990 resultados para PINE NEEDLES


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The goal of this thesis was to examine the ecophysiological responses of Scots pine (Pinus sylvestris L.), with an emphasis on the oxidative enzyme peroxidase and plant phenolics to environmental stresses like elevated levels of nickel (Ni) and copper (Cu), and herbivory. The effects of Ni and Cu were studied in a gradient survey at a sulphur dioxide contaminated site in the Kola Peninsula, and with experiments in which seedlings were exposed to Ni mist or to Ni and Cu amended into the soil. In addition, experimental Ni exposure was combined with disturbance of the natural lichen cover of the forest ground layer. Pine sawfly attack was simulated in the early season defoliation experiment, in which mature Scots pine were defoliated (100 %) during two successive years in a dry, nutrient-poor Scots pine stand. In addition, the effect of previous defoliation on the growth of sawfly (Diprion pini L.) larvae was studied. Apoplastic peroxidase activity was elevated in the needles of pine in a Ni- , Cu- and SO2- polluted environment, which indicated an increased oxidative stress. Increased foliar peroxidase activity due to Ni contamination was shown in the experiment, in which Ni was added as mist. No such response was found in peroxidase acitivity of the roots exposed to elevated Ni and/or Cu in the soil. Elevated Ni in the soil increased the concentration of foliar condensed tannins, which are able to bind heavy metals in the cells. Addition of low levels of Ni in the soil appeared to benefit pine seedlings, which was seen as promoted shoot growth and better condition of the roots. Wet Ni deposition of 2000 mg m-2 reduced growth and survival of pine seedlings, whereas deposition levels 200 mg m-2 or 20 mg m-2 caused no effects in a 2-y lasting experiment. The lichen mat on the forest floor did not act as an effective buffer against the adverse impacts of heavy metals on pine seedlings. However, some evidence was found indicating that soil microbes profited from the lichen mat. Artificial defoliation increased peroxidase activity in the Scots pine needles. In addition, defoliation decreased nitrogen, diamine putrescine and glucose concentrations in the needles and increased the concentrations of several phenolic compounds, starch and sucrose. Previous artificial defoliation led to poor growth of sawfly larvae reared on the pines, suggesting delayed induced resistance in Scots pine. However, there was no consistent relationship between inducibility (proportional increase in a compound following defoliation) and adverse effects on the growth of pine sawfly larvae. The observed inducible responses in needle phenolics due to previous defoliation thus appear to represent non-specific responses against sawflies.

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Heritable variation in plant secondary compounds in dominant species has been hypothesised to effect ecosystem function and the structure of associated assemblages of plants, microbes and animals. The functioning of this extended phenotype in relation to the understorey vegetation composition was tested within a boreal forest system dominated by Pinus sylvestris which contains a range of monoterpenes, the composition of which is largely under genetic control. A variance partitioning approach was adopted to identify the relative importance of tree chemistry, environment, spatial location and tree architecture in controlling the distribution of species in the ground flora under individual trees. The monoterpene composition of the pine needles appeared to contribute significantly to controlling understorey vegetation composition, but was less important than environmental factors, though similar to spatial factors. Thus there appears to be a link between variation in the chemical composition of the single, dominant tree species within this system and the pattern of occurrence and abundance in other species at the same trophic level.

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The pigment content of dark-grown primary needles of Pinus jeffreyi L. and Pinus sylvestris L. was determined by high-performance liquid chromatography. The state of protochlorophyllide a and of chlorophylls during dark growth were analyzed by in situ 77 K fluorescence spectroscopy. Both measurements unambiguously demonstrated that pine primary needles are able to synthesize chlorophyll in the dark. Norflurazon strongly inhibited both carotenoid and chlorophyll synthesis. Needles of plants treated with this inhibitor had low chlorophyll content, contained only traces of xanthophylls, and accumulated carotenoid precursors. The first form of chlorophyll detected in young pine needles grown in darkness had an emission maximum at 678 nm. Chlorophyll-protein complexes with in situ spectroscopic properties similar to those of fully green needles (685, 695, and 735 nm) later accumulated in untreated plants, whereas in norflurazon-treated plants the photosystem I emission at 735 nm was completely lacking. To better characterize the light-dependent chlorophyll biosynthetic pathway in pine needles, the 77 K fluorescence properties of in situ protochlorophyllide a spectral forms were studied. Photoactive and nonphotoactive protochlorophyllide a forms with emission properties similar to those reported for dark-grown angiosperms were found, but excitation spectra were substantially red shifted. Because of their lower chlorophyll content, norflurazon-treated plants were used to study the protochlorophyllide a photoreduction process triggered by one light flash. The first stable chlorophyllide photoproduct was a chlorophyllide a form emitting at 688 nm as in angiosperms. Further chlorophyllide a shifts usually observed in angiosperms were not detected. The rapid regeneration of photoactive protochlorophyllide a from nonphotoactive protochlorophyllide after one flash was demonstrated.

