Type Of Dormancy Research Articles

Seed dormancy and germination in Oenanthe stolonifera as affected by temperature and gibberellic acid

Our aim was to investigate the dormancy type of water dropwort seeds for developing seed germination methods in the future. The mature fruit is a schizocarp with sponge-like and thickened ribs. However, the seeds were able to absorb moisture normally. In this study, less than 14% of seeds germinated without any pretreatment after 4 weeks at 20, 25, or 25/15 °C (12/12 h). However, there was a further increase in germination percentage after 10 weeks of incubation at 5/5, 15/6, 20/10, and 25/15 °C. The seeds germinated at higher ratios under relatively colder temperature regimes. Embryo growth in the seeds occurred at both warm and cold temperatures. However, water dropwort seeds require a period of cold temperatures for embryo growth to be completed. The germination percentage was significantly higher in GA3-treated seeds, even though the absolute difference was relatively low. In water dropwort, GA can overcome seed dormancy but cold temperature alone for 8–10 weeks may effectively break seed dormancy and increase germination percentage. Based on these results, we propose that most water dropwort seeds showed intermediate complex morphophysiological dormancy and some seeds had morphological dormancy at the time of dispersal. These results provide useful information for seed propagation and a practical production plan for cultivation of water dropwort.

Local and distant tumor dormancy during early stage breast cancer are associated with the predominance of infiltrating T effector subsets

BackgroundAlthough breast cancer mortality is a result of distant recurrences associated with the establishment of tumor dormancy, current clinical practice guidelines recommend a wait and watch approach for tumor recurrences. This is because of our limited understanding of tumor dormancy and insufficient evidence in support of immunological control of tumor dormancy.MethodsWe used FVBN202 transgenic mice expressing rat neu oncogene in the mammary glands, and their parental FVB strain lacking neu expression. These models allowed the detection of tumor dormancy at distant sites using the rat neu protein as a tumor marker. We also used Ki67 for the detection of the indolent and quiescent types of tumor dormancy. Multicolor flow cytometry was used to detect dormant tumor cells and T cell subsets. Co-culture studies were performed to determine the role of T cells in preventing regrowth of dormant cells.ResultsWe demonstrated that dormant tumor cells were present at the site of primary breast cancer and at distant sites in the lungs and in the liver very early in the course of early stage breast cancer when no distant metastasis was evident. Dormant tumor cells were characterized as neu expressing Ki67− and Ki67low fractions associated with the induction of local immune responses predominated by CD4+ and CD8+ T effector cell subsets. The presence of neu-autoreactive T cells from FVBN202 mice only prevented regrowth of dormant cells. On the other hand, presence of neu-alloreactive anti-tumor T cells in FVB mice prior to tumor challenge resulted in the protection of mice from the dissemination of dormant tumor cells to distant organs.ConclusionOur results suggest that immunotherapeutic targeting of semi-allogeneic mutant neoantigens during tumor dormancy might prevent distant recurrence of the disease.

Seed Dormancy of <i>Viola mandshurica</i> and <i>V. albida</i> and Their Germination Characteristics by Seed Storage

The purpose of this study was to determine the seed dormancy types of Viola mandshurica and V. albida, and to investigate their germination characteristics during seed storage. V. mandshurica seeds were incubated at 25/15, 20/10, and 15/6°C with final germination rates of 86%, 66%, and 66%, respectively, indicating that these seeds have no physiological dormancy (PD). However, V. albida seeds were found to have PD, since germination hardly occurred during the 4-week experiment, and the final germination rate was 50% or less. When the seeds of V. albida were treated with GA3 1000 mg･L-1, the final germination rate was 100%. Moreover, the germination rate increased as the period of cold stratification for V. albida seeds increased. The germination characteristics of Viola seeds were also examined from seeds harvested in 2019. V. mandshurica seeds germinated at 25/15°C in one week, but the mean germination time decreased compared to seeds that were stored for 4 years. This shows that V. mandshurica has reduced seed viability during storage. V. albida seeds that were harvested in 2019 hardly germinated within the 4-week experiment, and the germination rate increased through cold stratification. Therefore, the seeds of V. mandshurica and V. albida do not change the seed dormancy type, but the seed viability might be affected by the type of long-term storage used.

