PHYSIOLOGICAL QUALITY OF Araucaria angustifolia (Bertol.) Kuntze SEEDS SUBMITTED TO DIFFERENT STORAGE CONDITIONS AND ESCARIFICATION

Abstract

As sementes de Araucaria angustifolia (Bertol.) Kuntze(pinheiro-do-Paran\ue1) s\ue3o recalcitrantes e, portanto, perdem rapidamente a viabilidade ap\uf3s a colheita, o que dificulta a sua utiliza\ue7\ue3o na produ\ue7\ue3o de mudas. Este trabalho teve como objetivos avaliar os efeitos do tempo de armazenamento refrigerado, do m\ue9todo de conserva\ue7\ue3o e da escarifica\ue7\ue3o na germina\ue7\ue3o e vigor das sementes de Araucaria angustifolia. As sementes foram submetidas a 0, 60, 120 e 180 dias de armazenamento refrigerado (0-1\ub0C/90-95% de UR), em condi\ue7\uf5es de ar normal (AN), atmosfera modificada (AM) e atmosfera controlada (AC). Em cada per\uedodo de remo\ue7\ue3o da c\ue2mara fria, as sementes foram escarificadas (pelo do corte de uma pequena parte da ponta do tegumento, sem danificar o endosperma) ou n\ue3o, e colocadas para germinar em condi\ue7\uf5es controladas de c\ue2mara de crescimento, em bandejas contendo vermiculita, durante 60 dias. O trabalho seguiu o delineamento inteiramente casualizado, segundo um fatorial 4 x 3 x 2, correspondendo a quatro tempos de armazenamento (0, 60, 120 e 180 dias), tr\ueas m\ue9todos de conserva\ue7\ue3o (AN, AM e AC), com e sem escarifica\ue7\ue3o, com quatro repeti\ue7\uf5es. Foi observada a manuten\ue7\ue3o da qualidade fisiol\uf3gica de sementes de Araucaria angustifolia armazenadas sob diferentes m\ue9todos de conserva\ue7\ue3o, em condi\ue7\uf5es de refrigera\ue7\ue3o, durante o per\uedodo de at\ue9 180 dias. No entanto, a velocidade da germina\ue7\ue3o e o crescimento inicial das pl\ue2ntulas foi maior em sementes armazenadas em c\ue2mara refrigerada durante 60 dias do que em sementes utilizadas imediatamente ap\uf3s a colheita ou armazenadas durante per\uedodos maiores de tempo, de 120-180 dias. O armazenamento de sementes em condi\ue7\uf5es de AN, acondicionadas em embalagem perfurada, mostrou-se igual ou ligeiramente superior aos m\ue9todos de armazenamento em AM e AC na preserva\ue7\ue3o da qualidade das sementes. A escarifica\ue7\ue3o das sementes ap\uf3s o armazenamento refrigerado aumentou o vigor e promoveu o crescimento inicial de pl\ue2ntulas de Araucaria angustifolia.The seeds of Araucaria angustifolia (Bertol.) Kuntzeare recalcitrants and, therefore, they lose rapidly the viability after the harvest, limiting their use for nursery production of seedlings. This work was carried out to investigate the effects of cold storage duration, conservation method, and escarification on germination and vigour of seeds of Araucaria angustifolia. The seeds were cold stored (0-1\ub0C/90-95% RH) for 0, 60, 120, and 180 days, under normal air condictions (NA), modified atmosphere (MA), and controlled atmosphere (CA) storage. For each cold storage duration, after removal from cold storage, the seeds were submitted or not to scarification (by cutting a small portion of the apical seed tegument, avoiding the damage of the endosperm), letting the germinate in a chamber with controlled environment, in plastic trays filled with vermiculite, for 60 days. The experiment followed the completely randomized factorial design (4x3x2), with four cold storage durations (0, 60, 120, and 180 days), three storage methods (NA, MA, and CA), with or without escarification, and four replicates. There was a good preservation of physiological quality for seeds submitted to different conservation methods in cold storage along the 180-day period. However, there was a faster germination and initial growth of seedlings for seeds left in cold storage for 60 days than in seeds assessed at harvest or left in cold storage for 120-180 days. The NA storage of seeds in perfurated plastic bags was as efficient as MA and CA storage to preserve seeds quality. Seeds scarification increased vigor and promoted seedlings initial growth of Araucaria angustifolia after being removed from cold storage