Título:	Thermal stress and physiological changes in watermelon seeds.
Autoria:	SILVA, R. de C. B. da ARAÚJO, M. do N. ORNELLAS, F. L. S. DANTAS, B. F.
Afiliação:	RITA DE CÁSSIA BARBOSA DA SILVA; MARCELO DO NASCIMENTO ARAUJO; FÁBIO LUIZ SANTOS ORNELLAS, Universidade Estadual de Santa Cruz, Ilhéus, BA; BARBARA FRANCA DANTAS, CPATSA.
Ano de publicação:	2018
Referência:	Pesquisa Agropecuária Tropical, Goiânia, v. 48, n. 1, p. 66-74, jan./mar. 2018.
Conteúdo:	Given that watermelon is a crop widespread around the world, there is considerable interest in verifying how its seeds physiologically behave under unfavorable temperature conditions. This study aimed to evaluate the biochemical changes mobilization and reserves degradation, as well as the enzyme activity, during seed germination and initial growth of watermelon seedlings subjected to thermal stress, using temperature, germination percentage, germination rate and relative germination frequency over the incubation time as evaluation parameters. The experimental design was completely randomized, in a 5 x 3 factorial scheme, with five temperatures (17 ºC, 20 ºC, 25 ºC, 30 ºC and 35 ºC) and three cultivars (Charleston Gray, Fairfax and Crimson Sweet), with 4 replicates of 50 seeds. Germination, seedling growth, reserve degradation and stress protection system were evaluated. Thermal stress caused deleterious effects on watermelon seeds with germination capacity at well defined temperature limits, being 25 ºC the ideal temperature, with the highest percentage of normal seedlings. Sub- (17 ºC) and supra-optimal (30 ºC) temperatures presented more than 80 % of abnormal seedlings. The α-amylase enzyme activity is intense only at the beginning of germination. Under thermal stress, the proline contents increase mainly in the cotyledons.
Thesagro:	Melancia Semente Germinação Fisiologia Atividade Enzimática Citrullus Lanatus
NAL Thesaurus:	Germination
Palavras-chave:	Enzymatic activity
ISSN:	1983-4063
Digital Object Identifier:	10.1590/1983-40632018v4850404
Tipo do material:	Artigo de periódico
Acesso:	openAccess
Aparece nas coleções:	Artigo em periódico indexado (CPATSA)