Monday, 11 July 2016

Seed structure and germination in buriti (Mauritia flexuosa), the Swamp palm

Published Date

November 2014, Vol.209(11):674–685, doi:10.1016/j.flora.2014.08.012

Title

Seed structure and germination in buriti (Mauritia flexuosa), the Swamp palm

Author

Renata Santana Silva^a

Leonardo Monteiro Ribeiro^a,^,^,

Maria Olívia Mercadante-Simões^a

Yule Roberta Ferreira Nunes^a

Paulo Sérgio Nascimento Lopes^b

aDepartamento de Biologia Geral, Universidade Estadual de Montes Claros, Campus Prof. Darcy Ribeiro, Montes Claros, MG 39401-089, Brazil
bInstituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Avenida Universitária, 1.000, Montes Claros, MG 39404-006, Brazil

Received 12 March 2014. Revised 15 August 2014. Accepted 25 August 2014. Available online 30 September 2014. Edited by Shahin Zarre

Highlights

•
Seeds of M. flexuosa show structural characteristics related to recalcitrance.
•
Seeds and seedlings of M. flexuosa are adapted to swampy environments.
•
Dormancy and recalcitrance are crucial to the reproductive success of M. flexuosa.

Abstract

Associations of recalcitrance and dormancy are rare, and little information is available concerning the structure of seeds demonstrating this type of behavior or their ecological implications. Mauritia flexuosa is a palm tree associated with swampy environments in the Amazon rainforest and areas of Cerrado (neotropical savanna), the latter biome having marked climatic seasonality. We describe the structures and physiological aspects of the seeds and seedlings of this species to examine its adaptations to swampy environments and its germination control mechanisms, as well as the relationship between recalcitrance and dormancy in terms of reproductive success. Morphoanatomy and histochemistry of the seeds and seedlings were evaluated using standard methodologies, and the effects of temperature and operculum removal on germination were investigated. Differentiated tracheal elements in the embryo are associated with recalcitrance, and presence of numerous stomata on the embryo and the abundance of secondary metabolite compounds in the seedling indicate their adaptations to swampy environments. The inability of the embryo to overcome the resistance of the adjacent tissues determines dormancy of the physiological type, thus the removal of the operculum is an efficient method for promoting propagation. Cellular elongation in the cotyledon promotes seedling protrusion. Mobilization of endosperm reserves is achieved by symplastic flux and is associated with overcoming of dormancy by weakening the tissues adjacent to the embryo. The association between recalcitrance, which favors adaptation to swampy environments, and dormancy, which favors dispersal, is crucial for the reproductive success of this species and its broad geographical distribution.