Among-population variation in seed mass for 190 Tibetan plant species: Phylogenetic pattern and ecological correlates

It is widely assumed that seed mass, as a proxy of both dispersability and competitiveness, can affect community composition and diversity. Numerous studies have validated the influence of seed mass at the interspecific level. However, little is known about patterns of among-population variation in seed mass (APVSM), which may influence a species’ persistence under climate change. We characterized the naturally occurring variation in seed mass among populations across 190 Tibetan plant species (2503 populations). We tested for relationships between APVSM and plant life-history traits (mean seed mass, seed dormancy type, seed dispersal mode, life form, and pollination system) and an environmental factor, elevation. We also tested patterns of phylogenetic signal in APVSM and identified the lineages (clades) with an exceptionally high or low APVSM. We found that APVSM varied > 5-fold among species, ranging from 0.085 in Bromus sinensis to 0.447 in Anaphalis flavescens. Furthermore, wind-dispersed species tended to have greater APVSM. Finally, we found that APVSM exhibited a significant phylogenetic signal (i.e., closely related species were more or less variable in their seed size than would be expected by chance) that was driven by a few major lineages. Clades with significantly less APVSM included Brassicaceae, Campanulaceae, Ranunculaceae (including Thalictrum, Trollius, Aconitum and Anemone), Roegneria, Rumex. Clades with significantly greater APVSM included Bignoniaceae, Lamiaceae, Orobanchaceae, Anaphalis, Cotoneaster and Sorbus. In summary, our study suggested that APVSM is partly due to trade-offs in evolutionary history and its associations with other life-history traits.

Water Uptake and Germination of Caper (Capparis spinosa L.) Seeds

Caper is a perennial deciduous sub-shrub that grows in almost all circum-Mediterranean countries. The specialized literature presents three possible dormancy types that can cause low germination of caper seeds: Physiological dormancy (PD), physical dormancy (PY), and combinational dormancy (PY + PD). We conducted three experiments to analyze the imbibition, viability, and germination of seeds of different ages, provenances, and the level of deterioration of the seed cover. None of the commercialized lots of standard seeds tested exceeded 6% germination, nor 35% viability, while the owned seeds reached 90% in both parameters, indicating that all viable seeds germinated. The seed moisture content along the soaking period followed the first two phases of the typical triphasic model of water uptake in seed germination: The imbibition and lag phases (phase I and II of germination, respectively). Seed hydration began through the hilar region. The fact that all viable owned seeds germinated, together with their moisture content being lower than that of standard seeds, indicated that caper seeds do not have a water-impermeable coat sensu stricto, i.e., they do not show PY; nevertheless, the need to use gibberellic acid to obtain high germination percentages, demonstrated the presence of PD.

Embryo transcriptome and miRNA analyses reveal the regulatory network of seed dormancy in Ginkgo biloba.

Seed dormancy is crucial for plant survival and prevents seed germination out of season. However, little is known about the regulatory mechanism of morphophysiological seed dormancy. Ginkgo biloba L. is one of the most ancient gymnosperms, and the completion of seed germination in this species requires cold and moist stratification. Here, we observed that at the mature seed stage, the embryo was not fully developed in G. biloba seeds. During dormancy stages, the length and weight of the embryo significantly increased, and nutrients accumulated in cotyledons. We further found that abscisic acid (ABA), gibberellic acid (GA), cytokinin and ethylene were integrated in the seed dormancy induction, maintenance and release processes, and GA biosynthesis and signaling transduction specifically act on dormancy release. Combining mRNA and miRNA analyses, we demonstrated that miRNA156 is involved in the regulation of morphophysiological dormancy. Our analyses revealed that G. biloba seed dormancy belongs to the ancestral morphophysiological dormancy type, which is not only regulated by the balance of ABA/GA, but also by other hormones associated with embryo morphological development, as well as genes related to embryo differentiation and development. These findings helped with elucidating the comprehensive regulatory network of morphophysiological dormancy in tree seeds.

