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1.
以叶片的气体传输过程为基础,将蒸腾作用包括在以往光合作用-气孔导度的耦合模型中,建立了光合作用-蒸腾作用-气孔导度的耦合模型。该模型可以模拟边界层导度对生理过程的影响。模拟了C3植物叶片对环境因子,如光照、温度、湿度、边界层导度和CO2浓度等的生理响应(光合作用、蒸腾作用、气孔导度)以及Ci和水分利用效率的变化。在环境因子变化于较大范围的情况下,模拟结果符合许多实验结论。  相似文献   

2.
以叶片的气体传输过程为基础,将蒸腾作用包括在以往光合作用气孔导度的耦合模型中,建立了光合作用蒸腾作用气孔导度的耦合模型。该模型可以模拟边界层导度对生理过程的影响。模拟了C3植物叶片对环境因子,如光照、温度、湿度、边界层导度和CO2浓度等的生理响应(光合作用、蒸腾作用、气孔导度)以及Ci和水分利用效率的变化。在环境因子变化于较大范围的情况下,模拟结果符合许多实验结论。  相似文献   

3.
为了研究骨髓内皮细胞的造血调控功能,采用串联超波技术脞小鼠骨髓内皮细胞无血清条件培养液(mBMEC-CM)中制血出不同相对分子质量(Mgt)范围的超滤组分,进行细胞集落形成实难,检测了mBMEC-CM及其超滤组分对骨髓成纤维祖细胞(CFU-F)、粒巨噬系造血祖细胞(CFU-GM)和小鼠业单系白现细胞系WEHI-3细胞生长的作用。结果显示:mBMEC-CM抑制CFU-F的生长,对CFU-GM和WEH  相似文献   

4.
芦苇(Phragmites communis)光合作用与蒸腾作用的日进程   总被引:18,自引:1,他引:18  
测定了野生芦苇(Phragmitescommunis)光合作用、蒸腾作用及相关指标的日变化。叶片的净光合作用率在10∶00~15∶00间保持一个高的稳定阶段,平均为73~99μmolCO2·m-2·s-1,光饱和状态下的最大值为127μmolCO2·m-2·s-1,处于挺水植物的低限。蒸腾作用强度的峰值达48mmolH2O·m-2·s-1。光合作用和蒸腾作用的日进程均未发生“午休”现象;相反,二者都是在正午前后强度最大。光合光量子流密度与净光合作用率、蒸腾强度、叶面传导率均存在不同程度的正相关。芦苇的光合作用强度和水分利用效率相对较低,但年生产量却较高,这是因为芦苇具有密实的叶子、有利的叶片配置结构和高的蒸腾作用强度。  相似文献   

5.
本文观察了锂对BALB/C小鼠骨髓高增殖潜能集落形成细胞(HPP-CFC)和粒巨噬系祖细胞CFU-GM体外增殖的影响。HPP-CFC集落由IL-1、IL-6、WEHI3条件培养液(WEHI3-CM,含有IL-3)及L929条件培养液(L929-CM,含有M-CSF)所支持,而CFU-GM由WEHI3-CM所支持。结果显示,LiCl浓度在0.4-2mmol/L时呈现剂量依赖性抑制HPP-CFC增殖;而在0.4-1mmol/L的浓度范围内,则对CFU-GM的增殖起剂量依赖性促进作用。这些结果提示LiCl对HPP-CFC和CFU-GM的作用不同,可能锂有诱导HPP-CFC向成熟细胞分化的作用  相似文献   

6.
花的衰老与切花保鲜   总被引:33,自引:0,他引:33  
花的衰老与切花保鲜李宪章(中国科学院植物研究所北京100044)FLOWERSENESCENCEANDPRESERVATIONOFCUTFLOWERS¥LiXian-zhang(InstituteofBotany,AcademiaSinica,Bei...  相似文献   

7.
谷子叶片光合速率日变化及水分利用效率   总被引:51,自引:0,他引:51  
通过降低空气湿度(从约30%减少到5%)、增加CO2浓度(从400μlCO2/L啬到730μlCO2/L)、烫叶鞘破坏韧皮部等处理对谷子叶片光合速率日变化和水分利用效率(WUE)进行了研究,发现中午光合速率降低与不合冰物积累有关;虽然低大所相对湿度(5%)使光合速率有所降低,但提高WUE。而烫叶鞘使光合物质积累既抑制了光合速率,又降低了WUE。  相似文献   

8.
紫外线-B辐射降低豌豆、大豆和黄瓜3种植物幼苗的净光合作用速率(Pn)和表观量子效率(AQE),Pn和AQE的减少幅度随紫外线-B辐射时间的延长逐渐增大。3种植物的光合作用对此外线-B辐射的敏感性依为:豌豆〉黄瓜〉大豆,光合作用光抑制的发生程度与光合作用对UV-B辐射敏感性有内在联系。定量分析显示,光合作用光抑制的发生程度随UV-B辐射时间增加,是UV-B辐射剂量的累积效应。  相似文献   