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The aim of this study was to explore soil microbial activities related to C and N cycling and the occurrence and concentrations of two important groups of plant secondary compounds, terpenes and phenolic compounds, under silver birch (Betula pendula Roth), Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris L.) as well as to study the effects of volatile monoterpenes and tannins on soil microbial activities. The study site, located in Kivalo, northern Finland, included ca. 70-year-old adjacent stands dominated by silver birch, Norway spruce and Scots pine. Originally the soil was very probably similar in all three stands. All forest floor layers (litter (L), fermentation layer (F) and humified layer (H)) under birch and spruce showed higher rates of CO2 production, greater net mineralisation of nitrogen and higher amounts of carbon and nitrogen in microbial biomass than did the forest floor layers under pine. Concentrations of mono-, sesqui-, di- and triterpenes were higher under both conifers than under birch, while the concentration of total water-soluble phenolic compounds as well as the concentration of condensed tannins tended to be higher or at least as high under spruce as under birch or pine. In general, differences between tree species in soil microbial activities and in concentrations of secondary compounds were smaller in the H layer than in the upper layers. The rate of CO2 production and the amount of carbon in the microbial biomass correlated highly positively with the concentration of total water-soluble phenolic compounds and positively with the concentration of condensed tannins. Exposure of soil to volatile monoterpenes and tannins extracted and fractionated from spruce and pine needles affected carbon and nitrogen transformations in soil, but the effects were dependent on the compound and its molecular structure. Monoterpenes decreased net mineralisation of nitrogen and probably had a toxic effect on part of the microbial population in soil, while another part of the microbes seemed to be able to use monoterpenes as a carbon source. With tannins, low-molecular-weight compounds (also compounds other than tannins) increased soil CO2 production and nitrogen immobilisation by soil microbes while the higher-molecular-weight condensed tannins had inhibitory effects. In conclusion, plant secondary compounds may have a great potential in regulation of C and N transformations in forest soils, but the real magnitude of their significance in soil processes is impossible to estimate.

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Sirex woodwasp (Sirex noctilio F: Hymenoptera: Siricidae) is a major worldwide pest of pine (Pinus) species. The female woodwasp undertakes exploratory drills with the ovipositor prior to egg-laying to assess tree suitability. Previous work has shown that this behaviour is associated with assessing the osmotic pressure of the tree. Here we show that, in addition, the ovipositor is electrophysiologically active and capable of detecting ethanol and chemical components of solvent extracts of pine needles and bark. Scanning electron micrographs of the ovipositor show the presence of structures which may have a chemoreceptive function. Our research expands our knowledge of the role that the Sirex ovipositor plays in egg-laying site selection.

