Germination Response of Ornamental Pine Seeds on a Two-Way Thermogradient Plate

Marcos Vieira Ferraz,Tim Marks,Marcelo Vieira Ferraz,Hugh W Pritchard,Leandro José Grava De Godoy,Kathia Fernandes Lopes Pivetta

doi:10.4236/ajps.2018.91002

Abstract

The objective of this study was to evaluate the effect of temperature on germination of Pinus tabuliformis Carriere seed, Pinus gerardiana Wall. ex D. Don and Pinus roxburghii Sarg. Seeds of three species were distributed in Petri dishes with 1% agar solution; for the first step it was placed on a 2-way Grant’s thermogradient plate (a bi-directional incubator) for a period of 28 days and during the second step in an incubator type B.O.D. also for 28 days with non-germinated seeds in the first step. This instrument allows an assessment of a wide regime of constant and alternating temperatures, resulting to 144 different combinations of temperature, scheduled to the temperatures 4°C - 40°C. The lighting regime was 12 hours photoperiod for the two stages of the experiment. The best temperature for the germination of P. tabuliformis was 26.2°C (minimum of 7.9°C and maximum 37.0°C) and P. roxburghii was 15.6°C (minimum 10, 4°C and maximum 37.0°C). The seeds are neutral photoblastic. P. gerardiana showed low germination percentage (below 10%). The temperature that provided the highest germination percentage for P. tabuliformis was 26.2°C and 15.6°C for P. roxburghii.

Highlights

IntroductionIt is necessary that some intrinsic factors of the seed and related environmental act favorably
P. gerardiana showed low germination percentage
The P. gerardiana species, probably due to the low seed quality, presented low germination for some temperature regimes at the thermogradiente plate and, was not evaluated for this experiment

Summary

Introduction

It is necessary that some intrinsic factors of the seed and related environmental act favorably. To this end, it is essential that the seed is alive, there is no numbness and has availability of water, temperature and oxygen [1]. Each species requires specific conditions for germination to happen, especially the quality of the presence of light and proper temperature [2]. These two environmental factors are of fundamental importance in controlling germination, and are considered to be the main extrinsic factors that influence germination [3] [4] [5]

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Results