十溴联苯醚对秀丽隐杆线虫毒性研究

十溴联苯醚(BDE-209)是一类新型持久性有机污染物,可导致神经系统和生殖发育等多种生理毒性。本文以秀丽隐杆线虫(Caenorhabditis elegans)为模式生物,通过分析十溴联苯醚(BDE-209)对其繁殖、寿命、细胞凋亡以及体内超氧化物歧化酶基因sod-3、类p-53蛋白基因cep-1、细胞色素P450基因cyp35a2以及谷胱甘肽转移酶基因gst-1的影响,来评价BDE-209的生理、细胞及分子水平毒性。试验结果表明,与空白对照相比,BDE-209低剂量(5 mg kg-1)短时间暴露,对秀丽线虫细胞凋亡及产卵影响不显著;高浓度长时间暴露(30 mg kg-1)会导致秀丽隐杆线虫产卵数目下降,寿命缩短,细胞凋亡。Real-time PCR试验表明,低剂量(5 mg kg-1)暴露使得sod-3、cep-1、cyp35a2基因表达显著增加;高剂量暴露(30 mg kg-1),虽然sod-3表达显著增加,但增加幅度低于低浓度暴露组,cep-1、cyp35a2基因表达显著受到抑制。说明长期暴露在高浓度(30 mg kg-1)十溴联苯醚环境中,会促使秀丽隐杆线虫产生氧化应激反应,秀丽隐杆线虫通过调控相关抗氧化基因的表达来修复这种损伤,而高浓度的BDE-209会造成其机体氧化损伤、细胞凋亡及产卵量下降。     

聚苯乙烯微塑料对秀丽隐杆线虫取食偏好的影响

以土壤模式动物秀丽隐杆线虫为受试对象,研究了不同粒径、不同浓度的聚苯乙烯(PS)微塑料在短期暴露和长期暴露条件下对线虫取食偏好的影响,结果显示,1、10、100 mg/L浓度下,1μm和5μm的PS微塑料短期暴露后,线虫对B.amyloliquefaciens JX1(X1)和P.fluorescens Y1(Y1)的...     

两种土著食细菌线虫对五种细菌的取食偏好及相关机制

食细菌线虫通过取食细菌改变土壤微生物的活性和群落结构从而影响土壤生态系统功能,而食细菌线虫取食细菌存在选择偏好。本试验通过设置"自助餐"式平板培养试验,研究了2种土著食细菌线虫(拟丽突属线虫和中杆属线虫)对5种细菌的活菌体、灭活菌体及菌体分泌物的取食偏好,以为进一步揭示土壤生态系统中食细菌线虫与细菌相互作用关系奠定基础。研究结果显示:拟丽突属和中杆属线虫对活菌体的取食偏好基本一致,均对G-菌具有偏好,其偏好顺序为:荧光假单胞菌大肠杆菌贪噬菌解淀粉芽孢杆菌巨大芽孢杆菌。拟丽突属线虫对5种细菌分泌物的辨识和取食不存在选择性偏好,从而使其对活菌体及灭活菌体的取食偏好顺序基本一致;而中杆属线虫对活菌体及灭活菌体的取食偏好存在显著差异,这可能与中杆属线虫对5种细菌分泌物的辨识和取食具有选择性偏好有关。细菌分泌物对中杆属线虫的取食偏好机制还有待进一步研究。     

苏云金芽孢杆菌对新秀丽小杆线虫的作用

新秀丽小杆线虫是一种模式生物，能够在室内培养。本研究采用大肠杆菌饲养，获得大量虫源，通过观察该线虫对不同Bt菌株产生毒力反应的情况，筛选含有毒力的Bt菌株。经筛选获得6个菌株的伴孢晶体对新秀丽小杆线虫进行毒性比较，野生菌株Bt-010杀虫快速而持久，毒力强，作用时间大约在36h左右，测得其理想的LC50为0.498µg/ ml。初步纯化其毒性蛋白，发现其主要作用成分是大小为25 – 35 kD的蛋白。DNA Ladder检测发现在这个毒性蛋白不象化学农药一样对线虫的DNA造成损伤。     

