Seed dormancy revisited: Dormancy‐release pathways and environmental interactions

Abstract

1. Many internal (inherent) and environmental (imposed) factors control seed dormancy and germination that we divide into three basic dormancy-release pathways: Maternal structures and embryo physiology control inherent dormancy that is broken by various types of scarification and physiological changes, followed by imposed-dormancy release when the prevailing environment is replaced by certain 'standard' conditions that stimulate germination (Pathway 1); imposed dormancy prevails even if inherent dormancy is broken or not applicable that is released when replaced by certain 'standard' environmental conditions which stimulate germination (Pathway 2); and release from inherent dormancy by light/ dark or cold stratification is contingent on the pre-existence of certain environmental conditions that stimulate germination (Pathway 3).2. On-plant seed storage (serotiny) and frugivorous seeds are recognized here as representing special types of physical dormancy, as their properties are consistent with those of hard diaspores. Warm stratification does not require seeds to be moist as it is just a physical response. Heat may promote germination of non-hard, as well as hard, seeds as it may increase their permeability further.3. Levels of germination gauge the net effect of inherent-and imposed-dormancy release so that it is only possible to identify the extent of inherent-dormancy release when conditions for germination are optimal (imposed dormancy has been annulled). While imposed dormancy may be protracted after inherent dormancy is broken by heat or chilling during the dry or cold seasons, release from both states may effectively coincide if smoke chemicals or light are received during the (wet) growing season.4. We suggest reserving the term secondary dormancy for seeds that return to (inherent or imposed) dormancy due to changed environmental conditions. Under seasonal climates, fluctuations in environmental conditions can lead to secondary dormancy and even dormancy cycling. 5. We recognize four types of functional interactions between any two environmental factors that induce inherent-dormancy release: binary interactions are ineffective, only one stimulus is effective, both are effective but non-additive, or | 1107Functional Ecology LAMONT and PAUSAS

Paternal intergenerational plasticity in the plant species Paeonia ostii: Implications for parental fitness and offspring performance

“…Both paternal drought and maternal drought had negative effects on seed production of P. ostii , with maternal drought exhibiting a stronger influence (Figure 2). Our results generally are consistent with previous studies that found the paternal effect on seed development and seed mass is smaller than the maternal effect (Baskin & Baskin, 2019; Lacey, 1996; Lamont & Pausas, 2023). This is because maternal drought not only reduces the potential for zygote formation and increases embryo abortion, but it also decreases maternal provisioning.…”

“…Possibly this is due to the significant role of nuclear genes in regulating photosynthesis-related phenomena despite the maternal inheritance of chloroplasts (Stern et al, 2004). Overall, the somewhat larger number of performance traits affected by interaction with maternal environments appears to be small compared to the much larger maternal dosage in the endosperm, maternally derived nuclear genes or maternal contribution to the embryo's cytoplasm (Kong et al, 2020;Lacey, 1996;Lamont & Pausas, 2023;Roach & Wulff, 1987).…”

“…Polygonum-type embryo sac development), which may affect expression of nuclear genes (Danchin et al, 2011;Fukushima et al, 2023;Kong et al, 2020). Second, maternal environments may affect seed-coat thickness, and thereby timing of germination (Lacey, 1996;Lamont & Pausas, 2023).…”

“…Polygonum‐ type embryo sac development), which may affect expression of nuclear genes (Danchin et al., 2011; Fukushima et al., 2023; Kong et al., 2020). Second, maternal environments may affect seed‐coat thickness, and thereby timing of germination (Lacey, 1996; Lamont & Pausas, 2023). Third, mothers may affect the development of adjacent offspring through provisioning of hormones, nutrients, proteins and transcripts (Baskin & Baskin, 2019; Earley et al., 2023).…”

Seed Dormancy Breaking and Germination Rate Improvement in Mucuna (Mucuna bracteata) Seeds using Mechanical and Fungicide Treatments

“…Naturally, the seed's outer shell abrades mechanically and chemically in the gastrointestinal tract of an animal [27,28]. Some species also need to experience extreme heat or freeze to trigger germination [29].…”