scholarly journals Relações Hídricas e Produção de Pigmentos Fostossinteticos em Mudas de Eugenia Uniflora l. Sob Condições de Salinidade (Water Relations and Production of Pigments in Seedlings Photosynthetic Eugenia Uniflora l. Under Salinity Conditions)

2011 ◽  
Vol 4 (3) ◽  
pp. 497
Author(s):  
Rayana Pires Marques ◽  
Clarissa Soares Freire ◽  
Hugo Henrique Costa do Nascimento ◽  
Rejane Jurema Mansur Custósio Nogueira

Esta pesquisa objetivou avaliar os efeitos da salinidade nas relacoes hidricas e teor de pigmentos fotossintetizantes em mudas de pitangueira. Para tanto, foi desenvolvido um experimento em casa de vegetacao do Laboratorio de Fisiologia Vegetal, pertencente ao Departamento de Biologia da UFRPE, no periodo de dezembro de 2010 a abril de 2011. O delineamento experimental utilizado foi o inteiramente casualizado com quatro tratamentos salinos: 0 (controle), 30, 60 e 90 mM de NaCl, e com cinco repeticoes por tratamento. Aos 35 e 95 DAD (dias apos diferenciacao) decorreram as analises fisiologicas. Foram mensurados o potencial hidrico foliar e o teor relativo de agua em dois horarios: antemanha (4h) e meiodia (12h) e os pigmentos fotossintetizantes. A alta demanda evaporativa (12 horas) ocasionou reducoes significativas para o potencial hidrico foliar e teor relativo de agua na pitangueira. Nestes horarios tambem ocorreram diferencas nos pigmentos, entre os niveis de salinidade estudados. Os resultados indicam que a imposicao da salinidade propiciou reducoes no status hidrico das plantas. Em relacao aos pigmentos fotossinteticos, o estresse em curto prazo gerou sua diminuicao, porem em longo prazo, gerou aumento dos mesmos. A variavel fotossintetica estudada mais afetada foram os carotenoides. Palavras-chave: Potencial Hidrico Foliar, Teor Relativo de Agua, estresse salino, pigmentos fotossinteticos  Water Relations and Production of Pigments in Seedlings Photosynthetic Eugenia Uniflora l. Under Salinity Conditions   ABSTRACT This research had as objective evaluate the effects of salinity in the hydric relations and photosynthetic pigments amount in Eugenia uniflora L.. A experiment was developed in the greenhouse of the Laboratory of Vegetal Phisiology, UFRPE, Brazil, between December 2010 and April 2011. The experimental was designed with four treatments: 0 (control), 30, 60 and 90 mM NaCl with five repetitions each treatment. At 35 and 95 days of experiment physiological analysis were performed. It was measured the leaf hydric potential and the relative water content, at two different moments: pre-morning, AND MID DAY and the photosynthetic pigments. The high evaporative demand (mid day) caused significant reductions in the leaf hydric potential and relative water content in the E. uniflora. At the referred times it was also possible to observe differences in the photosynthetic pigments between the levels of stressing. Results indicate that the imposition of high salinity reduced the hydric status of the subjects. Relating to the photosynthetic pigments the short-term salt stress caused a reduction that was overcome in the long-term stressing. The most affected pigment studied were the carotenoids.  Keywords: Leaf hydric potential, relative water content, salt stress, photosynthetic pigments

2021 ◽  
Vol 53 (4) ◽  
Author(s):  
Juan José Reyes-Pérez ◽  
Bernardo Murillo-Amador ◽  
Alejandra Nieto-Garibay ◽  
Luis G. Hernández-Montiel ◽  
Francisco H. Ruiz-Espinoza ◽  
...  

AoB Plants ◽  
2019 ◽  
Author(s):  
Luana C C Braz ◽  
Pedro D Fernandes ◽  
Daniela D Barbosa ◽  
Wellison F Dutra ◽  
Carliane R C Silva ◽  
...  