农药废水对秀丽隐杆线虫毒性效应及其主要有毒组分

应用battery生物测试法,检测研究农药废水对秀丽隐杆线虫的生命周期、繁殖速率、生殖能力、头摆和身体弯曲频率等影响的生物毒性,及其引发生物毒性的主要有机污染物。结果表明,在已经达到国家废水排放标准[GB 8978—1996]情况下,处理出水对受试动物仍然存在致毒效应;线虫的世代周期对进水的毒性最为敏感,产卵数量对出水的毒性最为敏感;进水毒性主要来自易受酸性调节影响的有机污染物,出水毒性主要来自易受碱性调节影响的有机污染物。结果表明,该项生物测试的毒性参数,可用于指示存在于低CODCr废水中的生物毒性;所用的毒性鉴别评价（TIE）方法,可用于鉴别废水中引发致毒效应的关键污染物。废水中悬浮颗粒污染物的生物毒性至关重要,尚未研究,有待继续。     

蒙东地区玉米田土壤线虫营养与生活史类群结构特征

为进一步了解玉米田覆膜后对土壤生态系统的影响,本文对覆膜和未覆膜玉米田土壤线虫群落的营养类群和生活史类群结构特征进行了研究。结果表明:所调查的土壤中相对多度≥10%的属有巴兹尔属(Basiria)、真滑刃属(Aphelenchus)、丝尾垫刃属(Filenchus)、垫咽属(Tylencholaimus)、拟丽突属(Acrobeloides)和丽突属(Acrobeles),不同处理中土壤线虫个体数的顺序为覆膜1年未覆膜覆膜4年。覆膜处理影响了土壤线虫的营养类群和生活史类群的个体数和相对丰度,连续覆膜4年食真菌线虫、食细菌线虫和植物寄生线虫的个体数量均显著降低,捕食-杂食线虫数量稳定但相对丰度却显著增加;覆膜种植玉米4年后c-p2类群数量和相对丰度均显著降低而c-p4类群却显著增加。不同处理间F/B和NCR值无显著差异,但土壤分解主要依靠细菌分解途径。MI、MI2-5、MMI、MMI2-5和PPI指数在覆膜4年的处理中均显著增加,连续覆膜4年的玉米田土壤生态系统的稳定性增加。因此,线虫群落组成和结构的变化对玉米田土壤生态系统具有很好的指示作用。     

斯氏属线虫生物学特性对冷驯化寄主昆虫的响应

为研究经不同温度驯化的寄主昆虫对昆虫病原线虫生物学特性的影响,开展了室内生测试验,调查了2种斯氏属线虫对不同温度驯化的5龄脐橙螟幼虫的致病力、侵入力和繁殖力及寄主体内繁殖出线虫的冷冻存活率。结果表明,线虫Steinernema carpocapsae对经10℃、15℃、20℃和25℃驯化7 d的5龄脐橙螟幼虫的致死率没有显著影响,但线虫S. feltiae对经10℃驯化的5龄脐橙螟幼虫致死率为96. 7%,显著高于25℃处理81. 4%;线虫S. carpocapsae和S. feltiae对经10℃处理的5龄脐橙螟幼虫的侵入率分别为49. 3%和39. 7%,均显著高于25℃处理(26%和24%);随着驯化温度的降低,2种线虫从体表出现的寄主数量占总寄主数量的比率呈升高的趋势,线虫S. feltiae的升高趋势更明显; 2种线虫在经10℃驯化的5龄脐橙螟幼虫体内繁殖的产量均显著高于25℃处理,并且随驯化温度的降低S. feltiae产量呈上升的趋势较S. carpocapsae更明显;低温驯化寄主昆虫可提高其体内寄生的2种线虫的冷冻存活能力。10℃驯化7 d的5龄脐橙螟幼虫有助于提高S. feltiae线虫的致病力、侵入力、繁殖速度和产量及其冷冻存活力,提高程度较S. carpocapsae更明显。     

不同有机物料对连作大豆根际土壤线虫的影响

为探讨大豆连作体系下农业废弃物为主的不同有机物料对根际土壤线虫的影响,选用6种不同有机物料,设正茬和连作两种处理进行对比分析根际土壤线虫群落差异。结果表明:土壤线虫中重要的优势属和关键属种cp值均为3,说明其繁殖和抗干扰能力比较强。连作7年后根际土壤线虫营养类群中杂食-捕食性线虫相对丰度下降明显,植物寄生线虫相对丰度显著提高,食细菌线虫、食真菌线虫丰度略有提高;相较单施化肥(CK)处理,添加有机物料明显抑制连作大豆根际土壤中植物寄生线虫的大量增长,不同施肥处理效果分别为:猪粪秸秆菌渣牧草鸡粪黄腐酸生物有机肥CK,与正茬相比,各连作处理依次增长6.48%、15.34%、15.98%、18.51%、24.35%、26.33%和27.4%。土壤线虫的生态指数较CK相比也有明显改善。土壤线虫对肥料的响应取决于作物及肥料的质量和养分含量;土壤线虫优势营养类群、优势属种和关键属种可以有效地指示农业土壤健康状况和大豆田间线虫病害的发生程度。     

