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1.
Leaf litter respiration (R LL) was directly measured in situ to evaluate relationships with the water content in leaf litter (WC), which is distributed heterogeneously under natural conditions. To do so, we developed a small, closed static chamber system using an infrared gas analyzer, which can measure instantaneous R LL. This study focuses on the measurement of CO2 effluxes from leaf litter using the chamber system in the field and examines the relationship between R LL and WC among seven broadleaf species in a temperate forest. The measurements focused on the position of leaves within the litter layer, finding that both R LL and WC were significantly higher in the lower layer. The value of R LL increased with increasing WC, and the response of R LL to WC was similar among all seven species. Moreover, the temporal variation in WC differed among three species and was associated with leaf litter thickness. The observed heterogeneity in WC induced by the physical environment (e.g., position and thickness of leaf litter) affects the variation in WC and, therefore, both R LL and the decomposition rates of organic matter in the litter layer.  相似文献   

2.
Soil respiration (RS) is a major carbon pathway from terrestrial ecosystems to the atmosphere and is sensitive to environmental changes. Although commonly used mechanical thinning and prescribed burning can significantly alter the soil environment, the effect of these practices on RS and on the interactions between RS and belowground characteristics in managed forests is not sufficiently understood. We: (1) examined the effects of burning and thinning treatments on soil conditions, (2) identified any changes in the effects of soil chemical and physical properties on RS under burning and thinning treatments, and (3) indirectly estimated the changes in the autotrophic soil respiration (RA) and heterotrophic soil respiration (RH) contribution to RS under burning and thinning treatments. We conducted our study in the Teakettle Experimental Forest where a full factorial design was implemented with three levels of thinning, none (N), understory thinning (U), and overstory thinning (O; September to October 2000 for thin burn combination and June and July 2001 for thin only treatments) and two levels of burning, none (U) and prescribed burning (B; fall of 2001). RS, soil temperature, soil moisture, litter depth, soil total nitrogen and carbon content, soil pH, root biomass, and root nitrogen (N) concentration were measured between June 15 and July 15, 2002 at each plot. During this period, soil respiration was measured three times at each point and averaged by point. When we assumed the uniform and even contribution of RA and RH to RS in the studied ecosystem without disturbances and a linear relationship of root N content and RA, we calculated the contributions of RA to RS as 22, 45, 53, 48, and 45% in UU, UO, BN, BU, and BO, respectively. The results suggested that after thinning, RS was controlled more by RH while after burning RS was more influenced by RA. The least amount of RS variation was explained by studied factors under the most severe treatment (BO treatment). Overall, root biomass, root N concentration, and root N content were significantly (p < 0.01) correlated with soil respiration with correlation coefficients of 0.37, −0.28, and 0.29, respectively. This study contributes to our understanding of how common forestry management practices might affect soil carbon sequestration, as soil respiration is a major component of ecosystem respiration.  相似文献   

3.
以广西凭祥中国林业科学研究院热带林业实验中心第二代桉树人工纯林(PP2)及其与降香黄檀混交的混交林(MP2)为研究对象,采用壕沟法,利用LI-8100土壤呼吸测定系统,对两种林分土壤呼吸组分进行分离研究。结果表明:PP2和MP2土壤呼吸速率及其各呼吸组分季节变化与土壤5 cm处的温度季节变化相似,峰值出现在6—8月份,谷值出现在12月底至次年1月初,土壤呼吸速率与土壤含水量无关;PP2全年土壤总呼吸为1 147.41 g·m-2,比MP2(844.07 g·m-2)增加了26.44%,MP2的自养呼吸(RR)累积量(136.87 g·m-2)比PP2(506.72 g·m-2)降低72.99%,而其异养呼吸(RH)累积量(707.21 g·m-2)却比PP2(640.69 g·m-2)增加了10.38%。纯林和混交林的细根生物量差异以及土壤有机质含量、凋落物有机质含量、土壤C/N、凋落物量和凋落物C/N的不同是导致自养呼吸和异养呼吸产生差异的主要原因。  相似文献   

