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PubMed2026

From dormancy to germination: Transcriptome analysis reveals the potential involvement of heat shock proteins in gibberellin-induced seed dormancy release in Solanum torvum.

Solanum torvum, a superior vegetable grafting rootstock and medicinal Solanaceae plant, exhibits strong seed dormancy, which limits its commercial cultivation. Among various strategies explored to improve the germination rate of S. torvum, exogenous application of gibberellin (GA) has been shown to be effective. In this study, a GA concentration of 2.5 mM was established as the optimal for breaking dormancy in S. torvum seeds. Transcriptome analysis of dry, water-soaked, GA-soaked, and GA-induced germinated seeds was conducted to investigate the molecular mechanism of GA-mediated dormancy release. During the soaking period, GA application significantly induced transcriptome changes in processes including protein processing, translation, and peptide biosynthesis. Concurrently, GA treatment promoted plant hormone signal transduction, enhanced DNA-binding transcription factor activity, and activated monocarboxylic acid biosynthetic process, all of which facilitated seed water absorption. Furthermore, the differentially expressed genes (DEGs) induced by GA during soaking primarily functioned in signal transduction or activation. While most of these DEGs returned to their pre-treatment expression levels before subsequent recovery, a subset persisted until seed germination. During radicle protrusion, the persistent DEGs were associated with energy metabolism and cell structure establishment. Notably, heat shock protein (HSP) genes showed dynamic expression across all stages (soaking, germination, and radicle penetration). Furthermore, by adjusting germination conditions, temperature was confirmed to be a necessary but not sufficient condition for GA-induced S. torvum seed germination. However, functional validation (e.g., using HSP inhibitors or genetic approaches) is still required to confirm the causal role of HSPs. Collectively, these findings not only clarify the molecular basis of GA-regulated seed dormancy breaking in S. torvum but also provide practical guidance for optimizing its commercial propagation protocols.

Gibberellins↗
PubMed1977

The effect of gamma radiation on breaking of dormancy in Phycomyces spores.

Dormant sporangiospores of Phycomyces blakesleeanus were activated by Cs-137 gamma rays. After a dose of about 300 krad, between 80 and 90% of the spores germinated normally. However, further development of the mycelium was inhibited. Even with dry spores a partial activation was obtained. Activation by gamma rays was not accompanied by an increase in trehalase activity.

Cesium Radioisotopes↗
PubMed1976

Effectiveness of various food preservatives in controlling the outgrowth of Byssochlamys nivea ascospores.

Potassium sorbate, sodium benzoate, sulfur dioxide, and diethylpyrocarbonate (DEPC) were tested for their effectiveness in preventing the outgrowth of Byssochlamys nivea Westling ascospores. Sulfur dioxide was the most inhibitory of the test antimycotics, complete inhibition of colony formation occuring in acidified (pH 3.5) potato dextrose agar containing 50 ppm of the preservative. Complete inhibition of B. nivea ascospore outgrowth in grape juice stored for 60 days was noted in the presence of 300 ppm sulfur dioxide, 400 ppm potassium sorbate, and 600 ppm DEPC. Growth was observed in grape juice containing 1000 ppm sodium benzoate. The presence of up to 100 ppm potassium sorbate in grape juice during heat activation appears to have a stimulatory effect on breaking dormancy, while the other test preservatives at this concentration decrease the heat resistance of B. nivea ascospores. The time elapsed between heat shock and exposure to DEPC or sodium benzoate is critical with respect to the sensitivity of ascospores to these preservatives.

Ascomycota↗
PubMed1975

Breaking of seed dormancy by catalase inhibition.

Germination of some dormant seeds is promoted by solutions of thiourea, sodium nitrite, and hydroxylamine salts. The promotions are accompanied by irreversible inhibition of catalase (EC 1.11.1.6) in extracts from the seeds. The seeds are also promoted in germination by catechol and pyrogallol solutions. These effects are recorded for lettuce (Lactuca sativa L. cv. Grand Rapids) and pigweed (Amaranthus albus L.) seeds. The results indicae that metabolically derived hydrogen peroxide, spared from decomposition by catalase inhibition, oxidizes reduced NADPH required as the oxidant in the pentose pathway of glucose use. The metabolic system for such use of H2O2 involves the enzymes, peroxidase (EC 1.11.1.7) and pyridine nucleotide quinone oxidoreductase (EC 1.6.99.2), which are present in the dormant seed prior to imbibition of water.