基于有限元模型的喷雾机喷杆弹性变形分析与控制

以研究和抑制喷杆弹性变形为目的,基于ANSYS平台建立了喷杆的有限元模型并进行了数值模态分析,利用试验模态分析的方法对有限元模型及其模态信息进行了验证。依据所建立模型及其模态信息,在ADAMS平台中建立了机架喷杆模型,并对偏转、振荡以及翻滚3种典型运动引起的喷杆末端弹性变形量分别进行了谐响应分析,结果表明振荡是造成喷杆弹性变形的主要因素。为了抑制喷杆的弹性变形,在喷杆与机架之间添加了拉索,并分析了拉索安装在4种不同位置时,喷杆受到频率范围为0~10 Hz振荡激励后的弹性变形情况,结果表明:3/4喷杆位置处为4种安装位置中最合适处,此时喷杆各处形变量均小于10 mm,为4种中最小,相较未添加拉索时喷杆末端产生接近80 mm弹性变形来说,对弹性变形的抑制效果明显。     

微囊藻毒素缺氧/厌氧降解产物Adda对秀丽线虫的毒性

微囊藻毒素（MCs）在缺氧/厌氧条件下可以被湖泊沉积物中的土著微生物降解,产生并积累一种降解产物Adda。为了揭示该降解过程的环境安全性,以秀丽线虫（Caenorhabditis elegans）作为模式生物研究了MCs缺氧/厌氧降解产物Adda的毒性。结果表明,低浓度Adda（≤0.05μmol·L-1）暴露对秀丽线虫各项指标均无显著影响,而0.1μmol·L-1的Adda可显著降低线虫的头部和身体摆动频率,说明Adda对线虫运动能力影响较大。当Adda暴露浓度达到0.5μmol·L-1时,可显著影响线虫的寿命、发育、运动能力和生殖能力,但是对畸形率没有显著影响。这些结果说明,Adda的毒性远小于MCLR,因此缺氧/厌氧降解可以有效降低MCLR的毒性。但是考虑到高浓度Adda具有一定毒性,如果Adda大量积累仍可能造成一定的生态影响。     

Responses of root-feeding nematodes (Helicotylenchus spp.) to local and non-local populations of the host plant Ammophila arenaria

The root-feeding nematode community of wild plants may vary throughout their natural range. Little is known about how the variation of wild plants along their range affects their relationship with root-feeding nematodes. In the present study, we examined local and non-local combinations of host plants and root-feeding nematodes to test the hypothesis that nematode reproduction is favoured by local hosts. In two indoor experiments, we exposed populations of the wild dune grass Ammophila arenaria from northern and southern European coastal sand dunes to plant parasitic nematode species (Helicotylenchus spp.) from those same geographical origins. First, we used the southern nematode species to determine whether the effect of a local versus a non-local host may depend on nematode density. Then, in a cross-inoculation experiment we investigated how both nematode species performed with their local, as compared to the non-local hosts.

In both experiments, plant biomass and ontogenetic characteristics were not significantly different between the northern and southern populations. The applied nematode densities did not have a negative impact on plant performance. This allowed us to consider the response of the two different nematode species and their host plants without co-varying differences in plant responses. Reproduction of the nematode species differed according to host origin, but contrary to what we expected, nematode species did not perform better on their local hosts. Helicotylenchus n. sp., the southern species originating from Portugal, performed better on the non-local than on the local host. Male to female ratios were significantly different between the two nematode populations and were lowest in Helicotylenchus pseudorobustus from The Netherlands. Female and juveniles percentages were also quite distinct, with more females in the nematode species from The Netherlands and more juveniles in the nematode species from Portugal.

