C_3、C_4植物叶片净CO_2同化速率的模拟及其对环境因子的响应(英文)

本文首先模拟建立了叶片光合作用机制模型，然后，考虑环境因子对叶光合作用的影响，进 行了三种敏感性试验，包括C3、C4植物叶片净CO2同化速率对胞间CO2浓度、叶片温度和光合 有效辐射（PAR）的影响。结果表明数值模拟的叶光合作用机制模型可以指示C3、C4植物的 光合作用的主要特征，进一步可以作为陆面过程模式的一部分耦合到区域气候模型中，更好 地研究植被和大气的相互作用关系。     

Effects of elevated CO2 on net photosynthetic rate of trees in Changbai Mountain

Net photosynthetic rates (NPRs) of four species seedlings,Pinus koraiensis, Pinus sylvestriformis, Fraxinus mandshurica andPhellodendron amurense, were measured at different CO₂ concentrations and time respectively in Changbai Mountain during the growing season in 1999. The seedlings were cultivated in open-top chambers (OTCs), located outdoors and exposed to natural sunlight. The experimental objects were divided into four groups by tree species. CO₂ concentrations in chambers were kept at 500 μL·L⁻¹ and 700 μL·L⁻¹ and contrast chamber and contrast field were set. The results showed that the effects of elevated CO₂ on NPR of the trees strongly depended on tree species and time. NPRs ofPinus koreainsis andPinus sylvestriformis seedlings increased with the rising of CO₂ concentration, while that ofPhellodendron amurense andFraxinus mandshurica increased at some time and decreased at another time. This project was supported by Chinese Academy of Sciences Responsible editor: Chai Ruihai     

Relationships between soil CO2 concentration and CO2 production, temperature, water content, and gas diffusivity: implications for field studies through sensitivity analyses

Soil CO₂ levels reflect CO₂ production and transport in soil and provide valuable information about soil CO₂ dynamics. However, extracting information from soil CO₂ profiles is often difficult because of the complexity of these profiles. In this study, we constructed a simple numerical model that simulated soil CO₂ dynamics and performed sensitivity analyses for CO₂ production rates, soil water content and temperature, and gas diffusivity at the soil surface to clarify the relationships among these parameters. Increased soil surface CO₂ flux did not always coincide with higher soil CO₂ concentrations; increased CO₂ production at shallow depths had little effect on soil CO₂ concentrations, while the opposite may be true for high levels of soil water content. Higher soil CO₂ concentration did not always coincide with greater soil surface CO₂ flux; under high soil water conditions, soil surface CO₂ flux sometimes decreased despite increased soil CO₂ concentration. Increases in soil water content did not always enhance both soil surface CO₂ flux and soil CO₂ concentration. Under high soil water conditions, increases in soil water content could lower soil surface CO₂ flux and increase soil CO₂ concentration. Increases in soil temperature resulted in greater soil surface CO₂ flux and higher soil CO₂ concentration in our simulation (extremely high temperatures were not assumed in this study). Gas diffusivity in very shallow layers did affect, albeit weakly, soil CO₂ concentration. The findings of this study may help direct future observations and aid in the interpretation of their results.     

Response of five dry tropical tree seedlings to elevated CO2: Impact of seed size and successional status

The impact of seed size and successional status on seedling growth under elevated CO₂ was studied for five dry tropical tree species viz. Albizia procera, Acacia nilotica, Phyllanthus emblica, Terminalia arjuna and Terminalia chebula. Seedlings from large (LS) and small seeds (SS) were grown at two CO₂ levels (ambient and elevated, 700–750 ppm). CO₂ assimilation rate, stomatal conductance, water use efficiency and foliar N were determined after 30 d exposure to elevated CO₂. Seedlings were harvested after 30 d and 60 d exposure periods. Height, diameter, leaf area, biomass and other growth traits (RGR, NAR, SLA, R:S) were determined. Seedling biomass across species was positively related with seed mass. Within species, LS seedlings exhibited greater biomass than SS seedlings. Elevated CO₂ enhanced plant biomass for all the species. The relative growth rate (RGR), net assimilation rate (NAR), CO₂ assimilation rate, R:S ratio and water use efficiency increased under elevated CO₂. However, the positive impact of elevated CO₂ was down regulated beyond 30 d exposure. Specific leaf area (SLA), transpiration rate, stomatal conductance declined due to exposure to elevated CO₂. Fast growing, early successional species exhibited greater RGR, NAR and CO₂ assimilation rate. Per cent enhancement in such traits was greater for slow growing species. The responses of individual species did not follow functional types (viz. legumes, non-legumes). The enhancement in biomass and RGR was greater for large-seeded species and LS seedlings within species. This study revealed that elevated CO₂ could cause large seeded, slow growing and late successional species to grow more vigorously.     

