O Aumento da Temperatura Reduz a Tolerância ao Estresse Hídrico na Germinação de Sementes de Pereskia grandifolia Haw. subsp. grandifolia (Cactaceae)?

Oliveira, Daianne Maria de; Lima, Ayslan Trindade; Rocha, Emerson Antônio; Meiado, Marcos Vinícius

doi:10.22478/ufpb.1981-1268.2017v11n4.35466

Cited by 8 publications

(7 citation statements)

References 12 publications

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“…During the evaluation of whether increased temperature reduces water stress tolerance in the germination of Pereskia grandifolia Haw. (Cactaceae) seeds while using polyethylene glycol (PEG 6000) to simulate the water deficit, Oliveira et al (2017) found a decrease in seed germination rate with the osmotic potential reduction, regardless of the evaluated temperature. However, the increased temperature reduced the water stress tolerance in the germination of P. grandifolia seeds.…”

Section: Resultsmentioning

confidence: 94%

Water restriction in seeds of Cereus jamacaru DC.

Silva

Azerêdo

Ferreira

et al. 2021

Agraria

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Mandacaru (Cereus jamacaru DC.) is a cactus widely found in the Caatinga, with its seeds usually subjected to adverse conditions. Therefore, the objective of this study was to evaluate the effect of water restriction on germination and vigor of mandacaru seeds by using different salts and osmotic potentials. To that end, we used saline solutions of NaCl, KCl, CaCl 2 and MgCl 2 prepared at the osmotic potentials of 0.0; -0.2; -0.4; -0.6; -0.8; -1.0 and -1.2 MPa. Four replicates of 50 seeds per treatment were used, distributed in "gerbox" boxes between blotter paper and under temperature of 25 °C. Counts of the number of germinated seeds were performed daily for 21 days after root protrusion. The variables analyzed were the following: water content (%), germination (%), mean germination time and normal seedlings (%). A completely randomized following the factorial scheme 4 × 7 (salts × osmotic potentials) was employed. Results obtained suggest that mandacaru seeds show the ability to germinate in saline soils, a characteristic found in arid and semi-arid areas. Decreased osmotic potential promoted reductions in germination (%) and vigor of Cereus jamacaru DC seeds. The MgCl 2 salt was the one that most negatively affected the germination and initial seedling development.

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Section: Resultsmentioning

confidence: 94%

Water restriction in seeds of Cereus jamacaru DC.

Silva

Azerêdo

Ferreira

et al. 2021

Agraria

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“…Irwin & Barneby (Fabaceae) . Each species germinates at a specific critical osmotic potential (Oliveira et al 2017). In addition, the environmental conditions from which the seeds were produced may influence the physiological responses to the abiotic conditions present during the germination of these seeds (Lima and Meiado 2017).…”

Section: Discussionmentioning

confidence: 99%

Effect of hydration and dehydration cycles on Macroptilium atropurpureum seeds germination under water deficit conditions

Lima¹,

Oliveira²,

Meiado³

2018

Commun. Plant Sci.

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The imbibition process, which is essential for seed germination, can be interrupted due to lack of water in the environment. Once this occurs, seeds have its germination process interrupted and loses the water absorbed to the environment. The objective of this study was to evaluate the effects of hydration and dehydration cycles (HD cycles) on seed germination of Macroptilium atropurpureum under water deficit conditions. Seeds of M. atropurpureum were submitted to 0 (control), 1, 2 and 3 HD cycles at different hydration times. In addition, the seeds were also submitted to osmotic potentials of 0.0, -0.1, -0.3, -0.6 and -0.9 MPa for water deficit simulation. Although the seeds germinated in all of the osmotic potentials used, the seeds presented a reduction in the percentage of germination, independently of the number of HD cycles and the hydration time between each cycle. In addition, HD cycles also negatively affected the mean germination rate, promoting a reduction of this parameter as seeds were submitted to HD cycles and osmotic potentials. Thus, the results demonstrated that HD cycles did not provide an increase in water stress tolerance in M. atropurpureum seeds during germination. Highlighted Conclusions 1)Macroptilium atropurpureum seeds can germinate even in low osmotic potentials conditions. 2) Discontinuous hydration confers a negative effect on M. atropurpureum germination and does not provide a greater tolerance to water deficit.Seed imbibition is a key process in the plant life cycle determining whether seed germination and individual growth will be successful or not (Ribeiro et al. 2015). The imbibition process, which is essential for seed germination, can be interrupted due to lack of water in the environment. Once this occurs, the seed has its germination process interrupted and loses the water absorbed to the environment (Fenner and Thompson 2005). These interruptions during germination process occur in arid and semi-arid environments, where water presents a limit of space and time in its availability, subjecting seeds to hydration and dehydration cycles (HD cycles) (Lima and Meiado 2017). Dubrovsky (1998) pointed that discontinuous hydration ensures a high survival rate during desiccation, demonstrating that seeds may present seed hydration memory, caused by the discontinuous imbibition process.In addition to the high survival rate during desiccation highlighted by Dubrovsky (1998), HD cycles may provide other advantages during the germination process of the seeds of some species. Rito et al. (2009) demonstrated that seeds of Cereus jamacaru DC. subsp. jamacaru (Cactaceae) present seed hydration memory, since, after being submitted to HD cycles, seeds had their percentage of seed germination increased. Pedrero-López et al. (2016), in experiments with seeds of Dodonaea viscosa Jacq. (Sapindaceae) also observed a significant increase of germinability after HD cycles from 22.5% to 63.3%. Discontinuous hydration may also provide greater tolerance to abiotic stress conditions, as observed by Li et ...