We concluded that ectoparasitic root-feeding nematodes Helicotylenchus spp. do not necessarily perform best on their local host population of the foredune grass A. arenaria. Our results imply that the natural distribution of Helicotylenchus spp. along the European coast is determined by other factors than host populations. These other factors that could be abiotic, e.g. water availability, or biotic, e.g. local natural enemies adapted to Helicotylenchus spp. Introducing plant genotypes from other parts of the natural range will, therefore, not necessarily lead to reduced abundance of semi-endo or ectoparasitic root-feeding nematodes.     

Effects of Bacterial-Feeding Nematode Grazing and Tea Saponin Addition on the Enhanced Bioremediation of PyreneContaminated Soil Using Polycyclic Aromatic Hydrocarbon-Degrading Bacterial Strain

As one of the most widely distributed bacterial predators in the soil, the role of bacterivorous nematodes on the enhanced bioremediation of polycyclic aromatic hydrocarbon-contaminated soils is crucial, but remains to be investigated.A microcosm-level study was conducted to examine the effects of bacterial-feeding nematode grazing and tea saponin(TS) addition on bioremediation of a pyrene-contaminated soil enhanced by the polycyclic aromatic hydrocarbon(PAH)-degrading bacterial strain Sphingobium sp.PHE9.After 180 d of incubation, the highest pyrene dissipation(71.3%) was achieved through a combination of Sphingobium sp.PHE9 inoculation with nematode and TS addition.Meanwhile, high counts of culturable PAH-degrading bacteria, soil enzyme activity, and biodiversity indices were observed under the combined treatment, implying that the microbiological function of the contaminated soil was significantly restored.Additionally, the results of Tenax~ extraction with the first-order three-compartment model indicated that rate-limiting factors varied among treatments.The lack of degrading microorganisms was the main rate-limiting factor for the treatments involving TS/nematode addition, and inadequate bioaccessible pyrene was the vital rate-limiting factor in the treatments involving Sphingobium sp.PHE9 inoculation.The proposed combined clean-up strategy proved to be a promising bioremediation technology for aged pyrene-contaminated soils.     

荧光原位杂交技术检测土壤中博德特氏菌探针的设计与应用

根据博德特氏菌(Bordetellasp.)的16S rRNA基因序列,设计荧光原位杂交(FISH)检测博德特氏菌的寡核苷酸探针FW_iso_62和FW_iso_761,在20%～60%甲酰胺均有很强的荧光信号。采用探针FW_iso_62及其竞争探针,结合Nycodenz和DAPI技术,建立定量检测土壤中博德特氏菌的DAPI-FISH方法。该方法可排除土壤颗粒的自动荧光对细菌信号的掩盖,保证图片中有大量微生物供统计分析,还能有效保存微生物的原位信息。应用该方法分析土壤中1,2,4-三氯苯降解菌-博德特氏菌,结果未受氯苯污染的农田土壤中没有检测到博德特氏菌,而氯苯污染土壤中检测到大量的博德特氏菌,每克土壤含3.78×106个。将该污染土壤中分离的博德特氏降解菌及其降解菌群接种至农田土壤中,降解菌的数量均随培养而增加,一个月后分别占DAPI计数的1.7%和3.8%。本研究设计的探针可有效用于复杂环境样品中博德特氏菌的定性与定量检测。     

食细菌线虫和葡萄糖对恶臭假单胞菌去除菲的影响

Bacterial-feeding nematodes can promote the bacterial activity through feeding.Bacterial abundance and their activity affect the degradation of polycyclic aromatic hydrocarbons (PAH) such as phenanthrene.The effects of bacterial-feeding nematodes,bacteria,and their interactions on the degradation of phenanthrene with or without glucose were studied through a microcosm experiment.The results showed that up to 57.0％ of phenanthrene in mineral medium contaminated with phenanthrene was degraded in the control with bacteria alone and bacteria with the presence of nematodes and/or glucose increased the degradation of phenanthrene by 25.6％ to 36.6％.Although both nematode and bacteria abundance decreased gradually,catechol 2,3-dioxygenase (C23O) activity increased during the incubation period.Compared with bacteria alone,the presence of nematodes significantly increased C23O activity as well as the abundance of bacteria;this effect was more pronounced when glucose was present.The results imply that nematodes might promote the removal of phenanthrene from medium by stimulating bacteria and C23O activities.     

