Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduc...Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduction,its molecular mechanisms remain incompletely understood.This study investigated two grape transcription factors:EARLY BUD BREAK(VvEBB)and SHORT VEGETATIVE PHASE 4(VvSVP4).Through heterologous transformation in poplar,the research demonstrated that VvSVP4 functions as a negative regulator of bud break,while VvEBB serves as a positive regulator.Transcriptome analysis revealed significant enrichment of plant hormone signaling pathways particularly ABA,IAA,and CK in plants overexpressing VvSVP4(VvSVP4-OE)and VvEBB(VvEBB-OE)compared to controls.Endogenous hormone level changes correlated positively with transcriptome data.During endodormancy,VvSVP4 directly and positively regulated the ABA receptor gene Vv PYL9 expression,maintaining bud dormancy.Conversely,during ecodormancy,rapid upregulation of VvEBB negatively regulated the expression of sucrose nonfermenting 1-related protein kinase 2 gene(Vv SAPK2),facilitating dormancy release.This study provides comprehensive insights into how VvSVP4 and VvEBB genes regulate dormancy and bud break through cell cycle regulation and multiple hormone signaling pathways.展开更多
Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are kno...Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are known to play crucial roles during seed dormancy and germination in P.koraiensis,it remains unclear whether these metabolic pathways function differentially across tissues.P.koraiensis seeds that had undergone different durations of moist chilling in their natural environment,yielding seeds with relatively deeper primary physiological dormancy(DDS)and seeds with released primary physiological dormancy(RDS).A non-targeted metabolomic analysis was conducted on the radicle and hypocotyl-cotyledon portions of both DDS and RDS,before and after a two-week incubation under favorable conditions.Under germination conditions,RDS and DDS showed divergent metabolic profiles,especially regarding carbohydrate metabolism.Specifically,RDS seeds showed significantly reduced substrates of respiratory metabolic pathways in both radicles and hypocotyl-cotyledons.Conversely,the intermediates of the carbohydrate metabolism pathway(particularly the tricarboxylic acid cycle)accumulating in radicles of DDS seeds under germination conditions.Moreover,in RDS,the carbohydrate metabolic pathways were more prevalent in the hypocotyl-cotyledon,while lysine degradation and ascorbate and aldarate metabolism were the dominant metabolic pathways in radicles.In contrast,the tricarboxylic acid cycle showed higher activity in DDS radicles compared to hypocotyl-cotyledons.We further demonstrated that carbohydratemetabolic pathways continue to play a dominant role in both dormancy maintenance and germination processes of P.koraiensis seeds.Notably,the carbohydratemetabolism in radicles likely exerts more critical regulatory functions in these two physiological processes compared to that in cotyledon and hypocotyl tissues.展开更多
Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes...Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes the urgent need to comprehend tumor dormancy and its implications for cancer recurrence.Despite notable advancements,significant gaps remain in our understanding of the mechanisms underlying dormancy and the lack of reliable biomarkers for predicting relapse.This review provides a comprehensive analysis of the cellular,angiogenic,and immunological aspects of dormancy.It highlights the current therapeutic strategies targeting dormant cells,particularly combination therapies and immunotherapies,which hold promise in preventing relapse.By elucidating these mechanisms and proposing innovative research methodologies,this review aims to deepen our understanding of tumor dormancy,ultimately facilitating the development of more effective strategies for preventing cancer recurrence and improving patient outcomes.展开更多
1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this...1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.展开更多
[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were use...[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were used for soaking the seeds in the soil seed bank from different degraded grasslands,and the germination number of seeds was detected. [Result] When the seeds from soil seed bank were soaked with 60%,70%,80% and 90% H2SO4,the germination number of seeds was 0,indicating that the germination of seeds was inhibited; when the seeds were soaked with GA3,the germination number of seeds increased with the concentration of GA3 increasing. When the concentration of GA3 increased to 0.10%,the germination of seeds was inhibited; when the seeds were soaked with 0.2% KNO3,the germination number of seeds was greater than the blank control. [Conclusion] The number of remaining seeds was more in the soil seed banks collected from moderately degraded grassland and heavily degraded grassland; while the number of remaining seeds was small in the soil seed banks collected from lightly degraded grassland and extremely degraded grassland.展开更多
[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean see...[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of （50.08-58.26 g）; among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.展开更多
Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in cons...Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in constant expanding and deepening. With the wide application of means of quantitative genetics method and mutant in the study on seed dormancy, a large number of quantitative trait loci（QTL） and mutant genes related with dormancy have been identified, which is of great significance for the further revelation of the detail mechanisms of plant seed dormancy and germination. This paper briefly introduced the genetic variation of seed dormancy in recent years, described the inductive formation of plant seed dormancy from the four aspects of dormancy specific gene, chromatin, seed growth development and hormone, and stated the action mechanism of environmental factors on seed dormancy from genetic and molecular levels, as well as the regulation and control mechanism of dormancy release, with the aim to provide certain references for the study on seed dormancy.展开更多
Pre-harvest sprouting(PHS)is a disadvantageous trait in cereal production worldwide,causing large economic losses each year.Its regulation mechanism is still unclear.We generated the Oryza sativa Viviparous1(OsVP1)mut...Pre-harvest sprouting(PHS)is a disadvantageous trait in cereal production worldwide,causing large economic losses each year.Its regulation mechanism is still unclear.We generated the Oryza sativa Viviparous1(OsVP1)mutant using gene editing technique,which shows increased PHS compared with that of the wild type Nipponbare.OsVP1 is localized mainly in the nucleus and expressed in various tissues and organs.Expression of Seed dormancy 4(Sdr4),a key gene controlling PHS,was sharply reduced in OsVP1 mutants.OsVP1 bound to the specific motif CACCTG in the promoter of Sdr4 and activated its expression in rice protoplasts.Overexpression of Sdr4 reduced the high seed germination rate of OsVP1 mutant cr-osvp1-1,showing that Sdr4 acts as a downstream target of OsVP1.Both OsVP1 and Sdr4 loss-of-function mutants were insensitive to exogenous ABA and employed the ABA signaling pathway in regulating seed dormancy.These findings shed light on the control of seed dormancy aimed at preventing PHS in rice.展开更多
Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes ...Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most （413.8%）, followed by peroxidase （278.7%）, lipase （161.0%）, glucose-6-phosphate dehydrognase （149.1%） and amylase （60.6%） after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pal# urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.展开更多
Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the c...Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(DAR) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, DAR seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. DAR released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in two Rh. nobile populations; 76.92 and 83.33℃d, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.展开更多
Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activ...Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.展开更多
Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of s...Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica （L.） Willd. ex Del., Prosopis juliflora （Sw.） DC. ：and Dodonaea viscosa （L.） Jacq. The following treatments were applied： T1, untreated seed （control）; T2, sulphuric acid （97%） for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog （MS） medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable Seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds （80.8%-90.8%） and for scarified seeds of A. nilotica （50.2%） boiled in water. The germination indices, i.e., final germination percentage （FG）, mean daily germination （MDG） and germination rate （GR）, were significantly affected by treatments and species （p 〈 0.01）.展开更多
Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,re...Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,reduced quality and biosafety issues.However,informati on regarding the molecular mecha nism un derlyi ng sec on dary dormancy is limited.The MOTHER OF FT AND TFL1(MFT)gene,which is evolutionarily conserved in the plant kingdom,acts in a complex gene network in the seed dormancy or germination processes.In this study,we identified four B.napus genes that share high homology with AtMFT,named as BnaMFT.Analyses of c/s-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements,and various stress-and hormone-responsive elements.Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed,with peaks at 35-42 days after pollination.BnaMFTs were not sufficient for primary dormancy;however,they were significantly enhanced by secondary dormancy induction with PEG6000 treatment.Moreover,BnaMFTtranscripts were elevated by treatment with abscisic acid(ABA),which is known to be accumulated duri ng sec on dary dorma ncy.These results collectively suggest that increased BnaMFT tra nscription levels are associated with sec on dary dorma ncy inducti on in an ABA-depe ndent mariner in B.napus.展开更多
