Stratification, Scarification and Application of Phytohormones Promote Dormancy Breaking and Germination of Pelleted Scots Pine (Pinus sylvestris L.) Seeds

Katarzyna Nawrot-Chorabik,Krzysztof Słowiński,Małgorzata Osmenda,Sylwester Tabor,Dariusz Latowski,Stephen Woodward

doi:10.3390/f12050621

Katarzyna Nawrot-Chorabik, Krzysztof Słowiński + Show 4 more

Open Access

https://doi.org/10.3390/f12050621

Copy DOI

Abstract

Seed quality is an important issue in forestry as it is an essential parameter in the production of high quality planting material. Many factors may hinder the harvesting of high quality seeds, including an insufficient number of sunny days, external conditions in temperate climate zones, and fungal pathogens affecting development of seedlings. We undertook to develop a procedure maximizing seed protection and promoting the optimum physiological development of seedlings by examination of the impact of seed pelleting (a general seed protection method) on germination rates and seedling development of Scots pine (Pinus sylvestris L.). Germination of pelleted seeds was examined in relation to substrate (water vs. soil) and LED light spectrum (white vs. red-blue). Several dormancy breaking treatments were applied: stratification/scarification, and growth regulator treatments including gibberellic acid (GA3), indole-3-acetic acid (IAA) and 1-naphthaleneacetic acid (NAA), to stimulate seed germination. Experiments included independent tests for each treatment (stratification/scarification and plant growth regulators), and combinations of both stratification/scarification and phytohormone treatments. The impacts of these treatments and various controlled germination conditions on the fluorescence of chlorophyll were analyzed using the maximum efficiency of photosystem II photochemistry parameter (Fv/Fm). In addition, chlorophyll a and b content in Scots pine seedlings germinated from pelleted seeds, were quantified using high-performance liquid chromatography (HPLC). The combined stratification/scarification and growth regulator treatment was the most effective germination promoting method for pelleted Scots pine seeds. Scots pine seeds are highly likely to be photoblastic. The best germination rate, while maintaining optimal physiological parameters, was achieved in acidic soil (pH 5.0) with white LED light.

Highlights

Seed quality is an essential factor in the production of high quality planting material.The germination rate of seeds and development of viable seedlings can be hindered by external conditions during the growing season in Poland and the occurrence of dampingoff pathogens, including Pythium, Phytophthora and Fusarium spp
Differences between the levels of chlorophyll fluorescence resulting from the wavelength and from stimulation by particular growth regulators were examined
The measurements showed a clear problem with the germination of enveloped or non-enveloped seeds growing in the soil under daylight conditions, without dormancy break treatments

Summary

Introduction

The germination rate of seeds and development of viable seedlings can be hindered by external conditions during the growing season in Poland and the occurrence of dampingoff pathogens, including Pythium, Phytophthora and Fusarium spp This adverse impact of fungus-like and fungal pathogens, and environmental conditions was the main reason for the development of seed pelleting in trees. The adaptive advantage of seed dormancy in natural conditions pertains to the lower probability of regeneration failure due to unfavorable environmental conditions, as not all seeds of a given generation germinate at the same time This physiological property of seeds can result in uneven germination in forest nurseries and cause problems in the consistent production of high quality planting material [2].

Methods

Results

Discussion

Conclusion