ABSTRACT. Germination metabolism of recalcitrant seeds of Araucaria angustifolia is activated in storage, which complicates the seeds conservation and utilization. This study aimed to identify the changes in the reserve metabolites of A. angustifolia seeds throughout storage in order to understand the processes of hydrolysis caused by germination metabolism. Mature seeds were harvested in southern Brazil and stored in an ambient environment and cold chamber conditions. Biochemical analyses were performed for embryos and megagametophytes from seeds stored for 0, 15, 30, 45, and 90 days. Due to seeds being in advanced germination in storage, they were evaluated at 90 days in different early developmental categories: I - seeds with mature embryos, II - seeds with embryos showing apparent elongation along the embryonic axis, and III - seeds with root protrusion. Higher contents of carbohydrate, protein, and amino acids were observed in embryos compared to megagametophytes, and these metabolites were decreased after onset of germination, especially in the embryo tissue. Mobilization of metabolites in megagametophytes would probably increase in later stages of germination. It is suggested that such alterations are not due to deterioration of reserve components, but instead are based on seed metabolism, which remains active after harvest with hydrolysis of metabolites providing energy for germination.

ABSTRACT Brazilian pine seeds (Araucaria angustifolia) are recalcitrant, and there are no studies evaluating the longevity of their different varieties. Our objective was to evaluate the capacity of different varieties of Brazilian pine seeds to maintain their physiological quality during storage. Seeds of the varieties: sancti josephi (I), angustifolia (II), caiova (III) and indehiscens (IV) were collected from two populations located in Santa Catarina, and stored under laboratory conditions and in a cold room for 90 days. On average, freshly harvested seeds showed 88% viability, and varieties II and III maintained the greatest viability (with the greatest vigor for variety II) after 90 days in storage. Varieties I and II maintained their pre-germinative metabolism for a longer period than the other varieties during storage. Therefore, seeds from the angustifolia variety (II) have higher storage potential than the other varieties, maintaining approximately 61% viability at 90 days of storage.

RESUMO Sementes de Araucaria angustifolia servem de base para a economia de muitas famílias rurais do sul do Brasil e apresenta diferentes variedades botânicas. Este estudo objetivou avaliar a diversidade das características físicas, fisiológicas e bioquímicas de sementes de Araucaria angustifolia das variedades locais sancti josephi, angustifolia, caiova e indehiscens. Sementes foram coletadas nos municípios de Painel e Urubici - Santa Catarina e submetidas aos testes: grau de umidade, massa de 1000 sementes, emergência, índice de velocidade de emergência - IVE, comprimento da raiz e parte aérea, condutividade elétrica, tetrazólio, teores de açucares solúveis e amido. A variedade angustifolia de Painel apresentou maior massa de sementes e vigor pelo IVE, condutividade elétrica e comprimento parte aérea. Enquanto, a variedade sancti josephi apresentou baixa porcentagem de emergência, massa de sementes, IVE, comprimento de raiz/parte aérea e teores de açucares. Na análise de cluster baseada na distância euclidiana, verificaram-se três grupos formados pelas variedades sancti josephi, indehiscens e caiova/angustifolia. As variedades angustifolia e caiova apresentaram similaridade e melhor qualidade fisiológica. A caracterização destas variedades possibilitou obter informações que podem auxiliar na coleta e aproveitamento das sementes para produção de mudas e conservação da espécie.

ABSTRACT Araucaria angustifolia seeds are the basis for the rural economy in southern Brazil, and the species presents different botanical varieties. The objective of this work was to evaluate the diversity of physical, physiological and biochemical characteristics of Araucaria angustifolia seeds from local varieties: 'sancti josephi', 'angustifolia', 'caiova', and 'indehiscens'. Seeds were collected from the cities of Painel and Urubici in Santa Catarina State and tested for moisture content, 1000-seed weight, emergence, emergence speed index (ESI), root and shoot length, electrical conductivity, tetrazolium, soluble carbohydrates, and starch content. Among the varieties cited above, the angustifolia variety from Painel displayed a greater 1000-seed weight, ESI, electrical conductivity and shoot length. However, the sancti josephi variety displayed a lower emergence percentage, 1000-seed weight, ESI, root and shoot length, and carbohydrate content. In a cluster analysis, based on Euclidean distance, three groups constituting the sancti josephi, indehiscens, and caiova/angustifolia varieties were found. In conclusion, there is great diversity in A. angustifolia seeds. The angustifolia and caiova varieties displayed similar diversity, and their physiological quality was better than that of other varieties. Variety characterization allowed for the compilation of information regarding seed collection and use for seedling production and species conservation.

Araucaria angustifolia seeds are recalcitrant, and their metabolism remains high during storage. This research aimed to describe the initiation of germination in A. angustifolia seeds during storage in order to standardize the assessment of physiological quality and to promote seed conservation. Seeds were collected from two populations and stored for 270 days in the natural laboratory environment and cold chamber. Seeds were classified according to four early developmental stages: I - mature seeds; II - seeds with elongation along the embryonic axis; III - beginning of root protrusion; IV - advanced germination stage, with seedling shoots. After categorization, physical and physiological quality was assessed. In freshly collected seeds, only category I was observed. At 270 days, approximately 40% of seeds were in category III in laboratory conditions, while the maintenance in a cold chamber delayed germinative metabolism. Viability tests showed that seeds in categories III and IV were more susceptible to damage caused by storage. In conclusion, the percentage of viable A. angustifolia seeds depends on the development stage after collection. Seeds that have reached early developmental category III should be prioritized for propagation, while those remaining in categories I and II should be longer stored with periodic assessment for reduction in physiological quality.

RESUMOEste estudo objetivou verificar a eficiência de métodos de pré-condicionamento e períodos de embebição em água para a realização do teste de pH do exsudato para avaliação da viabilidade de sementes de Araucaria angustifolia. Testaram-se três pré-condicionamentos (semente inteira; semente seccionada longitudinalmente; embrião excisado) e três períodos de embebição em água (30, 60 e 90 minutos), avaliando-se a coloração da solução. Adicionalmente, as sementes foram envelhecidas artificialmente por 4 e 8 dias, a 40 °C. A viabilidade foi superior em embriões excisados e embebidos por 30 minutos, apresentando elevado coeficiente de correlação com os testes de germinação e tetrazólio. Para sementes em avançado estádio de deterioração, a avaliação deve associar a coloração da solução ao aspecto dos tecidos. Conclui-se que o teste do pH do exsudato é eficiente na avaliação da viabilidade de sementes de A. angustifolia, devendo ser realizado utilizando-se apenas o embrião embebido em água por 30 minutos.

ABSTRACTThis study aimed to verify the efficiency of methods of pre-conditioning and periods of water immersion to perform the pH exudate test to evaluate the viability of Araucaria angustifolia seeds. Three pre-conditioning methods (whole seed, seed longitudinally sectioned, excised embryo) and three water imbibition periods (30, 60 and 90 minutes) were tested, and the solution color was evaluated. Additionally, the seeds were artificially aged for four and eight days at 40 °C. The viability was higher in embryos excised, after 30 minutes of imbibition, showing high coefficient of correlation with the germination and tetrazolium tests. Seeds at advanced stage of deterioration should be evaluated by associating the solution color with the tissue aspect. In conclusion, the pH exudate test is efficient to evaluate the viability of A. angustifolia seeds, and it should be performed using excised embryo imbibed in water for 30 minutes.