Photosynthetic response to variation in CO2 concentrations and temperature of four broad-leaved trees in Beijing region

Responses of the photosynthetic characteristics to variation in CO₂ concentration and temperature of Ginkgo biloba, Eucommia ulmoides, Magnolia denudata and Tilia japonica were measured during the peak growing season. The results show that the ambient CO₂ concentration could not meet the requirements for photosynthesis of these four species. The optimal temperatures for photosynthesis were lower than the average daytime air temperature. Hence, the photosynthesis of these four species was restricted by the low CO₂ concentration and high daytime air temperature at the time of measurement. Marked enhancements in the net photosynthetic rate were found in all four species when the CO₂ concentration was doubled. When the dependency on CO₂ and temperature were examined simultaneously, it was seen that for increased CO₂ concentrations there was a shift in the optimum temperature for M. denudata and T. japonica towards higher temperatures. Due to their independence on CO₂ concentrations, this trend could not be found in the G. biloba and E. ulmoides data sets. The stomatal conductance (G _s) was sensitive to a vapor pressure deficit (VPD) which in turn was sensitive to temperature. An increase in temperature would cause the VPD to increase and plants might be assumed to react by reducing their stomatal apertures. The effect on stomatal resistance would be most significant at high temperatures. The restriction to stomatal conductance for these four species would increase if CO₂ concentrations were elevated at the same temperature. __________ Translated from Journal of Agricultural University of Hebei, 2006, 29 (6): 39–43 [译自: 河北农业大学学报]     

Stomatal response ofPinus sylvestriformis to elevated CO2 concentrations during the four years of exposure

Four-year-oldPinus sylvestriformis were exposed for four growing seasons in open top chambers to ambient CO₂ concentration (approx. 350 μmol·mol⁻¹) and high CO₂ concentrations (500 and 700 μmol·mol⁻¹) at Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences at Antu Town, Jilin Province, China (42°N, 128°E). Stomatal response to elevated CO₂ concentrations was examined by stomatal conductance (g _s), ratio of intercellular to ambient CO₂ concentration (c _i/c _a) and stomatal number. Reciprocal transfer experiments of stomatal conductance showed that stomatal conductance in high-[CO₂]-grown plants increased in comparison with ambient-[CO₂]-grown plants when measured at their respective growth CO₂ concentration and at the same measurement CO₂ concentration (except a reduction in 700 μmol·mol⁻¹ CO₂. grown plants compared with plants on unchambered field when measured at growth CO₂ concentration and 350 μmol·mol⁻¹CO₂). High-[CO₂]-grown plants exhibited lowerc _i/c _a ratios than ambient-[CO₂]-grown plants when measured at their respective growth CO₂ concentration. However,c _i/c _a ratios increased for plants grown in high CO₂ concentrations compared with control plants when measured at the same CO₂ concentration. There was no significant difference in stomatal number per unit long needle between elevated and ambient CO₂. However, elevated CO₂ concentrations reduced the total stomatal number of whole needle by the decline of stomatal line and changed the allocation pattern of stomata between upper and lower surface of needle. Foundation Item: This research was supported by National Basic Research Program of China (2002CB412502), Project of Key program of the National Natural Science Foundation of China (90411020) and National Natural Science Foundation of China (30400051). Biography: ZHOU Yu-mei (1973-), female, Ph. Doctor, assistant research fellow, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China. Responsible editor: Song Funan     

