期刊文献+
共找到897篇文章
< 1 2 45 >
每页显示 20 50 100
EFFECTS OF TEMPERATURE AND DISSOLVED OXYGEN CONTENT ONOXYGEN CONSUMPTION RATE OF CHINESE PRAWN, GIANT TIGER PRAWN AND GIANT FRESHWATER PRAWN 被引量:1
1
作者 戴习林 臧维玲 +4 位作者 王为东 施永海 刘文翠 徐桂荣 李士华 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1999年第2期119-124,共6页
temperature and the diasolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn (Penaeus chinensis), giant tiger prawn (P. monodon) and giant freshwater prawn(Macrobrachium rosenbergii). There... temperature and the diasolved oxygen content affect the oxygen consumption of juveniles of Chinese prawn (Penaeus chinensis), giant tiger prawn (P. monodon) and giant freshwater prawn(Macrobrachium rosenbergii). There is good correlation between the oxygen consumption rate (V, mg/g·h) of the above three prawn species and the water temperature, and dissolved oxygen. In the range of test temperature, V increased with water temperature and diassolved oxygen content. The V of the above three prawn species increased 0.085 mg/g·h, 0. 093 mg/g·h and 0. 08 mg/g·h respectively with each ℃ of rising temperature. The comatose point and stifling point of the juveniles rose obviously at unsuitable temperature. 展开更多
关键词 water TEMPERATURE dissolved OXYGEN JUVENILE instantaneous rate OXYGEN consumption
下载PDF
Effect of Irrigation System, Tillage System, and Seeding Rates on Wheat (<i>Triticum aestivum</i>L.) Growth, Grain Yield and Its Water Consumption and Efficiency
2
作者 Alaa M. Akol Nadine Nassif +3 位作者 Khudhair Abbas Jaddoa Haider M. Zwain Kareem Radhi Nadhir Al-Ansari 《Engineering(科研)》 2021年第11期574-594,共21页
<span style="font-family:Verdana;">A field trial was conducted at a private farm in AL-Hashimiya district Babylon Governorate—the republic of Iraq during the 2016</span><span style="font... <span style="font-family:Verdana;">A field trial was conducted at a private farm in AL-Hashimiya district Babylon Governorate—the republic of Iraq during the 2016</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">2017 and 2017</span><span style="font-family:Verdana;">-</span><span style="font-family:;" "=""><span style="font-family:Verdana;">2018 growing seasons.</span><span style="color:red;"> </span><span style="font-family:Verdana;">This study was conducted using two irrigation methods, sprinkler and surface irrigation, for each of them had three Tillage methods (zero-tillage</span></span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> medium-tillage</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> deep-tillage) and each tillage system had four seeding rate of wheat yield (120</span><span style="font-family:Verdana;">, </span><span style="font-family:Verdana;">180</span><span style="font-family:Verdana;">, </span><span style="font-family:Verdana;">240</span><span style="font-family:Verdana;">, </span><span style="font-family:Verdana;">300) kg<span style="white-space:nowrap;">&#8729;</span>ha</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">.</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">Results indicated that the consumptive water use was 557.5 and</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">535.9 mm for surface irrigation and 460.9 and 442.6 mm for sprinkler irrigation in </span><span style="font-family:Verdana;">the </span><span style="font-family:;" "=""><span style="font-family:Verdana;">2016-2017 and 2017-2018 growing seasons. Sprinkler irrigation significantly increased the flag leaf area with no significant effect on plant height. However, the minimum tillage and seeding rate (240 kg<span style="white-space:nowrap;">&#8729;</span>ha</span><sup><span style="font-family:Verdana;">-1</span></sup></span><span style="font-family:;" "=""><span