期胸径数据或1期胸径和年龄数据,就可预测未来生物量动态,简单方便,在森林资源连续清查和碳汇造林的碳汇量计量中具有极大应用价值,区域尺度上的估计误差也可基本满足精度要求。     

华北落叶松播种苗施肥效果的研究

科学施肥是提高苗木质量和合格苗产量的关键措施之一。采用不同的肥料种类和施肥方法,对华北落叶松1a生播种苗进行田间对比试验,结果表明:1)追施尿素、碳酸氢铵、硝酸铵、硫酸铵4种化肥,其中硫酸铵效果最好,苗木平均地径、苗高和产量分别比对照提高51.81%,76.19%和123.52%;2)基施有机肥对苗木生长影响显著,苗木平均地径、苗高和产量分别比对照提高24.10%,26.84%和100.00%;3)用磷酸二氢钾进行叶面喷肥对苗木生长影响显著,苗木平均地径、苗高、根长和须根长分别比对照提高17.27%,25.76%,20.42%和17.17%。     

Growth and mineral nutrition of Gmelina arborea Roxb. seedlings fertilized with four sources of nitrogen on a latosolic soil

The growth and mineral nutrition of Gmelina arborea Roxb. seedlings were investigated in response to four nitrogen-based fertilizers applied at 0, 2.5, 5.0 or 7.5 g N per plant. Nitrogen sources included NH(4)-N as ammonium sulfate, NO(3)-N as potassium nitrate, NH(4)NO(3)-N as calcium ammonium nitrate, and urea-N as urea. Seedlings fertilized with NH(4)NO(3)-N or urea-N had greater height, collar diameter, dry weight, net assimilation rate, and relative growth rate than seedlings fertilized with NH(4)-N or NO(3)-N. For all sources of nitrogen, increasing the amount of exogenously supplied N per plant promoted shoot growth more than root development, hence the root to shoot ratios of all fertilized seedlings were smaller than those of the unfertilized controls. Applications of NO(3)-N increased the nitrogen, potassium, and phosphorus concentrations of fertilized seedlings. Regardless of source, a nitrogen application of 2.5 g N per plant was apparently optimal for the growth of Gmelina seedlings on a latosolic soil.     

Effects of nitrogen source on growth and activity of nitrogen-assimilating enzymes in Douglas-fir seedlings

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown for 68 days in a growth chamber in nutrient solutions with ammonium, nitrate or ammonium nitrate as the nitrogen source. Among the nitrogen sources tested, whole-seedling biomass, relative growth rate (RGR), root and shoot elongation, and number of lateral roots, were greatest in seedlings grown with ammonium. In the absence of nitrogen, plant growth and formation of lateral roots were poor. Initially, glutamine synthetase, NAD-glutamate dehydrogenase and aspartate aminotransferase activities were high in young roots and shoots, but all three enzymatic activities decreased after one month of culture. In root apices, glutamine synthetase and aspartate aminotransferase activities were higher than NAD-glutamate dehydrogenase activity. Enzymatic activities were often higher in ammonium-fed seedlings than in seedings supplied with the other forms of nitrogen. Activities of all three enzymes were significantly reduced in seedlings grown in the absence of nitrogen. The beneficial effect of ammonium is discussed on the basis of its involvement in the assimilation pathways of Douglas-fir.     

