Water relations and yield inAzospirillum-inoculated wheat exposed to drought in the field

2004 ◽  
Vol 82 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Cecilia M Creus ◽  
Rolando J Sueldo ◽  
Carlos A Barassi

There are scarce data connecting water relations in Azospirillum-inoculated wheat suffering drought during anthesis with the yield and mineral content of grains. Azospirillum brasilense Sp245-inoculated seeds of Triticum aestivum 'Pro INTA Oasis' were sown in nonirrigated and control plots. Water potential, water content, and relative water content were determined on flag leaves. Plant water status was calculated from pressure–volume curves. At maturity, grain yield and its components were determined. P, Ca, Mg, K, Fe, Cu, and Zn were determined in dried grains. Even though the cultivar underwent osmotic adjustment, significantly higher water content, relative water content, water potential, apoplastic water fraction, and lower cell wall modulus of elasticity values were obtained in Azospirillum-inoculated plants suffering drought. Grain yield loss to drought was 26.5% and 14.1% in noninoculated and Azospirillum-inoculated plants, respectively. Grain Mg and K diminished in nonirrigated, noninoculated plots. However, grains harvested from Azospirillum-inoculated plants had significantly higher Mg, K, and Ca than noninoculated plants. Neither drought nor inoculation changed grain P, Cu, Fe, and Zn contents. A better water status and an additional "elastic adjustment" in Azospirillum-inoculated wheat plants could be crucial in promoting higher grain yield and mineral quality at harvest, particularly when drought strikes during anthesis.Key words: Azospirillum, wheat, drought, pressure–volume curves, yield, mineral content.

Irriga ◽  
1998 ◽  
Vol 3 (3) ◽  
pp. 81-88
Author(s):  
Carlos Augusto Lima Porto ◽  
Antonio Evaldo Klar ◽  
José Vicente Vasconcelos

EFEITOS DO DÉFICIT HÍDRICO EM PARÂMETROS FISIOLÓGICOS DE FOLHAS DE SORGO (Sorghum bicolor, L.)  Carlos Augusto Lima PortoAntonio Evaldo Klar(2)José Vicente VasconcelosDepartamento de Engenharia Rural – Faculdade de Ciências Agronômicas – UNESPFone: (014) 821-3883  Fax: (014) 821-343818603-97’ – Botucatu - SP  1 RESUMO O experimento foi conduzido em casa de vegetação no Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - UNESP/Botucatu, SP, com delineamento experimental inteiramente casualizado, com 12 repetições. A cultura do sorgo (Sorghum bicolor, L.) foi plantada em vasos que continham 8,0 kg de solo (base em peso de solo seco), pertencente ao grande grupo Terra Roxa Estruturada para os dois tratamentos: a) plantas submetidas a défices  hídricos, sendo irrigadas quando o potencial de água no solo chegava a -1,5 MPa, elevando-o às imediações de -0,01 MPa), e b) plantas irrigadas constantemente por capilaridade. Todas as plantas foram irrigadas aos 55 dias após a emergência e os parâmetros avaliados foram: condutância estomática, potencial de água e teor relativo de água nas folhas mais novas totalmente expandidas, com determinações diárias entre as onze e treze horas, até que o potencial de água no solo atingisse valores em torno de -1,5 MPa. Da análise geral dos dados obtidos, pode-se inferir que a variação no status de água na folha observado através do potencial e do teor relativo de água nas folhas pode ser utilizado para indicar o momento de irrigar; ainda estas medições podem ser indicativas das plantas ou cultivares de sorgo que se mostram mais tolerantes à seca e que o mecanismo de adaptação é o  “avoidance”. UNITERMOS: Condutividade estomática, potencial de água na folha, teor relativo de água na folha,  tolerância à seca.  PORTO, C. A . L.., KLAR, A. E. , VASCONCELLOS, V. J.  Water deficit on physiological parameters of soybean  leaves (Sorghum bicolor L).  2 ABSTRACT A study was carried out at Agricultural Engineering Department, UNESP, Botucatu - SP, with a sorghum crop (Sorghum bicolor, L.) in order to physiologically evaluate the crop response to drought. A completely random design with twelve replications were used. Pots with 8 kg of a medium texture soil (dry weight basis) were used in order to test the influence of the two treatments: a) plants being submitted to a water stress, where irrigation were done when the water potential in the soil (s) were -1,5 MPa, raising it to about -0,01 MPa, and b) plants being always irrigated by capillary. The parameters evaluated were water vapor stomata conductivity, water potential  and relative water content in the leaves.  All plants were irrigated at 55 days after emergency, with daily determinations from eleven AM to thirteen PM, until soil water potential reaches around -1,5MPa. From the general data analysis, it can be inferred that there was a significant variation in the water status in the leaves by determinations of water potential and relative water content in the leaves, indicating that the method may be used to indicate the moment of irrigation and the plants and cultivars more tolerant to drought.  Sorghum plants showed adaptation to water stress under avoidance mechanism. KEYWORDS: Stomata conductivity, water potential in the leaves, relative water content, drought tolerance.


