松突圆蚧为害对马尾松针叶主要次生物质的影响

对受松突圆蚧不同程度为害的马尾松针叶主要次生物质的测定表明,不同受害程度的马尾松与其针叶内的次生物质含量呈显著的相关性。黄酮、单宁和总酚含量随着为害程度的加重而发生变化,先增加,后降低,这说明了受害程度的强弱对马尾松诱导化学物质变化有影响,次生代谢物质的合成需要消耗能量和物质,影响主要代谢。这是被害松树针叶枯黄、枝干枯死直至植株枯死的原因之一。     

重庆南山马尾松衰亡症状的研究

于1985年至1986年对南山马尾松林衰亡现象进行了研究,内容包括针叶受害症状,枝叶生长情况,针叶解剖,树干解析和根系观察等,濒死马尾松针叶呈现枯斑,枯尖或会叶枯黄,针叶组织破坏,针叶提前脱落,根系不发达,细根少,分枝减少,侧枝死亡,树干生长率下降,从树干解析可知,这种生长势减弱现象大约在十几年以前就已开始,初步研究结果启示,南山马尾松林衰亡可能与环境污染（如酸雨等）有关。     

重庆南山马尾松衰亡症状的研究

于1985年至1986年对南山马尾松林衰亡现象进行了研究,内容包括针叶受害症状,枝叶生长情况,针叶解剖,树干解析和根系观察等,濒死马尾松针叶呈现枯斑,枯尖或会叶枯黄,针叶组织破坏,针叶提前脱落,根系不发达,细根少,分枝减少,侧枝死亡,树干生长率下降,从树干解析可知,这种生长势减弱现象大约在十几年以前就已开始,初步研究结果启示,南山马尾松林衰亡可能与环境污染（如酸雨等）有关。     

不同林龄和密度马尾松人工林针叶和根系的生态化学计量特征

为了解不同林龄和密度马尾松人工林针叶和根系的养分变化特征,该文在广西南宁市横县镇龙林场选择了四种林龄(幼龄林、中龄林、成熟林和过熟林)和四种密度(低密度林、中低密度林、中高密度林和高密度林)马尾松林共八种林分,分析了马尾松针叶和根系的C、N、P含量和比值及其与土壤养分的关系。结果表明:(1)所有龄林与密度林的马尾松针叶N∶P比值均大于16,表明该地区马尾松明显受P限制,幼龄林更加明显。(2)马尾松针叶C含量随着林龄增长逐渐增大后下降,N与P含量呈微弱下降趋势,导致C∶N比值、C∶P比值和N∶P比值呈微弱上升趋势,但没达到显著水平;根系C含量、P含量和C∶N比值逐渐增大,N含量、C∶P比值和N∶P比值呈U字型且都在幼龄林最大;针叶和根系在成熟林阶段均具有较高的P含量和最高的C含量。(3)中密度林的马尾松针叶的C和N含量较高且P含量最高,C∶N比值较低且C∶P比值和N∶P比值最低;根系的C、N和P含量较高,而C∶N比值、C∶P比值和N∶P比值较低。(4)马尾松的根系养分尤其是P含量在不同龄林和不同密度林之间的变化比针叶更加剧烈,且其与土壤养分之间的相关性比针叶更强。综上结果表明,马尾松人工林受P限制,在低龄林加强P肥管理和选择合适的林分密度(中等密度)则有利于缓解马尾松受P限制的状态。     

