Physiological adjustment of two full-sib families of ponderosa pine to elevated CO(2)

Seeds from two full-sib families of ponderosa pine (Pinus ponderosa) with known differences in growth rates were germinated and grown in an ambient (350 micro l l(-1)) or elevated (700 micro l l(-1)) CO(2) concentration. Gas exchange at both ambient and elevated CO(2) concentrations was measured 1, 6, 39, and 112 days after the seed coat was shed. Initial stimulation of CO(2) exchange rate (CER) by elevated CO(2) was large (> 100%). On Day 1, CER of seedlings grown in elevated CO(2) and measured at ambient CO(2) was significantly lower than the CER of seedlings grown and measured at ambient CO(2), indicating physiological adjustment of the seedlings exposed to elevated CO(2). Physiological acclimation to elevated CO(2) was complete by Day 39 when there was no significant difference in CER between seedlings grown and measured at ambient CO(2) and seedlings grown and measured at elevated CO(2). After 4 months, the light response of seedlings in the two treatments was determined at both ambient and elevated CO(2). Light compensation point, CER at light saturation, and apparent quantum efficiency of seedlings grown and measured at ambient CO(2) were not significantly different from those of seedlings grown and measured at elevated CO(2). With a short-term increase in CO(2), CER at light saturation (5.16 +/- 0.52 versus 3.13 +/- 0.30 micro mol CO(2) m(-2) s(-1)) and apparent quantum efficiency (0.082 +/- 0.011 versus 0.045 +/- 0.003 micro mol CO(2) micro mol(-1) quanta) were significantly increased. Leaf C/N ratio was significantly increased in the elevated CO(2) treatment. There were few significant differences between families for any response to elevated CO(2). Under the experimental conditions, high growth rate was not correlated with a greater response to elevated CO(2).     

Gas exchange and dry matter allocation responses to elevation of atmospheric CO(2) concentration in seedlings of three tree species

Photosynthetic rates of 13-month-old Pinus radiata D. Don, Nothofagus fusca (Hook f.) ?rst. and Pseudotsuga menziesii (Mirb.) Franco seedlings grown and measured at elevated atmospheric concentrations of CO(2) (~620 microl l(-1)) were 32 to 55% greater than those of seedlings grown and measured at ambient (~310 microl l(-1)) concentrations of CO(2). Seedlings grown in ambient and elevated concentrations of CO(2) had similar rates of photosynthesis when measured at ~620 microl l(-1) CO(2), but when measured at ~310 microl l(-1) CO(2), the P. radiata and N. fusca seedlings which were grown at elevated CO(2) had lower rates of photosynthesis than the seedlings grown at an ambient concentration of CO(2). Stomatal conductances in general were lower when measured at ~620 microl l(-1) CO(2) than at ~310 microl l(-1) CO(2). Stomatal conductances declined in all species grown at both CO(2) concentrations when the leaf-air water vapor concentration gradient (DeltaW) was increased from 10 to 20 mmol H(2)O mol(-1) air. The percent enhancement in photosynthesis for P. radiata and P. menziesii at elevated CO(2) was greater at 20 mmol than at 10 mmol DeltaW, suggesting that elevated CO(2) may moderate the effects of atmospheric water stress. Dry matter allocation patterns were not significantly different for plants grown in ambient or high CO(2) air.     

Responses of foliar gas exchange to long-term elevated CO(2) concentrations in mature loblolly pine trees