The effect of gut passage by waterbirds on the seed coat and pericarp of diaspores lacking "external flesh": Evidence for widespread adaptation to endozoochory in angiosperms.

The widely accepted "endozoochory syndrome" is assigned to angiosperm diaspores with a fleshy, attractive tissue and implies the existence of adaptations for protection against digestion during gut passage. This syndrome has led diaspore fleshiness to be emphasized as the exclusive indicator of endozoochory in much of the ecology and biogeography research. Crucially, however, endozoochory in nature is not limited to frugivory, and diaspores without "external flesh" are commonly dispersed, often over long distances, via birds and mammals by granivory. A key question is: are such diaspores somehow less prepared from an architectural point of view to survive gut passage than fleshy diaspores? To answer this question, we selected 11 European angiosperm taxa that fall outside the classical endozoochory syndrome yet are known to be dispersed via endozoochory. We studied their seed coat/pericarp morphology and anatomy both before and after gut passage through granivorous waterfowl, and determined their seed survival and germinability. We found no fundamental differences in the mechanical architecture of the seed coat and pericarp between these plants dispersed by granivory and others dispersed by frugivory. Neither diaspore traits per se, nor dormancy type, were strong predictors of diaspore survival or degree of damage during gut passage through granivores, or of the influence of gut passage on germinability. Among our 11 taxa, survival of gut passage is enabled by the thick cuticle of the exotesta or epicarp; one or several lignified cell layers; and diverse combinations of other architectural elements. These protection structures are ubiquitous in angiosperms, and likely to have evolved in gymnosperms. Hence, many angiosperm diaspores, dry or fleshy, may be pre-adapted to endozoochory, but with differing degrees of specialization and adaptation to dispersal mechanisms such as frugivory and granivory. Our findings underline the broad ecological importance of "non-classical endozoochory" of diaspores that lack "external flesh".

RETRACTED ARTICLE: The role of seed appendage in improving the adaptation of a species in definite seasons: a case study of Atriplex centralasiatica

BackgroundAs a common accompanying dispersal structure, specialized seed appendages play a critical role in the successful germination and dispersal of many plants, and are regarded as an adaptation character for plants survival in diverse environments. However, little is known about how the appendages modulate the linkage between germination and environmental factors. Here, we tested the responses of germination to seasonal environmental signals (temperature and humidity) via seed appendages using Atriplex centralasiatica, which is widely distributed in salt marshlands with dry-cold winter in northern China. Three types of heteromorphic diaspores that differ in morphology of persistent bracteole and dormancy levels are produced in an individual plant of A. centralasiatica.ResultsExcept for the nondormant diaspore (type A, with a brown seed enclosed in a persistent bracteole), bracteoles regulated inner seed dormancy of the other two dormant diaspore types, i.e., type B (flat diaspore with a black inner seed) and type C (globular diaspore with a black inner seed). For types B and C, germination of bracteole-free seeds was higher than that of intact diaspores, and was limited severely when incubated in the bracteole-soaking solution. Dormancy was released at a low temperature (< 10 °C) and suitable humidity (5–15%) condition. Oppositely, high temperature and unfit humidity induced secondary dormancy via inhibitors released by bracteoles. Type C with deeper dormancy needed more stringent conditions for dormancy release and was easier for dormancy inducement than type B. The germination windows were broadened and the time needed for dormancy release decreased after the bracteole flushing for the two dormant types in the field condition.ConclusionsBracteoles determine the germination adaptation by bridging seeds and environmental signals and promising seedlings establishment only in proper seasons, which may also restrict species geographical distribution and shift species distributing ranges under the global climate change scenarios.

