Alterações fisiológicas e bioquímicas em sementes de café secas em sílica gel e soluções salinas saturadas

Coelho, Stefânia Vilas Boas; Figueiredo, Madeleine Alves de; Clemente, Aline da Consolação Sampaio; Coelho, Luis Filipe Serafim; Rosa, Sttela Dellyzete Veiga Franco da

doi:10.1590/s0100-204x2015000600007

Cited by 17 publications

(24 citation statements)

References 19 publications

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“…These results corroborate those obtained by Coelho et al (2015), who, upon studying the effect of different drying rates on the quality of coffee seeds stored at 10 ºC, observed that the damage from drying is more related to the endosperm than to the embryo. In a similar manner, Dussert and Engelmann (2006) demonstrated that endosperms of coffee seeds are more sensitive to damage from drying and from immersion in liquid nitrogen compared to zygotic embryos.…”

Section: Resultssupporting

confidence: 91%

Tolerance of Coffea arabica L. seeds to sub zero temperatures

et al. 2017

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Preservation of the quality of coffee seeds is hindered by their intermediate behavior in storage. However, long-term storage at sub zero temperatures may be achieved by adjusting the water content of the seeds. The aim of this study was to evaluate the tolerance of coffee seeds to freezing, in relation to physiological and enzymatic modifications. Coffee seeds were dried in two manners, rapid and slow, to water contents of interest, 0.67, 0.43, 0.25, 0.18, 0.11, and 0.05 g H 2 O g -¹ dw (dry basis). After drying, the seeds were stored at a temperature of -20 ºC and of 86 ºC for 24 hours and for 12 months, and then compared to seeds in cold storage at 10 ºC. The seeds were evaluated through calculation of percentage of normal seedlings, percentage of seedlings with expanded cotyledonary leaves, dry matter of roots and of hypocotyls, and viability of embryos in the tetrazolium test. Expression of the enzymes superoxide dismutase, catalase, and peroxidase were evaluated by means of electrophoretic analysis. Only seeds dried more slowly to 0.18 g H 2 O g -1 dw present relative tolerance to storing at -20 °C for 12 months. Coffee seeds do not tolerate storage at a temperature of -86 ºC for 12 months. Water contents below 0.11g H 2 O g -¹ dw and above 0.43 g H 2 O g -¹ dw hurt the physiological quality of coffee seeds, regardless of the type of drying, temperature, and storage period. Coffee seed embryos are more tolerant to desiccation and to freezing compared to whole seeds, especially when the seeds are dried to 0.05 g H 2 O g -¹ dw. The catalase enzyme can be used as a biochemical marker to study tolerance to freezing in coffee seeds.Index terms: Drying; silica gel; saturated saline solutions; freezing; antioxidant enzymes. RESUMOA preservação da qualidade de sementes de café é dificultada pelo comportamento intermediário no armazenamento. Porém, a conservação a longo prazo em temperaturas subzero pode ser conseguido com o ajuste do teor de água das sementes. Objetivou-se neste trabalho avaliar a tolerância de sementes de café ao congelamento, com relação às modificações fisiológicas e enzimáticas. As sementes foram submetidas a dois tipos de secagem, rápida e lenta, até os teores de água de interesse, de 0,67, 0,43, 0,25, 0,18, 0,11, 0,05 g H 2 O g -¹ dw (base seca). Após secagem, as sementes foram armazenadas em temperatura de -20 e de -86 ºC, por 24 horas e por 12 meses, sendo comparadas às sementes armazenadas em câmara fria a 10 ºC. As sementes foram avaliadas pela porcentagem de plântulas normais, plântulas com folhas cotiledonares expandidas, matéria seca de raízes e de hipocótilos e viabilidade dos embriões no teste de tetrazólio. A expressão das enzimas superóxido dismutase, catalase e peroxidase foi avaliada por meio de análise eletroforética. Apenas as sementes secadas lentamente até 0,18 g H 2 O g -¹ dw apresentam relativa tolerância ao armazenamento a -20 °C por 12 meses. Sementes de café não toleram o armazenamento à temperatura de -86 ºC por 12 meses. Umidades abaixo de 0,11g H 2 O g -¹ dw ...