Increased degradation of phenanthrene in soil by Pseudomonas sp. GF3 in the presence of wheat

A phenanthrene-degrading bacterial strain Pseudomonas sp. GF3 was examined for plant-growth promoting effects and phenanthrene removal in soil artificially contaminated with low and high levels of phenanthrene (0, 100 and 200 mg kg⁻¹) in pot experiments. Low and high phenanthrene treatments significantly decreased the growth of wheat. Inoculation with bacterial strain Pseudomonas sp. GF3 was found to increase root and shoot growth of wheat. Strain GF3 was able to degrade phenanthrene effectively in the unplanted and planted soils. Over a period of 80 days the concentration of phenanthrene in soil in which wheat was grown was significantly lower than in unplanted soil (p<0.05). At the end of the 80-d experiments, 62.2% and 42.3% of phenanthrene had disappeared from planted soils without Pseudomonas sp. GF3 when the phenanthrene was added at 100 and 200 mg kg⁻¹ soil, respectively, but 84.8% and 70.2% of phenanthrene had disappeared from planted soils with the bacterial inoculation. The presence of vegetation significantly enhances the dissipation of phenanthrene in the soil. There was no significant difference in soil polyphenol oxidase activities among the applications of 0, 100 and 200 mg kg⁻¹ of phenanthrene. However, the enzyme activities in planted and unplanted soils inoculated with the strain Pseudomonas sp. GF3 were significantly higher than those of non-inoculation controls. The bacterial isolate was also able to colonize and develop in the rhizosphere soil of wheat after inoculation.     

Determinants of trophic modes of the nematophagous fungus Arthrobotrys oligospora interacting with bacterivorous nematode Caenorhabditis elegans

The determinants of saprotrophic or predatory modes of the nematophagous fungus Arthrobotrys oligospora were investigated in soil microcosms and on solid nutrient media. A sterilized soil amended with 1% w/w alfalfa meal (C:N=32) and inoculated with conidia of A. oligospora, showed lower mycelium biomass and higher specific rate of conidia production in the presence of the bacterivorous nematode Caenorhabditis elegans than in its absence. As few as 10 nematodes g⁻¹ soil were sufficient to enhance spore formation by the vegetative mycelium. Given that the fungus was not limited by available carbon and nitrogen, this indicates that nematodes provide essential growth factors regulating the development of A. oligospora. Carbon mineralisation by A. oligospora, measured as the rate of CO₂ production, was found to be 25–35% lower in the presence of 20–60 C. elegans g⁻¹ soil compared to soil without nematodes. This showed that A. oligospora had lower saprotrophic activity in the predaceous phase. Trap formation and nematophagous activity of A. oligospora were observed only where conidia were inoculated on nutrient poor medium (water agar), on low-nitrogen medium (Yeast Carbon Base agar) or on medium containing no amino-acids or vitamins (Czapek-Dox agar). A. oligospora did not form trapping structures when grown on nutrient-rich media containing three amino-acids (l-histidine monohydrocloride, dl-methionine and dl-tryptophan) and vitamins (biotin, calcium pantothenate, folic acid, inositol, niacin, p-aminobenzoic acid, pyridoxine hydrochloride, riboflavine, thiamine hydrochloride). It is concluded that predaceous behaviour of A. oligospora can be regulated either by nitrogen sources or by physiologically active compounds (amino-acids or vitamins) present in nematodes.     

生物表面活性剂及Tween-80在一株菲降解菌降解过程中的作用研究

Numerous studies have been devoted to the physical-chemical weathering processes leading to the creation of unique soil formations having their own history that induce soil-biotic diversity. However, the extent to which unique geomorphic formations influence soil biotic seasonal variation is not clear. Our aim was to define seasonal variations of soil biota in soils of different-aged terraces of the Makhtesh Ramon anticline erosional cirque in southern Israel. The strong effect of Makhtesh Ramon (Ramon Crater) erosional fluvial terrace age initiated by climatic changes during the Late Pleistocene–Early Holocene period on seasonal variations in both soil properties and the abundance and composition of soil biota were demonstrated. However, age dependence was not constant and values for observed soil properties and microbial activity were negligible between younger and older terraces for certain seasons, while free-living nematodes along with bacteria-feeding group were strongly dependent on the geomorphic features of the ages throughout the study period.     