Branches of field-grown mature loblolly pine (Pinus taeda L.) trees were exposed for 2 years (1992 and 1993) to ambient or elevated CO(2) concentrations (ambient + 165 micro mol mol(-1) or ambient + 330 micro mol mol(-1) CO(2)). Exposure to elevated CO(2) concentrations enhanced rates of net photosynthesis (P(n)) by 53-111% compared to P(n) of foliage exposed to ambient CO(2). At the same CO(2) measurement concentration, the ratio of intercellular to atmospheric CO(2) concentration (C(i)/C(a)) and stomatal conductance to water vapor did not differ among foliage grown in an ambient or enriched CO(2) concentration. Analysis of the relationship between P(n) and C(i) indicated no significant change in carboxylation efficiency of ribulose-1,5-bisphosphate carboxylase/oxygenase during growth in elevated CO(2) concentrations. Based on estimates derived from P(n)/C(i) curves, there were no apparent treatment differences in dark respiration, CO(2) compensation point or P(n) at the mean C(i). In 1992, foliage in the three CO(2) treatments yielded similar estimates of CO(2)-saturated P(n) (P(max)), whereas in 1993, estimates of P(max) were higher for branches grown in elevated CO(2) than in ambient CO(2). We conclude that field-grown loblolly pine trees do not exhibit downward acclimation of leaf-level photosynthesis in their long-term response to elevated CO(2) concentrations.     

不同含量引诱剂对落叶松八齿小蠹及其天敌红胸郭公虫的引诱(英文)

在内蒙古阿尔山的田间诱捕试验中,落叶松八齿小蠹引诱剂1共诱集到16头落叶松八齿小蠹和1319头天敌红胸郭公虫,而落叶松八齿小蠹引诱剂2诱集到24104头落叶松八齿小蠹和776头红胸郭公虫。室内的触角电位试验结果表明:落叶松八齿小蠹对引诱剂2的触角反应(雌虫2.139mV±0.678mV,雄虫2.169mV±0.473mV)大于引诱剂1(雌虫0.440mV±0.232mV,雄虫0.297mV±0.142mV),对引诱剂1的反应值和对照差不多;而红胸郭公虫对引诱剂1的触角反应(雌虫4.618mV±1.106mV,雄虫4.534mV±1.087mV)明显大于引诱剂2(雌虫2.209mV±0.680mV,雄虫1.953mV±0.601mV),对引诱剂2也有一定的反应值。触角电位试验与田间诱捕试验结果相符合。GC-MS分析结果表明:引诱剂1的主要成分为3.06%的cis-geraniol,1.98%的Ipsenol,80.36%的(S)-cis-verbenol和1.03%的1-verbenone;结合卖方公司提供的数据,引诱剂1的主要成分为4.78%的2-methyl-3-buten-2-ol,63.71%的Ipsenol(纯度为96.9%),1.46%的Cedrene和22.42%的Isocaryophillene。结合以上数据分析得出:不同成分引诱剂对落叶松八齿小蠹及天敌红胸郭公虫引诱能力显著不同,Ipsenol对诱集落叶松八齿小蠹起重要作用,而(S)-cis-verbenol则对诱集天敌红胸郭公虫起重要作用。     

Flavonoids with DNA strand-scission activity from Rhus javanica var. roxburghiana

The flavonoids isolated from the stems of Rhus javanica var. roxburghiana, taxifolin (1), fisetin (2), fustin (3), 3,7,4'-trihydroxyflavanone (4) and 3,7,4'-trihydroxyflavone (5) caused breakage of supercoiled plasmid pBR322 DNA in the presence of Cu(II). Cu(I) was shown to be an essential intermediate by using the Cu(I)-specific sequestering reagent neocuproine. The Cu(II)-mediated DNA scissions induced by 1, 2, 3 and 5 were inhibited by the addition of catalase and exhibited DNA strand break by the addition of KI and superoxide dimutase (SOD), while in the Cu(II)-mediated DNA scissions induced by 4 was inhibited by the addition of KI, SOD, and catalase. It is concluded that 1, 2, 3, and 5 can induce H(2)O(2) and superoxide anion, while 4 can induce OH() and H(2)O(2) and subsequent oxidative damage of DNA in the presence of Cu(II).     

