濒危植物天目铁木和羊角槭的光合及蒸腾特性日动态比较

分别对浙江西天目山濒危植物天目铁木(Ostrya rehderiana)和羊角槭(Acer yangjuechi)进行叶片气体交换参数日动态测定,探讨其光合与蒸腾作用的影响因素,比较光能利用效率和水分利用效率.结果显示,天目铁木的净光合速率日动态有午休现象;当光合有效辐射没有显著差异时,天目铁木的净光合速率显著大于羊角槭(p0.05),与其林冠层阳生环境相适应;二者光能利用效率日变化无明显差异,但弱光条件下,羊角槭的光能利用效率高于天目铁木(p0.05),与其林下层耐阴植物的特性相符;二者的水分利用效率日动态不同,羊角槭高于天目铁木(p0.05),表明羊角槭蒸腾活动降低而导致.     

Changes of photosynthetic capacity of some plant species under very high CO2 concentrations in Biosphere 2

Conclusions The initial slope of A/ light curve became steep under high CO₂ (700 μmol · mol^-1) compared with that under low CO₂ (350 μmol · mol^-1) for the C₃ species growing in very high CO₂(>2 200 μmol · mol^-1) for a long period. The light compensation points remained unchanged, but the light saturation points were found increased. The ϕ_m,_app and A_max of the C₃ species increased respectively by 79 % and 80 %, while those of C₄ species decreased by 10% and 14%, respectively. The shape of A/light curve of C₄ species did not change. Such results indicated that C₃ species increased the capacity of photosynthesis, while C₄ did not change, otherwise it decreased a little. This work only compared the changes of capacity in photosynthesis of some species under different CO₂ levels in Biosphere 2. We need further investigation on the effects of high CO₂ on the same species outside Biosphere 2, in order to fully undertand the effects and mechanism of response of plants to the elevated CO₂.     

Selection of judging indicators for surface morphology of soil crack under different development degrees in Yuanmou arid-hot valley region

Quantification of complicated surface morphology of soil crack is a prerequisite and key to soil crack study. This paper takes soil crack quads in Yuanmou arid-hot valley region as examples, selecting several morphological indicators, and analyzes the soil crack＇s morphological features under various development degrees. By statistic analysis, three quantitative indicators for surface morphology are selected, namely soil crack area density, area weighted mean fractal dimension and connectivity index R, which can not only express the development intensity of soil cracks, but also effectively describe its morphological complexity and connectivity. The research results set a good base for the establishment of soil crack assessment system in Yuanmou arid-hot valley region.     

巨尾桉与针叶树种光合生理特性的比较研究

【目的】比较桂林市灵田乡人工巨尾桉(Eucalyptus grandis×E.urophylla)林和针叶混交林的光合生理特性,探究该地区是否适应巨尾桉的生长。【方法】采用Li-6400型便携式光合仪测定巨尾桉与马尾松、杉木在春季叶片净光合速率(Pn)及其光合生理因子的日变化,并通过相关性分析了解净光合速率与其它光合生理因子的关系。【结果】这3种树种净光合速率在春季均呈现"双峰型"的特点,光合有效辐射(PAR)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度是影响这3种树种叶片净光合速率日变化的重要因子。【结论】巨尾桉具有较高的水分利用效率(WUE)、光能利用效率(LUE)和CO2利用效率(CUE),还具有适应桂林土山生境且生长快速的特性。     

The characteristics of CO2 assimilation of photosynthesis and chlorophyll fluorescence in transgenic PEPC rice

With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C₄ photosynthesis enzymes, the chlorophyll fluorescence parameters, CO₂ exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (ⅰ) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO₂ compensation point decreased by 27%. (ⅱ) The PSⅡ photochemical efficiency (F_v/F_m) and photochemical quenching (q_P) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3 h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC transgenic rice to photoinhibition and photooxidation was enhanced. (ⅲ) Under the condition of high light intensity, the activity of RuBPCase in PEPC transgenic rice did not obviously vary while the activity induced of carbonic anhydrase (CA) in PEPC transgenic rice increased by 1.8 fold. These results would provide some beneficial enlightment for revealing the mechanism of high photosynthetic efficiency and breeding with high photosynthetic efficiency in rice.     