野外模拟酸雨胁迫下接种外生菌根真菌对马尾松幼苗的缓解作用

外生菌根真菌能够提高宿主植物对外界环境胁迫的抵抗力。主要探讨野外条件下外生菌根真菌对酸雨胁迫下马尾松(Pinus massoniana)幼苗生长、养分元素以及表层土壤的影响,以期为酸雨严重区马尾松林恢复提供科学依据。以2年生马尾松幼苗为材料,采用原位试验,共设置6个处理:p H5.6(对照)处理未接种、对照处理接种、p H4.5酸雨处理未接种、p H4.5酸雨处理接种、p H3.5酸雨处理未接种、p H3.5酸雨处理接种。研究表明:(1)酸雨处理与对照处理相比显著降低了非菌根苗总生物量及各部位生物量(根、茎、叶),对株高无显著影响,接种外生菌根真菌可以缓解酸雨对马尾松幼苗生长的不利影响;(2)与对照处理相比,酸雨处理的非菌根苗的针叶中N、P、Ca含量升高,Mg含量降低,根系中N、P、Ca含量降低,Mg含量随p H的降低先升高后降低。接种外生菌根真菌显著提高了p H3.5酸雨处理的马尾松幼苗根系中N、P、Ca、Mg含量,而对针叶中N、P、Ca、Mg含量无显著影响。(3)在非菌根土壤中,p H3.5酸雨处理与对照处理相比显著降低了土壤中有机质、速效磷、速效钾、可溶性碳、可溶性氮、铵态氮、硝态氮含量,而接种外生菌根真菌显著提高了上述指标。酸雨对土壤阳离子交换量无显著影响。总而言之,接种外生菌根真菌促进了酸雨处理的马尾松幼苗生长、缓解了酸雨对马尾松幼苗养分元素和表层土壤的不利影响,由此可见接种外生菌根真菌是减轻酸雨对马尾松危害的一个重要途径。     

铝胁迫对马尾松幼苗根系形态及活力的影响

采用砂基栽培,研究不同铝胁迫强度(0、50、100、150、200μmol.L-1)和胁迫时间(30d、60d和100d)条件下,对马尾松(Pinus massoniana)幼苗单株根长、根干重、根系质膜透性、根系吸收总面积、活跃吸收面积和根系活力的影响。结果表明:低水平胁迫(0~50μmol.L-1)对马尾松幼苗根系生理指标影响较小;中等水平胁迫(100μmol.L-1)是马尾松根系生长和活力变化的转折点;重度胁迫(150~200μmol.L-1)条件下,根系生理指标呈现大幅度下降变化趋势。根长、根质量、质膜透性和根系活力可作为马尾松幼苗根系受铝毒害的鉴定指标。短时间(30d)根际供铝,马尾松幼苗适应能力较强,根系生长抑制不明显;栽培30d以上时,马尾松根部对铝胁迫的响应随胁迫时间的增加而加剧。     

马尾松诱导化学物质变化的时空动态

研究了受害程度不同的马尾松针叶内诱导化学物质在时间序列上的变化和局部受害后空间序列上的变化。结果发现：受害马尾松针叶内次生代谢物质（单宁、酚类物质）含量随时间的变化而不断上下波动,先增加,后逐渐降低,恢复到原来的水平;营养物质（可溶性糖）含量先降低,后逐渐恢复到原来水平。反映了马尾松受害后的应激反应是一种快速、间断、被调节的过程。危害程度的强调对马尾松诱导化学物质的变化有一定的影响。中度的危害（针叶损失50％）所诱导产生的次生物质最多,轻度（针叶损失25％）或重度（针叶损失75％）的危害所诱导产生的次生代谢物质较低。以7年生（共5个轮枝）的马尾松作为实验材料,对第3轮枝进行剪叶75％,在空间序列上,观察其余各轮枝松针内化学物质的变化。发现第3轮枝受害后马尾松其余各轮针叶内也产生诱导化学物质含量变化,并且因轮枝部位的不同,其诱导产生的变化也不相同。说明松针所产生的诱导化学物质含量的变化是全株性的、异质性的。     

不同配比施肥对马尾松幼苗生长特征的影响

为获得马尾松幼苗最佳施肥配方,该文以1年生马尾松幼苗为试验材料,采用L₁₆（4³）正交设计,并通过测定幼苗苗高、地径、生物量、叶绿素含量、叶片N、P、K含量,探讨不同N、P、K配比施肥对马尾松幼苗生长特征影响。结果表明：（1）不同配比施肥处理间马尾松幼苗苗高、地径、生物量、质量指数、叶绿素和养分含量存在显著差异,其中,处理12生物量、质量指数、叶绿素a和总叶绿素含量、隶属值最高。（2）施N对幼苗生长及生理指标均有极显著影响;施K对苗高、地径、地上生物量、总生物量有显著影响,对叶绿素和针叶养分有极显著影响;施P对叶绿素a、叶绿素b、针叶N和P含量有极显著影响,对苗高、地下生物量、总叶绿素含量有显著影响。（3）施N对苗高、地径、地上生物量、总生物量、质量指数、叶绿素a含量、总叶绿素含量和针叶N含量的影响最大,K次之,P最小。各因素对地下生物量和针叶P含量的影响均表现为N>P>K。（4）N3水平利于幼苗苗高地径的生长及生物量的积累,N4水平利于叶绿素a和总叶绿素含量及针叶N、P含量的积累,P4水平利于生物量、叶绿素含量和养分P含量的积累...     