9.
十字苣苔属一新记录种   总被引:2,自引:0,他引:2  
朱华  王洪 《云南植物研究》1996,18(2):144-144
十字苣苔属一新记录种朱华,王洪,李保贵(中国科学院西双版纳热带植物园,云南勐腊666303)STAURANTHERA,ANEWRECORDFROMCHINA¥ZHUHua;WANGHong;LIBao-Gui(XishuangbannaTropica...  相似文献   

10.
目的:探讨人脐带清(CBS)在骨髓造血祖细胞培养中的效应。方法:用人骨髓细胞进行CFU、GM、VFU-E、BFU-E、CFU-GEMM培养。结果:CBS能直接刺激骨髓细胞CEU-GM的形成。与血型相同害无关。四人份以上的混合CBS(MCBS),刺激活性高且稳定。10%MCBS相当于65.6μg/L GM-CSF、0.23、0.3、0。.46kU/L EpO对CFU-GM、CFU-E、BFU-E、C  相似文献   

11.
By incorporating Ball-Berry model of stomatal conductance into the models of photosynthesis and transpiration, a model of leaf water use efficiency (WUE) as affected by several environmental variables [irradiance (Ⅰ), vapor pressure deficit (VPD) and atmospheric CO2 concentration (Ca) ] was constructed. Because the environmental variables influenced the photosynthetic rate and transpiration rate in different ways, the changes of leaf WUE with these factors were quite complicated. The rates of photosynthesis and transpiration of wheat leaves were also measured in the phytotron where the environmental variables were kept within certain ranges, and leaf WUE was calculated therefrom. The results of simulation fit quite well with the measurements except at high Ca.  相似文献   

12.
Increased leaf phosphorus (P) concentration improved the water-use efficiency (WUE) and drought tolerance of regularly defoliated white clover plants by decreasing the rate of daily transpiration per unit leaf area in dry soil. Night transpiration was around 17% of the total daily transpiration. The improved control of transpiration in the high-P plants was associated with an increased individual leaf area and WUE that apparently resulted from net photosynthetic assimilation rate being reduced less than the reductions in the transpiration (27% vs 58%). On the other hand, greater transpiration from low-P plants was associated with poor stomatal control of transpirational loss of water, less ABA in the leaves when exposed to dry soil, and thicker and smaller leaf size compared with high-P leaves. The leaf P concentration was positively related with leaf ABA, and negatively with transpiration rates, under dry conditions ( P < 0.001). However, leaf ABA was not closely related to the transpiration rate, suggesting that leaf P concentration has a greater influence than ABA on the transpiration rates.  相似文献   

13.
土壤水分状况及环境条件对水稻蒸腾的影响   总被引:25,自引:6,他引:19  
在南方红壤区用田间测坑试验,研究了高、中、低3种土壤水分条件下的早、晚稻蒸腾速率和水分利用效率的变化,蒸腾日变化结果表明,蒸腾速率受许多田间小气候因子的影响,相关分析及多元逐步回归分析表明,叶片与空气相对湿度差和叶面温度对水稻叶片蒸腾影响最大,处理B(中等土壤水分条件)可以明显提高叶片水利用率和产是,处理C提高了叶片水分利用效率,却导致晚稻减产,早稻中、低土壤水分条件可以减小叶片蒸腾速率,而晚稻上并不能明显减少叶片蒸腾。  相似文献   

14.
半干旱黄土丘陵区五种植物的生理生态特征比较   总被引:20,自引:0,他引:20  
通过测定陕北黄土丘陵区5种植物在旱季的光合速率、蒸腾速率和叶水势日变化,将植物划分为不同的水分生态适应类型.结果表明:柳枝稷的光合生理特征属于高光合、低蒸腾和高水分利用效率类型,其抗旱适应性特征属于高水势延迟脱水类型;苜蓿属于高光合高蒸腾低水分利用效率类型,耐旱性为高水势延迟脱水型;达乌里胡枝子属于低光合、低蒸腾、低水分利用效率类型,耐旱性为高水势延迟脱水型;白羊草属于高光合、蒸腾较高的水分利用效率中等型,耐旱性属于能忍耐脱水造成的低水势的一类.沙打旺属于高光合中等蒸腾速率中等水分利用效率类型,耐旱性为低水势延迟脱水型.  相似文献   

15.
The productivity of short‐rotation coppice (SRC) plantations with poplar (Populus spp.) strongly depends on soil water availability, which limits the future development of its cultivation, and makes the study of the transpirational water loss particularly timely under the ongoing climate change (more frequent drought and floods). This study assesses the transpiration at different scales (leaf, tree and stand) of four poplar genotypes belonging to different species and from a different genetic background grown under an SRC regime. Measurements were performed for an entire growing season during the third year of the third rotation in a commercial scale multigenotype SRC plantation in Flanders (Belgium). Measurements at leaf level were performed on specific days with a contrasted evaporative demand, temperature and incoming shortwave radiation and included stomatal conductance, stem and leaf water potential. Leaf transpiration and leaf hydraulic conductance were obtained from these measurements. To determine the transpiration at the tree level, single‐stem sap flow using the stem heat balance (SHB) method and daily stem diameter variations were measured during the entire growing season. Sap flow‐based canopy transpiration (Ec), seasonal dry biomass yield, and water use efficiency (WUE; g aboveground dry matter/kg water transpired) of the four poplar genotypes were also calculated. The genotypes had contrasting physiological responses to environmental drivers and to soil conditions. Sap flow was tightly linked to the phenological stage of the trees and to the environmental variables (photosynthetically active radiation and vapor pressure deficit). The total Ec for the 2016 growing season was of 334, 350, 483 and 618 mm for the four poplar genotypes, Bakan, Koster, Oudenberg and Grimminge, respectively. The differences in physiological traits and in transpiration of the four genotypes resulted in different responses of WUE.  相似文献   

