scholarly journals Dew formation characteristics of meadow plants canopy at different heights in Hulunbuir grassland, China

2021 ◽  
Author(s):  
Jingjie Xie ◽  
Derong Su ◽  
Shihai Lyu ◽  
He Bu ◽  
Qiang Wo
Keyword(s):  
Drought Stress ◽  
Leymus Chinensis ◽  
Compact Structure ◽  
C3 Plant ◽  
Height Range ◽  
Grassland Ecosystems ◽  
Dew Formation ◽  
Condensation Surface ◽  
The Difference ◽  
Dew Amount

Abstract A plant's foliar uptake of dew can mitigate the adverse effects caused by drought stress. However, in grassland ecosystems, it is inconclusive whether the dew condensation characteristics of plants at different heights are consistent. In this study, we wanted to know whether plant height had a significant effect on the formation of dew. In addition, we wanted to understand the difference of dew formation between C3 plant Leymus chinensis (LC) and C4 plant Cleistogenes squarrosa (CS) which have different heights and can succeed each other in the community. In nine dew nights, we measured the amount of dew formed on simulated condensation surface (different heights) and two plants at the same time. The results showed that in the height range of 5–80 cm, the dew amount increases with the canopy height, but its increase rate gradually slows down and approaches zero. The shorter CS (5–15 cm) has a similar dew amount (0.095 mm) as LC (40–70 cm) due to its compact structure of the leaves with pubescence and the more stable micro-meteorological conditions. The CS can obtain more potential dew per unit organic matter, and this may be one of the potential mechanisms for the succession from LC communities to CS communities under drought stress.

scholarly journals A Semi-Theoretical Model for Water Condensation: Dew Used in Conservation of Earthen Heritage Sites

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Xiang He ◽  
Sijia Wang ◽  
Bingjian Zhang
Keyword(s):  
Mass Transfer ◽  
Theoretical Model ◽  
Field Experiments ◽  
Environmental Control ◽  
Mass Transfer Process ◽  
Formation Processes ◽  
Heritage Sites ◽  
Dew Formation ◽  
The Difference ◽  
Two Parameter

Dew is a common but important phenomenon. Though water is previously considered to be a threat to earthen heritage sites, artificial dew is showing potential in relic preservation. A model of dew prediction on earthen sites will be essential for developing preventive protection methods, but studies of dew formation processes on relics are limited. In this study, a two parameter model is proposed. It makes approximations according to the features of earthen heritage sites, assuming that a thin and steady air layer exists close to the air–solid interface. This semi-theoretical model was based on calculations of the mass transfer process in the air layer, and was validated by simulations of laboratory experiments (R > 0.9) as well as field experiments. Additionally, a numerical simulation, performed by the commercial software COMSOL, confirmed that the difference between fitting parameter δ and the thickness of assumed mass transfer field was not significant. This model will be helpful in developing automatic environmental control systems for stabilizing water and soluble salts, thus enhancing preventive protection of earthen heritage sites.

A Physically Based Algorithm for Non-Blackbody Correction of Cloud-Top Temperature and Application to Convection Study

2014 ◽  
Vol 53 (7) ◽  
pp. 1844-1857 ◽  
Author(s):  
Chunpeng Wang ◽  
Zhengzhao Johnny Luo ◽  
Xiuhong Chen ◽  
Xiping Zeng ◽  
Wei-Kuo Tao ◽  
...  
Keyword(s):  
Brightness Temperature ◽  
Weighting Function ◽  
Convective Cloud ◽  
Transfer Model ◽  
Height Range ◽  
Convective Clouds ◽  
Physically Based ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Difference ◽  
Cloud Top Temperature