植物对氯化钠和硫酸钠胁迫生理响应研究进展

氯化钠是一种最为常见的盐胁迫类型,在我国乃至全球分布面积最大。但在某些地区(如我国"三北"的局部地区),硫酸钠、碳酸钠和碳酸氢钠等类型盐渍土的面积更大、危害更深,且有很多植物(如碱蓬、白刺、柽柳等)常分布于多种不同类型的盐碱地。因此,开展植物对不同类型盐碱胁迫对比研究、探讨其内在生理机制的异同显得尤为迫切和必要,并极具现实意义和理论价值。根据国内外文献资料,文中在总结盐胁迫生长抑制效应的基础上,对比、分析了植物对氯化钠和碳酸钠胁迫的生理响应异同,主要包括离子代谢生理、水分与渗透调节生理、光合生理等,并对该领域存在的问题和未来研究重点进行了探讨,以期为同类研究提供参考与借鉴。     

Cost, energy and carbon dioxide (CO2) effectiveness of a harvesting and transporting system for residual forest biomass

The purpose of this study is to examine the feasibility of a system to harvest logging residues (or slashes) as a new resource for energy in Japan. A harvesting and transporting system for residual forest biomass was constructed with reference to some European countries where the utilization of bioenergy is making steady progress and examined on the basis of field experiments in Japanese forestry. The feasibility of the system is discussed from the standpoints of cost and energy, and the system is compared with those of the European countries. With respect to the system proposed in this study, it is desirable that the process of chipper comminuting is incorporated into the system as early as possible, considering the trends of harvesting cost and fuel consumption per unit weight of residual forest biomass. Such a system is not particularly feasible in Japan from the standpoint of the harvesting cost per MWh of bioenergy. However, no specific problems are found from the point of view of the energy input rate, and it is clarified that it is possible for Japan to reduce domestic carbon dioxide emissions by utilizing biomass as an energy resource. A comparison with the European countries and a preliminary sensitivity analysis of the system demonstrate that the technical development to reduce the harvesting cost,e.g., improving the forwarding and transporting efficiency, and support from the government are essential for realizing bioenergy utilization in Japan. A part of this paper was orally presented at the 111th Annual Meeting of the Japanese Forestry Society (2000). JSPS Research Fellow. This study was supported in part by a Grant-in-Aid for Scientific Research from the Japan Ministry of Education, Science and Culture (No. 10460061).     

Nutrient contents and efficiencies of beech and spruce saplings as influenced by competition and O<Subscript>3</Subscript>/CO<Subscript>2</Subscript> regime

Saplings of Fagus sylvatica and Picea abies were grown under conditions of intra and interspecific competition in a 2-year phytotron study under combinations of ambient and elevated ozone (+O₃ which is 2 × O₃, but <150 nl l⁻¹) as well as carbon dioxide concentrations (+CO₂ which is amb. CO₂ + 300 μl CO₂ l⁻¹) in a full factorial design. Saplings were analysed for various mineral nutrients in different plant organs as well as biomass production and crown development. The study was based on the assumption that nutritional parameters important for growth and competitiveness are affected by stress defence under limiting nutrient supply. The hypotheses tested were (1) that nutrient uptake-related parameters (a) as well as efficiencies in nutrient use for above-ground competition (b) of beech rather than spruce are impaired by the exposure to elevated O₃ concentrations, (2) that the efficiency in nutrient uptake of spruce is enhanced by elevated CO₂ concentrations in mixed culture, and (3) that the ability to occupy above-ground space at low nutrient cost is co-determinant for the competitive success in mixed culture. Clear nitrogen deficiencies were indicated for both species during the 2-year phytotron study, although foliar nitrogen-biomass relationships were not so close for spruce than for beech. O₃ stress did not impair nutrient uptake-related parameters of beech; thus hypothesis (1a). was not supported. A negative effect of elevated O₃ (under amb. CO₂) on the N and P based efficiencies in above-ground space occupation (i.e. lower crown volume per unit of N or P invested in stems, limbs and foliage) of beech supported hypothesis (1b). It appeared that ozone stress triggered a nutrient demand for stress defence and tolerance at the expense of above-ground competition (trade-off). Crown volume of beech under O₃ stress was stabilized in monoculture by increased nutrient uptake. In general, the +CO₂-treatment was able to counteract the impacts of 2 × O₃. Elevated CO₂ caused lower N and S concentrations in current-year foliage of both tree species, slightly higher macronutrient amounts in the root biomass of spruce, but did not increase the efficiencies in nutrient uptake of spruce in mixed culture. Therefore hypothesis (2) was not supported. At the end of the experiment spruce turned out to be the stronger competitor in mixed culture as displayed by its higher total shoot biomass and crown volume. The amounts of macronutrients in the above-ground biomass of spruce individuals in mixed culture distinctly exceeded those of beech, which had been strongly reduced by interspecific competition. The superior competitiveness of spruce was related to higher N and P-based efficiencies in above-ground space occupation as suggested in hypothesis (3). This article belongs to the special issue “Growth and defence of Norway spruce and European beech in pure and mixed stands”.     

