共查询到20条相似文献,搜索用时 46 毫秒
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黄土丘陵沟壑区狼牙刺的光合特征及其水分利用效率 总被引:2,自引:0,他引:2
~~黄土丘陵沟壑区狼牙刺的光合特征及其水分利用效率@卜崇峰$中国科学院地理科学与资源研究所!北京100101;中国科学院水利部水土保持研究所陕西杨陵712100;中国科学院研究生院,北京100039;中国科学院陆地水循环及地表过程重点实验室,北京100101
@刘国彬$中国科学院水利部水土保持研究所!陕西杨陵712100
@赵姚阳$南京大学城市与资源学系!南京210093~~~~[1] JIANG G M (蒋高明) , ZHU G J(朱桂杰). Effects of natural hightemperature and irradiation on photosynthesis and related parameters in three arid sandy shrub… 相似文献
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伤根对谷子叶片光合速率及其产量的影响 总被引:2,自引:0,他引:2
~~伤根对谷子叶片光合速率及其产量的影响@柴世伟$同济大学环境科学与工程学院!上海200092;中国科学院水利部水土保持研究所,陕西杨陵712100
@刘文兆$同济大学环境科学与工程学院!上海200092
@李秧秧$中国科学院水利部水土保持研究所!陕西杨陵712100~~~~[1] LIU W Z (刘文兆) , LI Y Y(李秧秧). Effect of crop root-cutting on grain yield and water use efficiency: a review[J]. Acta Agriculturae
Boreali-Occidentalis Sinica (西北植物学报)2003,23(8): 1 320- 1 324(in Chinese).
[2] YU S L(余松烈… 相似文献
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OPS玻璃化冷冻对山羊卵母细胞超微结构的影响@刘海军$天津市畜牧兽医研究所! 中国 天津 300112
@张美佳$成都野生濒危动物繁殖与遗传开放实验室! 中国 成都610081
@候蓉$成都野生濒危动物繁殖与遗传开放实验室! 中国 成都610081
@张志和$成都野生濒危动物繁殖与遗传开放实验室! 中国 成都610081
@王基山$成都野生濒危动物繁殖与遗传开放实验室! 中国 成都610081
@兰景超$成都野生濒危动物繁殖与遗传开放实验室! 中国 成都610081
@钱菊汾$西北农林科技大学畜牧兽医学院!, 中国 陕西杨凌712100
@张安… 相似文献
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~~烟草花粉母细胞细胞融合过程中微丝的免疫定位观察@杨军$兰州大学细胞生物学研究所!兰州730000;西华师范大学生命科学学院,四川南充637002;西华师范大学珍稀动植物研究所,四川南充637002
@彭正松$兰州大学细胞生物学研究所!兰州730000;西华师范大学生命科学学院,四川南充637002
@李卫$兰州大学细胞生物学研究所!兰州730000
@高欢欢$兰州大学细胞生物学研究所!兰州730000
@郑国锠$兰州大学细胞生物学研究所!兰州730000~~~~[1] ZHENG G CH(郑国錩).Cytormxis[J]. Acta Gen. Sin. (遗传学报) ,1974,1(1) ;117-124(in Ch… 相似文献
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大鼠妊娠早期血清雌、孕激素水平的变化以及屈洛昔芬对妊娠大鼠的抗着床作用@黄勇$中国科学院上海药物研究所药理一室! 中国上海 200031
@冷颖$中国科学院上海药物研究所药理一室! 中国上海 200031
@曹霖$中国科学院上海药物研究所药理一室! 中国上海 200031
@顾芝萍$中国科学院上海药物研究所药理一室! 中国上海 200031 相似文献
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细菌视紫红质分支光循环研究的新起点——蓝膜@张国艳$中国科学院化学研究所分子科学中心!北京100080
@李宝芳$中国科学院化学研究所分子科学中心!北京100080
@江龙$中国科学院化学研究所分子科学中心!北京100080~~ 相似文献
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黄孢原毛平革菌降解机制研究进展@唐振兴$浙江工业大学!博13#,浙江杭州310014
@石陆娥$浙江工业大学!博13#,浙江杭州310014
@单剑峰$浙江工业大学!博13#,浙江杭州310014~~~~[1]李慧蓉.白腐真菌的研究进展[J].环境污染治理技术与设备,1998,4(6):2-4.
[2] Kawai et al . ligin - degrading enzyme from Phanerochacte chrysospfeium Purification Characterization and Catalytic properties of a Unique H2O2-requiring oxygense[J]. Proc. Natl. Aead. Set. USA, 1994,81(2) :280-284.
