Physiological analysis and heat-resistant protein (LEA) activity in squash hybrid seeds during development

Abstract

-This study has aimed to evaluate the best time to harvest squash seeds and verify the effect of fruit storage on protein activity and in the physiological quality of 'Jabras' squash hybrid seeds. The fruits were harvested at 15, 30, 45, 60 and 75 days after anthesis (DAA). In every period, thirty fruits were harvested and fifteen had their fruit extracted immediately after harvesting, and the other fifteen fruits were stored for twenty days in plastic boxes under shade conditions, and only after this period the seeds were extracted. Seed quality was evaluated for the following parameters: moisture content, germination, first count, germination rate, seedling emergence, emergence rate, seed mass and seedling dry matter. Also, the electrophoretic profile analysis of heat-resistant proteins (Late Embryogenesis Abundant -LEA) was performed. Seed physiological maturity occurred in fruits harvested at 60 days after anthesis and stored for 20 days. During this period, seeds reached the maximum dry matter, maximum germination and vigor, and a high concentration of LEA proteins.Index terms: Cucurbita maxima, Cucurbita moschata, seed quality.Análise fisiológica e atividade de proteínas resistentes ao calor (LEA) em sementes híbridas de abóbora durante o desenvolvimento RESUMO -O objetivo nesse trabalho foi avaliar a melhor época para a realização da colheita e verificar o efeito do armazenamento dos frutos na atividade de proteínas e na qualidade fisiológica de sementes do híbrido de abóbora 'Jabras'. Os frutos foram colhidos aos 15, 30, 45, 60 e 75 dias após a antese (DAA). Em cada época, foram colhidos trinta frutos, sendo que quinze frutos tiveram suas sementes extraídas imediatamente após a colheita e os outros quinze frutos foram armazenados por vinte dias em caixas plásticas em condições de galpão, e somente após este período, tiveram suas sementes extraídas. Avaliou-se a qualidade das sementes por meio do grau de umidade, germinação, primeira contagem, índice de velocidade de geminação, emergência, índice de velocidade de emergência, massa de 1000 sementes e massa seca de plântulas, além da análise do perfil eletroforético de proteínas resistentes ao calor (Late Embryogenesis Abundant -LEA). A maturidade fisiológica das sementes ocorreu em sementes oriundas de frutos colhidos aos 60 dias após a antese e armazenados por 20 dias. Nesse período, as sementes encontravam-se com o máximo de matéria seca, máxima germinação e vigor e alta concentração de proteínas LEA.Termos para indexação: Cucurbita maxima, Cucurbita moschata, qualidade das sementes.

Morphological and physiological changes during maturation of okra seeds evaluated through image analysis

“…Post-harvest temporary storage was beneficial to seed germination and vigor. This fact has been reported for various species that produce fleshy fruits Araujo et al, 2007;Silva et al, 2015). The absence of significant variations in seed dry matter, mostly during the temporary rest period, may increase the physiological potential that are attributed to metabolic adjustments (Dias, 2009;Bewley et al, 2013).…”

“…Germination was higher than the minimum standard (70 %) established for okra seed marketing in Brazil, from harvests at 35 DAA, reaching the maximum value at 50 DAA, when most fruits were yellowish bright brown and germination first count and seedling emergence also achieved the maximum. These values occurred after the time when seeds achieved maximum dry matter (30 DAA), a usual characteristic of seeds produced in fleshy fruits (Demir and Ellis, 1992;TeKrony and Egli, 1997;Vidigal et al, 2006;Silva et al, 2015).…”

“…In those species, the possibility of the seed maturation process to continue after the fruit harvest is an advantage because it allows early harvest, keeping fruits under temporary storage or a post-harvest rest period, sufficient for immature seeds to achieve a developmental degree similar to fruits harvested at physiological maturity. This allows the production of seed lots of high germination and vigor and avoids prolonged exposure of fruits to less favorable effects of biotic and abiotic factors in the field (Nascimento et al, 2000;Araujo et al, 2007;Vidigal et al, 2009, andSilva et al, 2015).…”

Effects of sewage sludge and length on initial growth of guava seedlings

“…The seed germination depends on the your origin, highlighting soil nutrient availability, since it directly influences embryo formation, the genetics and chemical composition of the species as it was verified in several studies on nutritional management of the "mother-plant", mainly in the beginning of the reproductive stage when nutrients are translocated to the seeds, and the seed storage after its physiological maturation, which may compromise the physiological quality, which are factors considered as mandatory steps in a seed production program (Carvalho and Nakagawa, 2012;Silva et al, 2015).…”

Physiological maturity and drying speed in the quality of zucchini ( Cucurbita pepo L.) seeds

“…The practical recognition of the seed physiological maturity for curcubitaceae species has been performed based on morphological fruit markers (color of the epidermis) and on the number of days after anthesis (Medeiros et al, 2010;Marrocos et al, 2011;Nakada et al, 2011;Figueiredo Neto et al, 2014;Silva et al, 2015). However, due to the fact that zucchini plants present continuous flowering and fruits whose epidermis color has little alterations during maturation, the number of days after anthesis may be characterized as the most promising technique to identify the stage of maximum seed quality for this species.…”