AbstractCloud-top temperature (CTT) is an important parameter for convective clouds and is usually different from the 11-μm brightness temperature due to non-blackbody effects. This paper presents an algorithm for estimating convective CTT by using simultaneous passive [Moderate Resolution Imaging Spectroradiometer (MODIS)] and active [CloudSat + Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] measurements of clouds to correct for the non-blackbody effect. To do this, a weighting function of the MODIS 11-μm band is explicitly calculated by feeding cloud hydrometer profiles from CloudSat and CALIPSO retrievals and temperature and humidity profiles based on ECMWF analyses into a radiation transfer model. Among 16 837 tropical deep convective clouds observed by CloudSat in 2008, the averaged effective emission level (EEL) of the 11-μm channel is located at optical depth ~0.72, with a standard deviation of 0.3. The distance between the EEL and cloud-top height determined by CloudSat is shown to be related to a parameter called cloud-top fuzziness (CTF), defined as the vertical separation between −30 and 10 dBZ of CloudSat radar reflectivity. On the basis of these findings a relationship is then developed between the CTF and the difference between MODIS 11-μm brightness temperature and physical CTT, the latter being the non-blackbody correction of CTT. Correction of the non-blackbody effect of CTT is applied to analyze convective cloud-top buoyancy. With this correction, about 70% of the convective cores observed by CloudSat in the height range of 6–10 km have positive buoyancy near cloud top, meaning clouds are still growing vertically, although their final fate cannot be determined by snapshot observations.

An ABA-flavonoid relationship contributes to the differences in drought resistance between different sea buckthorn subspecies

2020 ◽  
Author(s):  
Guori Gao ◽  
Zhongrui Lv ◽  
Guoyun Zhang ◽  
Jiayi Li ◽  
Jianguo Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Rna Sequencing ◽  
Drought Resistance ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Normal Growth ◽  
Carotenoid Biosynthesis ◽  
Sea Buckthorn ◽  
Mutual Regulation ◽  
The Difference

Abstract Drought is the most severe abiotic stress and hinders the normal growth and development of plants. Sea buckthorn (Hippophae rhamnoides Linn.) is a typical drought-resistant tree species. In this study, the leaves of the H. rhamnoides ssp. sinensis (“FN”) and H. rhamnoides ssp. mongolica (“XY”) were selected during drought-recovery cycles for RNA sequencing, and physiological and biochemical analyses. The results revealed that drought stress significantly decreased leaf water potential, net photosynthetic rate, and stomatal conductance in both sea buckthorn subspecies. Similarly, the contents of flavone, flavonol, isoflavone and flavanone significantly decreased under drought stress in “XY.” Conversely, in “FN,” the flavone and abscisic acid (ABA) contents were significantly higher under drought stress and recovered after rehydration. Meanwhile, 4,618 and 6,100 differentially expressed genes (DEGs) were identified under drought stress in “FN” and “XY,” respectively. In total, 5,164 DEGs were observed in the comparison between “FN” and “XY” under drought stress. This was more than the 3,821 and 3,387 DEGs found when comparing the subspecies under control and rehydration conditions, respectively. These DEGs were mainly associated with carotenoid biosynthesis, flavonoid biosynthesis, photosynthesis, and plant hormone signal transduction. Six hub DEGs (ABCG5, ABCG22, ABCG32, ABCG36, ABF2 and PYL4) were identified to respond to drought stress based on WGCNA and BLAST analysis using DroughtDB. These six DEGs were annotated to play roles in the ABA-dependent signaling pathway. Sixteen RNA sequencing results involving eight genes and similar expression patterns (12/16) were validated using quantitative real-time PCR. The biochemical and molecular mechanisms underlying the regulation of drought responses by ABA and flavonoids in sea buckthorn were clarified. In this study, gene co-expression networks were constructed, and the results suggested that the mutual regulation of ABA and flavonoid signaling contributed to the difference in drought resistance between the different sea buckthorn subspecies.

