Seasonal variation in native hydraulic conductivity between two deciduous oak species

2019 ◽  
Vol 13 (1) ◽  
pp. 78-86
Author(s):  
Dilia Mota-Gutiérrez ◽  
Guadalupe Arreola-González ◽  
Rafael Aguilar-Romero ◽  
Horacio Paz ◽  
Jeannine Cavender-Bares ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Drought Tolerance ◽  
Water Use ◽  
Negative Impact ◽  
Dry Season ◽  
Turgor Loss Point ◽  
Xylem Vulnerability ◽  
Short Period ◽  
Quercus Species ◽  
Leaf Shedding

Abstract Aims Mechanisms of plant drought resistance include both tolerance and avoidance. Xylem vulnerability to embolism and turgor loss point are considered traits that confer tolerance, while leaf abscission and deciduousness characterizes the avoidance strategy. While these mechanisms are thought to trade-off expressing a continuum among species, little is known on how variation in the timing and duration of leaf shedding in response to drought affect the relationship between xylem and leaf tolerance. In the present study, we explored the extent to which drought tolerance differs between two oak (Quercus) species that exhibit different leaf shedding behaviours. Particularly, we predicted that Q. deserticola Trel., which loses leaves at the end of the dry season (late-deciduous) and is thus exposed to a greater risk of cavitation, would be more drought tolerant and more conservative in its water use than Q. laeta Liebm., which loses its leaves for only a short period of time in the middle of the dry season (brevideciduous). Methods The study was conducted in central Mexico in a single population of each of the two oak species, separated from each other by a distance of 1.58 km, and by an altitudinal difference of 191 m. Quercus deserticola (late deciduous) is more frequent down slope, while Q. laeta (brevideciduous) tends to occur at higher elevations along the gradient. We assessed seasonal differences (rainy versus dry season) in native stem hydraulic conductivity, and tested for variation in xylem vulnerability to cavitation, leaf water use and leaf turgor loss point between the two species. Important Findings The two oak species did not differ in traits conferring drought tolerance, including xylem vulnerability to embolism, leaf turgor loss point, or stomatal conductance. However, both species had different performance during the dry season; the brevideciduous species had lower negative impact in the xylem function than the late-deciduous species. Overall, seasonal changes in plant physiological performance between the two oak species were determined by a reduction in the canopy leaf area.

scholarly journals Clonal variability for vulnerability to cavitation and other drought-related traits in Hevea brasiliensis Müll. Arg.

2015 ◽  
Vol 2 ◽  
pp. e001 ◽  
Author(s):  
Wanploy Jinagool ◽  
Ratchanee Rattanawong ◽  
Krissada Sangsing ◽  
Têtè Sévérien Barigah ◽  
Frederic Gay ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Rubber Tree ◽  
Stomatal Response ◽  
Plant Materials ◽  
Vulnerability To Cavitation ◽  
Xylem Vulnerability ◽  
Precipitation Regimes ◽  
Simulated Drought ◽  
Leaf Shedding ◽  
Clonal Variability

Selection for drought-tolerant clones has become a major challenge in rubber breeding programs undertaken to ensure the sustainability of natural rubber production, as rubber plantations are expanding in drought-prone areas. Xylem vulnerability to cavitation is a trait related to drought-induced mortality. It can be rapidly evaluated without subjecting plant materials to drought stress, making it useful in large-scale screening for drought tolerance in the near future. We first compared the most widely used techniques for measuring vulnerability to cavitation (air pressurization and Cavitron) on this species, and the effect of sample conditions (size, age and sunlight exposure), in order to ensure reliable analysis. Secondly, ten rubber clones were compared for their xylem vulnerability to cavitation in branches and petioles, and for other traits related to drought response, including stomatal response and leaf shedding occurring during a simulated drought. We also tested the plasticity of vulnerability to cavitation on two clones grown in three locations with contrasting precipitation regimes. We found no clonal variability and a small phenotypic plasticity for xylem vulnerability to cavitation in branches. However, clonal differences in xylem vulnerability to cavitation were found in petioles, and clones also showed differences in stomatal response and in leaf shedding behavior in response to a simulated drought. Our study suggests a genetic canalization for vulnerability to cavitation in organs critical for survival, such as branches, whereas there are clonal differences for traits related to drought avoidance: vulnerability to cavitation of petioles, leaf shedding behavior and stomatal response. The insights gained in this study for screening rubber tree clones for drought tolerance is also discussed. 

scholarly journals Seasonal Variation of Rainy and Dry Season Per Capita Water Consumption in Freetown City Sierra Leone