4.
Trees on sand dunes are more sensitive to environmental changes because sandy soils have extremely low water holding capacity and nutrient availability. We investigated the dynamics of soil respiration(Rs) for secondary natural Litsea forest and plantations of casuarina,pine, acacia and eucalyptus. Results show that significant diurnal variations of Rsoccurred in autumn for the eucalyptus species and in summer for the pine species, with higher mean soil respiration at night. However, significant seasonal variations of Rswere found in all five forest stands. Rschanged exponentially with soil temperatures at the 10-cm depth; the models explain 43.3–77.0% of Rs variations. Positive relationships between seasonal Rsand soil moisture varied with stands. The correlations were significant only in the secondary forest, and the eucalyptus and pine plantations. The temperature sensitivity parameter(Q10 value) of Rsranged from 1.64 in casuarina plantation to 2.32 the in secondary forest; annual Rswas highest in the secondary forest and lowest in the pine plantation. The results indicate that soil temperatures and moisture are the primary environmental controls of soil respiration and mainly act through a direct influence on roots and microbial activity. Differences in root biomass, quality of litter,and soil properties(pH, total N, available P, and exchangeable Mg) were also significant factors.  相似文献   

5.
Because soil CO2 efflux or soil respiration (RS) is the major component of forest carbon fluxes, the effects of forest management on RS and microbial biomass carbon (C), microbial respiration (RH), microbial activity and fine root biomass were studied over two years in a loblolly pine (Pinus taeda L.) plantation located near Aiken, SC. Stands were six-years-old at the beginning of the study and were subjected to irrigation (no irrigation versus irrigation) and fertilization (no fertilization versus fertilization) treatments since planting. Soil respiration ranged from 2 to 6 μmol m−2 s−1 and was strongly and linearly related to soil temperature. Soil moisture and C inputs to the soil (coarse woody debris and litter mass) which may influence RH were significantly but only weakly related to RS. No interaction effects between irrigation and fertilization were observed for RS and microbial variables. Irrigation increased RS, fine root mass and microbial biomass C. In contrast, fertilization increased RH, microbial biomass C and microbial activity but reduced fine root biomass and had no influence on RS. Predicted annual soil C efflux ranged from 8.8 to 10.7 Mg C ha−1 year−1 and was lower than net primary productivity (NPP) in all stands except the non-fertilized treatment. The influence of forest management on RS was small or insignificant relative to biomass accumulation suggesting that NPP controls the transition between a carbon source and sink in rapidly growing pine systems.  相似文献   

6.
Heterotrophic respiration strongly influences carbon cycles at the ecosystem and global scales. We used an automated chamber system to measure the heterotrophic respiration of coarse woody debris (CWD) and leaf litter in a secondary broadleaved forest in southern Kyoto Prefecture. This system, which targeted only organic matter, could detect heterotrophic respiration responses to changes in environmental factors, especially rainfall events. The temporal trends and responses of respiration to environmental factors differed dramatically between CWD and leaf litter. CWD respiration showed a clear diurnal change corresponding to changes in CWD temperature and a clear decrease during rainfall events. Leaf litter respiration did not change clearly but increased at the beginning of rain events and returned to pre-rain rates when soil water content declined. The temporal patterns of the residuals between the observed respiration and baseline respiration, developed from the temperature?Cresponse curves under pre-rain conditions, differed between CWD and leaf litter respiration. The typical trend in CWD respiration response to rainfall events was a clear decrease and then gradual increase in the residuals after the event. The response of leaf litter respiration to wetting was an increase in the residuals during rainfall events and then a gradual decrease during drying. The difference in the responses of these respirations to wetting and drying processes are likely caused by differences in the physical characteristics of the CWD and the leaf litter layer. Measurements targeting only organic matter using an automated chamber system could detect the responses of heterotrophic respiration to environmental factors.  相似文献   

7.
[目的]分离并量化土壤自养呼吸和异养呼吸,探讨各自贡献率及其随季节变化的动态特征。[方法]采用壕沟法和气体红外分析法,研究黄河小浪底库区山地栓皮栎人工林土壤总呼吸、自养呼吸和异养呼吸速率的季节动态变化、贡献率和环境影响因子。[结果]表明:栓皮栎人工林总土壤呼吸、自养呼吸和异养呼吸均呈夏季速率高、冬季速率低。栓皮栎土壤总呼吸、自养呼吸及异养呼吸速率与5 cm土壤温度均呈极显著指数相关,温度敏感性系数Q_(10)值大小为自养呼吸(3.40)异养呼吸(2.90)土壤总呼吸(2.45);栓皮栎土壤总呼吸、自养呼吸、异养呼吸速率与0 10 cm土壤体积含水量均显著线性相关;土壤总呼吸、自养呼吸速率与0 10 cm土壤电导率显著相关。土壤总呼吸和异养呼吸的温度敏感系数Q_(10)值均在冬季最大,夏秋季最小;而自养呼吸的Q_(10)值则呈相反的变化趋势。栓皮栎人工林自养呼吸和异养呼吸对土壤总呼吸的月贡献率为13.23%37.33%和62.67%86.76%,且自养呼吸的贡献率与土壤温度的季节变化规律相似。土壤总呼吸、异养呼吸与自养呼吸的CO2年通量分别为1 616.41、1 199.39、417.02 g·m~(-2)·a~(-1)。[结论]经过区分与定量化土壤总呼吸及其组分,确定异养呼吸为本研究区栓皮栎人工林土壤总呼吸的主要组分,作用于异养呼吸的生物与非生物因子均能显著影响整个森林生态系统表层CO_2总排放通量的大小,进一步为该研究区森林生态系统碳循环与能量流动的进一步量化研究提供参考。  相似文献   