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Section: Resultssupporting

confidence: 91%

Tolerance of Coffea arabica L. seeds to sub zero temperatures

et al. 2017

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“…As fast drying provided better physiological results (Coelho et al, 2015), this drying method was chosen in this experiment.…”

Section: Procedures For Cryopreservation Of Coffee Seedsmentioning

confidence: 99%

“…The great advantage of the method used here, besides the positive results in seed cryopreservation, is the ease of the dehydration process on silica gel, when compared to dehydration in saline solutions. In addition, it has already demonstrated that rapid dehydration for coffee seeds is less damaging than the slow one (Coelho et al, 2015).…”

Section: Experimental Designmentioning

confidence: 99%

“…Coffee seeds were successfully cryopreserved, forming normal seedlings (11 to 67% viability, depending on the lot used) after slow dehydration in saline solutions (Dussert and Engelmann, 2006). However, it has recently been reported that slow dehydration (in saline solutions) is more damaging than rapid dehydration (on silica gel) for coffee beans and it takes almost twice as long to reach the desired moisture (Coelho et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

“…According to Coelho et al (2015), the water content remaining in the coffee seeds after drying and the speed with which it occurs can affect the seeds physiological quality. These authors have stated that these seeds tolerate greater loss of water when submitted to rapid drying.…”

Section: Introductionmentioning

confidence: 99%

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Exploratory studies for cryopreservation of Coffea arabica L. seeds

et al. 2017

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-Cryopreservation is a viable option for conservation of coffee germplasm. However, for this technique to be completely successful, it is of fundamental importance to carry out studies that ensure maintenance of cell integrity before and after immersion in liquid nitrogen (LN). Therefore, the aim in this study was to investigate the water content, cooling rate, and final temperature most suitable for cryopreservation of Coffea arabica L. seeds. The seeds were dried by silica gel to water contents of 5, 10, 15, 20, 30 and 40 % wb, subjected to slow cooling treatments at speeds of -1, -3 and -5 °C min.-1 to final temperatures of -40, -50 and -60 °C and then directly immersed in LN. After storage, seeds were rewarmed at 40 °C for two minutes. The survival rate and viability of the seeds and embryos were evaluated by the tetrazolium and germination tests.Results of the tetrazolium test indicate that embryos excised from cryopreserved seeds are less sensitive to cryopreservation than whole seeds are. The water content of 20% wb and the use of zygotic embryos led to the highest survival rate of the coffee seeds, depending on the cooling rate and the final temperature of precooling.Index terms: silica gel, water content, slow cooling, liquid nitrogen, coffee.Estudos exploratórios para a criopreservação de sementes de Coffea arabica L.RESUMO -A criopreservação é uma opção viável para a conservação de germoplasma de café. Entretanto, para que essa técnica apresente total sucesso é de fundamental importância realizar pesquisas que garantam a manutenção da integridade celular antes e após a imersão em NL. Portanto, o objetivo neste estudo foi investigar o teor de água, velocidade e temperatura final de resfriamento mais adequados para criopreservar sementes de Coffea arabica L. As sementes foram secadas em sílica gel até teores de água de 5, 10, 15, 20, 30 e 40% bu, submetidas a tratamentos de resfriamento lento nas velocidades -1, -3 e -5 ºC min -1 até às temperaturas finais de -40, -50 e -60 ºC e diretamente imersas em NL. Após armazenamento as sementes foram reaquecidas por dois minutos à 40 ºC. A sobrevivência e a viabilidade de sementes e embriões foram avaliadas por meio do teste de tetrazólio e de germinação. Por meio do teste de tetrazólio, observa-se que embriões excisados das sementes criopreservadas são menos sensíveis à criopreservação quando comparados às sementes inteiras. O teor de água de 20% bu permite maior sobrevivência das sementes de Coffea arabica L., bem como de embriões zigóticos após a criopreservação, dependendo das velocidades e temperaturas finais de pré-resfriamento.Termos para indexação: sílica gel, teor de água, resfriamento lento, nitrogênio líquido, café.

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