1968 ◽  
Vol 16 (3) ◽  
pp. 487 ◽  
Author(s):  
DJ Connor ◽  
BR Tunstall

The relationship between the relative water content and the water potential of the phyllodes in brigalow and mulga is compared. It is shown that brigalow phyllode tissue is more resistant to desiccation than that of mulga. This is of interest because mulga has previously been considered to represent an extreme in drought tolerance of Australian arid zone plants.


Author(s):  
SK Sah ◽  
OB Zamora

A pot experiment was conducted to study the effects of water deficit on vegetative and reproductive stages of Hybrid, Open pollinated (OPV) and Local varieties of maize. Water deficit at vegetative stage significantly reduced plant height, leaf area, shoot dry matter, root dry matter of the upper 25 cm depth, kernel number and grain yield per plant as compared to well watered plant. Water deficit at reproductive stage reduced more leaf area, kernel number and grain yield per plant than water deficit at vegetative stage. Water deficit at reproductive stage also reduced shoot dry matter, kernel size and harvest index. Leaf water potential and relative water content taken at 58 and 60 days after planting were also reduced by water deficit. The Local variety was taller with smaller kernel size and lower harvest index than Open pollinated and Hybrid varieties. There were no significant interactions among the varieties and water deficit treatments. Key words: Leaf water potential, relative water content, vegetative and reproductive stages, harvest index J. Inst. Agric. Anim. Sci. 26:37-42 (2005)


1999 ◽  
Vol 54 (9-10) ◽  
pp. 693-697 ◽  
Author(s):  
Domingo Morales ◽  
Juliane Peters ◽  
M. Soledad Jiménez ◽  
Michael Tausz ◽  
Astrid Wonisch ◽  
...  

Chlorophyll fluorescence, gas exchange, water potential and relative water content were measured in the needles of five year old seedlings of Pinus canariensis in order to know their response to mild water stress. Two trial plots of ten plants per plot, of similar age and characteristics were irrigated daily until the experiment was undertaken, then one of the plots was left without watering while the other one was irrigated as before. After a week of treatment, the water potential at midday did not change in any of the irrigated or non-irrigated plants maintaining around -0 .4 MPa, and the relative water content changed from 93% in irrigated to 84% in non-irrigated seedlings. The stomatal conductance decreased 60% in non irrigated plants and as a result CO2 assimilation decreased by 50% and transpiration was reduced at a higher proportion (70% ), indicating a good control against water loss, before any change in water status in the needles could be observed suggesting an isohydric water economy in this plant


1982 ◽  
Vol 30 (4) ◽  
pp. 393 ◽  
Author(s):  
P Dawson ◽  
G Weste

Changes in water relations associated with infection by Phytophthora cinnamomi were measured for three native species from the Brisbane Ranges forest. Measurements included leaf conductance, stomatal aperture, transpiration, water potential and relative water content in container-grown plants of Isopogon ceratophyllus (highly susceptible), Eucalyptus macrorhyncha (field-susceptible) and E. goniocalyx (field-resistant) maintained in a glasshouse. I. Ceratophyllus showed a large and highly significant difference in water relations between infected and control plants. Infection was associated with stomatal closure, reduced transpiration, reduced relative water content and leaf water potential. These reactions to infection were not observed for either of the glasshouse-reared Eucalyptus species. In the forest diseased E. macrorhyncha showed significant differences in leaf conductance compared with healthy trees, whereas E. goniocalyx forest trees showed less infection-associated variation. This variation in leaf conductance was not associated with water stress.