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一.应用高通量技术筛选松树抗微生物分子的研究 我们提出一种对纯化组分的抗菌活力进行高通量技术筛选的比色方法。该方法利用一种新型四氮唑盐MTS(methyl tetrazolium salt)在电子偶联剂PMS( phenazine methosulfate)的辅助下对供试样品进行比色分析,其原理是MTS能穿透进完整活性细胞,在接受电子偶联剂PMS提供的电子后,被其中细胞器膜或质膜上的脱氢酶还原成一种水溶性的显色甲替(formazan)化合物。甲替在490nm波长的吸收值能直接用96孔酶标板读取,无须通过额外的溶解步骤。甲替的产生量(吸收值)和基质中的活细胞数成正比。因此,抗菌成分作用于供试细菌后,其抗菌活力大小可通过对照孔(未加抗菌成分)和试验孔吸收值的差异反映出来。借助该技术和对影响MTS转化的各种因素标准化,定量研究6种细菌菌株包括革兰氏阴性菌和革兰氏阳性菌的生长。通过反相C18柱浓缩、凝胶过滤层析和亲和层等技术,从受马尾松毛虫危害的马尾松针内分离和纯化出几种增强的抗微生物活力,证实了。该方法对临床供试菌株的可行性和应用潜力;同时,对植物宿主受害后的诱导生理和功能意义亦进行了探讨。 二.向日葵种质资源相关基础研究中文摘要 1) 维生素E的天然产物有八种类型,分别为α、β、γ、δ一生育酚( tocopherol)和α、β、γ、δ一生育三烯酚( tocotrienol),对植物、动物和人类都具有十分重要的生理作用。绿色植物是人类和动物VE的基本来源。本文对有关植物中VE生物合成途径和相关酶基因克隆研究现状,以及VE在植物体内的作用和功能研究进展进行了综述,以期为VE的机理探寻和功能开发提供进一步的思路。 2) 以20份向日葵种质资源为实验材料,通过对维生素E含量、含油率、皮壳率以及百粒重的测定及统计分析,试图了解向日葵种质资源中维生素E含量变异及相关数据。结果表明,在20份向日葵种质资源中,油葵的维生素E含量和含油率明显高于食葵:含油率与维生素E含量在0.01水平呈极显著正相关,含油率与百粒重在0,05水平呈显著负相关;百粒重与皮壳率在0.01水平呈极显著负相关。通过初步评价,发现3份富含天然维生素E的向日葵种质。 3) 由自由基介导的脂过氧化、酶失活或蛋白降解、胞膜破裂和遗传完整性(核酸)的损害是种子衰老的主要原因。种子在高温和高含水量情况下曝露数天诱发的加速衰老比一般衰老引起更多的生化分解;另一方面,在长期贮存条件下的低温贮存环境和种子低含水量可能使种子处于玻璃态。种子胞质的极高粘度和低分子运动能够阻止或抑制很多有害过程。尽管种子衰老的生理机制已有大量研究,但衰老过程中的主要过程和相互作用仍未完全清楚。本文报道向日葵种子在宽范围的含水量和温度条件下的脂过氧化、非酶蛋白糖基化对种子衰老的影响;同时,对种子玻璃态在长期贮存中对生化分解的阻滞作用并由此延长种子存活力也进行了探讨。