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 499
Author(s):  
Salmatta Ibrahim A ◽  
Fayyaz Ali Memon ◽  
David Butler
Keyword(s):  
Seasonal Variation ◽  
Water Use ◽  
Water Consumption ◽  
Low Income ◽  
Rainy Season ◽  
Predictor Variable ◽  
Dry Season ◽  
Data Set ◽  
Per Capita ◽  
End Use

Ensuring a sustainable urban water supply for developing/low-income countries requires an understanding of the factors affecting water consumption and technical evidence of individual consumption which can be used to design an improved water demand projection. This paper compared dry and rainy season water sources available for consumption and the end-use volume by each person in the different income groups. The study used a questionnaire survey to gather household data for a total of 398 households, which was analysed to develop the relationship between per capita water consumption characteristics: Socio-economic status, demographics, water use behaviour around indoor and outdoor water use activities. In the per capita water consumption patterns of Freetown, a seasonal variation was found: In the rainy season, per capita water consumption was found to be about 7% higher than the consumption for the full sample, whilst in the dry season, per capita water consumption was almost 14% lower than the full survey. The statistical analysis of the data shows that the average per capita water consumption for both households increases with income for informal slum-, low-, middle- and high-income households without piped connection (73, 78, 94 and 112 L/capita/day) and with connection (91, 97, 113 and 133 L/capita/day), respectively. The collected data have been used to develop 20 statistical models using the multiple linear stepwise regression method for selecting the best predictor variable from the data set. It can be seen from the values that the strongest significant relationships of per capita consumption are with the number of occupants (R = −0.728) in the household and time spent to fetch water for use (R = −0.711). Furthermore, the results reveal that the highest fraction of end use is showering (18%), then bathing (16%), followed by toilet use (14%). This is not in agreement with many developing countries where toilet use represents the largest component of indoor end use.

Dry season water use patterns underGuiera senegalensisL. shrubs in a tropical savanna

1998 ◽  
Vol 40 (1) ◽  
pp. 53-67 ◽  
Author(s):  
Stephen R Gaze ◽  
Joost Brouwer ◽  
Lester P Simmonds ◽  
John Bromley
Keyword(s):  
Water Use ◽  
Dry Season ◽  
Tropical Savanna ◽  
Use Patterns ◽  
Water Use Patterns

Intraspecific variation in drought susceptibility in Eucalyptus globulus is linked to differences in leaf vulnerability

2019 ◽  
Vol 46 (3) ◽  
pp. 286 ◽  
Author(s):  
Christopher J. Lucani ◽  
Timothy J. Brodribb ◽  
Greg Jordan ◽  
Patrick J. Mitchell
Keyword(s):  
Drought Tolerance ◽  
Intraspecific Variation ◽  
Eucalyptus Globulus ◽  
Forest Tree ◽  
Species Variation ◽  
Important Species ◽  
Phenotypic Differences ◽  
Hydraulic Failure ◽  
Xylem Vulnerability ◽  
Alternative Approach

Understanding intraspecific variation in the vulnerability of the xylem to hydraulic failure during drought is critical in predicting the response of forest tree species to climate change. However, few studies have assessed intraspecific variation in this trait, and a likely limitation is the large number of measurements required to generate the standard ‘vulnerability curve’ used to assess hydraulic failure. Here we explore an alternative approach that requires fewer measurements, and assess within species variation in leaf xylem vulnerability in Eucalyptus globulus Labill., an ecologically and economically important species with known genetic variation in drought tolerance. Using this approach we demonstrate significant phenotypic differences and evidence of plasticity among two provenances with contrasting drought tolerance.

Factors affecting the phenology of the first brood of the sugar-cane froghopper Aeneolamia varia saccharina (Dist.) (Homoptera, Cercopidae) in Trinidad

1975 ◽  
Vol 65 (3) ◽  
pp. 359-372 ◽  
Author(s):  
A. B. S. King
Keyword(s):  
Adult Emergence ◽  
Dry Season ◽  
Soil Conditions ◽  
Factors Affecting ◽  
Expected Time ◽  
Short Period ◽  
Incubation Periods ◽  
Close Relationship ◽  
Dry Soil ◽  
Predictive Relationship