白皮松针叶内皮层在盐胁迫中的屏障作用研究

应用荧光显微技术、傅里叶变换显微红外光谱分析(FTIR)、扫描电镜及X-射线能谱微区分析等手段,对白皮松(Pinus bungeana)子叶、初生叶及2a生针叶内皮层细胞径向壁的显微结构特征、化学成分,以及在叶子横切面上Na和Cl的微区分布进行分析。通过荧光显微观察发现,白皮松子叶内皮层不具凯氏带,而初生叶及2a生针叶均存在凯氏带加厚现象。根据FTIR的检测结果显示:子叶内皮层细胞径向壁不含木栓质或极少,2a生针叶内皮层细胞径向壁木栓质含量高于初生叶。对相应区域的X射线微区分析表明,子叶内皮层对Na和Cl在质外体运输中不起障碍作用,而初生叶与2a生针叶内皮层阻碍Na和Cl以质外体途径进入维管组织。研究结果表明:具凯氏带加厚的内皮层细胞壁中木栓质含量决定其在质外体运输过程中的生理功能。     

鼎湖山异龄马尾松针叶长度序列元素分布

利用植物体元素化学分析结果来诊断环境污染对森林健康影响和监测环境污染程度已成为诸多生态学家和环境学者广为采用的方法之一。该研究选择广东肇庆鼎湖山健康马尾松(Pinus massoniana)前年生针叶和当年生针叶为研究对象, 将相同年龄针叶分为叶尖、叶中、叶基等长3段, 分析了两种针叶全S、全P、K、Mg、Na、Ca、Al、Mn、Zn、Cu、Fe、Pb、Cr、Cd和Ni15种元素及相应Ca/Al值在叶尖、叶中部、叶基部和叶鞘的分布模式。结果表明: 前年生针叶元素平均值除全S、全P、K和Cd外, 其它元素浓度都高于当年生针叶, Ca/Al值则是当年生针叶小于前年生针叶, 表明当年生针叶受Al毒大于前年生针叶; 在针叶长度序列不同部位间, 元素分布不均匀, 全S、Na、Ca、Al和Mn在两种针叶长度序列上没有显著性差异, K、Mg、Zn、Fe、Cr、Cd、Ni和Ca/Al值差异均达显著水平, 而全P、Cu、Cd和Pb仅在前年生针叶不同部位间差异显著; 针叶Al浓度和Ca/Al值都表明马尾松已经处于严重Al毒胁迫下; 两种针叶各部位Fe、Zn和Cu浓度远超出该地区马尾松元素的背景值, 暗示马尾松针叶已受到严重重金属毒害; 马尾松叶鞘Fe、Cu、Zn、Pb、Cd、Ni和Cr含量显著高于针叶其它部位, 表明叶鞘能累积环境重金属, 可以作为马尾松在污染环境下遭受重金属危害指标加以利用, 是一种有广泛应用前景的生物指示物。该研究所采用的技术和方法对环境监测, 尤其是对利用生物化学方法评价环境污染对森林健康影响评价体系的完善和生物监测指标的利用具有指导意义, 可为今后评估相似环境污染地区森林健康和树木正常生长提供参考。     

Suillus variegatus causes significant changes in the content of individual polyamines and flavonoids in Scots pine seedlings during mycorrhiza formation in vitro