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土壤可溶性有机物质(Dissolved organic matter,DOM)作为土壤有机质的活性组分,在陆地生态系统物质循环中扮演非常重要的角色。土壤DOM的主要成分可溶性有机碳(Dissolved organic carbon,DOC)和氮(Dissolved organic nitrogen,DON)参与C、N循环过程。为深入揭示全球C、N循环过程机制,在未开展DOC和DON的地区进行相关研究是有必要的。森林土壤(包括枯枝落叶层)DOC、DON动态及调控机理的研究是目前国际上森林生态系统C、N循环研究热点之一。本研究立足于暖温带岷江上游茂县地区人工林植被,对土壤DOC和DON的库容量,季节动态及其与其它养分之间的关系进行了系统研究,旨在了解DOC和DON在该区生态系统中的重要作用,并探讨作为DOM主要来源的叶凋落物对DOC和DON的动态影响,研究有助于更加详细地了解该区生态系统C和N循环过程。本论文主要研究结论如下: 1研究了岷江上游地区两大主要土壤类型(棕壤和褐土)不同植物群落下土壤的DOC和DON含量及特征,结果表明:DOC和DON在两种土壤类型中均有库容量存在,DOC在0-10cm和10-20cm土层的含量幅度分别111.96~159.95 mg kg-1和69.02~100.84 mg kg-1。DON在0-10cm和10-20cm土层的含量幅度分别11.88~23.08 mg kg-1和4.70~10.77 mg kg-1。游离氨基酸在0-10cm和10-20cm土层的含量幅度分别0.84~1.66 mg kg-1和0.39~0.73 mg kg-1。DOC、DON与土壤中的一些养分因子表现出了显著的相关关系,共同反映了土壤的状况和质量,在该区开展DOC和DON的系统研究是有必要的。 2 对油松与连香树林地土壤DOC、DON以及其它化学指标的季节动态进行了研究,结果表明:油松与连香树林地土壤DOC和DON的季节动态变化表现了类似的规律,DOC和DON的含量均以秋季最高。DOC和DON的季节动态变化主要受凋落物生物因素的影响,但其微生物活力的生物因素以及降雨、温度等非生物因素也是控制土壤DOC和DON含量的重要因素。土壤DON在土壤中的行为不同于矿质氮,其季节动态不同于NO3--N和NH4+-N的季节动态,在研究N循环过程中,应考虑DON的变化情况。 3 对油松与连香树林地分解层和表层土壤(0-10cm)氨基酸周转动态进行了研究,结果表明:油松林地和连香树林地均以分解层的氨基酸含量高于矿质表层土壤的含量。每个取样时期,油松林地内各层次的氨基酸含量高于连香树林地内相应层次的含量。两林地各层次无机氮含量均超过了氨基酸的含量,并且室内培养30天后无机N的含量仍然高于氨基酸的含量,所以可以认为该区立地条件下无论是在有机分解层还是矿质土层植物吸收利用的氮素仍是以无机N为主。 4 松林下松针凋落物易于累积,这与松针凋落物分解缓慢有关,从而导致松林内养分周转缓慢。通过用不同性质凋落物和灌丛地土壤构建微生态系统,比较油松、辐射松、连香树、灌丛虎榛子凋落物分解对C、N循环过程的影响,结果显示油松和辐射松针叶凋落物比连香树、虎榛子凋落物分解更慢,减缓了养分循环过程。然而将针叶凋落物与阔叶凋落物混合后,油松和辐射松针叶凋落物的分解加快,C、N元素的循环过程也加速。此结果表明在松林内维持具有高质量凋落物的灌丛植被或在松林内栽植一些阔叶树种如连香树对维持和增进松树人工林的土壤肥力有重大的作用。室内培养的结果还显示添加凋落物后土壤DOC和DON的含量显著增加,表明凋落物是土壤DOM的直接来源。然而不同物种凋落物处理下土壤DOC和DON的含量有所不同,并随时间发生改变。混合凋落物处理下土壤DOC和DON的含量均高于松针凋落物单独处理下土壤DOC和DON的含量。DON是一个主要的水溶性N库,随时间的变化趋势与无机N的变化趋势不同,在土壤N循环过程中起到了中间N库的作用。 As a labile fraction of soil organic matter, dissolved organic matter (DOM) plays a very important role in material cycling of terrestrial ecosystem. The turnover of DOM is now being considered as main components in nutrient cycling. DOM mainly includes dissolved organic carbon (DOC), -nitrogen (DON), -phosphorous (DOP) and –sulfur (DOS). Among these constituents, DOC and DON directly participate in C and N cycling. It is essential to study DOC and DON dynamics and their controlling factors in the areas where no related study has ever been carried out. Study about them can provide data supports on understanding the mechanism of the global C and N cycling. DOC and DON dynamics and their controlling factors have been focused on in the research of C and N cycling of forest ecosystems. Based on forest plantations of Maoxian, Minjiang River in warm temperate zone, soil DOC and DON pool size, their seasonal dynamics, and the correlation between DOC, DON and other nutrients were studied in order to understand the importance of DOC and DON in the study area. Soil DOC and DON dynamics induced by leaf litter decomposition were also studied. The study contributed to comprehensively understanding C and N cycling processes and providing baseline data for including DOC and DON into the indices system of evaluating nutrient conditions. The results were as follows: 1 Several different plant communities under brown soil and Cinnamon soil were chosen as sampling plots. The contents and features of soil DOC and DON were evaluated. The results showed that DOC and DON were present under the two soil types. DOC contents in the top soil (0-10 cm) and the subsoil (10-20 cm) respectively varied from 111.96 mg kg-1to 159.95 mg kg-1, and 69.02 mg kg-1 to 100.84 mg kg-1. DON contents in the top soil (0-10 cm) and the subsoil (10-20 cm) respectively varied from 11.88 mg kg-1to 23.08 mg kg-1, and 4.70 mg kg-1 to 10.77 mg kg-1. Free amino acid contents in the top soil (0-10 cm) and the subsoil (10-20 cm) respectively varied from 0.84 mg kg-1to 1.66 mg kg-1, and 0.39 mg kg-1 to 0.73 mg kg-1. Significant correlations were found between DOC, DON and some nutrient indices, which together reflected soil condition and quality. It was hence essential to study DOC and DON in the study area. 2 Seasonal dynamics of DOC, DON, inorganic N, microbial biomass C and N were studied under Pinus tabulaeformis and Cercidiphyllum japonicum plantation. The results indicated that seasonal dynamics of soil DOC and DON under the two plantations performed similar change pattern, with the highest values in autumn. The seasonal dynamics of soil DOC and DON were mainly influenced by the litterfall. However, biotic factors such as soil microbial activities and abiotic factors such as precipitation and temperature also controlled the dynamics of soil DOC and DON. The seasonal dynamic of DON was different from that of NO3--N and NH4+-N, which showed that the behavioral differences between DON and inorganic nitrogen. And hence, it was proposed to include DON into soil N cycling in the study area. 3 Amino acid dynamics in Oa and topsoil (0-10 cm) under P. tabulaeformis and C. japonicum plantation were studied. The results showed that amino acid content in Oa was significantly higher than that in mineral soil. At each sampling time, significantly higher amino acid contents were found in P. tabulaeformis plantation than in C. japonicum plantation. The content of inorganic nitrogen was much higher than the content of amino acid in each sampling layer at each sampling time. After a 30-days laboratory incubation the content of amino acid was still lower than the content of inorganic nitrogen. The results implicated that the form of N absorbed by plants in these study sites were mainly inorganic nitrogen. 4 Usually needle litter is more resistant to decomposition, which leads to needle litter accumulation in pure coniferous stands and slows down the rate of nutrient circulation. By constructing microcosms with local shrubland soil and containing the four single-species (P. tabulaeformis, P. radiata, C. japonicum, Ostryopsis davidiana) litters, the decomposition rates and related C and N dynamics of needle litters and broadleaved litters during the early stage were compared. The results showed that the decomposition rates of pine needles were lower than those of broadleaved litters, which descended C and N cycling processes. However, the presence of C. japonicum or O. davidiana litter into pine needles increased the decomposition rates of pine needles and also dramatically promoted C and N cycling processes. It should be appropriate for plantation managers to consider C. japonicum as an ameliorative species or remain O. davidiana in pine plantations to improve soil conditions and help maintain soil fertility. The laboratory incubation still showed that DOC and DON contents in all litter-amended treatments were significantly higher than no litter-amended treatment, which proved that litter could be a direct source of DOM in soils. Different species litters induced different soil DOC and DON contents, which correspondingly changed over time. DOC and DON contents in mixed litter treatments were higher than those in pine needle litter treatments. As a major soluble N pool, DON developed a different changing pattern over time compared with inorganic N and played a role of interim N pool in soil N cycling.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This study extends the current knowledge regarding the use of plants for the passive accumulation of anthropogenic PAHs that are present in the atmospheric total suspended particles (TSP) in the tropics and sub-tropics. It is of major relevance because the anthropic emissions of TSP containing PAHs are significant in these regions, but their monitoring is still scarce. We compared the biomonitor efficiency of Lolium multiflorum 'Lema' and tropical tree species (Tibouchina pukka and Psidium guajava 'Paluma') that were growing in an intensely TSP-polluted site in Cubatao (SE Brazil), and established the species with the highest potential for alternative monitoring of PAHs. PAHs present in the TSP indicated that the region is impacted by various emission sources. L. multiflorum showed a greater efficiency for the accumulation of PAH compounds on their leaves than the tropical trees. The linear regression between the logBCF and logKoa revealed that L. multiflorum is an efficient biomonitor of the profile of light and heavy PAHs present in the particulate phase of the atmosphere during dry weather and mild temperatures. The grass should be used only for indicating the PAHs with higher molecular weight in warmer and wetter periods. (C) 2012 Elsevier Inc. All rights reserved.