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“…Esse comportamento verificado nas sementes de facheiro pode estar associado às características genéticas da espécie e aos fatores climáticos da área de procedência dessas sementes, visto que há relação entre a temperatura ótima de germinação e o ecossistema de ocorrência da espécie, partindo do princípio de que a temperatura ótima para a germinação é resultado da adaptação fisiológica das sementes às condições ambientais do local onde elas foram produzidas [34]. Oliveira et al (2017) [18] ao avaliarem se o aumento da temperatura reduz a tolerância ao estresse hídrico na germinação de sementes de Pereskia grandifolia ssp. grandifolia (Cactaceae), os autores perceberam diferenças no desempenho germinativo entre as temperaturas de 25 e 30 °C em todos os potenciais avaliados e verificaram que a redução do potencial osmótico propiciou uma diminuição da germinabilidade das sementes, independentemente da temperatura avaliada.…”

Section: Figura 2: Germinação (%) De Sementes De Pilosocereus Pachycladus Fritter Subsp Pernambucoensis (Fritter) Zappi (Facheiro) (A) E unclassified

“…Estudos sobre as exigências hídricas para germinação das sementes de cactos podem ser esclarecedores para se conhecer as estratégias de sobrevivência desse grupo de plantas, uma vez que poucos são os dados encontrados na literatura, a exemplo dos trabalhos com Cereus jamacaru [14,15], Hylocereus spp. [8,16,17], Pereskia grandifolia [18], Pilosocereus catingicola [19,20] e Discocactus spp. [21].…”

Section: Introductionunclassified

Resposta germinativa de sementes de cactáceas colunares sob diferentes regimes de temperatura e de potencial hídrico

2021

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O mandacaru (Cereus jamacaru DC. subsp. jamacaru) e o facheiro (Pilosocereus pachycladus F.Ritter subsp. pernambucoensis (F.Ritter) Zappi) são duas cactáceas colunares endêmicas do semiárido brasileiro, região caracterizada por apresentar áreas em que ocorre déficit hídrico. Assim sendo, este estudo objetivou avaliar o efeito do estresse hídrico sobre a germinação e o vigor de sementes dessas duas espécies sob diferentes temperaturas e potenciais hídricos. Para simular o estresse hídrico foram utilizadas soluções de polietilenoglicol (PEG 6000) nos seguintes potenciais hídricos: 0,0 (controle); -0,2; -0,4; -0,6 e -0,8 MPa. As sementes foram distribuídas em caixas tipo “gerbox” entre papel “mata borrão”, sob as temperaturas de 25 e 30 °C. A contagem do número de sementes germinadas foi realizada diariamente durante 21 dias após a protrusão radicular. As variáveis analisadas foram: teor de água (%), germinação (%), índice de velocidade de germinação (IVG) e tempo médio de germinação (TMG). O delineamento foi inteiramente casualizado seguindo o esquema fatorial de 2 × 5 (temperatura × potencial hídrico) para cada espécie. Os resultados obtidos neste estudo sugerem que o C. jamacaru subsp. jamacaru e o P. pachycladus subsp. pernambucoensis são capazes de germinar em solos com baixa disponibilidade hídrica e que a redução dos níveis osmóticos das soluções de PEG 6000 no meio germinativo provoca decréscimos na viabilidade e vigor das sementes de mandacaru e facheiro. A 30 °C há menor tolerância das sementes ao estresse hídrico.

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O Aumento da Temperatura Reduz a Tolerância ao Estresse Hídrico na Germinação de Sementes de Pereskia grandifolia Haw. subsp. grandifolia (Cactaceae)?

Cited by 8 publications

References 12 publications

Water restriction in seeds of Cereus jamacaru DC.

Water restriction in seeds of Cereus jamacaru DC.

Effect of hydration and dehydration cycles on Macroptilium atropurpureum seeds germination under water deficit conditions

Resposta germinativa de sementes de cactáceas colunares sob diferentes regimes de temperatura e de potencial hídrico

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