Changes in the concentrations of individual flavonoids and polyamines (PAs) in Scots pine (Pinus sylvestris L.) cotyledonary seedlings were studied during the establishment of an ectomycorrhizal (ECM) symbiosis with two Suillus variegatus strains in vitro. Both flavonoids and PAs were analysed after 3, 7, and 14 d in dual culture, and changes in concentrations were compared with growth of the seedlings. Both S. variegatus strains caused similar responses in Scots pine seedlings. Free putrescine accumulated immediately but only transiently after inoculation. This was followed by continuous accumulation of PA conjugates in needles and stems, and free spermidine and spermine in roots, which was accompanied by mycorrhiza formation and improved growth. The fungi induced lateral root formation and main root and primary needle elongation. Inoculation caused no qualitative changes in flavonoid composition, while quantitative changes in flavonols, catechins, and condensed tannins were observed in shoots during mycorrhiza formation. These results indicate that in this in vitro system conjugated PAs and specific flavonoids, generally related to the plant's defence reactions, did not play a major role in the regulation of the establishment of the ectomycorrhizal (ECM) symbiosis in Scots pine roots. The results also clearly show that positive growth responses in shoots and roots due to S. variegatus were supported by different and highly specific changes in the synthesis of both primary and secondary metabolites in these parts of the seedling.     

樟根生产法培育的苗与常规苗的丛枝菌根真菌多样性

以湖南省林业科学院龙伏实验基地的3年生樟根生产（root production method,RPM）苗和同龄常规技术培育的苗木（以下简称常规苗）为研究对象,采集两种苗木的根系和根际土,观察根系上菌根形态,并对其苗木样品进行高通量测序研究,探索二者根系菌根特征及根系、根际土丛枝菌根真菌（arbuscular mycorrhizal fungi,AMF）群落结构及土壤微生境差异,旨在为进行接种有效性菌根苗木来改善常规苗木的土壤微生境,进而培育高质量苗木提供理论依据。结果显示：2种樟苗木根系均显示AM菌根特征,未见外生菌根结构。测序得到属于AMF群落的有效序列共25 738条,隶属1门,2纲,3目,5科,5属,按有效序列占比从高到低依次为Acaulospora、Glomus、Diversispora、Rhizophagus和Paraglomus。根生产法（RPM）苗和常规苗的优势属均为Acaulospora和Glomus,只是RPM苗中Glomus占比高（在根、根际土内占比分别为28.04%、57.36%）而常规苗中Acaulospora占比高（在根、根际土内占比分别为99.58%、42.2%）。2种苗木均是根际土内的丰富度指数（Ace和Chao）远高于根系,并且RPM苗根际土的丰富度指数高于常规苗,但二者根系内的丰富度指数无显著差异（P<0.05）。冗余分析结果显示,土壤pH和有效磷是决定AMF群落结构的主要影响因子。不同理化因子对AMF群落的菌属影响程度也不同。     

The effects of toxic metals,content of nutrients and inoculation with mycorrhizal fungi on the level of phenolics in roots and growth of Scots pine seedlings

The effects of two substrates and several strains of mycorrhizal fungi on the content of soluble phenolics in roots and growth of Scots pine seedlings was investigated. The first substrate was fertile and contaminated with copper, zinc and lead, whereas the second one displayed nutrient deficiency. The dry weights of needles, trunks, roots and the total biomass were higher in groups of seedlings inoculated with mycorrhizal fungi on fertile and polluted substrate. Inoculation of pine seedlings on this substrate resulted in a decrease in concentration of phenolics in roots and except for seedlings inoculated with Laccaria laccata negatively influenced the above-ground part: root ratio.     