[3] Keyser T K. and Zeik… 相似文献
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Freshwater scarcity is a growing concern, placing considerable importance on the accuracy of indicators used to characterize and map water scarcity worldwide. We improve upon past efforts by using estimates of blue water footprints (consumptive use of ground- and surface water flows) rather than water withdrawals, accounting for the flows needed to sustain critical ecological functions and by considering monthly rather than annual values. We analyzed 405 river basins for the period 1996-2005. In 201 basins with 2.67 billion inhabitants there was severe water scarcity during at least one month of the year. The ecological and economic consequences of increasing degrees of water scarcity--as evidenced by the Rio Grande (Rio Bravo), Indus, and Murray-Darling River Basins--can include complete desiccation during dry seasons, decimation of aquatic biodiversity, and substantial economic disruption. 相似文献
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Soil water availability for plants as quantified by conventional available water, least limiting water range and integral water capacity 总被引:1,自引:0,他引:1
Hossein Asgarzadeh Mohammad Reza Mosaddeghi Ali Akbar Mahboubi Akram Nosrati Anthony Roger Dexter 《Plant and Soil》2010,335(1-2):229-244
There are different approaches to define the soil available water (SAW) for plants. The objectives of this study are to evaluate the SAW values of 12 arable soils from Hamadan province (western Iran) calculated by plant available water (PAW), least limiting water range (LLWR) and integral water capacity (IWC) approaches and to explore their relations with Dexter’s index of soil physical quality (i.e., S-value). Soil water retention and mechanical resistance were determined on the intact samples which were taken from the 5–10 cm layer. For calculation of LLWR and IWC, the van Genuchten-Mualem model was fitted to the observed soil water retention data. Two matric suctions (h) of 100 and 330 cm were used for the field capacity (FC). There were significant differences (P?<?0.01) between the SAW values calculated by PAW100, PAW330, LLWR100, LLWR330 and IWC. The highest (i.e., 0.210 cm3 cm?3) and the lowest (i.e., 0.129 cm3 cm?3) means of SAW were calculated for the IWC and LLWR330, respectively. The upper limit of LLWR330 for all of the soils was h of 330 cm, and that of LLWR100 (except for one soil that was air-filled porosity of 0.1 cm3 cm?3) was h of 100 cm. The lower limit of LLWR330 and LLWR100 for five soils was h of 15,000 cm and for seven soils was mechanical resistance of 2 MPa. The IWC values were smaller than those of LLWR100 for two soils, equal to those of LLWR100 for three soils and greater than those of LLWR100 for the rest. There is, therefore, a tendency to predict more SAW using the IWC approach than with the LLWR approach. This is due to the chosen critical soil limits and gradual changes of soil limitations vs. water content in the IWC calculation procedure. Significant relationships of SAW with bulk density or relative bulk density were found but not with the clay and organic matter contents. Linear relations between IWC and LLWR100 or LLWR330 were found as: IWC?=??0.0514 + 1.4438LLWR100, R 2?=?0.83; and IWC?=??0.0405 + 2.0465LLWR330, R 2?=?0.84, respectively (both significant at P?<?0.01). Significant relationships were obtained between the SAW values and S indicating the suitability of the index S to explain the availability of soil water for plants even when complicated approaches like IWC are considered. Overall, the results demonstrate the importance of the choice of the approach to be used and its critical limits in the estimation of the soil available water to plants. 相似文献
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PETER CULLEN 《Freshwater Biology》1990,24(1):201-209
SUMMARY. 1. It is common to observe friction between limnologists and the managers of water resources. This is often a result of misunderstandings about the cultures within which each works.
2. There are a number of ways that science can contribute to effective management of water resources, but limnologists must appreciate that there are value questions which are not the sole prerogative of science to answer.
3. Managers often misunderstand science and expect it to deliver a truth that is non-arguable. They fail to understand the very process of science demands no such truths, so that assumptions, methods and conclusions can always be challenged.
4. One way to bridge this boundary is to develop the scientific broking role. Another is to do better and more relevant science. Ways of doing both are discussed. 相似文献
2. There are a number of ways that science can contribute to effective management of water resources, but limnologists must appreciate that there are value questions which are not the sole prerogative of science to answer.
3. Managers often misunderstand science and expect it to deliver a truth that is non-arguable. They fail to understand the very process of science demands no such truths, so that assumptions, methods and conclusions can always be challenged.