小球藻(Chlorella vulgaris)抗铵品系的紫外诱变选育

【目的】获得耐受高铵浓度的优良养殖小球藻(Chlorella vulgaris)品系,可以有效防止其在养殖过程中被轮虫,纤毛虫等污染生物吞食。【方法】首先对小球藻进行紫外线诱变,然后用高浓度NH_4HCO_3作为筛选压力对其进行筛选。【结果】筛选到具有生长优势的小球藻突变株B4和C6,培养12d,在NH_4HCO_3浓度为800mg/L、1 000mg/L、1 200mg/L条件下,B4和C6的生物量比出发藻株分别提高41.18%和9.54%,32.64%和29.41%,37.74%和22.85%;对比出发藻株,B4和C6的最大光能转化效率有显著提高。【结论】突变株B4和C6在高铵培养条件下更能显示生长优势,且它们的生长优势可能来自光合效率的提高。     

4种攀援植物光合作用对不同光照的适应

以4种攀援植物为材料,测定其阴生、阳生叶片叶绿素a,b含量,光反应曲线、叶绿素荧光及其在强光下的变化.最大光合速率阴生叶片较阳生叶片的下降幅度,华南和鸡蛋果较小,绞股蓝最大,白粉藤次之,表明4种植物耐阴性不同,华南和鸡蛋果的耐阴性较绞股蓝强.4种植物对高光照的适应性也不同,在饱和光条件下,鸡蛋果的非光化学猝灭(NPQ)值最低,不耐高光照的华南NPQ值最高.且4种植物在叶绿素含量上对光照的适应依种和光照条件的不同而有差异.并讨论了以饱和光条件下的NPQ值作为植物对强光照环境适应能力的一个指标的可能性.     

濒危植物暖地杓兰的叶解剖结构和光合特性

暖地杓兰(Cypripedium subtropicum)是兰科(Orchidaceae)杓兰属(Cypripedium)目前已知的唯一一种多年生常绿草本植物,其野生资源遭受严重破坏,野外居群数量急剧减少,已被列为我国一级重点保护野生植物。为探讨暖地杓兰不同生长期叶片的解剖结构和光合生理特性的差异,本研究对其叶表皮特征、叶解剖结构、光合特性以及光合色素含量展开研究,以期为暖地杓兰的保育和引种驯化提供科学依据。结果表明：(1)暖地杓兰叶片上、下表皮的形状不规则,呈波状,并且气孔和表皮毛仅分布于下表皮;叶片结构由表皮、叶肉和叶脉组成,叶肉无栅栏组织和海绵组织的分化。结实植株的气孔面积、叶片厚度和叶主脉厚度均极显著大于幼苗。(2)暖地杓兰结实植株和幼苗的最大净光合速率(P_max)、光补偿点(LCP)、表观量子效率(AQY)均较低,且结实植株极显著大于幼苗,说明其具有阴生植物的特征。(3)暖地杓兰结实植株叶片的光合色素含量极显著大于幼苗。(4)暖地杓兰叶片的P_max、LSP、AQY、暗呼吸速率(R_d)与Chl(a+b)、叶主脉厚...     

滇重楼光合作用与环境因子的关系

 利用LI-6400光合测定仪和人工气候箱研究了滇重楼叶片的光合补偿点、光合饱和点、羧化效率和CO₂补偿点,并进行温度、相对湿度对光合速率的单因子影响研究.滇重楼叶片的光合补偿点为5.7μmol/(m²·s),光合有效辐射增至2000μmol/(m·s)²仍未测到光合饱和点,最适光合有效辐射为750～2000μmol/(m·s)².叶片的羧化效率为0.0295,CO₂补偿点为65μmol/mol,光合速率随CO₂浓度升高而明显增加,高于大气正常值的CO₂浓度对增加滇重楼光合作用的光能利用率是有利的.光合速率在温度11～20℃范围内,随温度升高上升;20～35℃随温度升高下降,最适温度为16～28℃.相对湿度20%～85%的试验范围内,叶片光合速率随湿度增加而增大,最适相对湿度条件在75%以上.     