马尾松根生产苗与常规苗外生菌根真菌多样性特征

以湖南省林业科学院龙伏试验基地3年生常规方法培养的马尾松苗Pinus massoniana（以下简称常规苗）和3年生马尾松根生产（root production method,RPM）苗根、根际土为研究对象,采用 Illumina MiSeq 测序技术研究其根系及根际土壤外生菌根真菌（ectomycorrhizal fungi,ECMF）群落结构特征,旨在探明其土壤微生境的差异,进而为人工接种菌根真菌及改良常规苗的土壤微生境奠定基础。测序共获得170 148条ECMF序列,划分为20个OTUs（operational taxonomic units,OTU）,隶属于2门、3纲、7目、8科、11属。Chao1丰富度指数、Ace丰富度指数、Simpson多样性指数与Shannon-Wiener多样性指数均表现为常规苗根际土的OTUs丰富度高于RPM苗根际土,并且根样OTUs丰富度低于根际土样（P<0.05）。不同样品的ECMF优势属占比也不同,RPM苗根样中占比最大的为Amphinema（47.89%）,常规苗根样为Tomentella（70.60%）;RPM苗土样中占比最大的为Tylospora（62.33%）,常规苗土样为Tomentella（55.69%）。冗余分析表明,土壤pH值对ECMF的影响程度最大,其次为速效磷和有机质;同时,不同理化因子对群落多样性指数及优势属的影响也存在差异。     

楸树实生苗和嫁接苗根相关真菌群落结构和多样性

以1、2、3年生的楸树实生苗和嫁接苗（梓树砧木）根系为研究对象,通过对ITS rDNA区域标记扩增子的Illumina MiSeq测序,分析不同苗龄楸树实生苗和嫁接苗根相关真菌的结构组成和多样性。获得根相关真菌OTU共842个,分属4门、24纲、70目、134科、233属、347种;丛枝菌根真菌（arbuscular mycorrhizal fungi）AMF-OTU共42个,分属1门、1纲、3目、3科、3属、13种。根相关真菌和AMF的OTU数量、丰度和多样性在实生苗中均随苗龄的增加而降低,而在嫁接苗中则随着苗龄的增加而增加。门水平上,实生苗与嫁接苗根相关真菌的优势菌都是子囊菌门Ascomycota、担子菌门Basidiomycota和接合菌门Zygomycota,但它们的相对丰度有所差异;属水平上,实生苗和嫁接苗根相关真菌的优势菌种在组成和数量上都具有一定的差异性。楸树根相关真菌拥有3种营养模式和12个生态功能群,其中实生苗根系中病理营养型真菌的比例大于嫁接苗,腐生营养型则差异不大,而共生营养型则小于嫁接苗。生态功能群分析显示大多数楸树根系真菌表现出多种生存策略,部分真菌可以在植物-真菌-动物中跨界侵染。该研究可为楸树根相关真菌的利用提供一定的理论依据和基础。     

Fine-scale distribution of ectomycorrhizal fungi colonizing Tsuga diversifolia seedlings growing on rocks in a subalpine Abies veitchii forest

Numerous species of ectomycorrhizal (ECM) fungi coexist under the forest floor. To explore the mechanisms of coexistence, we investigated the fine-scale distribution of ECM fungal species colonizing root tips in the root system of Tsuga diversifolia seedlings in a subalpine forest. ECM root tips of three seedlings growing on the flat top surface of rocks were sampled after recording their positions in the root system. After the root tips were grouped by terminal-restriction fragment length polymorphism (T-RFLP) analysis of ITS rDNA, the fungal species representing each T-RFLP group were identified using DNA sequencing. Based on the fungal species identification, the distribution of root tips colonized by each ECM fungus was mapped. Significant clustering of root tips was estimated for each fungal species by comparing actual and randomly simulated distributions. In total, the three seedlings were colonized by 40 ECM fungal species. The composition of colonizing fungal species was quite different among the seedlings. Twelve of the 15 major ECM fungal species clustered significantly within a few centimeters. Some clusters overlapped or intermingled, while others were unique. Areas with high fungal species diversity were also identified in the root system. In this report, the mechanisms underlying generation of these ECM root tip clusters in the root system are discussed.     