8.
In this study, the stand level root respiration was estimated for two monoculture plantations: Acacia crassicarpa and Eucalyptus urophylla, based on in situ measurement of specific root respiration using simplified root chamber method. The respiration rates of fine roots (<5 mm) were significantly higher than those of coarse roots (>5 mm) for both A. crassicarpa and E. urophylla species. The root respiration of A. crassicarpa showed a clear seasonal pattern with a higher value in the wet season. For E. urophylla, the seasonal pattern was observed for fine roots but not for coarse roots. After determining the biomass of fine roots and coarse roots and their specific rates of respiration at different time points, root respiration at the stand level (Ra) was estimated using a direct up-scaling model. We found that the Ra accounted for 14% and 19% of total soil respiration (Rs) for A. crassicarpa and E. urophylla, respectively. The fine (RTf) and coarse (RTc) root respiration at the stand level accounted for about 47% and 53% of the Ra for A. crassicarpa, and accounted for 58% and 42% for E. urophylla. This suggests that coarse root respiration cannot be ignored when estimating the root respiration at the stand level. Our results showed that the Q10 values were more accurate in representing the temperature dependence when the confounding effect of soil moisture was considered. This study introduces an alternative approach to estimate stand level root respiration, but its reliability is largely dependent on the accuracy of root biomass quantification.  相似文献   

9.
Partitioning the respiratory components of soil surface CO2 efflux is important in understanding carbon turnover and in identifying the soil carbon sink/source function in response to land-use change. The sensitivities of soil respiration components on changing climate patterns are currently not fully understood. We used trench and isotopic methods to separate total soil respiration into autotrophic (R A ) and heterotrophic components (R H ). This study was undertaken on a Robinia pseudoacacia L. plantation in the southern Taihang Mountains, China. The fractionation of soil 13CO2 was analyzed by comparing the δ13C of soil CO2 extracted from buried steel tubes with results from Gas Vapor Probe Kits at a depth of 50 cm at the preliminary test (2.03‰). The results showed that the contribution of autotrophic respiration (fR A ) increased with increasing soil depth. The contribution of heterotrophic respiration (fR H ) declined with increasing soil depth. The contribution of autotrophic respiration was similar whether estimated by the trench method (fR A , 23.50%) or by the isotopic method in which a difference in value of 13C between soil and plant prevailed in the natural state (RC, 21.03%). The experimental error produced by the trench method was insignificant as compared with that produced by the isotopic method, providing a technical basis for further investigations.  相似文献   

10.
Forests accumulate much less carbon than the amount fixed through photosynthesis because of an almost equally large opposing flux of CO2 from the ecosystem. Most of the return flux to the atmosphere is through soil respiration, which has two major sources, one heterotrophic (organisms decomposing organic matter) and one autotrophic (roots, mycorrhizal fungi and other root-associated microbes dependent on recent photosynthate). We used tree-girdling to stop the flow of photosynthate to the belowground system, hence, blocking autotrophic soil activity in a 120-yr-old boreal Picea abies forest. We found that at the end of the summer, two months after girdling, the treatment had reduced soil respiration by up to 53%. This figure adds to a growing body of evidence indicating (t-test, d.f. = 7, p < 0.05) that autotrophic respiration may contribute more to total soil respiration in boreal (mean 53 ± 2%) as compared to temperate forests (mean 44 ± 3%). Our data also suggests that there is a seasonal hysteresis in the response of total soil respiration to changes in temperature. We propose that this reflects seasonality in the tree below-ground carbon allocation.  相似文献   