川金丝猴食源地衣长松萝生长、存活与生理学特征对模拟氮沉降的响应

【目的】探讨氮沉降对长松萝生长、存活的影响及其生理响应特征,为理解氮沉降增加背景下神农架地区树生地衣群落的演替趋势、科学管理川金丝猴的地衣食物供应提供理论支撑。【方法】在野外对长松萝个体和繁殖体模拟施加不同强度的氮沉降,测定其个体生长速率和繁殖体存活率;同时开展室内试验,测定地衣体对铵态氮和硝酸盐氮吸收速率、地衣体的氮磷含量及其比值以及氮磷代谢关键酶(谷氨酰胺合成酶、硝酸还原酶和酸性磷酸酶)活性等指标,综合分析氮沉降影响长松萝生长、存活的规律及其生理学指标响应机制。【结果】低强度氮沉降(<20.94 kgN ·hm -2 a -1 )能促进长松萝个体生长,高强度氮沉降(>32.99 kgN ·hm -2 a -1 )则对长松萝生长与繁殖体存活均有显著不利影响( P ≤0.05);与硝态氮相比,长松萝偏向于吸收铵态氮,且吸收量随氮沉降强度增加而增加;长松萝地衣体氮磷比、酸性磷酸酶活性与氮沉降强度显著正相关( P ≤0.05);随氮沉降强度增加,长松萝谷氨酰胺合成酶和硝酸还原酶活性呈先增加后降低趋势。【结论】低强度氮沉降(<20.94 kgN ·hm -2 a -1 )促进长松萝生长和存活,而高强度氮沉降(>32.99 kgN ·hm -2 a -1 )抑制长松萝生长和存活。过量氮沉降损伤长松萝地衣健康是多种生理机制综合作用的结果,包括选择性吸收铵态氮导致的长松萝体内铵态氮的积累、铵态氮积累引起谷氨酰胺合成酶和硝酸还原酶的活性下降以及铵态氮积累导致地衣磷限制等方面。     

不同N源对兴安落叶松苗木生长,养分吸收及离子平衡的影响(英文)

本文研究了不同N源对落叶松苗木干物重、养分吸收及离子平衡的影响。结果表明:施铵态N的苗木干物重小于对照处理;施硝铵态N的苗木生长与对照和施硝态N的苗木差别不大,但较施铵态N的苗木生长要好。铵态N与硝铵态N处理苗木地上部的阳离子总浓度受N水平的影响很小,而硝态N处理时则阳离子浓度增加;各处理对地上部阴离子浓度的影响均不大。在根部除硫酸根与钙离子外,阳离子与阴离子浓度均变化不大。硝态N处理的苗木具有较高的C-A值;△(C-A)/△Norg值在硝态N处理的苗木中随N供应量的增加而略有变化,但铵态N处理则明显下降;硝铵态N处理苗木的△(C-A)/△Norg值界于铵态N处理与硝态N处理之间。     

Effect of different nitrogen and carbon sources and concentrations on the mycelial growth of ectomycorrhizal fungi under in-vitro conditions

Effect of different nitrogen and carbon sources and their concentrations in liquid media on the mycelial growth of six different ectomycorrhizal (ECM) fungal species was studied. Differences were found in the utilization of the different nitrogen and carbon sources between the fungal species. All the species showed better mycelial growth in the medium containing ammonium as nitrogen source. Growth was low in all species in medium in which nitrogen was supplied in nitrate form. All the ECM isolates investigated showed reduced growth in the medium containing maleic acid as the carbon source. The effect of glucose and di-ammonium hydrogen orthophosphate concentrations on mycelia growth of all the six fungal species was studied with ranges for glucose of 2–40 g/l, and for di-ammonium hydrogen orthophosphate of 2–20 g/l. Cortinarius fulvoconicus and Cortinarius flexipes showed maximal mycelial growth at a glucose concentration greater than 20 g/l. Suillus luteus, Scleroderma citrinum, Laccaria laccata, and Tricholoma aurantium showed maximal growth at a glucose concentration of 20 g/l. All six species showed maximal mycelial growth at 5–10 g/l of di-ammonium hydrogen orthophosphate concentration and with increased concentration mycelial growth in all species decreased.     