16.
Rates of water uptake by individual trees in a native Australian forest were measured on the Liverpool Plains, New South Wales, Australia, using sapflow sensors. These rates were up-scaled to stand transpiration rate (expressed per unit ground area) using sapwood area as the scalar, and these estimates were compared with modelled stand transpiration. A modified Jarvis-Stewart modelling approach (Jarvis 1976), previously used to calculate canopy conductance, was used to calculate stand transpiration rate. Three environmental variables, namely solar radiation, vapour pressure deficit and soil moisture content, plus leaf area index, were used to calculate stand transpiration, using measured rates of tree water use to parameterise the model. Functional forms for the model were derived by use of a weighted non-linear least squares fitting procedure. The model was able to give comparable estimates of stand transpiration to those derived from a second set of sapflow measurements. It is suggested that short-term, intensive field campaigns where sapflow, weather and soil water content variables are measured could be used to estimate annual patterns of stand transpiration using daily variation in these three environmental variables. Such a methodology will find application in the forestry, mining and water resource management industries where long-term intensive data sets are frequently unavailable.  相似文献   

17.
不同年代推出的冬小麦品种叶片气体交换日变化的差异   总被引:3,自引:0,他引:3  
选择 6 0年来北京地区广泛种植的 3个冬小麦 (TriticumaestivumL .)品种 ,在相同的环境条件下种植。为了研究它们的产量与单位叶面积的净光合速率 (Pn)的关系 ,测定了不同生育期Pn、蒸腾速率 (Tr)的日变化 ,并用Pn/Tr计算叶片瞬时的水分利用率 (WUE)。结果表明 :单位叶面积净光合速率与产量之间的关系随生育期不同而变化。在拔节期高产品种“京冬 8号”(九十年代推出 )的光合速率和蒸腾速率在一天中总是最高 ,一天中差异最大时 ,分别比低产品种“燕大 1817”(四十年代推出 )高 77%和 6 9%。而其水分利用率却小于低产品种。这种差异随小麦的生长发育而变化 ,一般上午 10 :0 0前“京冬 8号”的光合速率较高 ,而 10 :0 0后“燕大 1817”的光合速率较高。到腊熟期 ,低产品种“燕大 1817”的光合速率在一天中始终最高。蒸腾速率的变化规律与光合速率相似 ,然而“燕大1817”叶片的水分利用率一般最高。与现代推出的品种不同 ,老品种“燕大 1817”叶片的光合作用午休现象不明显 ,说明它可能具有一定的抗光氧化性。我们认为 ,在品种改良的过程中 ,叶片光合作用的潜力可能有所提高 ,但它的抗光氧化性可能减弱。  相似文献   

18.
冬小麦对有限水分高效利用的生理机制   总被引:18,自引:3,他引:15  
通过对不同土壤供水条件下的孕穗开花期的冬小麦叶片CO2/H2O气体交换参数的系统测定,研究了光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、细胞间隙CO2浓度(Ci)、叶温(Tl)与水分利用效率(WUE)间的关系。结果表明,WUE并不随Pn的增长直线增长,而是呈现出二次曲线的变化趋势;只有当蒸腾达到一定程度时,Tr才对WUE产生影响,而Tr过大时WUE则有下降的趋势;WUE与Ci呈负相关,随Ci的增加WUE呈递减趋势;叶温升高对光合和蒸腾都有促进作用,当超过了某种限度则表现为抑制作用,表明在一定温度范围内,Tl升高对水分利用不利;随Gs的增大,WUE增大到一定程度则不再增加,甚至出现一种回落趋势.  相似文献   

19.
比较盆栽 生榕树和两栖型树的形态差异、叶片叶绿素含量、叶绿素荧光特性和气体交换的日变化。两栖型榕树具有较发达的气生根和水生不定根,叶片比陆生榕树宽,并有向中生性 倾向,陆生榕树的叶绿素含量比两栖榕树高,净光合速率略高于水培两栖型榕树,但明显高于土培两栖型榕树,蒸腾速率以水培两栖型树最高,陆生榕树次之,土培两栖型榕树最低,线性回归分析表明,三者的叶片气孔导度与净光合速率变化均呈正相关,气孔导度的变化  相似文献   

20.
不同施肥对小时杨小老树光合速率、蒸腾速度、单叶面积均有明显的提高作用,水分利用率则表现出明显差异,随施磷肥量增加,光合作用增加明显而蒸腾作用基本一致,水分利用率则上升明显,N肥处理则水分利用率下降。N、P混施叶面积增加明显。  相似文献   

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