Beyond rest and quiescence (endodormancy and ecodormancy): A novel model for quantifying plant-environment interaction in bud dormancy release.

Bud dormancy of plants has traditionally been explained either by physiological growth arresting conditions in the bud or by unfavourable environmental conditions, such as non-growth-promoting low air temperatures. This conceptual dichotomy has provided the framework also for developing process-based plant phenology models. Here, we propose a novel model that in addition to covering the classical dichotomy as a special case also allows the quantification of an interaction of physiological and environmental factors. According to this plant-environment interaction suggested conceptually decades ago, rather than being unambiguous, the concept of "non-growth-promoting low air temperature" depends on the dormancy status of the plant. We parameterized the model with experimental results of growth onset for seven boreal plant species and found that based on the strength of the interaction, the species can be classified into three dormancy types, only one of which represents the traditional dichotomy. We also tested the model with four species in an independent experiment. Our study suggests that interaction of environmental and physiological factors may be involved in many such phenomena that have until now been considered simply as plant traits without any considerations of effects of the environmental factors.

Diversity in genome size and GC content shows adaptive potential in orchids and is closely linked to partial endoreplication, plant life-history traits and climatic conditions.

In angiosperms, genome size and nucleobase composition (GC content) exhibit pronounced variation with possible adaptive consequences. The hyperdiverse orchid family possessing the unique phenomenon of partial endoreplication (PE) provides a great opportunity to search for interactions of both genomic traits with the evolutionary history of the family. Using flow cytometry, we report values of both genomic traits and the type of endoreplication for 149 orchid species and compare these with a suite of life-history traits and climatic niche data using phylogeny-based statistics. The evolution of genomic traits was further studied using the Brownian motion (BM) and Ornstein-Uhlenbeck (OU) models to access their adaptive potential. Pronounced variation in genome size (341-54878Mb), and especially in GC content (23.9-50.5%), was detected among orchids. Diversity in both genomic traits was closely related to the type of endoreplication, plant growth form and climatic conditions. GC content was also associated with the type of dormancy. In all tested scenarios, OU models always outperformed BM models. Unparalleled GC content variation was discovered in orchids, setting new limits for plants. Our study indicates that diversity in both genome size and GC content has adaptive consequences and is tightly linked with evolutionary transitions to PE.

Dormancy characteristics and germination requirements of Phoebe bournei seed

In order to determine the dormant type, and improve germination of Phoebe bournei seeds, some measures, including stratification and GA3 solution soaking, had been taken, and the germination percentage, water permeability, respiration rate and germination inhibitory substance of Phoebe bournei seeds were investigated. The results showed that although the testa was water permeable, the fresh seed testa had some effect for the low respiration rate and low germination percentage of the seeds. In addition, the Phoebe bournei seeds contained some germination inhibitory substance which retarded seed germination. These indicated that the dormancy type of Phoebe bournei seeds belongs to physiological dormancy (PD). The respiration rate of the Phoebe bournei seeds was improved continuously with prolonging wet sand stratification at 4 ± 1 °C, and the dormancy of the Phoebe bournei seeds was released gradually thus the germination was early and quick, and germination percentage increased steadly (the germination percentage increased from 23.3% to 91.3% for the seeds stratification from 0 to 60 days). The dormancy was also released and the germination percentage increased while the Phoebe bournei seeds were treated with GA3 solution of different concentrations, and the 800 mg.L−1 solution had the best effect.

Noncoding RNA Regulation of Dormant States in Evolutionarily Diverse Animals.

Dormancy is evolutionarily widespread and can take many forms, including diapause, dauer formation, estivation, and hibernation. Each type of dormancy is characterized by distinct features; but accumulating evidence suggests that each is regulated by some common processes, often referred to as a common "toolkit" of regulatory mechanisms, that likely include noncoding RNAs that regulate gene expression. Noncoding RNAs, especially microRNAs, are well-known regulators of biological processes associated with numerous dormancy-related processes, including cell cycle progression, cell growth and proliferation, developmental timing, metabolism, and environmental stress tolerance. This review provides a summary of our current understanding of noncoding RNAs and their involvement in regulating dormancy.