Abstract Salinization leads to several worldwide damages in agricultural regions, mainly in semiarid regions where leaching of salt is poor due to limited and erratic rainfall. Cotton (Gossypium hirsutum L.) is a Malvaceae with wide genetic variability to salt stress. The identification of salinity tolerant genotypes is a dynamic target in a breeding program, and the selection is often based on plant phenotypes. Molecular markers are reliable tools to aid in these selection procedures. Aquaporin (AQPs) are channel proteins that play fundamental role in water relations and tolerance to environmental stresses. Plants have fine regulation of water transport through AQPs activities. In order to evaluate the AQP expressions of different cotton cultivars submitted to salt stress, we use molecular and physiological tools, based on RT-qPCR and gas exchange assays. Seven cultivars were submitted to 95 mM NaCl, started at V3 stage (21 days after emergence), during 72 h. At the end of stress treatment, root tissues were used to total RNA extraction, followed by cDNA synthesis and RT-qPCR analyzes. Three sets of specific primers were used, drawn from AQP accessions deposited in NCBI. Additionally, full expanded leaves were used to gas exchange assays and to estimate the relative water content. The dry matter of the shoots was also evaluated. Based on pattern of AQPs transcripts, we found that all semiarid tolerant cultivars (BRS Seridó, 7MH, CNPA MT 2009 152 and BRS 416) showed downregulation of AQP subtypes, mainly GhPIP1;1 and GhTIP2;1 whose action is characterized as tolerant to salinity. The results of gas exchanges, relative water content and dry matter were consistent with the molecular findings in these cultivars, confirming that GhPIP1;1 and GhTIP2;1, located at plasma membrane and vacuoles, respectively, could be adopted as AQP markers for identification of cotton tolerant to salt stress.


2021 ◽  
Vol 49 (1) ◽  
pp. 12049
Author(s):  
Tekam L. MEGUEKAM ◽  
Dany P. MOUALEU ◽  
Victor D. TAFFOUO ◽  
Hartmut STÜTZEL

Salinity is the main environmental factor accountable for decreasing crop productivity worldwide. The effects of NaCl salinity on plant growth (leaf relative water content (RWC), leaf dry weight (LDW), shoot length (SL), number of leaves (NL), number of branches (NB) and total leaf area (TLA) and physiological characteristics (stomatal conductance (gs), transpiration rate (TR), net photosynthetic (Pn), yield of photosystem II (ΦPsII) and the intercellular CO2 concentration (CO2int) in peanut (Arachis hypogaea L.) varieties (‘Vanda’, ‘P244601’ and ‘Pl184948’, widely used in Cameroon, Tanzania and Ghana, respectively, were investigated under hydroponic condition. Plants were subjected to four levels of NaCl (0, 40, 80 and 120 mM) at early seedling growth stage of plant development. Application of NaCl treatment led to a significant decrease in LDW, SL, NL, TLA, Pn, gs, TR and CO2int concentration of ‘Vanda’ and ‘P244601’ compared to untreated plants while the plant growth inhibition was notably noted at 120 mM NaCl in ‘P1184948’ for LDW, SL and NB. The highest depressive effect was detected in gs of salt-sensitive ‘Vanda’ while the lowest were recorded in gs of salt-tolerant ‘P1184948’ at high salinity level. Enhanced NaCl concentrations led to a significant increase in ΦPSII of ‘P1184948’ compared to ‘Vanda’, ‘P244601’ and untreated plants. Leaf CHL content was significantly increased in moderately-tolerant ‘‘P244601’ and salt-tolerant ‘P1184948’ at 80 mM NaCl compared to salt sensitive ‘Vanda’ and untreated plants. The depressive effect of salt on RWC was recorded at 120 mM NaCl in peanut leaves of all varieties. Under salt stress ‘P1184948’ was observed to have relatively higher tolerance on average of all growth and physiological traits than ‘Vanda’ and P244601’ suggesting that it could be grown in salt-affected soils.


2014 ◽  
Vol 73 (1) ◽  
pp. 312-321 ◽  
Author(s):  
Zamin S. Siddiqui ◽  
Jung-Il Cho ◽  
Sung-Han Park ◽  
Taek-Ryoun Kwon ◽  
Gang-Seob Lee ◽  
...  

Abstract Phenotyping of rice (Oryza sativa L. cv. Donggin) in salt stress environment using infrared imaging was conducted. Results were correlated with the most frequently used physiological parameters such as stomatal conductance, relative water content and photosynthetic parameters. It was observed that stomatal conductance (R2 = -0.618) and relative water content (R2 = -0.852) were significantly negatively correlated with average plant temperature (thermal images), while dark-adapted quantum yield (Fv/Fm, R2 = -0.325) and performance index (R2 = -0.315) were not consistent with plant temperature. Advantages of infrared thermography and utilization of this technology for the selection of stress tolerance physiotypes are discussed in detail.


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.


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