不同水分和光照处理对走马胎生理生化特性的影响

为了探究走马胎(Ardisia kteniophylla)在生境适宜性中对水分及光照的需求特性，以2年生的走马胎幼苗为材料，设置3个水分水平(90%-100%、70%-80%及50%-60%土壤持水量)与3个光照水平(30%-40%、20%-30%及10%-20%透光率)的双因素试验，分析不同水分及光照条件下其生长指标、生理指标、光合特性及总皂苷含量的变化情况。结果表明：较强的光照(L1，30%-40%透光率)和低水分逆境(W3，50%-60%土壤持水量)下，走马胎丙二醛含量积累增多，导致细胞质膜相对透性增大，促进了脯氨酸和可溶性糖的合成，使得株高、茎粗及生物量等的增长受到抑制；走马胎总皂苷的积累在W3逆境下大量合成积累；光合特性分析也表明走马胎耐强光能力较弱，利用弱光的能力较强。综上，走马胎作为典型的阴生植物，不同的水分和光照显著影响其生长和生理生化特性，70%-80%土壤持水量和20%-30%透光率最适宜走马胎的生长。此外，适当缺水胁迫有利于走马胎总皂苷的积累，可作为提高走马胎药材质量的一个潜在措施。     

Landscape ecological evaluation on the artificial forest of <Emphasis Type="Italic">Leucaena leucocephala</Emphasis>

Based on the theory of ecology, this article conducted a landscape ecological evaluation on Leucaena leucocephala artificial forest in the add-hot valley, Yuanmou Xiaokua hill, using a combination method of qualitative analysis and landscape comprehensive evaluation. The comprehensive evaluation indexes of landscape include forest coverage, biodiversity, stability, soil erosion, environmental quality, availability, scientific research characteristic, economic benefits. Using AHP （analytical hierarchy process）, determine the grade of ecological evaluation factors and the weight of evaluation index and calculate the CEI （comprehensive evaluation index） on ecological evaluation. Evaluation results showed that the area CEI was 0.714 225, a better quality of the ecological level, but biodiversity indicators was the lowest. To sum up, it was difficult to maintain ecological restoration effectiveness and process but also guarantee a good biodiversity in the add-hot valleys. We must reasonably arrange the alien species and the native species, in order to obtain a stable and sustainable eco-system.     

Vegetation Restoration Technique System and Its Ecological Functions of the Degraded Ecosystem in the Arid-Hot Valleys —— Taking the Example of Typical Mode in Small Watershed of Yuanmou

This paper concluded the vegetation restoration technique system in the arid-hot valleys and studied the anti-erosion function, environmental function and biological diversity effects of vegetation restoration on the ecosystem in the arid-hot valleys. The results showed that the soil erodibility decreased significantly after the vegetation restoration. The climate environment of the small watershed had a great improvement after the vegetation restoration, of which the temperature decreased, the humidity increased, the harsh environment of dry and hot in this region changed. The studies of the ecosystem biodiversity were mainly on the analysis of the relations between biodiversity and ecological function of the artificial ecological forest pattern and the natural enclosed treatment mode on the severely of degraded land. It could conclude that the natural enclosed treatment mode is helpful to the biodiversity of the ecosystem and the improvement and stability of the ecosystem, and Leucaena artificial forest restoration pattern reduced the species diversity but optimized the ecological function. Therefore, as to the severely and extremely severely degraded ecosystem in the arid-hot valleys, Leucaena pattern of gully control and natural enclosed treatment mode are the relatively optimal choices.     