Plant dormancy is essential for perennial plant survival.Different genotypes of Prunus mume,including Eumume group and Apricot Mei group,undergo leaf senescence and dormancy at different times.In order to verify the c...Plant dormancy is essential for perennial plant survival.Different genotypes of Prunus mume,including Eumume group and Apricot Mei group,undergo leaf senescence and dormancy at different times.In order to verify the cold resistance of P.mume,freeze resistance evaluation was carried out.Our results showed that Apricot Mei group had a stronger freezing tolerance than Eumume group and that leaf senescence and dormancy of Apricot Mei group occurred at an earlier period before winter.Based on phenotypic data in response to seasonal climate change,the significant candidate regions were selected using GWAS.Furthermore,through KEGG pathway and qRT-PCR analyses,we found that the ethylene-related genes,including PmEIL(Pm002057)and PmERF(Pm004265),were significantly upregulated in‘Songchun’Mei(Apricot Mei group)and downregulated in‘Zaohua Lve’Mei(Eumume group).Ethylene-related genes expression models showed that ethylene may be indirectly involved in the induction of dormancy.The PmEIL and PmERF genes were the core genes of the ethylene signal transduction pathway and were regulated by the exogenous ACC or PZA compounds.For non-dormant or weekly dormant perennial plants,application of ACC was able to induce plant dormancy and thus enhance cold/freeze tolerance.Overall,the expression of the major ethylene genes played a significant role in dormancy induction and freezing tolerance in P.mume;accordingly,application of ACC and PZA compounds were an effective approach for enhancing cold/freeze of tolerance of woody plant.展开更多
Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we...Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments： sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid （GA3） application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germina- tion percentage （86.6%） was observed after five minutes scarification with sulfuric acid （75% v/v）, followed by 60 days of cold stratification. Duration of sulfuric acid scarification （5, 10, and 20 min） did not affect germination rates, but increasing duration of cold stratification （from 15 to 60 days）, increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.展开更多
In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used...In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used as materials. Different aged seeds( 0,3,6 and 9 d) of these four varieties were acquired by artificial accelerated aging method. Effects of artificial aging on malondialdehyde( MDA) content and catalase( CAT),ascorbate peroxidase( APX),peroxidase( POD) and superoxide dismutase( SOD) activity were investigated. The results showed that with the prolongation of aging time,MDA contents of these four rice varieties increased significantly,while the activity of antioxidant enzymes decreased dramatically. Besides,MDA contents and SOD,CAT and APX activity of the two inbred lines were significantly lower than those of the hybrid varieties. In addition,the activity of antioxidant enzymes in 4 K58 and C178 was significantly lower than that in 4 K59 and C179,respectively. This study indicated that artificial aging treatment significantly inhibited the activity of antioxidant system in seeds,improved membrane lipid peroxidation degree,and thus aggravated the deterioration of seeds. In addition,it also suggested that rice seeds with dormant property were more intolerant to storage.展开更多
Echinochloa crus-galli, one of the world＇s most serious weeds, influences seriously the yield and quality of cereal crop plant.It is well known that E.crus-galli grain is dormant, but its dormant type, as well as its...Echinochloa crus-galli, one of the world＇s most serious weeds, influences seriously the yield and quality of cereal crop plant.It is well known that E.crus-galli grain is dormant, but its dormant type, as well as its dormancy release and germination in relation to galactomannan-hydrolysing enzyme activity were poorly understood.The cooperation of endo-β-mannanase（EC 3.2.1.78）, β-mannosidase（EC 3.2.1.25） and α-galactosidase（EC 3.2.1.22） can hydrolyze the cell walls rich in mannan-based polymers.In the present paper, the mature grains are used as experimental materials, we investigated the water uptake of grains, the effect of removing partial endosperm, after-ripening, stratification and phytohormone on grain germination, and the change in endo-β-mannanase, β-mannosidase and α-galactosidase activities of grains during after-ripening and germination.The results showed that the freshly-collected grains were water-permeable and had only phase I and II of water uptake, while the grains after-ripened for 150 d had an obvious phase III of water uptake.In alternating photoperiod, the germination of grains freshly-collected was zero at 10–35°C, and that of half grains was 11% at 20°C only.The grain germination was notably promoted by after-ripening and stratification, but not by gibberellic acid and 6-benzyladenine at 0.0001–1 mmol L–1.β-Mannosidase activity increased during 0 to 300 d of after-ripening and then decreased.The activity of endo-β-mannanase and α-galactosidase of grains decreased with after-ripening.During grain germination, endo-β-mannanase and β-mannosidase activities obviously increased, while α-galactosidase activity decreased.Our data showed that E.crus-galli grain was a deep physiological dormant, the dormancy release by after-ripening was related to an increasing β-mannosidase activity, and its germination was closely associated with an increasing endo-β-mannanase and β-mannosidase activity; which have provided new knowledge to decrease the harm of E.crus-galli on production of cereal crop plant.展开更多