Catalase↗
PubMed1975

Some properties of trehalase from Phycomyces blakesleeanus.

Trehalase (alpha, alpha-trehalase glucohydrolase EC 3.2.1.28) from Phycomyces spores occurs in two different forms which are convertible in vivo: a form with low activity found in dormant spores and an active form after breaking the dormancy. Between the two forms no difference in molecular weight and electrophoretic mobility can be detected. The molecular weight is estimated by gel filtration at about 210 000. The relation between substrate concentration and trehalase activity follows the Michaelis-Menten equation (K-m plus or minus 55 mM) in activated spores whereas in dormant spores trehalase shows a different substrate binding, indicating a negative cooperative effect. They differ further in thermostability and in sensitivity to inhibition by ATP. Other nucleosidephosphates have no inhibiting effect. Heating the spores at different temperatures between 38 and 44 degrees C results in a partial breaking of dormancy of the spore population and a corresponding partial activation of trehalase. This suggests a close connection between breaking dormancy and trehalase activation.

Chromatography, Gel↗
PubMed2026

ATX1-COMPASS-like complex participates in the bud dormancy release of tree peony by regulating H3K4me3 modification.

Bud dormancy release in woody plants is crucial for survival, regrowth, flowering, and fruiting. Tree peony (Paeonia suffruticosa), an important ornamental and economic plant, undergoes bud endodormancy in winter, and sufficient chilling duration and exogenous gibberellins (GAs) can effectively break the dormancy. However, the epigenetic regulation mechanism remains poorly understood. Here, immunoblotting revealed that H3K4me3, but not H3K4me1 or H3K4me2, was associated with chilling- and GA3-induced dormancy release. Chromatin immunoprecipitation sequencing (ChIP-seq) combined with RNA-seq results revealed that H3K4me3 enriched near transcription start sites (TSS). H3K4me3 enrichment genes (HEGs) and differentially expressed genes (DEGs) were commonly enriched in KEGG pathways, such as plant hormone signal transduction and MAPK signaling. The expression patterns of these marker genes, such as EARLY BUD-BREAK 3 (PsEBB3), CYCLIND3.1 (PsCYCD3.1), CYCLIND3.3 (PsCYCD3.3), and β-1,3-glucanase 6 (PsBG6), were correlated with their H3K4me3 enrichment and were validated by chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR). Four COMPASS-like component homologs and one histone methyltransferase were screened; among them, PsWDR5a, PsRBL, PsASH2R, and PsATX1 were upregulated by prolonged chilling and GA3 treatments. Yeast two-hybrid (Y2H), yeast three-hybrid (Y3H), luciferase complementation (LCA), and co-immunoprecipitation (Co-IP) analyses revealed that PsRBL interacts with PsWDR5a and PsASH2R as a bridge. PsATX1 was confirmed as an H3K4me3 methyltransferase and interacted with PsWDR5a and PsRBL to form the PsATX1-COMPASS-like complex using Y2H, LCA, and Co-IP assays. Functional analyses showed that PsWDR5a, PsRBL, PsASH2R, and PsATX1 significantly promoted budburst by elevating genomic H3K4me3 levels. Our findings provide insights into the epigenetic regulation of dormancy transitions in woody perennials.

Histones↗
PubMed2025

Speed breeding: protocols, application and achievements.

One of the limiting factors in breeding and genetic research is the time required to develop pure lines. This is due, on the one hand, to the prolonged vegetative period of a single generation and, on the other hand, to the specifics of inbreeding, which typically requires 4-6 consecutive generations of self-pollination in plant material. Researchers have always sought approaches that enable the rapid development of homozygous plant lines. Consequently, methods such as greenhouse cultivation during the autumn-winter period, single-seed descent, shuttle breeding, embryo culture, and doubled haploid technology have been introduced into practice. All these methods have both advantages and limitations. One of the latest approaches facilitating a significant reduction in the vegetative period of plants is speed breeding (SB). This method is based on the application of factors that shorten the time from sowing to flowering, as well as techniques that accelerate the generative phase of development and overcome postharvest dormancy. This review provides a comprehensive list and characterization of all factors that influence the efficiency of speed breeding to varying degrees. Among the factors discussed that reduce the sowing-to-flowering period are photoperiod, light sources, spectral composition and light intensity, temperature, carbon dioxide levels, vernalization, mineral nutrition, substrate volume, mechanical shoot removal, and the use of plant growth regulators. To shorten the generative phase, the review summarizes the application of embryo culture and forced desiccation of immature seeds, along with methods to overcome postharvest dormancy. Additionally, applications of genetic approaches and genetic engineering for shortening generation time in speed breeding are described. The review also consolidates detailed protocols for approximately thirty crops. The high efficiency of speed breeding in reducing both the vegetative period per generation and the time required to develop pure lines has led to its increasing adoption in various research fields. This review highlights the application of speed breeding for hybridization and pure line development, introgression of target alleles, and genomic selection. A list of phenotypic traits exhibiting high correlation between controlled-environment and field conditions is provided.