Germination behavior of the extremely rare Hladnikia pastinacifolia Rchb. (Apiaceae) – a Pleistocene in situ survivor

Abstract The present-day diversity of European flora in temperate mountain ranges was mainly formed by the negative effects of Pleistocene glaciation, which caused extinctions, restricted survival in situ, and subsequent re-colonization. Only rarely can we find species that have retained the molecular information of in situ survival. One such example is the extremely rare H. pastinacifolia Rchb., a monotypic genus and a narrow endemic of a mountain plateau south-east of the Julian Alps (Slovenia). We investigated the germination behavior and dispersal indications, which are often closely related to rarity and persistence and thus valuable for species conservation. Additionally, results about H. pastinacifolia help us to understand better what kind of species survived glaciations in Europe in situ. Our results show that these seeds have an underdeveloped embryo and require an ecologically relevant moist chilling period of about 100 days. The temperature sequence of the colder period that H. pastinacifolia seeds received in nature was 20/15 °C (52 days), 10/5 °C (40 days), 5/0 °C (65 days), 10/0 °C (45 days), 15/5 °C (21 days). The germination rate was high, significantly increased by scarification, and therefore prevented long-term seed bank establishment. We found cryptic seed differences expressed by two types of dormancy, each related to the order of the umbel: simple and complex morphophysiological dormancy for the lateral and the main umbel, respectively. Seed dispersal was very much influenced by precipitation in autumn. The germination and dispersal characteristics could explain the rarity and at the same time the persistence of H. pastinacifolia.

Ecology and Physiology of Dormancy in a Changing World: Introduction to a Virtual Symposium in The Biological Bulletin.

Ecology and Physiology of Dormancy in a Changing World: Introduction to a Virtual Symposium in The Biological Bulletin.

Bleaching and cold stratification can break dormancy and improve seed germination in Cyperaceae

Seed germination of sedges is often difficult, due to physiological dormancy and the hard seed coat. It has been proposed that chemical scarification by sodium hypochlorite (‘bleach’) and cold stratification might successfully break this type of dormancy and improve seed germination rates. Yet the choice of the dormancy-breaking conditions in previous studies appears to be arbitrary, resulting in inconsistent results when applied to the seeds of other sedges.Here, we propose and test a strategy for optimizing the dormancy-breaking treatment to achieve higher germination rates and minimize the number of damaged seeds in 16 ‘hard-to-germinate’ members of the Cyperaceae family. The seeds were soaked in 0–10% bleach solutions for different periods of time (from 1 to 120 h) followed by immediate germination tests or cold stratification for either 9 or 18 weeks.To break dormancy, we recommend pretreatment of seeds with sodium hypochlorite, possibly followed by cold stratification, but details (bleach concentration-duration and stratification duration follow each species) varied by species: Bolboschoenus glaucus, Eleocharis palustris and E. uniglumis (2–6% for 6–48 h, 9 weeks), Cladium mariscus (4–10% for 72–120 h, 18 weeks), Schoenoplectiella mucronata (2–10% for 72–120 h, 0 weeks), Schoenoplectus tabernomontani (6–10% for 24–48 h, 18 weeks), Schoenus nigricans (4–6% for 24–72 h, 0 weeks), Bleach-scarification treatment negatively affected seed germination in Eleocharis ovata, Eriophorum latifolium, Rhynchospora alba, Schoenoplectiella supina and Scirpoides holoschoenus, whereas seeds of Bolboschoenus maritimus and Rhynchospora glomerata showed no response to the treatment.We conclude that careful selection of seed dormancy-breaking conditions plays a crucial role in optimizing sedge seed germination. The proposed range-searching approach can help to detect the species-specific, in some cases very narrow, optimum for the bleaching treatment followed by cold stratification, at least in some species of the Cyperaceae family.