The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. n...The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. nectariana cv. Shuguang） and involved three treatments： a short day treatment （8 h）, a long day treatment （16 h）, and the normal condition as the control. The dormancy status was determined with the growth of shoot and the sprouting ability, and the respiratory rate was mensurated with oxygen electrode. Short day treatment could induce the growth stopping of peach shoots ahead, promote the development of dormancy, and induce buds into dormancy with 21 d previous to control. Long day treatment postponed the growth stopping and the induction and development of dormancy. The respiratory rate decreased according to the development of dormancy induction. The minimum respiratory rate appeared about 7 days after the start of dormancy induction. Bud respiratory rate increased during this period and then declined and remained at low level during dormancy period. Long day reduced buds respiratory rate slightly. Short day could induce dormancy obviously, and long day postponed dormancy induction. The changes of respiratory rate were correlated with the development of dormancy induction, and the bud respiratory rate was also affected by photoperiod.展开更多
For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5...For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L^-1 and 500 mg·L^-1 and combinational treatment of scarification with gibberellic acid of 250 mg·L^-1 and 500 mg·L^-1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.展开更多
Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dorman...Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.展开更多
基金supported by the China Agriculture Research System of MOF and MARA(CARS-29)the Xinjiang Uygur Autonomous Region Tianchi Talent Introduction Program,Chinathe Key R&D Technology Commissioner Projects in Hainan Province,China(ZDYF2024KJTPY008)。
文摘Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduction,its molecular mechanisms remain incompletely understood.This study investigated two grape transcription factors:EARLY BUD BREAK(VvEBB)and SHORT VEGETATIVE PHASE 4(VvSVP4).Through heterologous transformation in poplar,the research demonstrated that VvSVP4 functions as a negative regulator of bud break,while VvEBB serves as a positive regulator.Transcriptome analysis revealed significant enrichment of plant hormone signaling pathways particularly ABA,IAA,and CK in plants overexpressing VvSVP4(VvSVP4-OE)and VvEBB(VvEBB-OE)compared to controls.Endogenous hormone level changes correlated positively with transcriptome data.During endodormancy,VvSVP4 directly and positively regulated the ABA receptor gene Vv PYL9 expression,maintaining bud dormancy.Conversely,during ecodormancy,rapid upregulation of VvEBB negatively regulated the expression of sucrose nonfermenting 1-related protein kinase 2 gene(Vv SAPK2),facilitating dormancy release.This study provides comprehensive insights into how VvSVP4 and VvEBB genes regulate dormancy and bud break through cell cycle regulation and multiple hormone signaling pathways.
基金supported by the National Natural Science Foundation of China(31901300).
文摘Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are known to play crucial roles during seed dormancy and germination in P.koraiensis,it remains unclear whether these metabolic pathways function differentially across tissues.P.koraiensis seeds that had undergone different durations of moist chilling in their natural environment,yielding seeds with relatively deeper primary physiological dormancy(DDS)and seeds with released primary physiological dormancy(RDS).A non-targeted metabolomic analysis was conducted on the radicle and hypocotyl-cotyledon portions of both DDS and RDS,before and after a two-week incubation under favorable conditions.Under germination conditions,RDS and DDS showed divergent metabolic profiles,especially regarding carbohydrate metabolism.Specifically,RDS seeds showed significantly reduced substrates of respiratory metabolic pathways in both radicles and hypocotyl-cotyledons.Conversely,the intermediates of the carbohydrate metabolism pathway(particularly the tricarboxylic acid cycle)accumulating in radicles of DDS seeds under germination conditions.Moreover,in RDS,the carbohydrate metabolic pathways were more prevalent in the hypocotyl-cotyledon,while lysine degradation and ascorbate and aldarate metabolism were the dominant metabolic pathways in radicles.In contrast,the tricarboxylic acid cycle showed higher activity in DDS radicles compared to hypocotyl-cotyledons.We further demonstrated that carbohydratemetabolic pathways continue to play a dominant role in both dormancy maintenance and germination processes of P.koraiensis seeds.Notably,the carbohydratemetabolism in radicles likely exerts more critical regulatory functions in these two physiological processes compared to that in cotyledon and hypocotyl tissues.