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Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013.

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Conifers are resistant to attack from a large number of potential herbivores or pathogens. Previous molecular and biochemical characterization of selected conifer defence systems support a model of multigenic, constitutive and induced defences that act on invading insects via physical, chemical, biochemical or ecological (multitrophic) mechanisms. However, the genomic foundation of the complex defence and resistance mechanisms of conifers is largely unknown. As part of a genomics strategy to characterize inducible defences and possible resistance mechanisms of conifers against insect herbivory, we developed a cDNA microarray building upon a new spruce (Picea spp.) expressed sequence tag resource. This first-generation spruce cDNA microarray contains 9720 cDNA elements representing c. 5500 unique genes. We used this array to monitor gene expression in Sitka spruce (Picea sitchensis) bark in response to herbivory by white pine weevils (Pissodes strobi, Curculionidae) or wounding, and in young shoot tips in response to western spruce budworm (Choristoneura occidentalis, Lepidopterae) feeding. Weevils are stem-boring insects that feed on phloem, while budworms are foliage feeding larvae that consume needles and young shoot tips. Both insect species and wounding treatment caused substantial changes of the host plant transcriptome detected in each case by differential gene expression of several thousand array elements at 1 or 2 d after the onset of treatment. Overall, there was considerable overlap among differentially expressed gene sets from these three stress treatments. Functional classification of the induced transcripts revealed genes with roles in general plant defence, octadecanoid and ethylene signalling, transport, secondary metabolism, and transcriptional regulation. Several genes involved in primary metabolic processes such as photosynthesis were down-regulated upon insect feeding or wounding, fitting with the concept of dynamic resource allocation in plant defence. Refined expression analysis using gene-specific primers and real-time PCR for selected transcripts was in agreement with microarray results for most genes tested. This study provides the first large-scale survey of insect-induced defence transcripts in a gymnosperm and provides a platform for functional investigation of plant-insect interactions in spruce. Induction of spruce genes of octadecanoid and ethylene signalling, terpenoid biosynthesis, and phenolic secondary metabolism are discussed in more detail.