AbstractThe size and occurrence of the first brood of adults of Aeneolamia varia saccharina (Dist.) are examined in relation to the pattern of egg eclosion and rainfall. The proportion of eggs hatching within a month of oviposition in the laboratory (short-period eggs) decreased from over 90% in August to less than 20% in January, but the incubation periods of the remaining, long-period eggs were longest in those laid during October and November. The overall hatching distributions tended to be bimodal with most eggs hatching during the early months of the year under moist conditions at 26°C. Dry soil conditions delay eclosion, and eggs obtained from fields during the dry season and then incubated under moist conditions tended to hatch at the normally expected time of the first rains in May. The numbers of eggs expected to produce the first brood, computed from laboratory hatching data and estimates of the numbers and fecundities of froghoppers during the second, third and fourth broods, were less than the actual numbers sampled just before the first rains. There was a close relationship between the first rainfall of over one inch within 48 h and adult emergence 27 and 34 days later, and 85% of field egg populations in May had hatched and/or died by the week after the first rains. However some variation in the date of their occurrence accounted for non-synchrony of first broods over the region. The numbers of diapause eggs in fields sampled during the dry season failed to give a good predictive relationship with first brood adult populations, probably because of density dependent mortality of eggs or hatchling nymphs.

scholarly journals Characterization of wheat genotypes for drought tolerance and water use efficiency

2021 ◽  
Vol 78 (5) ◽  
Author(s):  
Guilherme Filgueiras Soares ◽  
Walter Quadros Ribeiro Júnior ◽  
Lucas Felisberto Pereira ◽  
Cristiane Andréa de Lima ◽  
Daiane dos Santos Soares ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Wheat Genotypes ◽  
Use Efficiency

scholarly journals THE IMPACT OF EU STRUCTURAL FUND SUPPORT AND PROBLEMS OF ITS ABSORPTION

2013 ◽  
Vol 11 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Daiva Jurevičienė ◽  
Jūratė Pileckaitė
Keyword(s):  
National Economy ◽  
Direct Investment ◽  
Statistical Data ◽  
Negative Impact ◽  
Structural Fund ◽  
Economic Activities ◽  
Structural Support ◽  
Short Period ◽  
The Impact ◽  
Eu Support

Targeted allocation of EU support in Lithuania can help resolving a number of problems and achieving significant results in a variety of areas. However, rush to absorb support may lead to a little, zero or even negative impact on national economy. In addition, EU support opportunities may distort investment motivation. This paper deals with issues related to the impact of EU support and problems of its absorption. The impact of EU support on the national economy has been established in three areas: attraction of foreign direct investment state investments into capital formation, and experience of companies, which are EU support beneficiaries. The paper proposes using regression analysis in search and evaluation of relations while obtaining more information about programmes, priorities and the impact of structural support on different indicators. In addition, it focuses on ascertaining the effectiveness of governmental and company spending. Furthermore, as companies – EU support beneficiaries – are engaged in different economic activities, their experience cannot be ascertained from statistical data; consequently, findings of an expert survey are presented to demonstrate the experience acquired by business companies as well as problems they face. Limitation of research was a short period of time to evaluate (only four years of the current funding period)

scholarly journals Growth, yield and water use of drip irrigated cassava planted in the late rainy season of North Eastern Thailand

2018 ◽  
Author(s):  
A. Polthanee ◽  
M. Srisutham
Keyword(s):  
Water Use ◽  
Starch Content ◽  
Growth Yield ◽  
Dry Season ◽  
Storage Root ◽  
Root Yield ◽  
Supplementary Irrigation ◽  
Significant Difference ◽  
Four Levels ◽  
Cassava Varieties

Field experiment was carried out at Agronomy Experimental Farm, Faculty of Agriculture, Khon Kaen University in 2015-2016 to investigate the response of cassava to supplementary irrigation during the dry season month. The experiment was laid out in split plot design with four replications. The main plots comprised two cassava varieties (Huaybong 80 and Rayong 11). The sub l included four levels of drip irrigation [I-20, EV-40 mm (crop received 20 mm of water when daily cumulative pan evapolation value reached 40 mm during the dry season months)]; [I-20, EV-60 mm] ; [I-10, EV-40 mm] ; [I-10, EV-60 mm] and [I-10] (cassava under rainfed condition without additional irrigation)]. Results indicated that irrigation at (I-20, EV-40 mm) produced maximum the fresh (52 t ha-1) and dry (22 t ha-1) storage root yield. Huaybong 80 variety a gave significantly higher the storage root yield than that of Rayong 11 variety. The highest starch content also was obtained in the (I-20, EV-40 mm) treatment. There was no significant difference in the starch content between the two cassava varieties. Water were applied in treatment [I-20, EV-40 mm], [I-20, EV-60 mm], [I-10, EV-40 mm] and [I-10, EV-60 mm] was an average 299 mm, 194 mm, 150 mm and 97 mm, respectively during the growing season. Water use efficiency was the highest (35.3 kg ha-1 mm-1) in the [I-20, EV-60 mm] treatment.

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