Germination and vigor of long-pepper seeds (Piper hispidinervum) as a function of temperature and light

Francisco Pacheco Junior,Jacson Rondinelli Da Silva Negreiros,Mirla Rose Gomes Da Silva,Sirlley Braga Farias,Josué Bispo Da Silva

doi:10.1590/s1806-66902013000200015

Abstract

The long pepper is considered a promising species because of offering the prospect of making Brazil self- sufficient in the production of safrole, an important essential oil used as a fixative for fragrances and having therapeutic properties. In establishing areas intended for the cultivation of this species, it is necessary to evaluate the physiological quality of the seeds used in the production of seedlings. The objective was to determine the conditions of temperature and luminosity for the test of germination and vigor in seeds of the long-pepper. Seeds from four different lots were used to make the following measurements: moisture content (105 r 3 °C for 24 hours), germination (20; 25; 30 and 35 °C with photoperiods of 12 and 24 hours, and alternating between 20-30 °C and 20-35 °C with 12 hours of light at the higher temperature), speed of germination index, speed of germination, seedling dry matter, seedling emergence, emergence rate index and relative frequency of germination. The experimental design was completely randomized with averages being compared by the Tukey test (Pi0.05). The germination of long-pepper seeds can be assessed at 25 °C with 12h darkness - 12 h light, 25 °C with 24 h darkness, 30 °C with 12 h darkness - 12 h light and 30 °C with 24 h light, and the physiological potential at 30 °C with 24 h light.

Highlights

The Long Pepper (Piper hispidinervum), a shrublike species of the Amazon region, has considerable commercial value in the production of safrole, an important secondary metabolite in obtaining heliotropine which is used as a fragrance, and piperonyl butoxide, used in the production of biodegradable insecticides (PEREIRA et al, 2008)
A sequence of physiological events occur that are influenced by temperature and light, making it necessary to study the influence of these factors in order to understand the germination process of seeds from species of different ecological groups (FERREIRA; FIGLIOLIA; ROBERTO, 2007), especially aromatic and forest species, for which basic information about the germination eco-physiology is still lacking
Three batches of seeds of the Long Pepper were used, supplied by different local producers, and one lot belonging to the germplasm bank of Embrapa Acre

Summary

Introduction

The seeds of many of these species require specific temperature regimes in order to germinate due to the influence of the ecological characteristics of their habitat (SOUZA et al, 2007). The optimum temperature for germination is between 15 and 30 °C (MACHADO et al, 2002). There are species where germination is favored by an alternating daily temperature, but this need may be associated with dormancy, an alternating temperature can accelerate the germination of nondormant seeds (OAK; NAKAGAWA, 2000). Marcos Filho (2005) adds that the temperature needed for germination does not have a specific value, but may be expressed in terms of cardinal temperatures, i.e., minimum, maximum and optimum, the latter being defined as that at which maximum germination occurs in a relatively short time

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