Résumé
RESUMO O objetivo do presente trabalho foi avaliar a influencia do tamanho e da temperatura na germinação das sementes, assim como, da posição de escarificação do tegumento e a profundidade de semeadura na emergência de plântulas de jutaí. As sementes foram separadas em três grupos: sementes pequenas, médias e grandes. A germinação das sementes foram realizadas nas temperaturas de 5, 10, 15, 20, 25, 30, 35, 40 e 45 °C e com fotoperíodo de 12 horas. As sementes escarificadas foram colocadas para germinar em 0, 2, 4 e 6 cm de profundidade de semeadura. As sementes médias e grandes apresentaram maiores porcentagens e índices de velocidade de germinação. A faixa de temperatura ótima de germinação está entre 25 e 35°C. A escarificação no hilo da semente ou não é adequada para quebra de dormência de sementes de jutaí. Profundidades de semeadura iguais ou superiores a 4 cm são inadequadas para a emergência de plântulas de jutaí.
ABSTRACT The objective of this study was to evaluate the influence of seed size and temperature on seed germination, as well as the scarification position of the tegument and sowing depth on the emergence of jutai seedlings. The seeds were separated into three groups: large, medium and small. The temperatures to which the seeds were subjected for germination were 5, 10, 15, 20, 25, 30, 35, 40, and 45°C under a photoperiod of 12 hours. The scarified seeds were placed to germinate at depths of 0, 2, 4, and 6 cm. Seed germination was affected by seed size (large and medium seeds). The optimum temperature range was found to be between 25 and 35°C. The scarification in the hilum or the tegument was enough to break the dormancy of the jutai seeds. Sowing depths equal to or deeper than 4 cm were found to be inadequate for the emergence of jutai seedlings.
Sujets)
Graines/classification , Germination , Plant/classification , Hymenaea/classification , TempératureRésumé
Aims: Angelica glauca Edgew is a heavily exploited critically endangered medicinal cum aromatic herb of Himalayan region. Poor and erratic seed germination is one of the constraints in its in-situ as well as ex-situ conservation and large scale cultivation. Moreover, our understanding of the eco-physiological aspects of the seed germination in this species is very limited. The present study aimed to understand the effect of different temperature regimes, photoperiodic conditions and sowing depths on seed germination in A. glauca using laboratory and nursery conditions. Study Design: Complete Randomized Design was executed. Place and Duration of Study: G.B. Pant Institute of Himalayan Environment and Development, Mohal-Kullu (HP), India between April 2006 and July 2008. Methodology: Germinability of the seeds were evaluated under different temperature regimes viz.(5, 15, 25 and 30ºC) and photoperiods (light-24 hrs, dark-24 hrs and alternate photoperiods-16 hrs dark and 8 hrs light) in laboratory; and at sowing depths (0.5, 1.0, 1.5 and 2.0 cm) in controlled nursery conditions. Results: In photoperiodic conditions, encouraging results were obtained under alternate light regimes which favored maximum (77.78%; p<0.05) mean germination along with minimum MGT (42.08 days) and Germination Potential Index (114.6) under laboratory condition. All these parameters performed significantly better at 25ºC as compared to other temperature regimes tested. In nursery condition, seed sown at 1.0cm depth gave comparatively higher (p<0.05) seedling emergence. Poor seedling emergence at higher sowing depth clearly indicated the requirement of light for germination in A. glauca seeds. Conclusion: Study concludes that alternate photoperiods (16 hrs dark and 8 hrs light), temperature (25ºC) and soil depths not more than 1.0cm are effective treatments to achieve optimum germination in A. glauca. These technicalities could be easily adopted by the poor and unskilled farmers for economic cultivation of this species.
Résumé
Ruta graveolens L., também conhecida com arruda, é planta originária do sul da Europa, cultivada no Brasil e em outros países como planta medicinal, muito utilizada em rituais religiosos. Tendo em vista que a germinação constitui um fator primordial para que a semente possa gerar uma planta vigorosa e com alto potencial produtivo, o presente trabalho teve como objetivo avaliar a resposta germinativa de sementes para arruda sob condições de temperatura, luminosidade, estresse hídrico e salino e emergência de plântulas em diferentes profundidades de semeadura. Sementes de Ruta graveolens são indiferentes à luz, germinando melhor em temperatura constante de 25ºC ou alterna (20-30ºC). Os potenciais osmóticos induzidos por manitol a partir de -0,4MPa e por NaCl a partir de -0,8MPa influenciam negativamente o processo germinativo. Maiores percentuais de plântulas são obtidas quando a espécie é semeada na superfície do substrato.
Ruta graveolens L., also known as rue, is from the south of Europe, cultivated in Brazil and other countries as a medicinal plant greatly used in religious rituals. Since germination is essential for the seed to generate a vigorous plant of high productive potential, this work aimed to evaluate the germinative response of rue seeds under different temperatures, luminosity conditions, and water and salt stress, besides seedling emergence at different sowing depths. Ruta graveolens L. seeds are indifferent to light, better germinating at constant temperature of 25ºC or alternated temperature (20-30ºC). The osmotic potentials induced by mannitol from -0.4MPa and by NaCl from -0.8MPa negatively influenced the germination process. Higher seedling percentages are obtained when the species is sown on the substratum surface.