11.
We monitored variation in seasonal and annual net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (R E) based on 7-year eddy covariance measurements above a cool?Ctemperate deciduous broad-leaved forest (Japanese beech forest). The 7-year means (±SD) of annual NEP, GPP, and R E were 312?±?64, 1250?±?62, and 938?±?36?g?C?m?2?year?1, respectively. Variation in NEP was much larger than variation in GPP and R E. During the growing season, the main factor controlling carbon balance was air temperature; variation in seasonal integrated NEP was regulated by accumulated air temperature (degree-day) with a significant negative correlation, whereas the seasonal ratio of R E to GPP was correlated positively with accumulated air temperature. Because the deviation of seasonal NEP was also significantly correlated with seasonal R E/GPP, NEP was controlled by R E/GPP, depending on air temperature during the growing season. Seasonal R E in the defoliation and snow seasons was also important for evaluating the annual carbon balance, because the total number of days in the two seasons was quite large owing to a long snowy winter. In the defoliation and snow seasons, we found defoliation season length was a major factor determining seasonal integrated R E, illustrating the positive correlation between R E and defoliation season length. The major factors controlling interannual variations in forest carbon balance are discussed.  相似文献   

12.

The leaves and leaf litter of Cryptomeria japonica D. Don was collected from April 1994 to March 1995 to describe the seasonal changes in nutrient concentrations in leaves and leaf litter. Nitrogen (N), phosphorus (P) and potassium (K) concentrations were in the order new leaves > old leaves > leaf litter, whereas calcium (Ca) concentration was in the order leaf litter > old leaves > new leaves during the whole year. N, P and K concentrations were at their highest during the new leaf growth phase, and then decreased as a result of the diluting effect and translocation, whereas Ca increased with time. Magnesium did not show any clear seasonal trend compared with other nutrients. N resorption efficiency was lower than P resorption efficiency. There were two nutrient resorption peaks, which could be attributed to high nutrient translocation to new leaves in the spring and to translocation from old leaves before senescence in the autumn. A significant correlation between N and P resorption was observed.  相似文献   

13.
To estimate net ecosystem production (NEP), ecosystem respiration (R E), and gross primary production (GPP), and to elucidate the interannual variability of NEP in a cool temperate broadleaf deciduous forest in Sapporo, northern Japan, we measured net ecosystem exchange (NEE) using an eddy covariance technique with a closed-path infrared gas analyzer from 2000 to 2003. NEP, R E, and GPP were derived from NEE, and data gaps were filled using empirical regression models with meteorological variables such as photosynthetic active radiation and soil temperature. In general, NEP was positive (CO2 uptake) from May to September, either positive or negative in October, and negative (CO2 release) from November to the following April. NEP rapidly increased during leaf expansion in May and reached its maximum in June or July. The four-year averages (±?standard deviation) of annual NEP, GPP, and R E were 443?±?45, 1,374?±?39, and 931?±?11?g?C?m?2?year?1, respectively. The lower annual NEP and GPP in 2000 may have been caused by lower solar radiation in the foliated season. During the foliated season, monthly GPP varied from year to year more than monthly R E. Variations in the amount of incoming solar radiation may have caused the interannual variations in the monthly GPP. Additionally, in May, the timing of leaf expansion had a large impact on GPP. Variations in GPP affected the interannual variation in NEP at our site. Thus, interannual variation in NEP was affected by the incoming solar radiation and the timing of leaf expansion.  相似文献   

14.
We measured the rates of respiration from snags and logs (“coarse woody debris”, CWD) of Japanese red pine (Pinus densiflora Sieb. et Zucc.) to examine the rate of decomposition and CO2 efflux from these materials in a temperate secondary broad-leaved forest in Japan. At this site, a high quantity of CWD of P. densiflora had accumulated as a result of pine wilt disease during the 1970s. Respiration rates were measured using a dynamic closed chamber method combined with an infrared gas analyzer. We measured the respiration rate of 7 samples of snags and 10 samples of logs from August 2003 to January 2004. The responses of the respiration rates of snags (Rsnag) and logs (Rlog) to changing temperature were both exponential and the responses to water content were quadratic, and the same function could be used to estimate annual values of both Rsnag and Rlog. Intensive measurements of water contents of snags and logs showed a marked difference in water content. The mean water content of snags was 20% of log water content. This difference was likely responsible for the observed difference in annual Rsnag and Rlog. The decay rate constants estimated from the respiration rates measurement of snags and logs were 0.019 and 0.081 year−1, respectively. Despite being lower than Rlog, Rsnag was a significant compartment of the CWD carbon budget at this site.  相似文献   