Vigna radiata var. GM4 Plant Growth Enhancement and Root Colonization by a Multi-Metal-Resistant Plant GrowthPromoting Bacterium Enterobacter sp. C1D in Cr(VI)-Amended Soils

Contamination of agricultural soils by heavy metals has become a major concern due to their toxic effects on plant growth, symbiosis and consequently the yields of crops. In the present study, to enhance plant growth in Cr(VI)-amended soils, novel metalresistant plant growth-promoting bacteria (PGPB) were isolated from a soil contaminated with industrial waste effluent. One of the bacterial isolates, identified as Enterobacter sp. C1D by 16S rRNA gene sequencing, was found to be multi-metal resistant in nature with excellent plant growth-promoting (PGP) traits. Mung bean (Vigna radiata var. GM4) inoculation with Enterobacter sp. C1D significantly (P < 0.01) increased root and shoot length, shoot and root weight, and chlorophyll content in a range of Cr(VI) treatments. Plant tolerance towards Cr(VI) measured as effective concentration showed higher values with Enterobacter sp. C1Dtreated plants compared to un-inoculated plants. Root colonization study was also carried out using green fluorescence protein-labeled Enterobacter sp. C1D under a hydroponic system. Confocal laser scanning microscopy of the plant roots showed heavy bacterial loads on the surface of the plant root specifically at the root tip and the point of root hair/lateral root formation. The results of PGP traits showed that elevated indole acetic acid levels and 1-aminocyclopropane-1-carboxylate deaminase activity enabled Enterobacter sp. C1D to enhance V. radiata growth in Cr(VI)-amended soils, whereby it significantly increased plant tolerance towards elevated Cr(VI) concentrations.     

Interaction of Bradyrhizobium sp. with an antagonistic actinomycete in culture medium and in soil

Summary Experiments were conducted to determine the extent to which populations of Bradyrhizobium sp. strain Tal 209SR were suppressed by the antagonistic activity of a Streptomyces sp. isolated from a highly weathered tropical soil. The activity of the actinomycete was evaluated in culture medium in the presence or absence of clay minerals and in the soil from which the actinomycete was isolated after sterilization by gamma-irradiation. The presence of the actinomycete in culture medium was associated with a significant reduction in the density of Bradyrhizobium sp. (Tal 209SR). Nevertheless, the density of the Bradyrhizobium sp. surviving in the medium in the presence of the actinomycete was much higher than that normally observed when comparable densities of rhizobia are introduced into non-sterile soils. The presence of the antagonistic actinomycete in culture medium was associated with a drastic decrease in the optical density of the medium. This decrease was accompanied by a significant decrease in the insoluble exopolysaccharide content of the medium in addition to the significant decrease in bradyrhizobial cells. The actinomycete did not appear to significantly influence the growth and survival of the test Bradyrhizobium sp. in sterile soil. The inability of the actinomycete to significantly antagonize the test bacterium in sterile soil was not adequately explained by the presence of clay minerals.Hawaii Institute of Tropical Agriculture and Human Resources Journal Series No. 3129     

桂林市尧山桉树及马尾松林春、夏两季土壤碳通量特征

[目的]以广西壮族自治区桂林市尧山地区的4年生桉树林、20年生桉树林和22年生马尾松林为研究对象,旨在研究由森林类型、林龄及其它因子驱动的森林土壤呼吸动态变化特征,并为桉树、马尾松人工林生态系统碳动态模拟提供基础数据。[方法]采用Li-8100土壤碳通量测量系统于2013年3—8月(春、夏两季),分别对这3种林分的土壤呼吸及其组分、土壤温度、土壤湿度进行了6个月的观测。[结果](1)3种林分的土壤总呼吸速率无显著差异。(2)4年生桉树林的自养呼吸速率显著大于20年生桉树林及22年生马尾松林。20年生桉树林的异养呼吸速率显著大于4年生桉树林及22年生马尾松林。(3)土壤温度是影响土壤呼吸及其组分的主要环境因子,3种林分土壤呼吸及其组分与土壤温度均呈显著的指数关系;(4)4年生桉树林的土壤呼吸与土壤含水量的相关性不显著,20年生桉树林的土壤呼吸与土壤含水量呈显著正相关关系,22年生马尾松林的土壤呼吸与土壤含水量呈显著负相关关系。(5)对温度敏感性系数Q10值的分析表明,4年生桉树林的温度敏感性较大,20年生桉树林和22年生马尾松林较小。