Effect of CO<Subscript>2</Subscript> concentrations on the activity of photosynthetic CO<Subscript>2</Subscript> fixation and extracelluar carbonic anhydrase in the marine diatom <Emphasis Type="Italic">Skeletonema costatum</Emphasis>

The growth and activity of photosynthetic CO2 uptake and extracellular carbonic anhydrase (CAext) of the marine diatom Skeletonema costatum were investigated while cultured at different levels of CO2 in order to see its physio-logical response to different CO2 concentrations under either a low (30 靘ol·m-2·s-1) or high (210 靘ol·m-2·s-1) irradiance. The changes in CO2 concentrations (4—31 靘ol/L) affected the growth and net photosynthesis to a greater extent under the low than under the high light re-gime. CAext was detected in the cells grown at 4 mol/L CO2 but not at 31 and 12 靘ol/L CO2, with its activity being about 2.5-fold higher at the high than at the low irradiance. Photo- synthetic CO2 affinity (1/ K1/2(CO2)) of the cells de-creased with increased CO2 concentrations in culture. The cells cultured under the high-light show significantly higher photosynthetic CO2 affinity than those grown at the low-light level. It is concluded that the regulations of CAext activity and photosynthetic CO2 affinity are dependent not only on CO2 concentration but also on light availability, and that the de-velopment of higher CAext activity and CO2 affinity under higher light level could sufficiently support the photosyn-thetic demand for CO2 even at low level of CO2.     

八种草坪植物耐荫性的研究

用人工遮光方法,研究了8种草坪植物的耐荫性,结果表明8种草坪植物的耐荫性可划分为四类：第一类沿阶草,强耐荫;第二类马尼拉、高羊茅、早熟禾、较耐荫;第三类黑麦草、台湾草、狗牙根、中等耐荫;第四类地毯草,不耐荫。描述了8种草坪植物在不同光照条件下的生长表现。     

转SOD基因烟草的光合特性初探

 以转基因Fe-SOD,Mn-SOD高表达、转基因Mn-SOD反义低表达烟草及非转基因品系为供试材料,比较CO₂光强对烟草光合作用和蒸腾作用的影响及不同叶位叶片的光合差异.在相同条件下,Mn-SOD高表达烟草CO₂补偿点最高(105μmol·mol^-1),Mn-SOD低表达烟草最低(78μmol·mol^-1),CO₂浓度对非转基因烟草蒸腾作用的影响比对其他三个转基因品系的影响要强.Mn-SOD低表达烟草的光补偿点最高(45μmol·m^-2·s^-1),而Mn-SOD高表达烟草最低(25μmol·m^-2·s^-1),并且强光对非转基因烟草的光合作用抑制大,转基因品系对强光具有较强的耐受力.同一叶位叶片,转基因烟草的光合速率、蒸腾速率更强.但转基因SOD高表达烟草在整体上并没有表现出明显的光合作用优势.     

Cause analysis of gully erosion in Yuanmou basin of Jinshajiang valley

Some factors （i.e. lithology, topography, climate, the change of population as well as land use during the past 50 years） that could have great influence on the development of gully in the arid-hot basin of Jinshajiang valley were investigated. The results show that the factors leading to the strong gully erosion in this area include： the widely distributed Yuanmou group stratum, which promotes the development of gully erosion; the unique geomorphologic configuration that is prone to rock fall and gully erosion; the strong and time-concentrated rainfall; the arid-humid alternate climate characteristics that prepares the ground for the development of fissures in soils; the arid-hot climate that goes against the growth and recovery of vegetation; and the unreasonable and abusive human activities.     

Comparative study of the net exchange of CO<Subscript>2</Subscript> in 3 types of vegetation ecosystems on the Qinghai-Tibetan Plateau

Using the eddy covariance method, from 1 July 2003 to 30 June 2004, we conducted the observation and analysis of ecosystem CO2 flux in 3 types of alpine meadow vegetation （Kobresia humilis, Potentilla fruticosa shrub and Kobresia tibetica swamp meadows） on the Qinghai-Tibetan Plateau. The results show that the Kobresia humilis meadow, the shrub meadow and the swamp meadow＇s highest CO2 uptake rates are 16.78, 10.42 and 16.57 μmol·m^-2·-s^-1 respectively, while their highest CO2 release rates are 8.22, 7.73 and 18.67μmol·m^-2·-s^-1 respectively. The Kobresia humilis meadow and shrub meadow＇s annual atmospheric uptakes are 282 g CO2/m^2 and 53 g CO2/m^2, respectively, while swamp meadow＇s annual atmospheric release is 478 g CO2/m^2. This proves that the Kobresia humilis meadow and the shrub meadow on the Qinghai-Tibetan Plateau have relatively low potential for CO2 uptake and release compared to C4 grasslands, a number of lowland grasslands, and forests. Moreover, swamp meadow has relatively high release potential. This, in turn, reveals clear differences in carbon source/sink between different types of vegetation in the Qinghai-Tibetan Plateau alpine meadow ecosystem. These differences are mainly brought by differences in the vegetations＇ photosynthetic capacity and soil respiration.     