15.
The accurate assessment of respiration by woody vegetation, still a challenge in plant productivity models, is generally a problem of correctly scaling-up the process from organs to the whole plant. We used a large (41.6 m3), canopy chamber to enclose mature olive trees and to measure aboveground respiration (R ag ) under natural environmental conditions in an irrigated olive orchard in Córdoba (Spain). The 3-year study assessed nocturnal and seasonal R ag patterns in terms of temperature (T), plant dry matter composition, and phenology. The relative contributions of maintenance and growth respiration to R ag were determined empirically via an independent experiment. Although short-term variations in R ag rates were explained mainly by T variations, over seasonal time-scales this relationship was modulated by the vegetative composition of the olive trees and the contribution of growth respiration to R ag when the plants, in different seasons, allocated most of the new assimilates to actively growing shoots, flowers or fruits. Leaf mass and fruit load were the main determinants of R ag , which was weakly affected by differences in woody biomass since woody tissue respiration accounted for just 15 % of R ag . Respiration in olive trees during fruit setting periods is composed of approximately 30 % growth and 70 % maintenance. This study provides an independent evaluation of how, and to what degree, seasonally varying plant organ composition determines total respiration. Improved modelling of ecosystem respiration can be achieved by accounting for plant biological patterns characterising energy-requiring growth and maintenance processes, since biochemical kinetics alone cannot explain the observed seasonal variability.  相似文献   

16.
刘颖  韩士杰  林鹿 《林业研究》2009,20(4):367-371
2004年5月至9月,研究了长白山白桦林土壤呼吸以及根系呼吸对土壤呼吸的贡献随土壤温度和土壤湿度的季节变化,研究结果表明：土壤总呼吸、断根土壤呼吸和根系呼吸在生长季内有相似的季节变化趋势,夏季潮湿而且温度较高,呼吸速率也较高,春季和秋季温度较低,呼吸速率也较低。2004年5月至9月,土壤总呼吸、断根土壤呼吸和根系呼吸的平均值分别为4.44,2.30和2.14μmol&#183;m^-2s^-1,三者与土壤温度均呈指数相关,与土壤湿度呈线性相关,三者的Q10值分别为2.82,2.59和3.16,这与其他学者的结果相似。根系呼吸是土壤呼吸的一个重要组成部分,2004年5月至9月,根系呼吸对土壤总呼吸的贡献在29.3～58.7%之间。根据Q10模型估算的土壤总呼吸、断根土壤呼吸和根系呼吸的全年平均值分别为1.96、1.08和0.87μmol&#183;m^-2s^-1,即741.73、408.71和329.24gC&#183;m^-2&#183;a^-1,全年根系对土壤总呼吸的贡献为44.4%。土壤呼吸和土壤温度之间的关系模型是了解和预测长白山白桦林生态系统潜在的随森林管理和气候变化而变化的有用工具。  相似文献   

17.
The effect of temperature upon nighttime respiration was examined on four different sized sample trees in a 17-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand over two years. Seasonal changes inQ 10 values and their responses to mean temperature were investigated. On the basis of the monthly relationships between nighttime respiration (r) and temperature inside a chamber (θ),r=r 0exp (kθ), theQ 10 value (=exp(10k)) was calculated. TheQ 10 values were high (Q 10≥3.0) in winter when mean air temperature was low, and gradually decreased toward summer (Q 10≤1.5) through spring with increasing temperature. TheQ 10 values were negatively correlated with mean air temperature. The response ofQ 10 values to mean air temperature was described by a single equation, regardless of tree size. This result, which might be characteristic of this species, shows that respiration ofC. obtusa trees is promoted by slight increases of air temperature in winter season. On the other hand, temperature sensitivity of total respiration reduced during growing season when ambient temperature was high. These chaning temperature sensitivity according to seasons may depend on the seasonal change of the ratio of growth respiration to total respiration. It is concluded that changes in temperature due to changing seasons not only change respiration rate, but also change the response of respiration rate to temperature by shiftingQ 10 values.  相似文献   