Celastrus paniculatus seed water soluble extracts protect cultured rat forebrain neuronal cells from hydrogen peroxide-induced oxidative injury

The effects of aqueous extracts of Celastrus paniculatus (CP) seeds were shown to have antioxidant properties in rats. In the study reported here, we have investigated the free radical scavenging capacity of three aqueous extracts (WSEs) obtained from CP seeds: a room temperature extract (WF); a hot water extract (HF); an acid extract (AF). All the WSEs exhibited a dose-dependent free radical scavenging capacity for 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH) and also for superoxide-generated assays (in vitro assays). In addition, we used enriched forebrain primary neuronal cell (FBNC) cultures to evaluate the neuroprotective effects of the three CP-WSE extracts on H(2)O(2)-induced toxicity. FBNC were pre-treated with the CP-WSE and then with H(2)O(2) to evaluate the protection afforded against H(2)O(2)-induced toxicity. The criteria for neuroprotection by the WSEs were based on a mitochondrial function test following the H(2)O(2)-induced neurotoxicity. All the WSEs significantly attenuated H(2)O(2)-induced neuronal death, and AF was the most effective in protecting the neuronal cells against oxidative injury caused by H(2)O(2). In 10 day FBNC, cellular superoxide dismutase activity was not affected by the WSEs or H(2)O(2), but catalase activity was decreased and levels of malondialdehyde were increased by H(2)O(2) treatment. When the neuronal cells were treated with WSEs prior to H(2)O(2) exposure, catalase activity was increased and levels of malondialdehyde were decreased significantly. The data presented here suggest that CP seed WSEs protected neuronal cells in part by their free radical scavenging properties, by reducing lipid peroxidation, and also by their ability to induce the antioxidant enzyme catalase. Our results indicate that WSEs might exert neuroprotective effects against increased oxidative stress resulting from free radical damage that is associated with a number of neurodegenerative diseases.     

Leaf conductance and CO(2) assimilation of Larix gmelinii growing in an eastern Siberian boreal forest

In July 1993, we measured leaf conductance, carbon dioxide (CO(2)) assimilation, and transpiration in a Larix gmelinii (Rupr.) Rupr. ex Kuzen forest in eastern Siberia. At the CO(2) concentration of ambient air, maximum values (mean of 10 highest measured values) for CO(2) assimilation, transpiration and leaf conductance for water vapor were 10.1 micro mol m(-2) s(-1), 3.9 mmol m(-2) s(-1) and 365 mmol m(-2) s(-1), respectively. The corresponding mean values, which were much lower than the maximum values, were 2.7 micro mol m(-2) s(-1), 1.0 mmol m(-2) s(-1) and 56 mmol m(-2) s(-1). The mean values were similar to those of Vaccinium species in the herb layer. The large differences between maximum and actual performance were the result of structural and physiological variations within the tree crowns and between trees that reduced maximum assimilation and leaf conductance by about 40 and 60%, respectively. Thus, maximum assimilation and conductance values averaged over the canopy were 6.1 micro mol m(-2) s(-1) and 146 mmol m(-2) s(-1), respectively. Dry air caused stomatal closure, which reduced assimilation by an additional 26%. Low irradiances in the morning and evening had a minor effect (-6%). Daily canopy transpiration was estimated to be 1.45 mm day(-1), which is higher than the value of 0.94 mm day(-1) measured by eddy covariance, but similar to the value of 1.45 mm day(-1) calculated from the energy balance and soil evaporation, and less than the value of 2.1 mm day(-1) measured by xylem flux. Daytime canopy carbon assimilation, expressed on a ground area basis, was 0.217 mol m(-2) day(-1), which is higher than the value measured by eddy flux (0.162 mol m(-2) day(-1) including soil respiration). We discuss the regulation of leaf gas exchange in Larix under the extreme climatic conditions of eastern Siberia (temperature > 35 degrees C and vapor pressure deficit > 5.0 kPa).     