Dynamics of nitrogen nutrition of coexisting dominant trees in mixed broad-leaved/Korean pine forest

IntroductionThecapacityofwoodyplantstoassimilateavail-ablenitrogen(nitrateandammonium)hasbeenweIlstudied,especiaIIyintermsofhabitatandspe-cies-reIateddifferencesinnitrateandammoniumassimiIationcapacity(Addoms1937lHauck1968lAlGharbietaI.1984,L8eetaI.1978,Tamm,1991,Vi-touseketaI.,1982iLietaI1994a,1994b,1995)However,nostudyhasfocusedonspecies-specifictemporalvariationinnitrateandammoniumassimiIa-tionamongexplicitIyco-existingwoodyplants,eventhoughtemporaIdifferentiationintheuseofnitratean…     

Ammonium and nitrate uptake, nitrogen productivity and biomass allocation in interior spruce families with contrasting growth rates and mineral nutrient preconditioning

Four full-sib families of interior spruce (Picea glauca (Moench) Voss) x Picea engelmanii Parry ex Engelm.) with contrasting growth rates (two fast-growing and two slow-growing families) were grown aeroponically with either a 2% relative nitrogen addition rate or free access to nitrogen. Fast-growing families showed greater plasticity in allocating biomass to shoots at high nitrogen supply and to roots at low nitrogen supply than slow-growing families. Compared with the slow-growing families, short-term net ammonium uptake rate measured with an ion selective electrode was significantly greater in fast-growing families at high ammonium supply, but not at low supply. Net nitrate uptake showed the same trend, but differences among families were not significant. Results indicate that differences in seedling growth rate are partly a result of physiological differences in net nitrogen uptake efficiency and nitrogen productivity.     

The effects of different nitrogen sources on camptothecin content and related gene expression in Camptotheca acuminata seedlings

Camptotheac acuminata Decne is a unique tree species in China with an important secondary metabolite,camptothecin(CPT),used in the treatment of cancer.Nitrogen(N) is an important element that affects plant growth and the accumulation of CPT.Reports on the effect of N on CPT synthesis from a genetic perspective are scarce.To explore the effects of different N sources and levels on CPT synthesis in C.acuminata,two-year-old seedlings were fertilized with different concentrations of pure ammonium sulphate,source of ammonium N(NH_4~+-N),and potassium nitrate for nitrate N(NO_3~--N).Concentrations of 2.5,5,7.5,and10 g pot~(-1) NH_4~+-N and NO_3~--N were used.The results showed that 7.5 g NH_4~+-N and NO_3~--N treatments were best for growth and fresh weight of leaves.Compared with the other treatments,the CPT content,tryptophan synthase and tryptophan decarboxylase activities,and expression of the CaTSB and CaTDCl genes under the 2.5 g NH4+-N and NO_3~--N treatments peaked significantly at 30 days.However,the expression of CaTDC2 surpassed that of the other two genes at 60 days.Therefore,compared with NH4+-N source,the NO_3~--N source was more beneficial for growth,and NO_3~--N was better for CPT yield.Consequently,leaves of C.acuminata treated with 2.5 g NO_3~--N could be harvested after 30 days to obtain maximum CPT content.CaTDC1 is more closely linked to CPT synthesis.The results of this study improved the production of CPT in C.acuminata via fertilization.     

Nitrogen Mineralization and Organic Matter Decomposition in Scots Pine Humus

Nitrogen deficiency in many northern coniferous forests is associatedwith increasing age of the crop and is thought to be due toa slow rate of release of available nitrogen from the organiclayers of the forest floor. Practical ways of stimulating nitrogenrelease from this material by applications of nitrogen, phosphorus,and lime are being studied in a 40-year-old crop of nitrogen-deficientScots pine (Pinus sylveitris L.) at Culbin Forest, Moray. Threeyears after lime and phosphorus treatments, and two years afterthe second fertilizer nitrogen application, significant treatmenteffects included both markedly higher pH values and increasedrates of organic matter decomposition on incubation (at 30 °Cfor 62 days) for humus from plots given lime and higher ratesof net production of mineral nitrogen on incubation for humusfrom plots given fertilizer forms of ammonium sulphate, urea,and ammonium nitrate. Only urea-treated humus still showed asignificantly higher total nitrogen content at this time, I.54per cent of organic matter compared with 141 per cent in untreatedmaterial.