18.
We measured the seasonal and temperature responses of leaf photosynthesis and respiration of two co-occurring native New Zealand tree species with contrasting leaf phenology: winter-deciduous fuchsia (Fuchsia excorticata J. R. Forst & G. Forst) and annual evergreen wineberry (Aristotelia serrata J. R. Forst & G. Forst). There was no difference in the amount of nitrogen per unit leaf area (Narea, range 40-160 mmol m-2, P = 0.18) or specific leaf area (S, range 8-27 m2 kg-1, P = 0.87) in summer leaves of wineberry or fuchsia. The amount of nitrogen per unit leaf area and S varied significantly with height of leaves in the canopy for both species (r2 range 0.61-0.87). Parameters describing the maximum rates of rubisco carboxylation (Vcmax) and electron transport (Jmax) were related significantly to Narea, and were 60% higher on average in spring and summer leaves than in autumn and winter leaves for both species. The seasonal effect remained significant (P < 0.001) when Narea was included in a regression model, indicating that seasonal changes were not only due to changes in Narea. Values for Vcmax and Jmax were 30% lower in wineberry leaves than in fuchsia leaves on average, although the difference ranged from 15% in summer leaves to 39% in autumn leaves. Activation energies describing the temperature dependence of Vcmax and Jmax in wineberry were 111 and 114% of corresponding values for fuchsia (Ea (Vcmax) = 39.1 kJ mol-1, Ea (Jmax) = 32.9 kJ mol-1). Respiration at night was the same (P = 0.34) at 10 degrees C for both species (R10 = 0.7 micromol m-2 s-1), although activation energies (E0) were higher in wineberry than in fuchsia (47.4 and 32.9 kJ mol-1 K-1, respectively). These results show that rates of photosynthesis are higher in winter-deciduous fuchsia than in annual evergreen wineberry.  相似文献   

19.
Litter fall from upper storey trees in agroforestry systems contributes to nutrient cycling for the benefit of all components of the system besides serving as mulch. This study examined the seasonal changes in the quantity and quality of leaf litter fall from three sub-tropical fruit trees viz: avocado (Persea americana L.), mango (Mangifera indica L.) and litchi (Litchi chinensis L.) which have potential for use in agroforestry. Leaf litter production was estimated using nylon mesh litter traps erected over five randomly selected trees of each species in a completely randomised design. Litter quality was determined by analysing ash content and polyphenol, carbon, cellulose, lignin and nutrient concentrations over a 2?year period (2007?C2008). Total annual leaf litter production during the study period (dry matter basis) was 8.3, 6.3 and 5.6?t?ha?1?year?1 for litchi, mango and avocado, respectively. In both years, leaf litter fall was greatest during autumn and lowest during winter in all species. There were no significant differences in S, Ca, Mg and Mn concentrations in the leaf litter, but polyphenol, N, P and K concentrations differed significantly (P?<?0.05) between species. It was concluded that litter quality from all three tree species was low and would require appropriate management to improve its quality.  相似文献   

20.
The stem bark of Euonymus japonicus Thunb. led to the isolation of three new glycosylsphingolipids (1–3), 1-O-[-L-rhamnopyranosyl-(1 → 2)-β-D-glucopyranosyl]-(2S,3R,9E)-2-N-[(2R)-hydroxystearoyl]-octadecasphinga-9-ene (euojaposphingoside A, 1), 1-O-[β-D-glucopyranosyl-(1 → 2)-β-D-glucopyranosyl]-(2S,3R,4R,11E)-2-N-[(2R)-hydroxydocasanoyl]-octadecasphinga-11-ene (euojaposphingoside B, 2), 1-O-[β-D-glucopyranosyl]-2′-O-[β-D-glucopyranosyl]-(2S,3R,4R,11E)-2-N-[(2R)-hydroxytetracosanoyl]-octadecasphinga-11-ene (euojaposphingoside C, 3) along with three known glycosylsphingolipids (4–6), 1-O-[β-D-glucopyranosyl]-(2S,3R,9E)-3-hydroxymethyl-2-N-[(2R)-hydroxynonacosanoyl)-tridecasphinga-9-ene (4), 1-O-[β-D-glucopyranosyl]-(2S,3R,9E,12E)-2-N-[(2R)-hydroxytetracosanoyl] octadecasphinga-9,12–diene (5), 1-O-[β-D-glucopyranosyl]-(2S,3R,5R,9E)-2-N-[tridecanoyl] nonacosasphinga-9-ene (6), lupeol (7), stigmasterol (8), sitosterol (β and α) (9,10) and β-carotene (11). The structure of all the compounds was achieved by spectroscopic and chemical data analysis. The antiplasmodial, antileismanial and cytotoxic activity of all compounds was tested.  相似文献   

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