Ecophysiology of seed dormancy and germination in four Lonicera (Caprifoliaceae) species native to Korea

BackgroundTo exploit the ornamental and medicinal purposes of Lonicera harae Makino, L. subsessilis Rehder, L. praeflorens Batalin, and L. insularis Nakai, native to Korea, it is necessary to understand their seed ecology for propagation. In this study, we investigated the seed dormancy type and germination characteristics of seeds of the four Korean native Lonicera species.ResultsThe seeds of the four Lonicera species imbibed water readily, suggesting that the species do not have physical dormancy. Furthermore, the seeds exhibited underdeveloped embryos with only about 15–25% of the length of the seeds at dispersal. The embryos grew to the critical length with approximately 50–80% of the length of the seeds’ development before radicle protrusion. Further, 94.4% and 61.1% of freshly matured seeds of L. insularis and L. harae germinated within 4 weeks after sowing at 15 °C and 20 °C, respectively. Contrarily, L. praeflorens and L. subsessilis seeds did not germinate within 4 weeks under all temperature treatments. At 15 °C, L. praeflorens seeds started to germinate from 5 weeks and the final germination rate was 51.1% at 13 weeks. At 15 °C, L. subsessilis seeds started to germinate from 5 weeks after sowing and the final germination rate was 85.6% at 17 weeks after sowing. Embryo growth and germination of L. praeflorens and L. subsessilis occurred at a relatively high temperature (≥ 15 °C).ConclusionsOverall, L. insularis seeds have only morphological dormancy. The seeds of L. harae have approximately 60% and 40% of morphological dormancy and morphophysiological dormancy, respectively. Contrarily, L. praeflorens and L. subsessilis exhibited non-deep simple-type morphophysiological dormancy that requires relatively high temperature (≥ 15 °C) for embryo growth and dormancy breaking. The optimum temperature for the germination of seeds of L. insularis, L. harae, L. praeflorens, and L. subsessilis was 15 °C, 20 °C, 15 °C, and 20 °C, respectively. There was interspecific variation in seed dormancy and germination patterns in the four Lonicera species. The difference in these characteristics within the four Lonicera species could be useful for understanding the seed ecophysiological mechanisms of Lonicera species.

Heat shock-stimulated germination in Mediterranean Basin plants in relation to growth form, dormancy type and distributional range

Heat shock-stimulated germination is frequently considered a trait restricted to a few plant families with impermeable seed coats in the Mediterranean Basin. We aimed to ascertain this general idea by using 68 eastern Mediterranean plant taxa differing in growth form, dormancy type and geographic distributional range. We conducted a laboratory experiment including heat shocks (60, 80, 100, 120 and 140°C for 5 min) and a control treatment, and monitored germination for each species. Among the studied taxa, 24 (35%) showed a significant positive response for at least one of the treatments. Many Cistaceae and Fabaceae species showed a positive germination response to the heat shocks. However, we also observed heat shock-stimulated germination in the Brassicaceae, Malvaceae, Polygonaceae and Scrophulariaceae, and provided additional evidence for the Asteraceae, Lamiaceae, Liliaceae, Plantaginaceae and Rosaceae in the Mediterranean Basin. Distributional range and dormancy type were significant determinants of germination response to heat shocks whereas growth form and phytogeographic origin had lower and/or non-significant contribution. Species with wide or local distribution were less tolerant to moderate heat shocks than those with regional distributional ranges. Species with physically dormant seeds showed significantly more stimulated germination after heat shocks than those with permeable seeds. In conclusion, dormancy type is an important determinant of seed response to heat shock, and an association exists between distributional range and germination response to heat shocks. Our findings revealed that heat shock-stimulated germination is observed across a broader taxonomic spectrum in the Mediterranean Basin, including families not possessing physical dormancy.

