Longevidad y germinación de semillas de Syagrus romanzoffiana (Arecaceae) y sus implicaciones ecológicas

Túlio Gabriel Soares Oliveira,Anderson Cleiton José,Leonardo Monteiro Ribeiro,José Marcio Rocha Faria

doi:10.15517/rbt.v63i2.15614

Abstract

Syagrus romanzoffiana is a palm tree native and widely distributed of South America. The present study investigated the longevity and germination of the buried seeds of this species in an experimental seed bank. Laboratory germination and viability tests were performed for comparison with field results. Pyrenes (seeds enclosed by the endocarp) were buried in a forest fragment edge in July (dry season) in July 2012 and exhumed monthly during one year, for the assessment of water content and percentage of germinated and viable seeds. Germination tests were conducted in a Mangelsdorf-type germinator at 30°C under constant light and the viability was assessed by the tetrazolium test. An additional sample of pyrenes was buried to evaluate the percentage of seedling emergence and survival. Climatic and soil moisture data were recorded. In the laboratory, the pyrenes were stored for one year in a temperature-controlled room at 20ºC and 75% (±10%) relative air humidity to assess changes in the percentage of germination and viability over time. In the field, a reduction in seed viability was observed over the study period, with a total loss of viability of non-germinated seeds at seven months after burial. The maximum germination (close to 26%) was observed in the samples that were exhumed between five and seven months after burial. In the field, seedling emergence did not exceed 10% and seedling mortality was not observed. The percentages of germination and of viable seeds decreased both in burial and stored seeds. The stored seeds maintained viability at up to six months, with marked reduction thereafter. After the germination tests (four months) in the laboratory, all of the remaining seeds were nonviable. The ecological, physiological and reproductive characteristics of the species are discussed, and we concluded that S. romanzoffiana seeds have short longevity after imbibition, and low potential for soil seed bank formation.

Highlights

Syagrus romanzoffiana is a native palm tree that is widely distributed in South America (Lorenzi, Souza, MedeirosCosta, Cerqueira, & Behr, 1996)
We sought to assess changes in the germination, viability and water content of S. romanzoffiana seeds in natural and laboratory conditions to determine the following: i) are there differences in the longevity of laboratory stored and buried seeds? ii) does the species form a persistent seed bank? and iii) does the behavior of seeds in the bank explain the reproductive success of the species?
S. romanzoffiana seeds buried in the experimental seed bank showed short longevity, with total seed mortality after seven months of burial, characteristic of a transient seed bank

Summary

Introduction

Syagrus romanzoffiana (queen palm) is a native palm tree that is widely distributed in South America (Lorenzi, Souza, MedeirosCosta, Cerqueira, & Behr, 1996). The presence of fruit structures (such as the endocarp) restricts germination in certain palm tree seeds by imposing a mechanical barrier for germination (Broschat, 1998; Ribeiro, Souza, Rodrigues-Jr, Oliveira, & Garcia, 2011; Neves et al, 2013). These structures may play an important ecological role, especially in the prevention of water loss and protection against predation, contributing to an increase in seed longevity (Orozco-Segovia, Batis, Roja-Aréchiga, & Mendoza, 2003; Hu, Wang, & Wu, 2009). We sought to assess changes in the germination, viability and water content of S. romanzoffiana seeds in natural and laboratory conditions to determine the following: i) are there differences in the longevity of laboratory stored and buried seeds? ii) does the species form a persistent seed bank? and iii) does the behavior of seeds in the bank explain the reproductive success of the species?

Methods

Results

Conclusion