style="font-family:Verdana;">) significantly increased the plant height and flag leaf </span><span style="font-family:Verdana;">area in both growing seasons. For the grain yield, the sprinkler irrigation, m</span><span style="font-family:Verdana;">inimum tillage, and seeding rate (240 </span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">kg<span style="white-space:nowrap;">&#8729;</span>ha</span><sup><span style="font-family:Verdana;">-1</span></sup></span><span style="font-family:;" "=""><span style="font-family:Verdana;">) also increased the plant height and flag leaf area by 13%, 10, % 11%, 11%, 12%, and 14% in both growing seasons, respectively, through an increased number of spikes/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, the number of grain spike-1, and 1000-grain weight in both growing seasons, respe</span></span><span style="font-family:Verdana;">ctively. Interestingly the grain yield was increased by 33% and 32% in both growing seasons under the effects of these three factors altogether, respectively. It can be concluded that these factors act synergistically, resulting in a significant improvement in the wheat grain-yield of, less consumptive water use, and high water use efficiency.</span> 展开更多
关键词 IRRIGATION Tillage system Seeding rates Wheat (Triticum Aestivum L.) Grain yield water consumption
下载PDF
The Dynamic Study on Transpiration Consumption of Black Locust Forest 被引量:2
3
作者 贺康宁 侯振宏 《Forestry Studies in China》 CAS 2001年第2期10-17,共8页
To know the annual water consumption of forest, it is necessary to acquire the annual transpiration value of stands. This paper is based on the data measured in the typical weather of the growth season, from 1998 to 2... To know the annual water consumption of forest, it is necessary to acquire the annual transpiration value of stands. This paper is based on the data measured in the typical weather of the growth season, from 1998 to 2000, with the LI 1600 Steady Porometer and the general weather information. The daily variation of transpiration in black locust forest ( Robinia pesudoacacia L.) is modeled by Penman Monteith equation. As a result of the model, a continuous daily transpiration in the growth season was calculated. The net radiation, intercepted by black locust forest canopy, was acquired from a semi empirical equation of measuring net radiation R n with the extinction coefficient k and leaf area index LAI . The canopy integral stomatic resistance is a mimesis with an empirical equation of measuring data. Compared with measuring data, the relative error of the modeled ones is less than 12% averagely. At last, the total transpiration of black locust forest during the period of 1998 and 2000 in the growth season of May to October, as an average transpiration of the different density stands, were 192 46, 187 07 and 195 59?mm respectively. 展开更多
关键词 black locust transpiration net radiation leaf area index extinction coefficient stomatic resistance water consumption
下载PDF
Towards a new avenue for rapid synthesis of electrocatalytic electrodes via laser-induced hydrothermal reaction for water splitting
4
作者 Yang Sha Menghui Zhu +6 位作者 Kun Huang Yang Zhang Francis Moissinac Zhizhou Zhang Dongxu Cheng Paul Mativenga Zhu Liu 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第1期340-351,共12页
Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring ... Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production. 展开更多
关键词 electrocatalytic electrode laser-induced hydrothermal reaction NiFe layered double hydroxides hydrogen evolution reaction water splitting energy consumption production rate
下载PDF
Transpiration Rate and Leaf Water Potential as Indices for Cassava Yield in Inland Valley Ecology
5
