Influência da luz na germinação in vitro de sementes de tamareira (Phoenix dactylifera L.)

Abstract

RESUMOA tamareira (Phoenix dactylifera L.) é uma espécie da família arecaceae que produz frutos comestíveis altamente nutritivos e é de notável importância para muitos países do Norte da África, do Oriente Médio e da Ásia Oriental. Devido aos seus caracteres botânicos e à sua capacidade de desenvolvimento em regiões quentes e áridas e em diversos tipos de solos, a tâmara torna-se uma ótima opção para o Nordeste Brasileiro. Com o presente trabalho, objetivou-se estudar a germinação de sementes de tamareira, cv. Khadrawy, focalizando o comportamento fotoblástico das sementes. As sementes foram submetidas ao escuro contínuo e a fotoperíodo de 12 horas. O delineamento experimental utilizado foi completamente casualizado com quatro repetições de 25 sementes. Os parâmetros avaliados foram porcentagem e velocidade de germinação. A germinação das sementes não se restringiu a um dos tratamentos, respondendo positivamente tanto na presença quanto na ausência de luz. A velocidade de germinação, porém, foi sensivelmente mais alta nas sementes expostas ao escuro contínuo. Os resultados obtidos permitiram classificar as sementes de tamareira cv. Khadrawy como indiferentes à luz.Termos para indexação: Palmeira, fotoblastismo, escuro contínuo, fotoperíodo. ABSTRACTDate tree (Phoenix dactylifera L.) is a palm (Arecaceae) that produces nutritious fruits and has notable importance for many countries of the North of Africa, the Middle East and Eastern Asia. Due to the botanical characters and for the development in hot and barren regions and diverse types of soil, the date becomes an excellent option for the Brazilian Northeast. This study had as objective to study the seed germination of date palm cv. Khadrawy, being focused the photoblastic behavior of the seeds. The seeds were submitted to continuous dark and photoperiod of 12 hours. The experimental design used was completely randomized with four replicates of 25 seeds. Percentage and speed of germination were evaluated. Seed germination occurred in the presence of light and the dark, however the speed of germination was significantly higher in seeds submitted to continuous dark. The results allowed to classify the date palm seeds cv. Khadrawy as indifferent to light for germination.

Ample germination ability under wide‐ranging environmental conditions in a common understory tropical palm

“…Furthermore, buried seeds frequently experience better microclimate conditions for germination and may escape insect predation (Forget 1990;Silva & Tabarelli 2001). Indeed, seed germination under dark conditions has also been described in other palms (Aguiar et al 2005;Costa & Aloufa 2010;Braz et al 2014); a notable exception is L. weddellianum, which exhibited a marked decrease in germination for seeds subjected to dark conditions (Braz et al 2014). In contrast to a great number of small-seeded species, light is not a primary cue for germination in understory species from humid tropical forests (Milberg et al 2000;Baskin & Baskin 2014a).…”

“…Indeed, seed germination under dark conditions has also been described in other palms (Aguiar et al . ; Costa & Aloufa ; Braz et al . ); a notable exception is L .…”

“…According to Orozco-Segovia et al (2003), palms are not expected to have light requirements for seed germination. However, it has been observed that palms may have different light requirements for seed germination (Aguiar et al 2005;Costa & Aloufa 2010;Braz et al 2014). Moreover, some palms have recalcitrant seeds sensitive to dehydration, that may lose their viability when subjected to low soil water potential (Andrade 2001;Martins et al 2003).…”

“…However, it has been observed that palms may have different light requirements for seed germination (Aguiar et al . ; Costa & Aloufa ; Braz et al . ).…”

Micro propagation of Annona muricata using different concentration of 6-Benzylaminopurine (BAP).

“…Even though, a varieties of tropical tree species have been the subject of extensive tissue culture research, the Annonaceae have got little attention and showed uneven results (Bejoy and Hariharan 1992). Numerous research targeting micro propagation that have been carried out using meristems, buds, or nodal segments (Telles and Biasi 2005;Costa and Aloufa 2006).…”