Seed and Germination Characteristics of 20 Amazonian Liana Species

Abstract

Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark) and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C) was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g) and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches.

Patterns of liana succession in tropical forests

“…Lianas come from an immense diversity of evolutionary backgrounds and have a wide range of growth strategies, climbing modes, dispersal modes, phenologies (Ibarra-Manríquez et al 1991), seed germination strategies (Roeder et al 2013), seedling morphologies (Ibarra-Manríquez et al 2001), and physiological tolerances, etc. Building more comprehensive databases of traits will be the first step in developing functional classifications of lianas (Gallagher, Chapter 9 in this volume).…”

Germination of small tropical seeds has distinct light quality and temperature requirements, depending on microhabitat

“…This approach ultimately led Pearson et al (2002) to conclude that alternating temperatures improve germination of tropical large-seeded pioneers (from 4.6 to 70.0 mg), whereas small-seeded species (from 0.04 to 1.9 mg) respond negatively to alternating temperatures. Distinct germination responses among small-seeded species due to temperature fluctuations may reflect different tolerance levels under different irradiance conditions, in association with the essential requirements for the early establishment of these species (Pearson et al 2002;Roeder et al 2013).…”