作者 M. T. Lahai I.J. Ekanayake 《Journal of Agricultural Science and Technology》 2010年第6期34-44,共11页
Differences in transpiration and leaf water potential (LWP) in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpirat... Differences in transpiration and leaf water potential (LWP) in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars. 展开更多
关键词 transpiration rate leaf water potential root yield cassava cultivars water table depth weather condition inland valley ecology.
下载PDF
Responses of the seedlings of five dominant tree species in Changbai Mountain to soil water stress 被引量:1
6
作者 代力民 李秋荣 +1 位作者 王淼 姬兰柱 《Journal of Forestry Research》 SCIE CAS CSCD 2003年第3期191-196,共6页
Soil water stress was studied on the potted seedlings of five dominant tree species (Pinus koraienes Sieb.et Zucc., Fraxinus mandshurica Rupr., Juglans mandshurica Maxim, Tilia amurensis Rupr. and Quercus mongolica Fi... Soil water stress was studied on the potted seedlings of five dominant tree species (Pinus koraienes Sieb.et Zucc., Fraxinus mandshurica Rupr., Juglans mandshurica Maxim, Tilia amurensis Rupr. and Quercus mongolica Fisch.ex Turcz) from the broadleaved/Korean pine forest in Changbai Mountain. Leaf growth, water transpiration and photosynthesis were compared for each species under three soil moisture conditions: 85%-100% (high water, CK), 65%-85% (Medium water, MW) and 45%-65% (low water, LW) of 37.4% water-holding capacity in field. The results showed that the characteristic of typical drought-resistance of the leaves is significantly developed. The net photosynthetic rate and water use efficiency of Fraxinus mandshurica were higher in MW than those in CK. But for the other four species, the net photosynthetic rate and water use efficiency in CK were lower than those in MW and LW. The transpiration rate responding to soil moistures varied from species to species. 展开更多
关键词 water stress Net photosynthesis transpiration rate water use efficiency Broadleaf/Korean pine forest
下载PDF
CO_2, H_2O exchange and stomatal regulation of regenerated Camptotheca acuminata plantlets during ex vitro acclimatization 被引量:1
7
作者 WANG Hui-mei LI Yan-hua GAO Yin-xiang ZU Yuan-gang 《Journal of Forestry Research》 SCIE CAS CSCD 2006年第4期273-276,共4页
For finding the changes in CO2, H20 exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate (Pn), respiration rate (Ro), l... For finding the changes in CO2, H20 exchange and their stomatal regulation during ex vitro acclimatization of regenerated Camptotheca acuminata plantlets, the net photosynthesis rate (Pn), respiration rate (Ro), light compensation point (Lc) and light saturation point (Ls), transpiration rate (Tr), stomatal conductance (gs) and water use efficiency(WUE) were measured during 37 days of ex vitro acclimatization. The results showed that Pn sharply increased until 29 days, then slightly decreased. A substantial decrease in Lc and a substantial increase of Ls in the former two weeks were observed, indicating the light regime enlargement for effective leaf photosynthesis. Tr and gs abruptly decreased during the first week then linearly increased until 29days ex vitro acclimatization, reflecting the strong regulation effect of stomata on water changes of ex vitro acclimating plantlets. Stomatal regulation effect on CO2 exchange was different from that on water exchange, i.e. P, was almost independent of gs during the first week, while P. was significantly correlated with gs thereafter (i.e. dual patterns). Different from dual patterns of gs-Pn relation, the Tr monotonously linearly increased with gs. Furthermore, WUE was almost independent on gs during the first week, while a marked decreasing tendency with gs was found thereafter. At the beginning of the acclimatization, WUE was mainly determined by photosynthetic capacity, while transpiration becomes a main determinant factor for WUE from 7 to 37 days' acclimatization. 展开更多