Seedlings of five boreal tree species differ in acclimation of net photosynthesis to elevated CO(2) and temperature

Biochemical models of photosynthesis suggest that rising temperatures will increase rates of net carbon dioxide assimilation and enhance plant responses to increasing atmospheric concentrations of CO(2). We tested this hypothesis by evaluating acclimation and ontogenetic drift in net photosynthesis in seedlings of five boreal tree species grown at 370 and 580 &mgr;mol mol(-1) CO(2) in combination with day/night temperatures of 18/12, 21/15, 24/18, 27/21, and 30/24 degrees C. Leaf-area-based rates of net photosynthesis increased between 13 and 36% among species in plants grown and measured in elevated CO(2) compared to ambient CO(2). These CO(2)-induced increases in net photosynthesis were greater for slower-growing Picea mariana (Mill.) B.S.P., Pinus banksiana Lamb., and Larix laricina (Du Roi) K. Koch than for faster-growing Populus tremuloides Michx. and Betula papyrifera Marsh., paralleling longer-term growth differences between CO(2) treatments. Measures at common CO(2) concentrations revealed that net photosynthesis was down-regulated in plants grown at elevated CO(2). In situ leaf gas exchange rates varied minimally across temperature treatments and, contrary to predictions, increasing growth temperatures did not enhance the response of net photosynthesis to elevated CO(2) in four of the five species. Overall, the species exhibited declines in specific leaf area and leaf nitrogen concentration, and increases in total nonstructural carbohydrates in response to CO(2) enrichment. Consequently, the elevated CO(2) treatment enhanced rates of net photosynthesis much more when expressed on a leaf area basis (25%) than when expressed on a leaf mass basis (10%). In all species, rates of leaf net CO(2) exchange exhibited modest declines with increasing plant size through ontogeny. Among the conifers, enhancements of photosynthetic rates in elevated CO(2) were sustained through time across a wide range of plant sizes. In contrast, for Populus tremuloides and B. papyrifera, mass-based photosynthetic rates did not differ between CO(2) treatments. Overall, net photosynthetic rates were highly correlated with relative growth rate as it varied among species and treatment combinations through time. We conclude that interspecific variation may be a more important determinant of photosynthetic response to CO(2) than temperature.     

Echinosporins as new cell cycle inhibitors and apoptosis inducers from marine-derived Streptomyces albogriseolus

Bioassay-guided fractionation of the ethyl acetate extract from the fermentation broth of marine-derived Streptomyces albogriseolus A2002 led to the isolation of echinosporin (1) and 7-deoxyechinosporin (2). Compound 1 inhibited the proliferation of tsFT210, K562 and HCT-15 cancer cells (IC(50) 91.5 microM, 25.1 microM and 247 microM respectively) and 2 showed the same effect on K562 cells (IC(50) 143 microM). Flow cytometric analysis suggested that 1 and 2 exert their anti-proliferative effects on those cells through inhibiting cell cycle at the G(2)/M phase and inducing apoptosis.     

尾叶桉第1代与第2代群体间生长性状和木材材性的遗传控制对比研究

利用4个尾叶桉（Eucalyptus urophylla）自由授粉子代试验（其中D46、D54 2个试验为第1代子代试验,D135、SE35 2个试验为第2代子代试验）作为研究对象,对其生长性状和木材材性进行遗传参数估算.研究结果表明,生长性状和树皮性状受到较低的遗传控制,其狭义遗传力(h2):胸径(DBH) 0.0...     

Photosynthetic responses to needle water potentials in Scots pine after a four-year exposure to elevated CO(2) and temperature