基金supported by the National Natural Sciences Foundation of China(82170974)the Central South University Research Program of Advanced Interdisciplinary Studies(2023QYJC038).
文摘Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes the urgent need to comprehend tumor dormancy and its implications for cancer recurrence.Despite notable advancements,significant gaps remain in our understanding of the mechanisms underlying dormancy and the lack of reliable biomarkers for predicting relapse.This review provides a comprehensive analysis of the cellular,angiogenic,and immunological aspects of dormancy.It highlights the current therapeutic strategies targeting dormant cells,particularly combination therapies and immunotherapies,which hold promise in preventing relapse.By elucidating these mechanisms and proposing innovative research methodologies,this review aims to deepen our understanding of tumor dormancy,ultimately facilitating the development of more effective strategies for preventing cancer recurrence and improving patient outcomes.
文摘1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.
基金Supported by National Natural Science Foundation of China (30860061)National Science and Technology Support Program(2007BAC06B01)~~
文摘[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were used for soaking the seeds in the soil seed bank from different degraded grasslands,and the germination number of seeds was detected. [Result] When the seeds from soil seed bank were soaked with 60%,70%,80% and 90% H2SO4,the germination number of seeds was 0,indicating that the germination of seeds was inhibited; when the seeds were soaked with GA3,the germination number of seeds increased with the concentration of GA3 increasing. When the concentration of GA3 increased to 0.10%,the germination of seeds was inhibited; when the seeds were soaked with 0.2% KNO3,the germination number of seeds was greater than the blank control. [Conclusion] The number of remaining seeds was more in the soil seed banks collected from moderately degraded grassland and heavily degraded grassland; while the number of remaining seeds was small in the soil seed banks collected from lightly degraded grassland and extremely degraded grassland.
基金Supported by the"Twelfth Five-Year"Key Project for Crop Breeding of Sichuan Province(YZGG4-6)the Special Support Program for the Scientific Research Personnel of Sichuan Agricultural University~~
文摘[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of （50.08-58.26 g）; among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.
基金Supported by the Natural Science Foundation for Youth of Qinghai Province(2015-ZJ-926Q)~~
文摘Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in constant expanding and deepening. With the wide application of means of quantitative genetics method and mutant in the study on seed dormancy, a large number of quantitative trait loci（QTL） and mutant genes related with dormancy have been identified, which is of great significance for the further revelation of the detail mechanisms of plant seed dormancy and germination. This paper briefly introduced the genetic variation of seed dormancy in recent years, described the inductive formation of plant seed dormancy from the four aspects of dormancy specific gene, chromatin, seed growth development and hormone, and stated the action mechanism of environmental factors on seed dormancy from genetic and molecular levels, as well as the regulation and control mechanism of dormancy release, with the aim to provide certain references for the study on seed dormancy.
基金supported by grants from the National Major Science and Technology Program on New GMO Organism Variety Breeding(2016ZX08001-001)Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS)。
文摘Pre-harvest sprouting(PHS)is a disadvantageous trait in cereal production worldwide,causing large economic losses each year.Its regulation mechanism is still unclear.We generated the Oryza sativa Viviparous1(OsVP1)mutant using gene editing technique,which shows increased PHS compared with that of the wild type Nipponbare.OsVP1 is localized mainly in the nucleus and expressed in various tissues and organs.Expression of Seed dormancy 4(Sdr4),a key gene controlling PHS,was sharply reduced in OsVP1 mutants.OsVP1 bound to the specific motif CACCTG in the promoter of Sdr4 and activated its expression in rice protoplasts.Overexpression of Sdr4 reduced the high seed germination rate of OsVP1 mutant cr-osvp1-1,showing that Sdr4 acts as a downstream target of OsVP1.Both OsVP1 and Sdr4 loss-of-function mutants were insensitive to exogenous ABA and employed the ABA signaling pathway in regulating seed dormancy.These findings shed light on the control of seed dormancy aimed at preventing PHS in rice.
基金This work is supported by the National Natural Science Foundation of China （Grant No. 30371156）in part by Grant sx （2003） 083 from the ＂Three Agriculture Engineering Program of Jiangsu Province＂.
