Effects of low temperature and nitrogen addition during cold stratification on seed germination of Korean pine (Pinus koraiensis)

Abstract

<i>Pinus koraiensis </i>seeds are primary dormant following dispersal, restricting natural regeneration of populations. The aim of this study was to determine the combined effects of increasing low temperature and nitrogen addition during cold stratification on seed germination. We stratified seeds at 0 <sup>o</sup>C, 5 <sup>o</sup>C and 10 <sup>o</sup>C for 3.5 months. At each cold stratification temperature, seeds were subjected to 0 (0 nitrogen), 0.08 (low nitrogen), 0.16 (medium nitrogen) and 0.25 mol L<sup>-1</sup>(high nitrogen) nitrate additions. Seed germination response was tested at 25/15 <sup>o</sup>C and 10/5 <sup>o</sup>C. Under 0 nitrogen and high nitrogen levels, increasing cold stratification temperature did not remarkedly affect seed germination at 25/15 <sup>o</sup>C, but significantly inhibited seed germination at 10/5 <sup>o</sup>C. At medium nitrogen level, seed germination at both 25/15 <sup>o</sup>C and 10/5 <sup>o</sup>C were all significantly decreased. At low nitrogen level, increasing cold stratification temperature significantly decreased germination percentage at 25/15 <sup>o</sup>C from 86.7% (0 <sup>o</sup>C) to 50.2% (10 <sup>o</sup>C), but did not markedly change seed germination percentage at 10/5 <sup>o</sup>C. We suggest that the effect of increasing cold stratification temperature on seed germination of <i>Pinus koraiensis</i> depends on both the level of nitrogen addition during cold stratification and subsequent incubation temperature after cold stratification.

Deterioration in the Quality of Recalcitrant Quercus robur Seeds during Six Months of Storage at Subzero Temperatures: Ineffective Activation of Prosurvival Mechanisms and Evidence of Freezing Stress from an Untargeted Metabolomic Study

“…The majority of DAMs related to the activation of central metabolism, with an emphasis on phosphorylated carbohydrates and amino acid metabolism, were detected in embryonic axes, not in the storage tissue (Figures 5 and 6). A similar effect was reported previously for dormancy release in pine seeds [45], suggesting that the molecular response to storage is manifested particularly in embryonic axes [44]. The lower number of DAMs in cotyledons may also be related to their lower water content, which may be connected to increased macromolecular crowding affecting protein structure and eventually enzymatic activity [46].…”

“…In contrast to short-term cold stress, longer exposure to low temperature reduces the success of germination [50]. For example, at the seed-coat-rupture stage preceding radicle protrusion, a decrease in phosphorylated sugars, sugar alcohols, di-and trisaccharides, and amino acids was demonstrated in pine seeds compared with those in the metabolic state before germination was initiated [45]. In contrast, we found increased levels of these metabolites, supporting the thesis that germination had not yet been initiated.…”

The Impact of Water Potential and Temperature on Native Species’ Capability for Seed Germination in the Loess Plateau Region, China

“…However, the intra- and inter-annual temperature and precipitation variations in this region are drastic, which constrains the natural regeneration of seeds. Vegetation regeneration depends on seed germination, and there are interspecific differences in the response of germination to environmental variables [ 95 ]. Specifically, the cluster analysis showed that P. sepium was more tolerant to high temperatures than the other species.…”

Key Metabolite Differences Between Korean Pine (Pinus koraiensis) Seeds With Primary Physiological Dormancy and No-Dormancy

“…The dormancy status of seeds collected in September 2018 and May 2019 was determined at four incubation temperature regimes (10/5, 20/10, 25/15, and 30/20°C). The detailed germination test steps could be found in Song and Gao (2021) . Seeds collected in September 2018 were germinated to only 3–32% at four temperature regimes, indicating that these seeds are primary physiological dormant.…”

“…Seeds collected in September 2018 were germinated to only 3–32% at four temperature regimes, indicating that these seeds are primary physiological dormant. Seeds collected in May 2019 can be germinated to 27–90% at four temperature regimes, indicating that these seeds are non-primary physiological dormant ( Song and Gao, 2021 ).…”