单性木兰幼苗与成年植株叶片光合功能及结构比较

为探究单性木兰（Kmeria septentrionalis）幼苗、成年植株叶片结构和光合特性的差异情况以及内在联系,揭示单性木兰叶片结构对光合速率的影响规律,本研究采用Li-6400便携式光合仪测定单性木兰幼苗和成年植株叶片的光合-光响应曲线,并通过电镜扫描比较其幼苗和成年植株叶面解剖特征的差异。结果表明：单性木兰成年植株的净光合速率显著高于幼苗;最大净光合速率（P_max）和光饱和点（LSP）存在显著性差异;成年植株对强光的利用能力高于幼苗,而幼苗较成年植株有更好的弱光利用能力;幼苗和成年植株的总叶绿素[Chl（a+b）]、类胡萝卜素（Car）、叶片厚度（LT）、气孔面积（SA）、气孔密度（SD）、栅栏组织厚度（PPT）和气孔横轴长度（SW）均存在显著性差异;Car、Chl（a+b）、SA和SD对光合生理特性的影响最为显著。因此,建议在单性木兰的引种栽培中,将幼苗进行遮阴处理,随着植株生长可适当减小遮阴度,待植株成年后可不做遮阴处理。     

The Chinese carbon cycle data-assimilation system （Tan-Tracker）

In this study, the Chinese carbon cyle dataassimilation system Tan-Tracker is developed based on the atmospheric chemical transport model （GEOS-Chem） platform. Tan-Tracker is a dual-pass data-assimilation system in which both CO2 concentrations and CO2 fluxes are simultaneously assimilated from atmospheric observations. It has several advantages, including its advanced data-assimilation method, its highly efficient computing performance, and its simultaneous assimilation of CO2 concentrations and CO2 fluxes. Preliminary observing system simulation experiments demonstrate its robust performance with high assimilation precision, making full use of observations. The Tan-Tracker system can only assimilate in situ observations for the moment. In the future, we hope to extend Tan-Tracker with functions for using satellite measurements, which will form the quasioperational Chinese carbon cycle data-assimilation system.     

Development of CMAQ for East Asia CO2 data assimilation under an EnKF framework: a first result

Under an Ensemble Kalman Filter(EnKF)framework,Regional Atmospheric Modeling System and Models-3 Community Multi-scale Air Quality(RAMS–CMAQ)modeling system is developed to be a CO2data assimilation system EnKF–CMAQ,and the EnKF–CMAQ system is then applied to East Asia for validation with real continuous surface CO2concentration observations available in the study domain instead of using an observation simulation system experiment.Experiments with an experimental period of January 23 to February 7,2007 are conducted,and the experimental results of the EnKF–CMAQ system and the RAMS–CMAQ model are compared against continuous surface CO2observations from assimilation sites and independent reference sites.Distributions of daily mean CO2concentration increments show that the EnKF–CMAQ system confines the update of daily mean CO2within areas nearby and downwind of the assimilation sites.Both the CO2concentration ensemble spreads and background error covariances show flow-dependent patterns.The results indicate the crucial role of wind transport in the CO2data assimilation,which agrees with the previous studies.The average bias and the average root-mean-square error(RMSE)of daily mean CO2concentration at the assimilation sites are reduced by 1.00 and1.83 ppm,respectively,and those at the reference sites are reduced by 0.24 and 0.22 ppm,respectively.The results demonstrate the EnKF–CMAQ system is capable of assimilating the continuous surface CO2concentration observations to improve the simulation accuracy of the atmospheric CO2synoptic variation.Since growing CO2observations over East Asia are being available nowadays,this work is our first step to generate consistent spatial and temporal atmospheric CO2concentration fields over East Asia,particularly over China,using both in situ and satellite observations.