Germination and vigour of primed asparagus seeds

Abstract

The osmotic conditioning or priming is considered a promising technique to speed up germination and to improve seed performance. Four seed lots of asparagus, Mary Washington cultivar, were primed at 25°C for seven or 14 days using PEG 6000 at -1.0 or -1.2 MPa, or sea water at -3.3 MPa; or for three days in distilled water. The physiological quality of the seeds was evaluated by standard germination, first count germination, speed of seedling emergence, and germination percentage and seedling fresh and dry weights after controlled deterioration test. Primed seeds presented higher germination speed, independently of their initial physiological quality. Beneficial effects of priming on germination and vigour were more expressive in the seed lot of low physiological quality. Priming in PEG 6000 at -1.0 MPa for 14 days was the most beneficial treatment to improve asparagus seeds performance. Key words: Asparagus officinalis, osmotic conditioning, physiological quality GERMINAÇÃO E VIGOR DE SEMENTES DE ASPARGO OSMOTICAMENTE CONDICIONADASRESUMO: O condicionamento osmótico ou priming tem sido considerado uma técnica promissora para acelerar a germinação e melhorar o desempenho das sementes. Sementes de quatro lotes de aspargo, cv. Mary Washington, foram condicionadas em PEG 6000 a -1,0 e -1,2 MPa, por 7 e 14 dias, em água do mar a -3,3 MPa, por 7 e 14 dias e em água destilada por 3 dias, em BOD a 25°C. Sementes não condicionadas foram usadas como testemunha. A qualidade fisiológica das sementes foi avaliada pela germinação, primeira contagem de germinação, velocidade de emergência e pela porcentagem de geminação e pesos da matéria fresca e seca das plântulas obtidas no teste de deterioração controlada (45°C/24 horas). O experimento foi instalado no delineamento inteiramente casualizado com quatro repetições e oito tratamentos, sendo as médias comparadas pelo teste de Duncan a 5%. Sementes de aspargo condicionadas osmoticamente apresentaram maior velocidade de germinação, independentemente de sua qualidade fisiológica inicial. Efeitos benéficos do condicionamento osmótico, na germinação e no vigor, foram mais expressivos no lote de baixa qualidade fisiológica. O condicionamento em PEG a -1,0 MPa por 14 dias foi, em geral, o tratamento mais adequado para promover melhoria na qualidade fisiológica dessas sementes. Palavras-chave: Asparagus officinalis, condicionamento osmótico, qualidade fisiológica

Osmocondicionamento em sementes de pimenta 'amarela comprida' (Capsicum annuum L.) Submetidas à deterioração controlada

“…Segundo Nascimento, (2003), a eficiência do condicionamento osmótico depende, dentre outros fatores, do nível de qualidade da semente. Essa técnica tem se mostrado mais eficiente para lotes de sementes de baixa qualidade (Tilden & West, 1985;Bittencourt et al, 2004Bittencourt et al, , 2005.…”

Is the enhancement produced by priming in cottonseeds maintained during storage?

“…Only seed age affected this variable, significantly less for 2007 seeds (60-70%) with relation to 80% reached by 2008 seeds. In other species (Bittencourt et al, 2005;Choudhary et al, 2008), different treatments of osmopriming increased the percentage of normal seedlings in seed lots of different initial quality, while hydropriming was only effective in seed lots of lower or medium physiological quality. Dorna et al (2013) report a decrease in the percentage of normal seedlings after 6 to 12 months of storage in seeds hydro or osmoprimed in PEG, related to the increase of fungal infections during such period, which was not observed in the current study.…”

“…The added percentages of seedlings in the warm and cold tests resulted in the vigor index (CWVI = cool warm vigor index), which allows classifying cottonseeds as seeds of low vigor (less than 120), regular vigor (between 120 and 139), good vigor (between 140 and 159) and excellent vigor (above 160) (Baughman et al, 1994).…”

“…This treatment can be done in water or in osmotic solutions. Effectiveness of hydropriming has been shown in many species (Bittencourt et al, 2005;Choudhary et al, 2008;Dorna et al, 2013;Fanan and November, 2007;Fujikura et al, 1993;). Mannitol, though in general less tested (Parera and Cantliffe, 1994;Welbaum et al, 1998), has shown promising results in preliminary studies in cotton.…”

“…In melon, priming in healthy and high quality seeds is recommended (Nascimento, 2002). Nevertheless, in other cases, better responses were found in lots of seeds of low quality (Bittencourt et al, 2005;Choudhary et al, 2008;McDonald, 1999;Nascimento and Souza de Aragão, 2004).…”