关键词 Camptotheca acuminate ACCLIMATIZATION Photosynthesis transpiration water use efficiency Relation between stomatal conductance (gs) and net photosynthesis rate (Pn) gs-WUE relation
下载PDF
Study on Transpiration and Stomatal Conductance Characteristics of C3 and C4 Plant 被引量:1
8
作者 MENG Jinghui LU Yuanchang +1 位作者 Ronald Kohne LIU Gang 《Journal of Northeast Agricultural University(English Edition)》 CAS 2009年第4期1-8,共8页
The transpiration experiment was done under greenhouse conditions with a C3 plant sweet pepper (Capsicum annuum Linn.) and two C4 plants, sorghum (Sorghum bicolor L.Moench) and maize (Zea mays Linn.). Three spec... The transpiration experiment was done under greenhouse conditions with a C3 plant sweet pepper (Capsicum annuum Linn.) and two C4 plants, sorghum (Sorghum bicolor L.Moench) and maize (Zea mays Linn.). Three species were irrigated with three different water treatment levels of 100%, 66% and 33% which gave a comparison of tolerance and adaptation to irrigation and two different levels of water stress. The measurements of transpiration rate and stomatal conductance were done between 8.00 a.m. and 16.00 p.m. with measurements about each 1.5 h with an infrared gas analyzer. The results showed that Z. mays probably due to a higher leaf area had very low values and was significantly different (LSD pairwise comparison) from C. annuum and S. bicolor. The hypotheses that C4 plants and C3 plants have different transpiration rates and stomatal conductance could not be shown with the results. However, the hypotheses that for the same species, the highest values in transpiration rate and stomatal conductance were with the 100% irrigation treatment and the lowest values were with the 33% irrigation treatment could be accepted due to the results of this trial. 展开更多
关键词 transpiration rate stomatal conductance water stress
下载PDF
Analysis of Energy Consumption and Energy Conservation Measures for RFCCU at Shengli Petrochemical Company
9
作者 Li Ning Xu Zhenling (SINOPEC Shengli Petrochemical Complex, Dongying 257105) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2006年第2期45-53,共9页
This article introduces a string of energy conservation measures adopted over the past sev- eral years by the RFCC unit at Shengli Petrochemical Complex, including the optimization of feedstock properties, the adoptio... This article introduces a string of energy conservation measures adopted over the past sev- eral years by the RFCC unit at Shengli Petrochemical Complex, including the optimization of feedstock properties, the adoption of high-efficiency atomizing nozzles, the revamp of CO boiler, the atomization by means of dry gas, the post-burning of flue gas as well as the application of frequency converting machines and pumps, resulting in ideal effects. The energy consumption of the RFCC unit was gradually decreased to 2984.25 MJ/t from the original level of 3716.99 MJ/t. After comparing basic energy con- sumption values with actual consumption values, the authors have set forward measures for further energy conservation, such as the recovery of low-temperature excess heat contained in oil/gas streams exiting from the fractionation tower top, addition of the fourth cyclone, delivery of hot oil slurry, and heat tracing with hot water. 展开更多
关键词 energy consumption of FCC unit coke buildup rate STEAM power consumption water consumption
下载PDF
Comparative Study of Transpiration in Cooling Effect of Tree Species in the Atmosphere
10
作者 S. K. Gupta Jeet Ram Hukum Singh 《Journal of Geoscience and Environment Protection》 2018年第8期151-166,共16页
Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with spe... Trees create microclimate under their crowns in comparison to the outside ambient atmosphere, which is a result of physical as well as physiological functions of the tree. The cooling produced by trees varies with species due to variation in several anatomical, structural and physiological attributes of the species. Transpiration is one of the most significant physiological functions performed by plants, which affects cooling produced by a tree under its shade. When solar energy impinges on the leaf, water emerges from its surface through transpiration taking the latent heat to convert it into water vapour. This leads to a rise in humidity of the atmosphere and reduction in temperature of the leaf. To remain leaf in equilibrium, it takes heat from the surrounding atmosphere resulting in reduction in temperature of surroundings. Since, transpiration takes place through stomata which are normally located on the ventral side of the leaf, this reduction in temperature is more experienced beneath the crown of the tree. Therefore, the present study was carried out to analyze the role of transpiration in cooling effect of five forestry tree species. The cooling produced by tree species under their shades has been found positively correlated to the transpiration rate whereas the rate of transpiration has responded positively to the ambient temperature and water conductance. However, no definite relationship has been found between frequency of open stomata and the rate of transpiration. 展开更多
关键词 rate of transpiration AMBIENT Temperature Cooling STOMATA MICROCLIMATE water CONDUCTANCE Root Pressure
下载PDF
Comparison of Gas Exchange Characteristic in Leaves of Soybean Varieties with Different Yield Levels
11
作者 耿艳秋 张治安 +2 位作者 李大勇 赵洪祥 郑洪兵 《Agricultural Science & Technology》 CAS 2010年第8期98-101,共4页
[Objective] The aim was to explore the gases exchange characteristic in leaves of soybean cultivars at different yield levels to provide a certain theories basis for high yield breeding and cultivation of soybean cult... [Objective] The aim was to explore the gases exchange characteristic in leaves of soybean cultivars at different yield levels to provide a certain theories basis for high yield breeding and cultivation of soybean cultivars. [Method] Nine soybean cultivars divided into three yield levels were planted under the same environmental condition. At V4(seedling),R2(blooming),R4(pod-bearing),R6(pod-filling) and R7(maturing) growth stages,the net photosynthetic rate (Pn),stomatal conductance (Gs) and transpiration rate (Tr) in soybean leaves were measured with Li-6400 portable photosynthesis system. [Result] At all growth stages,the net photosynthetic rate,stomatal conductance in leaves of high yield soybean cultivars were significantly higher than low yield soybean cultivars. At V4,R2 and R4 stages,transpiration rate in leaves of high yield soybean cultivars was significantly higher than low yield soybean cultivars; there was no significant difference on transpiration rate in leaves of soybean cultivars at different yield levels at R6 and R7 stage. At V4 and R2 stage,water use efficiency (WUE) in leaves of soybean cultivars at different yield showed a trend of low yield cultivarsmiddle yield cultivarshigh yield cultivars,while it appeared high yield cultivarsmiddle yield cultivarslow yield cultivars at R4,R6 and R7 stage. [Conclusion] The gases exchange capacity in leaves of high yield soybean cultivars was significantly higher than low yield soybean cultivars,which had provided physiological basis of high yield. The net photosynthetic rate could be used as an selection index of high yield soybean. 展开更多
