ABSTRACT
A incidência de fungos em sementes interfere negativamente o seu potencial fisiológico, podendo ter início no campo, durante o armazenamento ou na pós-colheita. Desta forma o objetivo deste trabalho foi avaliar a qualidade fisiológica e sanitária de sementes de erva-doce armazenadas em diferentes embalagens. O trabalho foi realizado no Laboratório de análise de sementes da UFPB, em Areia-PB. As sementes foram colhidas em plantas tratadas e não tratadas com inseticida Actara, beneficiadas e acondicionadas nas embalagens papel alumínio, saco plástico e vidro. Em seguida, armazenadas em câmara fria durante 315 dias. Inicialmente e a cada 45 dias foram realizados as seguintes determinações e testes: teor de água, emergência de plântulas, primeira contagem de emergência, índice de velocidade de emergência, comprimento e massa seca das plântulas e sanidade das sementes pelo método "blotter-test". Utilizou-se o delineamento inteiramente casualizado, com quatro repetições, os tratamentos foram distribuídos em fatorial 2 x 3 x 8 (com e sem inseticida, 3 embalagens e 8 períodos de avaliação). Os resultados indicam que a qualidade fisiológica das sementes de erva-doce foi principalmente afetada pelo fungo Alternaria sp., ocorrendo a manutenção da viabilidade das sementes por aproximadamente 95 dias na embalagem de saco plástico; a aplicação do inseticida Actara mantém a qualidade fisiológica das sementes de Foeniculum vulgare no armazenamento.
The fungi incidence in seeds affect negatively their physiological potential may begin in the field, during storage or in post-harvest. The objective was to evaluate the sanitary quality of fennel seeds stored in packagings differents. The study was conducted in laboratory analysis of seeds of UFPB, in Areia-PB. Seeds were harvested in experimental field with plants treated and untreated with insecticide Actara, processed and packed in aluminum foil, plastic bag and glass and stored in cold chamber during 315 days. Initially and every 45 days were performed the following tests and determinations: water content, seedling emergence, first count of emergency, emergency speed index, length and seedling dry mass and seed health by the "blotter-test." We used a completely randomized design with four replications, the treatments were distributed in a factorial 2 x 3 x 8. The results indicated that the physiological quality of fennel seeds was negatively affected by the fungus Alternaria sp., occurring at maintaining the viability of seeds for about 95 days in the plastic bag packaging; the application of the insecticide Actara keeps the physiological quality of seeds of Foeniculum vulgare in storage.
Subject(s)
Pimpinella/physiology , Alternaria/isolation & purification , Seeds/physiology , Analysis of Variance , Seed Storage ProteinsABSTRACT
BACKGROUND AND AIMS: Perennial plant formations always include a mixture of various-aged individuals of community-creating species, but the physiological and competitive potentials of plants of differing age and the importance on whole community functioning are still not entirely known. The current study tested the hypothesis that ontogenetically old plants have limited biomass investments in leaves and enhanced foliage support costs. METHODS: Leaf structure, size and biomass allocation were studied in the perennial herb Pimpinella saxifraga during plant ontogeny from seedling to senile phases to determine age-dependent controls on key plant structural traits. The average duration of the full ontogenetic cycle is approx. 5-10 years in this species. Plants were sampled from shaded and open habitats. KEY RESULTS: Leaflet dry mass per unit area (M(A)) increased, and the fraction of plant biomass in leaflets (F(L)) decreased with increasing age, leading to a 5- to 11-fold decrease in leaf area ratio (LAR = F(L)/M(A)) between seedlings and senescent plants. In contrast, the fraction of below-ground biomass increased with increasing age. Leaflet size and number per leaf increased with increasing age. This was not associated with enhanced support cost in older plants as age-dependent changes in leaf shape and increased foliage packing along the rachis compensated for an overall increase in leaf size. Age-dependent trends were the same in habitats with various irradiance, but the LAR of plants of varying age was approx. 1.5-fold larger in the shade due to lower M(A) and larger F(L). CONCLUSIONS: As plant light interception per unit total plant mass scales with LAR, these data demonstrate major age-dependent differences in plant light-harvesting efficiency that are further modified by site light availability. These ontogenetic changes reduce the differences among co-existing species in perennial communities, and therefore need consideration in our understanding of how herbaceous communities function.