Gas exchange and growth responses of ectomycorrhizal Picea mariana, Picea glauca, and Pinus banksiana seedlings to NaCl and Na2SO4

Abstract: Black spruce (Picea mariana), white spruce (Picea glauca), and jack pine (Pinus banksiana) seedlings were inoculated with Hebeloma crustuliniforme or Laccaria bicolor and subjected to NaCl and Na₂SO₄ treatments. The effects of ectomycorrhizas on salt uptake, growth, gas exchange, and needle necrosis varied depending on the tree and fungal species. In jack pine seedlings, ectomycorrhizal (ECM) fungi reduced shoot and root dry weights and in the ECM white spruce, there was a small increase in dry weights. Sodium chloride treatment reduced net photosynthesis and transpiration rates in the three studied tree species. However, NaCl-treated black spruce and jack pine colonized by H. crustuliniforme maintained relatively high photosynthetic and transpiration rates and needle necrosis of NaCl-treated black spruce seedlings was reduced by the ECM fungi. Higher concentrations of Na+ were found in shoots compared with roots of the three examined conifer species. ECM fungi reduced the concentrations of Na+ mainly in the shoots and this reduction was greater in plants treated with NaCl compared with Na₂SO₄. Shoots contained generally higher concentrations of Cl^- compared with roots. In the NaCl-treated black spruce and white spruce, both ECM species significantly reduced Cl^- concentrations. Our results point to overall greater phytotoxicity of NaCl compared with Na₂SO₄ and support our earlier findings which demonstrated beneficial effects of ECM fungi for woody plants exposed to NaCl stress.     

Secondary embryonary root associated with seed germination in Garcinia intermedia (Clusiaceae) and its possible role in seedling survival

Germination tests on Garcinia intermedia (Clusiaceae) seeds showed the growth of two types of roots: additionally to the primary root, a secondary root crosses the seed lengthwise. To determine its possible role on the survival and growth of this species, 90 seedlings at least six months old (collected in Central Costa Rica) were planted in plastic bags with organic soil, and placed in a greenhouse. The seedlings were treated as follows: treatments in which the primary or secondary root was cut off, and a control group with both roots intact (30 replicates each). After three months 10 seedlings/month/treatment were extracted to measure their height, basal diameter, root length (main and secondary root), and biomass of the stem, roots and seed (without its coat). Control seedlings had the highest growth, followed by those without secondary roots. Nonetheless, more than 90% of the seedlings whose primary roots were cut off, survived after five months of the excision treatment, in part due to the capacity of this species to regenerate its radical system through the seed reserves, sprouting of a primary-like root, and/or the growth stimulus of the secondary root (60% of the total: 20% with sprouts from the primary root stump, 13.3% with a growth stimulus of the secondary root, and 26.7% with both conditions). The length of the sprouted roots was significantly different only on those plants that were extracted during the first two monthly measurements, when compared with the control (F6 = 18.6, F7 = 16.0, p < 0.01).     

Ribulose bisphosphate carboxylase, protein and nitrogen in Scots pine seedlings cultivated at different nutrient levels

Seedlings of Scots pine (Pinus sylvestris L.) of a northern provenance were cultivated in nutrient solution for 10 weeks in a climate chamber. The nutrient solution (renewed by solution exchange) contained 2.5, 10 or 50 mg N I^?1. All other essential elements were added in optimal proportion to the nitrogen. Seedlings cultivated at 10 and 50 mg N I^?1 were similar with respect to all characteristics studied. Seedlings cultivated at 2.5 mg N I^?1 showed a lower growth rate, especially for the shoot, and an altered morphology, with high root:shoot ratios and long, slender roots. The nitrogen concentrations in shoot and needles as well as in whole seedlings were not significantly affected by the nitrogen supply, while the nitrogen concentrations in the roots were somewhat lower at 2.5 mg N I^?1. Ribulose bisphosphate carboxylase (EC 4.1.1.39) activity and the concentrations of carboxylase, total and soluble protein and of chlorophyll in the needles were consistently much lower for seedlings cultivated at 2.5 mg N I^?1, than for seedlings grown at higher nutrient levels. A close correlation was observed between activity and concentration of the carboxylase (r=0.95). Carboxylase activity and protein were more sensitive to a low nutrient supply than was chlorophyll. The data show how activity and concentration of ribulose bisphosphate carboxylase and the concentrations of soluble and total protein and of chlorophyll in needles of pine seedlings can be negatively affected by the nutrient supply, also when the nitrogen concentrations in the needles are close to those observed at optimal nutrient supply. It is suggested that pine seedlings store assimilated non-protein nitrogen in the needles when protein synthesis is under restraint. The nitrogen concentration in needles and seedlings could not be used as a measure of the physiological state of the seedlings.