关键词 SOYBEAN Net photosynthetic rate Stomatal conductance transpiration rate water use efficiency
下载PDF
Changes of Gas Exchanges in Leaves of Different Cultivars of Winter Wheat Released in Different Years 被引量:5
12
作者 刘合芹 蒋高明 +6 位作者 张其德 孙家柱 渠春梅 郭仁俊 高雷明 白克智 匡廷云 《Acta Botanica Sinica》 CSCD 2002年第8期913-919,共7页
Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features w... Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features were investigated. Daily changes of net photosynthetic rate (P-n), transpiration (T-r) in different growth stages were measured in order to find the relationship between leaf photosynthesis and yield. Instantaneous water use efficiency (WUE) of leaf was calculated from P-n/T-r. It is suggested that relationship between photosynthetic rate and yield changed with the developing stages of wheat. High yield wheat cultivar Jingdong 8 (released in the 1990s) had a higher photosynthetic rate ( the maximal P-n increased by 77%) and transpiration rate (the maximal T-r increased by 69%), but a lower WUE than the low yield cultivar Yanda 1817 (released in the 1940s) during the day time at stem elongation stage. However; difference of P-n among the three cultivars changed with wheat growth process. Before 10 o'clock P-n in leaves of Jingdong 8 usually was the highest of the three cultivars, but P-n of Yanda 1817 was the highest after 10 o'clock. At dough ripe stage, P-n in leaves of Yanda. 1817 was the highest among the three cultivars during the whole day. The difference of changing trend of transpiration in three wheat cultivars was similar to P,, but WUE of Yanda 1817 was the highest in those three cultivars, indicating that the higher yield of Jingdong 8 was achieved via a greater consumption of water. Contrary to the cultivars released in the later period, midday depression of photosynthesis was small in Yanda 1817, which might suggest that Yanda 1817 was resistant to photoinhibition. It is possible that photosynthetic potential in leaves of wheat increased as wheat cultivars was improved over the past six decades. However, it became less resistant to photoinhibition. 展开更多
关键词 net photosynthesis daily change wheat cultivars transpiration rate water use efficiency
下载PDF
Canopy morphological changes and water use efficiency in winter wheat under different irrigation treatments 被引量:6
13
作者 ZHAO Hong-xiang ZHANG Ping +3 位作者 WANG Yuan-yuan NING Tang-yuan XU Cai-long WANG Pu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第4期1105-1116,共12页
Water is a key limiting factor in agriculture. Water resource shortages have become a serious threat to global food security. The development of water-saving irrigation techniques based on crop requirements is an impo... Water is a key limiting factor in agriculture. Water resource shortages have become a serious threat to global food security. The development of water-saving irrigation techniques based on crop requirements is an important strategy to resolve water scarcity in arid and semi-arid regions. In this study, field experiments with winter wheat were performed at Wuqiao Experiment Station, China Agricultural University in two growing seasons in 2013-2015 to help develop such techniques. Three irrigation treatments were tested: no-irrigation(i.e., no water applied after sowing), limited-irrigation(i.e., 60 mm of water applied at jointing), and sufficient-irrigation(i.e., a total of 180 mm of water applied with 60 mm at turning green, jointing and anthesis stages, respectively). Leaf area index(LAI), light transmittance(LT), leaf angle(LA), transpiration rate(Tr), specific leaf weight, water use efficiency(WUE), and grain yield of winter wheat were measured. The highest WUE of wheat in