4. One way to bridge this boundary is to develop the scientific broking role. Another is to do better and more relevant science. Ways of doing both are discussed. 相似文献
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Relative water content (RWC) and water potential as measuredwith the pressure chamber were evaluated as indicators of waterstatus of tissue-cultured apple shoots and plantlets (shootswith roots). During the hydration required for RWC measurement,both water content and water potential exhibited the same hydrationkinetics, indicating that 10 h were required for full hydration.Once full hydration was reached, shoot mass remained relativelyconstant. Moisture release characteristics were also constructedand the associated shoot and plantlet water relations parameterswere estimated. Underin vitroconditions, both shoot and plantletwater potential were similar to the water potential of the culturemedium in which they were grown. The moisture release characteristicof shoots and plantlets was consistent with that expected fortypical plant tissues, and gave estimates of maximum modulusof elasticity (6.201.14 MPa), osmotic potential at saturation(0.85 0.10 MPa), osmotic potential at zero turgor (1.16 0.14 MPa) and RWC at zero turgor (78 2%) which were similarto values in the literature. Higher values of leaf conductanceand RWC were found in shoots and plantlets placed at 95% RH(21 C) compared to those at 90% RH. Plantlets had higher valuesof both conductance and RWC compared to shoots, suggesting thatinvitroroots are functional in water uptake. Relative water contentwas related to measures of physiological activity such as leafconductance, and it was also easier to measure than water potential.Relative water content is suggested as a sound index of waterstatus in tissue culture plants. Key words: Conductance, microculture, water status, water stress. 相似文献
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Abstract. Wphen there is no external source of water, plants can grow by mobilizing internal water from nongrowing tissues. We investigated how this internal water moves by measuring continuously and simultaneously the water potential (ψw ) of soybean ( Glycine max L. Merr.) seedlings in the upper, growing stem tissues and the lower, non-growing stem tissues. When external water was available to the roots, the stems grew rapidly and the ψw of the growing tissue was continually below that of the nongrowing tissue and the medium around the roots. This indicated that a growth-induced gradient in ψw favoured water movement from the external source to the growing cells. When the external source was removed, the ψw of the growing tissue remained constant for a time and the ψw of the nongrowing tissue decreased somewhat. Growth took place slowly as water was withdrawn from the nongrowing tissue but ψw gradients continued to favour water transport to the growing cells. On the other hand, if this internal source was removed by excision, growth ceased abruptly. In this case, the cell walls relaxed and the ψw of the growing tissue decreased by about 0.1 MPa instead of remaining constant. The ψw of the detached nongrowing tissues remained constant instead of decreasing. This indicates not only that water mobilization required attached nongrowing or slowly growing tissues but also that mobilization affected wall relaxation. Thus, ψw differences may mobilize internal water, may explain the continued growth of plants and plant parts removed from external sources of water, and may account for discrepancies in measurements of cell wall properties in growing tissues. 相似文献
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B. H. Junker M. Stanik J. Adamca K. LaRiviere M. Abbatiello P. Salmon 《Bioprocess and biosystems engineering》1997,17(5):277-286
An ambient loop USP purified water system has been designed and implemented using carbon and ion exchange resin beds, ultraviolet light systems and polishing filters to produce water consistently meeting or exceeding all USP XXIII quality specifications for purified water. The circulation system is constructed of PVDF plastic piping material installed in a continuous fully-drainable loop. The system was sized for a pilot scale fermentation/harvest process at the 1000?l cultivation scale. This system passed all installation and operational qualification testing as well as sixty days of continuous performance qualification testing before entering into an ongoing monitoring regimen. Excursions outside acceptable water quality parameters during this extensive monitoring regimen were minimal. Sanitization of the system, along with bed and filter changes at the time of sanitization, was conducted every 3 to 6 months to insure consistent water quality. 相似文献
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Jana Pospíšilová 《Biologia Plantarum》1969,11(2):130-138
Intensity of transpiration, intensity of water absorption, water saturation deficit (w.s.d.) in different parts of samples and rate of water transport was investigated in samples from leaf tissue of fodder cabbage and banana-tree. In all experiments (at initial w.s.d. 0% and 20%, in samples from upper, middle and lower leaves of fodder cabbage and from leaves of banana-tree) a distinct gradient of w.s.d. in the direction of transport of water was determined, therefore the limiting factor in the water balance was rate of water transport and not rate of water absorption. The lowest amount of water was always transported within transpiring part of sample. When the initial w.s.d. was 0% not only the water transported by tissue from the environment, but also the water of the leaf tissue itself took part in water lost by transpiration and therefore water stress originated in the whole sample. At an initial w.s.d. of 20%, the rate of water absorption was higher than the rate of water transport and therefore the increase of w.s.d. in the transpiring part of the sample was accompanied by a simultaneous decrease of w.s.d. in the transporting part. An increase in the value of w.s.d. in leaf tissue proportionally increased the resistance of water transport in the liquid phase (on the average from 1·7 . 103 to 6·7 . 103 atm min cm2 g?1) and also in the gaseous phase (on the average from 2·7 . 10?2 to 14·0 . 10?2 min cm?1). It was proved that insufficient rate of water transport can be responsible for the origin of water stress. At the same time the rate of water transport was influenced by the value of the w.s.d. since every change of w.s.d. in leaf tissue not only the gradient of water potential changed but also the resistance to water transport. 相似文献