Current and Predicted Future Winter Warm Spells Would Affect Douglas Fir (Pseudotsuga menziesii (Mirb.), Franco) Seeds in the Early Stage of Germination More Than in the Late Stage of Germination

Abstract

Most tree species in the temperate climatic zone (including Douglas fir) disperse seeds in autumn. Some of them must be exposed to cold (0–10 °C) and moist conditions (cold stratification) to overcome dormancy and trigger germination. In the Northern Hemisphere, winter warm spells occur more frequently and last longer than in recent decades from eastern Canada to Europe. Our main research objective was to investigate the influence of current (1 or 3 days at day/night temperatures: 15 °C/10 °C) and future predicted (5 days at day/night temperatures: 25 °C/15 °C) winter warm spells on dormancy breaking and germination traits (germination energy—GE; germination capacity—GC; final germination capacity—FGC) of Douglas fir seeds from four old-growth stands in northern Poland. For this purpose, we interrupted cold stratification of seeds at different time points, i.e., after 3 weeks; 6 weeks; 9 or 3 weeks and 6 weeks; 3 and 9 weeks; 6 and 9 weeks; 3 and 6 weeks and 9 weeks. We found that for GE and GC, all main effects (populations—P; days of warm spell—D; stratification duration—W) and interactions were significant (except interaction P×D). FGC was significantly affected by the effects P and D and interactions of D × W and P × D × W. In addition, we found that the predicted warm spells negatively affected the early germination stage (GE and GC) of Douglas fir, but both current and future predicted winter conditions will not negatively affect the late germination stage (FGC).

Nondestructive Detection of Sunflower Seed Vigor and Moisture Content Based on Hyperspectral Imaging and Chemometrics

“…Various methods are employed for the assessment of traditional seed viability and moisture content, encompassing techniques such as germination tests, permeability tests, color detection, conductivity determination, respiration metabolism analysis, and enzymatic activity analysis [7,8]. In these methods, viability assessment typically relies on the performance of seed germination under favorable conditions or indirect evaluation through physiological parameters such as conductivity, respiration rate, and specific enzymatic activity.…”

Effects of warming on seed germination of woody species in temperate secondary forests

“…When a species is sensitive to warming, the germination percentage, germination energy, germination index, and duration of germination should increase, while mean germination time should decrease with warming (Zhou & He 2020). We proposed two hypotheses: (1) warming in non-stratified treatment can enhance the sensitivity of germination of woody species by increasing germination percentage, germination energy, germination index, thus prolonging the duration of germination and shortening the mean germination time in temperate secondary forests, as long as the increased temperature does not exceed the optimum temperature range for seed germination (Humphries et al 2018;Sentinella et al 2020); and (2) warming in the stratified treatment might be more likely to prevent seed germination because warming could shorten the duration of cold stratification and cold stratification is necessary to break dormancy (Flanigan et al 2020;Jastrze ˛bowski et al 2021). Our results can contribute to the understanding of reliable responses of seed germination to warming and predict the future direction of population dynamics in secondary forests.…”

“…2020; Jastrzębowski et al . 2021). Our results can contribute to the understanding of reliable responses of seed germination to warming and predict the future direction of population dynamics in secondary forests.…”