Effects of needle water potential (Psi(l)) on gas exchange of Scots pine (Pinus sylvestris L.) grown for 4 years in open-top chambers with elevated temperature (ET), elevated CO(2) (EC) or a combination of elevated temperature and CO(2) (EC + ET) were examined at a high photon flux density (PPFD), saturated leaf to air water vapor pressure deficit (VPD) and optimal temperature (T). We used the Farquhar model of photosynthesis to estimate the separate effects of Psi(l) and the treatments on maximum carboxylation efficiency (V(c,max)), ribulose-1,5-bisphosphate regeneration capacity (J), rate of respiration in the light (R(d)), intercellular partial pressure of CO(2) (C(i)) and stomatal conductance (G(s)). Depression of CO(2) assimilation rate at low Psi(l) was the result of both stomatal and non-stomatal limitations on photosynthetic processes; however, stomatal limitations dominated during short-term water stress (Psi(l) < -1.2 MPa), whereas non-stomatal limitations dominated during severe water stress. Among the nonstomatal components, the decrease in J contributed more to the decline in photosynthesis than the decrease in V(c,max). Long-term elevation of CO(2) and temperature led to differences in the maximum values of the parameters, the threshold values of Psi(l) and the sensitivity of the parameters to decreasing Psi(l). The CO(2) treatment decreased the maximum values of V(c,max), J and R(d) but significantly increased the sensitivity of V(c,max), J and R(d) to decreasing Psi(l) (P < 0.05). The effects of the ET and EC + ET treatments on V(c,max), J and R(d) were opposite to the effects of the EC treatment on these parameters. The values of G(s), which were measured simultaneously with maximum net rate of assimilation (A(max)), declined in a curvilinear fashion as Psi(l) decreased. Both the EC + ET and ET treatments significantly decreased the sensitivity of G(s) to decreasing Psi(l). We conclude that, in the future, acclimation to increased atmospheric CO(2) and temperature could increase the tolerance of Scots pine to water stress.     

Why do genotypes of Picea glauca differ in their growth response to elevated CO₂?

Meta-analyses reveal that fast-growing species have a greater growth response to elevated CO(2) than slow-growing species. It is unknown whether this is a direct response or whether inter-specific differences in growth are simply correlated with other physiological or morphological differences among species that affect the growth response to CO(2). Here we use intra-specific variation in Picea glauca to examine the mechanistic basis for this relationship. Relative growth rate (RGR) of 29 genotypes grown at ambient (370 μl l(-1)) or elevated (740 μl 1(-1)) CO(2) was measured. Physiological and morphological traits describing differences in allocation, canopy structure, stomatal function and photosynthesis were determined. Most variation in RGR (74%) was explained by traits associated with canopy structure. Although there was a strong correlation between RGR(740) and RGR(370), we found no evidence that genotypes that grew fast at ambient CO(2) had a greater relative growth response to CO(2). Given that the pattern found at the intra-specific level differed from that reported at the inter-specific level, our results suggest that RGR per se does not affect the growth response to CO(2). Rather, the CO(2) growth response is determined by traits that may or may not be correlated with RGR.     

Influence of gibberellic acid and stock plant irradiance on carbohydrate content and rooting in cuttings of Scots pine seedlings (Pinus sylvestris L.)

Seedlings of Pinus sylvestris L. were grown at three different irradiances (12, 30, or 60 W m(-2)) under a 17 h photoperiod. After six weeks, cuttings were excised and rooted at 30 W m(-2). Gibberellic acid (GA(3), 5 microl of 2 x 10(-4) or 2 x 10(-3) M) was applied to each cutting immediately after excision. Cuttings from stock plants grown at the low irradiance rooted most quickly, whereas the highest number of roots per cutting was obtained in cuttings from stock plants grown at 30 W m(-2). Gibberellic acid delayed rooting and reduced the number of roots in cuttings from stock plants grown at 12, 30, or 60 W m(-2). The initial carbohydrate content of cuttings increased with stock plant irradiance. For all carbohydrates, except myoinositol and an unknown inositol derivative, the content per cutting increased during the first 28 days of rooting. The GA(3) treatment significantly reduced the starch content of cuttings during the rooting period, but did not significantly change the content of ethanol soluble carbohydrates.     

Antibacterial activity of hydroxyalkenyl salicylic acids from sarcotesta of Ginkgo biloba against vancomycin-resistant Enterococcus

A chloroform fraction prepared from the sarcotesta of Ginkgo biloba showed potent inhibitory activity against vancomycin-resistant Enterococcus (VRE). The active compounds were elucidated to be 2-hydroxy-6-(8-pentadecenyl) salicylic acid (1) and 2-hydroxy-6-(10-heptadecenyl) salicylic acid (2) based on their spectral analysis. Compounds 1 and 2 showed significant antibacterial activities against VRE.     