the irrigated treatments was found under limited-irrigation and grain yield was only reduced by a small amount in this treatment compared to the sufficient irrigation treatment. The LAI and LA of wheat plants was lower under limited irrigation than sufficient irrigation, but canopy LT was greater. Moreover, the specific leaf weight of winter wheat was significantly lower under sufficient than limited irrigation conditions, while the leaf Tr was significantly higher. Correlation analysis showed that the increased LAI was associated with an increase in the leaf Tr, but the specific leaf weight had the opposite relationship with transpiration. Optimum WUE occurred over a reasonable range in leaf Tr. In conclusion, reduced irrigation can optimize wheat canopies and regulate water consumption, with only small reductions in final yield, ultimately leading to higher wheat WUE and water saving in arid and semi-arid regions. 展开更多
关键词 WINTER wheat limited-irrigation CANOPY characteristics transpiration rate water use efficiency
下载PDF
Root distribution of three co-occurring desert shrubs and their physiological response to precipitation 被引量:4
14
作者 GuiQing Xu Yan Li 《Research in Cold and Arid Regions》 2009年第2期120-127,共8页
Root distribution of three desert shrubs,Tamarix ramosissima Ledeb.,Haloxylon ammodendron(C.A.Mey.) Bunge and Reaumuria soongorica(Pall.) Maxim.was investigated under co-occurring conditions using a method for excavat... Root distribution of three desert shrubs,Tamarix ramosissima Ledeb.,Haloxylon ammodendron(C.A.Mey.) Bunge and Reaumuria soongorica(Pall.) Maxim.was investigated under co-occurring conditions using a method for excavating the whole root system.Assimilation shoot water potential and transpiration rates were monitored during the wet-dry cycle.Leaf-specific apparent hydraulic conductance and the index of water stress impact for the three species were calculated from shoot water potential and transpiration rate.The results showed that,along the soil profile,the root system of T.ramosissima mainly distributed at 50 to 310 cm interval,with an average total absorbing root-surface area of 30,249.2 cm2 per plant;the root system of H.ammodendraom distributed at 0 to 250 cm interval with an average total absorbing root-surface area of 12,847.3 cm2 per plant;the root system of R.soongorica distributed at 0-80 cm interval,with an average total absorbing root-surface area of 361.8 cm2.The root distribution shows the following:T.ramosissima uses groundwater as its main water source;H.ammodendraom uses both groundwater and rainwater;and R.soongorica uses rainwater only.During the wet-dry cycle,the hydraulic parameters of T.ramosissima showed no responses to precipitation.R.soongorica responded most significantly,and the responses of H.ammodendraom were intermediate.In conclusion,the plant response to rain events is closely related to their root distribution and plant water-use strategy. 展开更多
关键词 soil water content root distribution assimilation shoot water potential transpiration rate leaf-specific apparent hydraulic conductance
下载PDF
Application of genetic algorithm in cold end system optimization for thermal power plants
15
作者 LI Qianjun LIU Guangyao +2 位作者 ZHAO Quanbin JU Lincang CHONG Daotong 《热力发电》 CAS 北大核心 2014年第1期26-30,共5页
关键词 热力发电 电力行业 电力技术 电力管理
下载PDF
西藏东南部云杉的蒸腾耗水规律研究
16
作者 李艳 尤勇刚 +1 位作者 韩立鹤 赵留辉 《西部林业科学》 CAS 北大核心 2024年第5期123-129,139,共8页