Family Variation in the Morphology and Physiology of White Spruce (Picea glauca) Seedlings in Response to Elevated CO2 and Temperature

Tree improvement programs aim to develop families that are well-adapted to future growing conditions. To gain insight into the stability of the family genetic response to climate change, white spruce (Picea glauca) seedlings from 60 full-sib families were subjected to a combination of two temperature regimes and two levels of CO₂ over two growing seasons. There was positive effect of warmer temperatures and higher CO₂ on some growth variables but no significant family × treatment interactions. Instantaneous water use efficiency was the only physiological trait that was affected positively by the CO₂ treatment, showing a 51% increase that was consistent across families.     

Effect of (+)-limonene and 1-methoxy-2-propanol on Ips typographus response to pheromone blends

We compared two different strategies to increase the catches of Ips typographus (L.), particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone blends, targeting males and females respectively, in closely-spaced traps forming a barrier around forest stands. The second strategy, the single trap approach, used widely-spaced traps that were all baited with the same lure and intended to trap the highest possible numbers of males without compromising trapping of females. In the blend used for the barrier traps targeting primarily males, with a lower percentage of (4S)-cis-verbenol (cV), the (−)-α-pinene was replaced step wise with (+)-limonene at rates of 0%, 1%, 10%, 35%, 60% and 90%. This replacement had no significant effect on the numbers of responding I. typographus males, but there was a slight effect on the percentage of males caught. In the attractant blend for the barrier traps targeting females, with a higher percentage of cV, the 2-methyl-3-buten-2-ol (MB) was replaced with 1-methoxy-2-propanol (MP) in a similar fashion as for the male-specific blends. The replacement did not significantly affect the catch of females. Thus, it is possible to use the MP in the blend with cV and ipsdienol without significant change in catch efficacy. In the blends for single traps, the (−)-α- pinene was replaced with (+)-limonene and MB with MP. The replacement of (−)-α-pinene had only a slight effect on the percentage of males, but the results suggest that replacing MB with MP in the blend will not significantly reduce trapping efficacy. Foundation project: The research was supported by Slovak Research and Development Agency (APVV-51-P06005 and APVV-27-P05205) and by the Scientific Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences (2/6153/26)     

Extraction of <Emphasis Type="Italic">Trigonella foenum-graecum</Emphasis> L. by supercritical fluid CO<Subscript>2</Subscript> and its contact toxicity to <Emphasis Type="Italic">Rhyzopertha dominica</Emphasis> (Fabricius) (Coleoptera: Bostrichidae)

Rhyzopertha dominica (Fabricius) has developed extensive pesticide resistance in the last several decades. We have developed a supercritical fluid extraction method for Trigonella foenum-graecum L. (TFG) and studied the contact toxicities of the extracts to R. dominica. The extraction method was designed with orthogonal experiments to preserve and collect all the possible active components. Contact toxicity and efficiency of extraction were used as standard values to optimize extraction conditions, which were achieved at 55°C under 25 Mpa of pressure. The extraction efficiency for 200 g of dry sample reached 6.21% with 30 ml of 95% alcohol. Extracts loaded on filter paper showed dose and time dependent toxicities to adult R. dominica with a LC₅₀ value of 65.02 μg/cm² after 3 days post treatment. Our extensive in vivo studies indicated the extracts from Trigonella foenum-graecum seeds have high efficacy against pesticide resistant R. dominica. The active ingredient(s) from the extract shows promise as a novel pesticide candidate.