不同土壤水分下黄栌光合作用CO2响应过程

测定了不同土壤水分条件下黄栌光合作用的CO2响应过程,采用直角双曲线修正模型对其响应过程进行拟合。结果表明:黄栌的净光合速率(Pn)对土壤水分的变化具有显著的阈值响应。维持黄栌较高光合速率的RWC在42.1%-73.6%(MWC在11.0%-19.2%)之间时,最适宜的RWC为61.7%(MWC为16.1%)左右。黄栌的羧化效率(CE)、光合能力(Pnmax)、光呼吸速率(Rp)表现为对土壤水分具有明显的阈值响应,当RWC为61.7%(MWC为16.1%)时CE、Pnmax达到最大值,当RWC为73.6%(MWC为19.2%)时Rp达到最大值。黄栌的CO2补偿点(Γ)、CO2饱和点CSP随着土壤含水量的增加表现出先下降后上升的规律。     

异长叶烯基噻唑类化合物的合成及其抑菌、抗肿瘤活性研究

以异长烯酮为原料,通过缩合、亲核取代和环化等手段合成了11种新型异长叶烯基噻唑类化合物,同时采用1H NMR、13C NMR、LC-MS和FT-IR对化合物进行了鉴定,从而确定了化合物的结构。对目标化合物进行了抑菌活性实验,结果表明:(E)-4-(4-甲氧基苯基)-2-(2-(1,1,5,5-四甲基-3,4,5,6-四氢-1H-2,4a-亚甲基-7(2H)-亚基)肼基)噻唑(2e)与(E)-4-(4-甲基苯基)-2-(2-(1,1,5,5-四甲基-3,4,5,6-四氢-1H-2,4a-亚甲基-7(2H)-亚基)肼基)噻唑(2g)对细菌(大肠杆菌与金黄色葡萄球菌)具有较好的抑制效果,最低抑菌质量浓度(MIC)为7.8 mg/L。(E)-4-氯苯基-2-(2-(1,1,5,5-四甲基-3,4,5,6-四氢-1H-2,4a-亚甲基-7(2H)-亚基)肼基)噻唑(2b)对真菌(白念球菌与热带假丝酵母)抑制效果优于其他化合物,其MIC值为15.6 mg/L。采用噻唑蓝(MTT)法对目标化合物进行了人体肝癌细胞(HepG 2)抗癌活性测试,化合物2g(IC50=43.9±0.9 mg/L)对HepG 2具有较好的抗癌活性。     

New phenantrene alkaloids from Cryptocarya crassinervia

The bark of Cryptocarya crassinervia provided two new phenantrene alkaloids, 2-hydroxyatherosperminine (1) and N-demethyl-2-methoxyatherosperminine (2).     

Long-term elevation of atmospheric CO(2) concentration and the carbon exchange rates of saplings of Pinus taeda L. and Liquidambar styraciflua L

The relationship between carbon exchange rate (CER) and internal CO(2) concentration was measured in leaves of saplings of Liquidambar styraciflua L. (sweetgum) and Pinus taeda L. (loblolly pine) grown from seed for more than 14 months at atmospheric CO(2) concentrations of either 350 or 500 microl l(-1). An elevated concentration of CO(2) during growth reduced CER at any given internal CO(2) concentration in sweetgum, but not in loblolly pine. Stomatal limitation of CER showed little response to concentration of CO(2) during measurement, but was higher in both species when grown at 500 than at 350 microl l(-1) CO(2). The net effect of a long-term increase in CO(2) concentration from 350 to 500 microl l(-1) was an increase in CER of loblolly pine, but a slight decrease in CER of sweetgum. It is suggested that the depression of CER in sweetgum resulted from a reduction in the activity of ribulose-1,5-bisphosphate carboxylase-oxygenase.