Meteorological Factors Affected Dew Condensation in Marsh Ecosystem

2014 ◽  
Vol 535 ◽  
pp. 360-363 ◽  
Author(s):  
Ying Ying Xu ◽  
Bai Xing Yan ◽  
Hui Zhu
Keyword(s):  
Meteorological Factors ◽  
Meteorological Condition ◽  
Sanjiang Plain ◽  
Dew Point ◽  
Nutrient Cycle ◽  
The Sanjiang Plain ◽  
Dew Formation ◽  
Key Factor ◽  
The Relationship ◽  
Dew Amount

Dew is one of crucial factors in the water and nutrient cycle in wetland ecosystem, especially playing an important role in the water and nutrients balance. Identifying the meteorological factors which affect the formation of dew is necessary. The meteorological condition is the key factor of dew condensing; therefore, it is necessary to identify the relationship between meteorological factors and dew formation. Dew amount was monitored and collected in the Sanjiang Plain. The highest mean dew amounts at Sanjiang Plain were observed in Craex lasiocarpa community (0.130mm night-1). Nearly 50% dew events correspond to the smallest yields (<0.04 mm="" night="" sup="">-1) and it is implies there are around half days are unsuitable for dew condensation in Craex lasiocarpa community. Our study impies that dew data, taken in growthing season of 2003 to 2005 and 2008, correlated positive with relative humidity, dew point temperature, and vapour pressure.

scholarly journals Infrared heater warming system markedly reduces dew formation: An overlooked factor in arid ecosystems

2020 ◽  
Author(s):  
Tianjiao Feng ◽  
Lixu Zhang ◽  
Qian Chen ◽  
Zhiyuan Ma ◽  
Hao Wang ◽  
...  
Keyword(s):  
Climate Warming ◽  
Plant Traits ◽  
Ecosystem Processes ◽  
Arid Ecosystems ◽  
Plant Functional Groups ◽  
The Tibetan Plateau ◽  
Ambient Conditions ◽  
Dew Formation ◽  
Infrared Heater ◽  
Dew Amount

ABSTRACTDew plays a vital role in ecosystem processes in arid and semi-arid regions and is expected to be affected by climate warming. Infrared heater warming systems have been widely used to simulate climate warming effects on ecosystem. However, how this warming system affects dew formation has been long ignored and rarely addressed. In a typical alpine grassland ecosystem on the Northeast of the Tibetan Plateau, we measured dew amount and duration by artificial condensing surfaces, leaf wetness sensors and in situ dew formation on plants from 2012 to 2017. We also measured plant traits related to dew conditions. The results showed that (1) warming reduced the dew amount by 41.6%-91.1% depending on the measurement method, and reduced dew duration by 32.1 days compared to the ambient condition. (2) Different plant functional groups differed in dew formation. (3) Under the infrared warming treatment, the dew amount decreased with plant height, while under the ambient conditions, the dew amount showed the opposite trend. We concluded that warming with an infrared heater system greatly reduces dew formation, and if ignored, it may lead to overestimation of the effects of climate warming on ecosystem processes in climate change simulation studies.

scholarly journals Expression analysis of antioxidant genes in response to drought stress in the fl ag leaf of two Indonesian rice cultivars

2015 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
R. Refli ◽  
Sukarti Muljopawiro ◽  
Kumala Dewi ◽  
Diah Rachmawati
Keyword(s):  
Drought Stress ◽  
Pcr Analysis ◽  
Severe Drought ◽  
Rice Cultivars ◽  
Chain Reaction ◽  
Antioxidant Genes ◽  
Oxidative Defense ◽  
Mda Content ◽  
The Difference