accelerated flowering↗
PubMed1979

Polyamine biosynthesis during germination of yeast ascospores.

The role of the diamine putrescine during germination and outgrowth of ascospores of Saccharomyces cerevisiae was examined. Ornithine decarboxylase activity increased and declined rapidly during germination and outgrowth; peak activity was attained after the cells had proceeded through the G1 interval of the cell cycle, whereas minimal activity was present at the completion of the first cell division. alpha-Methylornithine inhibited both ornithine decarboxylase activity and the in vivo accumulation of putrescine. In the presence of alpha-methylornithireak dormancy and proceed through one cell division. Subsequent cellular growth, however, was retarded but not completely inhibited. The supplementation of Methylglyoxal bis(guanylhydrazone) to sporulation medium greatly inhibited this sexual process. These data suggest that the synthesis of putrescine is not required for the breaking of spore dormancy, but that polyamine biosynthesis may be essential for meiosis and sporulation.

Mitoguazone↗
PubMedDate not supplied

Effects of gamma irradiation on onion sprouting. I.--Influence of dose rate and post-harvest period of treatment.

Onions of "Dorata di Parma" variety were exposed to 10 Krads of Co60 gamma irradiation in 5, 10, 20, 40, and 80 minutes in December, 1975 and then stored in the cold storage (10 +/- 1 degree C; R.H. 65-70%) and at the room temperature (15-20 degrees C; R.H. 40-70%) for 3 months, to study the influence of dose-rate and post-harvest period of treatment. Average number of buds sprouted in each onion bulb under cold storage condition ranged from 2-3, while this number was found to increase to 3-4 under ambient storage conditions. Although no effect of either irradiation or dose rate was observed when onions were irradiated after the break of their dormancy, however, a significant slowing down effect of irradiation could be observed as far as the rate of growth of sprouts was concerned. Weight loss was also reduced significantly in the irradiated onions as compared with controls.

Food Irradiation↗
PubMed1978

Cytotoxic effects of maleic hydrazide.

Since 1950, maleic hydrazide (MH) has been introduced into agriculture as a major commercial herbicide and a depressant of plant growth in numerous circumstances such as suppression of sprouting of vegetables and stored food crops, control of sucker growth on tobacco plants, ratardation of flowering and prolongation of dormancy period. Since 1951 MH has been known as an effective chromosome-breaking agent in higher plants, in sharp contrast with its low effect on the chromosomes and general health of tested mammals. The selectivity of action of MH in plants and animals was obviously the main reason of low interest devoted to the chemical by people working the field of environmental mutagenesis. In early works the inhibitory effects of MH on plant growth were mainly considered to result from the suppression of plant metabolism (inhibition of enzymic activity) and interference of the compound with plant hormones and growth regulators. More recently, numerous experiments performed with various plant species have shown that MH acts as an inhibitor of the synthesis of nucleic acids and proteins. Similar results have been obtained with animal tumour cells. The chromosome-breaking effect of MH on plant chromosomes resembles very closely the chromosome-breaking properties of alkylating agents and other mutagenic compounds such as mitomycin C. MH-induced chromosomal aberrations have also been recorded in grasshoppers, fish and mice, although tests with some mammalian cell lines gave negative results. Among higher plants, selective sensitivity to the toxic effects of MH is well proved. This phenomenon seems to be due to the differential ability of various plant species to detoxicate the chemical. Plants can break down MH into several products, one of which, hydrazine, is a well-known mutagen and carcinogen. MH does not seem to be toxic to bacteria and fungi. The compound is degraded by soil microflora and hence can be utilized as a source of nitrogen nutrition. MH proved to be of low toxicity to mammals, but in some instances it decreased the fertility of rats. The reported carcinogenic effects of MH in mice and rats raise the question of its risks to man.

Animals↗
PubMed1992

Lattice degeneration of the retina and retinal detachment.

Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.

Cataract Extraction↗