文摘Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most （413.8%）, followed by peroxidase （278.7%）, lipase （161.0%）, glucose-6-phosphate dehydrognase （149.1%） and amylase （60.6%） after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pal# urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.
基金supported by National Key Research and Development Program of China (2017YFC0505201)NSFC (grant 31670206 to Z.-M. L. and 31570228 to B. S.),major Program of NSFC (grant 31590823 to H. S.)+1 种基金the Orientation Training Programme for Postdoctoral Fellows from Yunnan Province to D.-L. P.the Young Academic and Technical Leader Raising Foundation of Yunnan Province to B. S.
文摘Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(DAR) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, DAR seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. DAR released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in two Rh. nobile populations; 76.92 and 83.33℃d, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.
文摘Plasma membrane （PM） Ca2+-ATPase activity in poplar apical bud meristematic cells during short-day （SD）-induced dormancy development was examined by a cerium precipitation EM-cytochemical method. Ca2+-ATPase activity, indicated by the status of cerium phosphate precipitated grains, was localized mainly on the interior face （cytoplasmic side） of the PM when plants were grown under long days and reached a deep dormancy. A few reaction products were also observed on the nuclear envelope.When plant buds were developing dormancy after 28 to 42 d of SD exposure, almost no reaction products were present on the interior face of the PM. In contrast, a large number of cerium phosphate precipitated grains were distributed on the exterior face of the PM. After 70 d of SD exposure, when buds had developed a deep dormancy, the reaction products of Ca2+-ATPase activity again appeared on the interior face of the PM. The results seemed suggesting that two kinds of Ca2+-ATPases may be present on the PM during the SD-induced dormancy in poplar.One is the Ca2+-punlping ATPase, which is located on the interior face of the PM, for maintaining and restoring the Ca2+homeostasis. The other might be an ecto-Ca2+-ATPase, which is located on the exterior face of the PM, for the exocytosis of cell wall materials as suggested by the fact of the cell wall thickening during the dormancy developlnent in poplar.
文摘Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica （L.） Willd. ex Del., Prosopis juliflora （Sw.） DC. ：and Dodonaea viscosa （L.） Jacq. The following treatments were applied： T1, untreated seed （control）; T2, sulphuric acid （97%） for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog （MS） medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable Seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds （80.8%-90.8%） and for scarified seeds of A. nilotica （50.2%） boiled in water. The germination indices, i.e., final germination percentage （FG）, mean daily germination （MDG） and germination rate （GR）, were significantly affected by treatments and species （p 〈 0.01）.
基金This work was funded by the National Natural Science Foundation of China(31470572 and 31701514)and the Qing Lan Project of Jiangsu Province,China(2016).
文摘Brassica napus cultivars have little or no primary dormancy;however,they are prone to sec on dary dorma ncy in ducti on.Secondary dormant seeds can produce volunteer plants,which can result in genetic contamination,reduced quality and biosafety issues.However,informati on regarding the molecular mecha nism un derlyi ng sec on dary dormancy is limited.The MOTHER OF FT AND TFL1(MFT)gene,which is evolutionarily conserved in the plant kingdom,acts in a complex gene network in the seed dormancy or germination processes.In this study,we identified four B.napus genes that share high homology with AtMFT,named as BnaMFT.Analyses of c/s-acting elements showed that BnaMFT promoters contain multiple seed-specific regulatory elements,and various stress-and hormone-responsive elements.Further experiments validated that BnaMFTs were specifically expressed during seed maturation and in the dry seed,with peaks at 35-42 days after pollination.BnaMFTs were not sufficient for primary dormancy;however,they were significantly enhanced by secondary dormancy induction with PEG6000 treatment.Moreover,BnaMFTtranscripts were elevated by treatment with abscisic acid(ABA),which is known to be accumulated duri ng sec on dary dorma ncy.These results collectively suggest that increased BnaMFT tra nscription levels are associated with sec on dary dorma ncy inducti on in an ABA-depe ndent mariner in B.napus.
基金The research was supported by the National Key Research and Development Programof China(Grant No.2019YFD1001500)the National Natural Science Foundation of China(Grant No.31800595)Special Fund for Beijing Common Construction Project.