The objective of this study was to analysis the expression of antioxidant genes in response to droughtstress in Indonesian rice. The malondialdehyde (MDA) content and the expression of Cu-ZnSod1, cCu-ZnSod2,MnSod1, cApxa, cApxb, chl-sApx, Cat1, Cat2, Cat3, Gr1, Gr2, and Gr3 genes were assayed in the rice fl ag leaf ofCiherang and Situ Bagendit cultivars subjected to control, mild and severe drought during the grain fi llingphase. Increase in MDA content of Ciherang treated to mild and severe drought was almost two-fold andthree-fold respectively, while MDA content in Situ Bagendit subjected to mild and severe drought increasedapproximately one-fold and two-fold as compared to the control. The semi quantitative reverse transcriptionpolymerase chain reaction (sqRT-PCR) analysis showed that the expression of cCu-ZnSod1, MnSod1, Cat2, Gr3genes of Ciherang, and cCu-ZnSod2, MnSod1, cApxa, cApxb, chl-sAPX, Cat2 and Gr1 genes of Situ Bagendit increasedin fl ag leaf of plant treated to drought. Expressions of cApxb, chl-sApx, Cat3 of Ciherang and Cu-ZnSod1 and Gr2genes of Situ Bagendit were not changed signifi cantly by drought stress. Decreased expression was shownby cCu-ZnSod2, cApxa, Cat1, Gr1 and Gr2 genes of Ciherang, and Cat1, Cat3 and Gr3 genes of Situ Bagendit. Theresults indicated that the activity of oxidative defense was regulated by four genes; cCu-ZnSod1, MnSod1, Cat2,Gr3 in Ciherang, and eight genes; cCu-ZnSod1, cCu-ZnSod2, MnSod1, cApxa, cApxb, chl-sApx, Cat2 and Gr1 in SituBagendit. Therefore, differences in the number of antioxidant genes controlling oxidative defense systemmight determine the difference of the oxidative defense capacity between both cultivars in response to droughtstress during grain fi lling.

scholarly journals Photosynthesis and Growth of Pennisetum centrasiaticum (C4) is Superior to Calamagrostis pseudophragmites (C3) during Drought and Recovery

Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 991
Author(s):  
Yayong Luo ◽  
Xueyong Zhao ◽  
Ginger R. H. Allington ◽  
Lilong Wang ◽  
Wenda Huang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Water Status ◽  
Regional Climate ◽  
Co2 Assimilation ◽  
Photosynthetic Performance ◽  
Thermal Dissipation ◽  
Plant Responses ◽  
C4 Plant ◽  
C3 Plant ◽  
Ecosystem Level

Global warming and changes in rainfall patterns may put many ecosystems at risk of drought. These stressors could be particularly destructive in arid systems where species are already water-limited. Understanding plant responses in terms of photosynthesis and growth to drought and rewatering is essential for predicting ecosystem-level responses to climate change. Different drought responses of C3 and C4 species could have important ecological implications affecting interspecific competition and distribution of plant communities in the future. For this study, C4 plant Pennisetum centrasiaticum and C3 plant Calamagrostis pseudophragmites were subjected to progressive drought and subsequent rewatering in order to better understand their differential responses to regional climate changes. We tracked responses in gas exchange, chlorophyll fluorescence, biomass as well as soil water status in order to investigate the ecophysiological responses of these two plant functional types. Similar patterns of photosynthetic regulations were observed during drought and rewatering for both psammophytes. They experienced stomatal restriction and nonstomatal restriction successively during drought. Photosynthetic performance recovered to the levels in well-watered plants after rewatering for 6–8 days. The C4 plant, P. centrasiaticum, exhibited the classic CO2-concentrating mechanism and more efficient thermal dissipation in the leaves, which confers more efficient CO2 assimilation and water use efficiency, alleviating drought stress, maintaining their photosynthetic advantage until water deficits became severe and quicker recovery after rewatering. In addition, P. centrasiaticum can allocate a greater proportion of root biomass in case of adequate water supply and a greater proportion of above-ground biomass in case of drought stress. This physiological adaptability and morphological adjustment underline the capacity of C4 plant P. centrasiaticum to withstand drought more efficiently and recover upon rewatering more quickly than C. pseudophragmites and dominate in the Horqin Sandy Land.

Sign in / Sign up

Export Citation Format

Share Document