1996 ◽  
Vol 28 (3) ◽  
pp. 257-266 ◽  
Author(s):  
R. P. Beckett

AbstractThe thermocouple psychrometer was used to determine water potential, Ψ and its components in the lichen Parmotrema tinctorum. Data suggested that using conventional pressure-volume curves to study the water relations of lichens may give anomalous results, possibly because lichens may contain appreciable amounts of intercellular water. A way of correcting pressure-volume curves to remove the effect of intercellular water is discussed. Parmotrema tinctorum had a very low osmotic potential at full turgor (c. −2.5 MPa), and a low bulk modulus of elasticit (c. 2.1 MPa). As a result, P. tinctorum lost turgor only when the relative water content dropped below 0.47. Likely benefits of this for the lichen are discussed.


2010 ◽  
Vol 7 (1) ◽  
Author(s):  
Saraswati Prabawardani

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning /> <w:ValidateAgainstSchemas /> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables /> <w:SnapToGridInCell /> <w:WrapTextWithPunct /> <w:UseAsianBreakRules /> <w:DontGrowAutofit /> <w:UseFELayout /> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--> <!--[if gte mso 10]> <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} --> <!--[endif]--> <p class="MsoNormal" style="text-align: justify;"><span style="font-size: 10pt;">The measurement of plant water status such as leaf water potential (LWP) and leaf relative water content (RWC) is important part of understanding plant physiology and biomass production. Preliminary study was made to determine the optimum amount of leaf abrasion and equilibration time of sweet potato leaf inside the thermocouple psychrometer chambers. Based on the trial, the standard equilibration time curve of a Peltier thermocouple for sweet potato leaf was between 2 and 3 hours. To increase the water vapour conductance across the leaf epidermis the waxy leaf cuticle should be removed or broken by abrasion. The result showed that 4 times leaf rubbings was accepted as the most effective way to increase leaf vapour conductance of sweet potato in the psychrometer chambers. In calculating the leaf relative water content, unstressed water of sweet potato leaves require 4 hours imbibition, whereas water stressed of sweet potato leaves require 5 to 6 hours to reach the saturation time. Either leaf water potential or relative water content can be used as a parameter for plant water status in sweet potato.</span><span style="font-size: 10pt;"> </span></p>


2015 ◽  
Vol 10 (4) ◽  
pp. 208 ◽  
Author(s):  
Lorenzo Barbanti ◽  
Ahmad Sher ◽  
Giuseppe Di Girolamo ◽  
Elio Cirillo ◽  
Muhammad Ansar

A better understanding of plant mechanisms in response to drought is a strong premise to achieving high yields while saving unnecessary water. This is especially true in the case of biomass crops for non-food uses (energy, fibre and forage), grown with limited water supply. In this frame, we investigated growth and physiological response of two genotypes of biomass sorghum (<em>Sorghum bicolor</em> (L.) Moench) to contrasting levels of soil moisture in a pot experiment carried out in a greenhouse. Two water regimes (high and low water, corresponding to 70% and 30% field capacity) were applied to JS-2002 and Trudan-8 sorghum genotypes, respectively bred for dry sub-tropical and mild temperate conditions. Two harvests were carried out at 73 and 105 days after seeding. Physiological traits (transpiration, photosynthesis and stomatal conductance) were assessed in four dates during growth. Leaf water potential, its components and relative water content were determined at the two harvests. Low watering curbed plant height and aboveground biomass to a similar extent (ca. 􀀀70%) in both genotypes. JS-2002 exhibited a higher proportion of belowground to aboveground biomass, <em>i.e</em>., a morphology better suited to withstand drought. Despite this, JS-2002 was more affected by low water in terms of physiology: during the growing season, the average ratio in transpiration, photosynthesis and stomatal conductance between droughty and well watered plants was, respectively, 0.82, 0.80 and 0.79 in JS-2002; 1.05, 1.08 and 1.03 in Trudan-8. Hence Trudan-8 evidenced a ca. 20% advantage in the three traits. In addition, Trudan-8 could better exploit abundant moisture (70% field capacity), increasing aboveground biomass and water use efficiency. In both genotypes, drought led to very low levels of leaf water potential and relative water content, still supporting photosynthesis. Hence, both morphological and physiological characteristics of sorghum were involved in plant adaptation to drought, in accordance with previous results. Conversely, the common assumption that genotypes best performing under wet conditions are less suited to face drought was contradicted by the results of the two genotypes in our experiment. This discloses a potential to be further exploited in programmes of biomass utilization for various end uses, although further evidence at greenhouse and field level is needed to corroborate this finding.


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