为了解不同胸径云杉的蒸腾耗水规律,在西藏东南波密县云杉森林设置3个100 m×100 m样地,采用SFM1流体流量传感器,通过热比率法对西藏东南部不同胸径云杉树干液流速率进行监测。同时,利用美国ClimaVUE 50气象站对云杉群落生境的气象... 为了解不同胸径云杉的蒸腾耗水规律,在西藏东南波密县云杉森林设置3个100 m×100 m样地,采用SFM1流体流量传感器,通过热比率法对西藏东南部不同胸径云杉树干液流速率进行监测。同时,利用美国ClimaVUE 50气象站对云杉群落生境的气象因子进行监测。在日尺度和季节尺度上,分析不同胸径云杉的液流速率与气象因子的动态变化规律,以及每小时液流速率与气象因子的相关性。结果显示:(1)不同胸径云杉树干液流速率均表现出典型的昼高夜低的单峰型日变化特征,且不同月份的平均树干液流速率不同,云杉瞬间最大液流速率分别为207.34 cm·h^(-1)(胸径10~20 cm, 7月3日,184 d)、207.84 cm·h^(-1)(胸径20~30 cm, 5月29日,149 d)、286.18 cm·h^(-1)(胸径30~40 cm, 7月8日,189 d)。(2)影响云杉森林林分蒸腾的主要气象因子为VPD(饱和水汽压差)、太阳辐射、风速和降雨。(3)在生长季,不同胸径云杉蒸腾耗水量变化均呈“先增加后减少”的趋势。同时胸径10~20 cm的云杉月耗水量最小出现在2月份(约为0.17 m^(3)),最大出现在7月份(约为0.47 m^(3));胸径20~30 cm的云杉月耗水量最小出现在12月份(约为0.62 m^(3)),最大出现在5月份(约为1.61m^(3));胸径30~40 cm的云杉月耗水量最小出现在1月份(约为1.35 m^(3)),最大出现在7月份(约为3.87 m^(3))。 展开更多
关键词 液流速率 蒸腾耗水量 气象因子 藏东南 云杉
下载PDF
板栗全生长季树干液流及蒸腾耗水特征
17
作者 郭燕 张树航 +6 位作者 张馨方 李颖 刘金雨 范丽颖 刘师源 高倩 王广鹏 《中国农业科学》 CAS CSCD 北大核心 2024年第9期1794-1806,共13页
【目的】明确板栗(Castanea mollissima Bl.)蒸腾耗水特征,为板栗园制定科学合理的水分管理措施提供理论参考。【方法】采用热扩散探针法,对‘大板红’板栗植株全生长季树干液流速率进行连续监测,并同步观测7个相关环境因子:太阳辐射(so... 【目的】明确板栗(Castanea mollissima Bl.)蒸腾耗水特征,为板栗园制定科学合理的水分管理措施提供理论参考。【方法】采用热扩散探针法,对‘大板红’板栗植株全生长季树干液流速率进行连续监测,并同步观测7个相关环境因子:太阳辐射(solar radiation,SR)、水汽压亏缺(vapor pressure deficit,VPD)、空气温度(air temperature,AT)、空气相对湿度(air relative humidity,ARH)、风速(wind speed,WS)、土壤温度(soil temperature,ST)和土壤湿度(soil relative humidity,SRH),解析板栗树干液流规律和耗水特征及其与环境因子间的关联性。【结果】板栗树干明显液流启动于5月3日,结束于10月26日,前后历时176 d。板栗全生长季晴天树干液流速率日变化呈单峰“几”字形曲线,其在6、7、8月每日启动到达峰值时间早于5、9、10月,而下降时间晚于5、9、10月,致6、7、8月份液流速率峰值持续时间长于5、9、10月。板栗全生长季液流速率日均值、日均耗水量和月耗水量由高到低排序均为8月>7月>6月>9月>5月>10月,其中显著性检验表明7月和8月之间无显著差异,但显著高于其他月份。夜间液流量占比由高到低排序为10月>9月>5月>6月>7月>8月,其中显著性检验表明10月、9月和5月显著高于6月、7月和8月。板栗全生长季树干液流速率与太阳辐射、水汽压亏缺、空气温度和风速均呈极显著正相关,而与空气相对湿度均呈极显著负相关。分别建立了5—10月板栗树干液流速率与7个环境因子的6个回归模型。【结论】板栗树干有明显液流始于5月初、终于10月末;7—8月是板栗的关键需水期;建立的板栗植株液流速率与环境因子的回归模型,可用于通过环境因子估测不同月份及整个生长季的植株耗水量。 展开更多
关键词 板栗 液流速率 耗水量 环境因子 特征
下载PDF
广东毛茶资源及其生理生态特征研究
18
作者 缪绅裕 陈健辉 +2 位作者 廖初琴 黄建睿 陶文琴 《防护林科技》 2024年第2期33-36,共4页
为了解毛茶资源及其生理生态特征,采用样线法对广东67个自然保护地的毛茶资源进行了野外调查,测定了毛茶的净光合速率、蒸腾速率及环境因子的日变化、叶绿度、植物及生境的碳氮含量、稳定碳氮同位素组成。结果表明:在10个保护地的123个... 为了解毛茶资源及其生理生态特征,采用样线法对广东67个自然保护地的毛茶资源进行了野外调查,测定了毛茶的净光合速率、蒸腾速率及环境因子的日变化、叶绿度、植物及生境的碳氮含量、稳定碳氮同位素组成。结果表明:在10个保护地的123个生境记录到280株毛茶,其中珠海担杆岛和二洲岛、斗门黄杨山和锅盖栋、台山上川岛为毛茶新增分布点,以深圳三洲田的62处148株为最多。毛茶植物体的碳、氮含量显著高于生境土壤和岩石;叶片δ^(13)C、δ^(15)N比率分别为-34.51‰和-0.94‰,显著低于或高于根、茎的相应值。正常绿色叶片叶绿度(SPAD值)为41.0,显著高于黄叶的17.6;测定日的净光合速率平均为5.55μmol·m^(-2)·s^(-1);蒸腾速率平均为0.59 mmol·m^(-2)·s^(-1);水分利用效率平均为9.13,显示毛茶在冬季气温和大气相对湿度相对较低的情况下,以较低的净光合速率、蒸腾速率但较高的水分利用效率维持正常的生理活动。 展开更多
关键词 毛茶 稳定碳氮同位素 叶绿度 光合速率 蒸腾速率 水分利用效率
下载PDF
基于贝叶斯分析的干热河谷区橙子林冠层蒸腾耗水模拟 被引量:1
19
作者 张晶莹 陈滇豫 +3 位作者 马永胜 胡笑涛 杜敬斌 王书剑 《农业机械学报》 EI CAS CSCD 北大核心 2024年第1期305-315,共11页
需耗水机制是进行农田/果园水分管理和调控的基础。本文聚焦蒸腾耗水机制,基于贝叶斯参数估计方法对比了不同Jarvis-Stewart模型配置对干热河谷区橙子林蒸腾耗水量的模拟效果,探索了Jarvis-Stewart模型在影响因子交互效应较强条件下蒸... 需耗水机制是进行农田/果园水分管理和调控的基础。本文聚焦蒸腾耗水机制,基于贝叶斯参数估计方法对比了不同Jarvis-Stewart模型配置对干热河谷区橙子林蒸腾耗水量的模拟效果,探索了Jarvis-Stewart模型在影响因子交互效应较强条件下蒸腾耗水模拟中的适用性。结果表明,考虑不同影响因子及其限制函数会对模拟效果产生较大影响,其中考虑土壤含水率和叶面积指数对模拟效果改善作用明显,而引入饱和水汽压差和气温则不同程度地降低模拟精度;考虑的影响因子越多,模型结构越复杂,模拟效果不一定越好;筛选出的最佳模型结构基本实现了橙子林蒸腾耗水的可靠模拟,但模拟效果仍有明显改进空间,因此,应综合考虑模型复杂程度、模拟精度及不确定性等,进一步探究适宜的模型结构。研究可为果园节水灌溉技术体系建立和水分管理优化提供科学依据,也能为耗水模型的进一步发展和完善提供理论支撑。 展开更多
关键词 橙子林 蒸腾耗水模拟 干热河谷 Jarvis-Stewart模型 贝叶斯参数估计
下载PDF
干热河谷区橙子树蒸腾耗水环境响应与生理调节研究
20
作者 侯盼盼 朱厚霖 +3 位作者 陈滇豫 胡笑涛 张晶莹 孙骏 《农业机械学报》 EI CAS CSCD 北大核心 2024年第4期262-271,共10页
为探究西南干热河谷地区典型经济林木橙子树的蒸腾耗水机制,利用热扩散式探针TDP、冠层分析仪、土壤水分传感器TDR、全自动气象站等设备获取橙子树蒸腾量、叶面积指数、土壤含水率和气象因子(气温、辐射、饱和水汽压差、降雨量等)的长... 为探究西南干热河谷地区典型经济林木橙子树的蒸腾耗水机制,利用热扩散式探针TDP、冠层分析仪、土壤水分传感器TDR、全自动气象站等设备获取橙子树蒸腾量、叶面积指数、土壤含水率和气象因子(气温、辐射、饱和水汽压差、降雨量等)的长期数据。对橙子树蒸腾规律的环境控制和生理调节特征进行系统研究,结果表明:相比于干季和雨季,干热季橙子树表现出较为保守的水分利用机制,日蒸腾量、冠层导度和退耦系数都显著低于其他两个季节。干季和雨季,橙子树蒸腾活动受太阳辐射和饱和水汽压差的交替控制,而干热季蒸腾活动主要受饱和水汽压差的驱动。冠层导度与气象因子日内动态变化特征之间存在时滞效应,且这种效应在不同天气不同季节具有差异。受叶面积指数影响,饱和水汽压差与冠层导度在整个年份呈负对数相关关系,其他环境因子与冠层导度在叶面积指数小于4 m^(2)/m^(2)时呈负对数相关关系,大于等于4 m^(2)/m^(2)时呈二次函数相关关系。不同环境条件下虽然冠层导度对饱和水汽压差的敏感性不同,但蒸腾耗水在大多数环境条件下基本遵循等水势调节策略,但个别环境条件下存在环境胁迫应对失衡风险。研究结果可为干热河谷区橙子园环境胁迫诊断提供直接依据,有利于灌溉制度的科学优化和节水调控技术体系的高效制定。 展开更多
关键词 橙子树 蒸腾耗水 冠层导度 干热河谷
下载PDF
上一页 1 2 45 下一页 到第
使用帮助 返回顶部