Low-dose neoadjuvant chemotherapy dominates Ki67− quiescent tumor dormancy for an effective immunotherapy of breast cancer

Abstract Breast cancer mortality is mainly due to distant recurrence of the disease. The disease recurrence is usually because of the establishment of tumor dormancy following successful treatment of early stage breast cancer. In current clinical practice, dormant tumor cells are not actively treated, because they do not respond to chemotherapy or radiation therapies. Immunotherapeutic targeting of tumor dormancy is also challenging because of the induction of tumor immunoediting, leading to tumor escape and relapse. Recently, we have characterized Ki67− quiescent and Ki67low indolent types of tumor dormancy. We demonstrated that quiescent, but not indolent, dormant tumor cells fail to undergo immunoediting and remain highly susceptible to immunotherapy. Here, we sought to develop neoadjuvant therapies for dominating a quiescent type of tumor dormancy as the best target for immunotherapy. We showed that a low dose 5-FU+Adriamycin+Cyclophosphamide (FAC) dominated Ki67− quiescent type of tumor dormancy in the neu-overexpression mouse mammary carcinoma (MMC) tumor cells. These dormant cells were effectively controlled by immunotherapy in FVBN202 transgenic mouse model of spontaneous breast cancer. Since the antibiotic azithromycin has been shown to effectively eliminate senescent cells, we also sought to determine its efficacy against dormant tumor cells. We demonstrated that azithromycin specifically induced apoptosis in FAC-induced dormant tumor cells. All together, the results suggest that use of less toxic, low dose chemotherapy combined with azithromycin in a neoadjuvant setting could lead to the elimination of dormant tumor cells by immunotherapy.

Radicle emergence with increased temperatures following summer dispersal in Trillium camschatcense: A species with deep simple double morphophysiological dormancy in seeds

AbstractSeeds with deep simple double morphophysiological dormancy (MPD) need cold stratification during the first winter after dispersal for radicle emergence, followed by the summer for root and bud development and finally a second winter for shoot emergence. In a previous study, we demonstrated that Trillium camschatcense seeds have this type of dormancy with radicles emerging from most seeds after the first winter. However, radicles also emerged from a few seeds in autumn during the same year as dispersal. We thought that temperatures after seed dispersal played a role in radicle emergence before the first winter. To confirm our idea, we investigated germination phenology outdoors, relationships between temperatures after seed dispersal and radicle emergence in the first year outdoors, radicle emergence in the first winter under varied temperatures using incubators, and shoot emergence from seeds with an emerged radicle in the first year outdoors. Our phenology study confirmed that T. camschatcense seeds have deep simple double MPD. Over 7 years, 0.2–7.5% of radicles emerged in the first year before winter and these percentages were moderately positively correlated with temperatures, especially minimum temperatures. Increasing August and September temperatures increased radicle emergence in the laboratory. Shoots emerged from seeds with an emerged radicle in the first year after the first winter. With increased autumn temperatures in warmer regions or with global warming, we predict that germination phenology may shift: increased radicle emergence in the first year and shoot emergence following the first (and not second) winter.

Dormancy in cancer.

The idea of tumor dormancy originated from clinical findings that recurrence of cancer occurs several years or even several decades after surgical resection of the primary tumor. Tumor mass dormancy was proposed as a model, where there is equal balance between increases in the number of cancer cells by proliferation and decreases as a result of cell death. Tumor mass dormancy includes angiogenic dormancy and immune‐mediated dormancy. Another emerging type of tumor dormancy is cellular dormancy in which cancer cells are in a quiescent state. Cellular dormancy is induced by cues such as the extracellular matrix environment, metastatic niches, a hypoxic microenvironment, and endoplasmic reticulum stress. Even the oncogenic pathways, on which active cancer cells depend for survival and growth, are suppressed in the dormant state. As tumor dormancy is one of the mechanisms of resistance against various cancer therapies, targeting dormant cancer cells should be considered for future treatment strategies.