Data/hora: 22/05/2024 14:58:13

Biblioteca(s): | Embrapa Cerrados.
Data corrente: | 22/11/1999
Data da última atualização: | 22/11/1999
Autoria: | NOGUEIRA, P. C.
Título: | Seed dormancy in Johnsongrass (Sorghum halepense (L.) Pers).
Ano de publicação: | 1985
Fonte/Imprenta: | Mississippi: Mississippi State University, 1985.
Páginas: | 34p.
Idioma: | Inglês
Notas: | M.Sc. Thesis.
Conteúdo: | In Johnsongrass seed, dormancy is profound and persists for several years. The objective of this study was to evaluate several chemical and physical methods for overcoming dormancy of Johnsongrass seed. The physical methods were highly effective in breaking dormancy. Puncturing the pericarp was the most effective treatment and almost completely overcame seed dormancy. In this treatment , the hulled seeds were imbibed for 24 hours in water before puncturing the pericarp. Scarification of the seed in concentrated sulfuric acid for 30 minutes and soaking  the seeds in a 1% sodium hypochlorite solution for 48 hours also were effective in breaking domancy. There was no significant difference between these treatments. The chemical methods had no consistent effect or they were found to be injurious . Soaking the seeds in a 1000 ppm solution of gibberellic acid for 18 ours slightly increased the gemination percentage. The 6-benzylaminopurine treatment at the levels of concentration and soaking time tested had no effect. Sodium azide, hydrogen peroxide and high levels of potassium nitrate had a detrimental effect , since they reduced the germination percentege as compared with the check in which the seeds were imbibed in a 0.2% KNO3 solution. It was suggested that sodium hypochlorite scarification might be a better choice than sulfuric acid to treat the seeds on a large scale by the farmers before planting . Both treatments could be used for laboratory purposes with a reasonable degree of efficiency. Also, the duration of the test was shortened without losing much accuracy. The results of this experiment comfirm the teory that impermeability of the pericarp to gaseous exchange, particularly oxygen, is the major cause of dormancy in Johnsongrass seed.
Palavras-Chave: | Dormecia da semente; Troca de gas.
Thesagro: | Fisiologia; Sorghum Halepense.
Thesaurus Nal: | dormancy; gas exchange; plant physiology; seeds.
Categoria do assunto: | --
Registro original: | Embrapa Cerrados (CPAC)
Exemplares: | CPAC - (16035-1) - ADD - TS - -- - T041/85 - NOG - T041/85 - DIS