文摘Plant dormancy is essential for perennial plant survival.Different genotypes of Prunus mume,including Eumume group and Apricot Mei group,undergo leaf senescence and dormancy at different times.In order to verify the cold resistance of P.mume,freeze resistance evaluation was carried out.Our results showed that Apricot Mei group had a stronger freezing tolerance than Eumume group and that leaf senescence and dormancy of Apricot Mei group occurred at an earlier period before winter.Based on phenotypic data in response to seasonal climate change,the significant candidate regions were selected using GWAS.Furthermore,through KEGG pathway and qRT-PCR analyses,we found that the ethylene-related genes,including PmEIL(Pm002057)and PmERF(Pm004265),were significantly upregulated in‘Songchun’Mei(Apricot Mei group)and downregulated in‘Zaohua Lve’Mei(Eumume group).Ethylene-related genes expression models showed that ethylene may be indirectly involved in the induction of dormancy.The PmEIL and PmERF genes were the core genes of the ethylene signal transduction pathway and were regulated by the exogenous ACC or PZA compounds.For non-dormant or weekly dormant perennial plants,application of ACC was able to induce plant dormancy and thus enhance cold/freeze tolerance.Overall,the expression of the major ethylene genes played a significant role in dormancy induction and freezing tolerance in P.mume;accordingly,application of ACC and PZA compounds were an effective approach for enhancing cold/freeze of tolerance of woody plant.
文摘Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments： sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid （GA3） application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germina- tion percentage （86.6%） was observed after five minutes scarification with sulfuric acid （75% v/v）, followed by 60 days of cold stratification. Duration of sulfuric acid scarification （5, 10, and 20 min） did not affect germination rates, but increasing duration of cold stratification （from 15 to 60 days）, increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.
基金Supported by National Key Research and Development Project(2018YFD0101000)
文摘In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used as materials. Different aged seeds( 0,3,6 and 9 d) of these four varieties were acquired by artificial accelerated aging method. Effects of artificial aging on malondialdehyde( MDA) content and catalase( CAT),ascorbate peroxidase( APX),peroxidase( POD) and superoxide dismutase( SOD) activity were investigated. The results showed that with the prolongation of aging time,MDA contents of these four rice varieties increased significantly,while the activity of antioxidant enzymes decreased dramatically. Besides,MDA contents and SOD,CAT and APX activity of the two inbred lines were significantly lower than those of the hybrid varieties. In addition,the activity of antioxidant enzymes in 4 K58 and C178 was significantly lower than that in 4 K59 and C179,respectively. This study indicated that artificial aging treatment significantly inhibited the activity of antioxidant system in seeds,improved membrane lipid peroxidation degree,and thus aggravated the deterioration of seeds. In addition,it also suggested that rice seeds with dormant property were more intolerant to storage.
基金supported by grants from the National Science and Technology Support Program of China(2012BAC01B05)
文摘Echinochloa crus-galli, one of the world＇s most serious weeds, influences seriously the yield and quality of cereal crop plant.It is well known that E.crus-galli grain is dormant, but its dormant type, as well as its dormancy release and germination in relation to galactomannan-hydrolysing enzyme activity were poorly understood.The cooperation of endo-β-mannanase（EC 3.2.1.78）, β-mannosidase（EC 3.2.1.25） and α-galactosidase（EC 3.2.1.22） can hydrolyze the cell walls rich in mannan-based polymers.In the present paper, the mature grains are used as experimental materials, we investigated the water uptake of grains, the effect of removing partial endosperm, after-ripening, stratification and phytohormone on grain germination, and the change in endo-β-mannanase, β-mannosidase and α-galactosidase activities of grains during after-ripening and germination.The results showed that the freshly-collected grains were water-permeable and had only phase I and II of water uptake, while the grains after-ripened for 150 d had an obvious phase III of water uptake.In alternating photoperiod, the germination of grains freshly-collected was zero at 10–35°C, and that of half grains was 11% at 20°C only.The grain germination was notably promoted by after-ripening and stratification, but not by gibberellic acid and 6-benzyladenine at 0.0001–1 mmol L–1.β-Mannosidase activity increased during 0 to 300 d of after-ripening and then decreased.The activity of endo-β-mannanase and α-galactosidase of grains decreased with after-ripening.During grain germination, endo-β-mannanase and β-mannosidase activities obviously increased, while α-galactosidase activity decreased.Our data showed that E.crus-galli grain was a deep physiological dormant, the dormancy release by after-ripening was related to an increasing β-mannosidase activity, and its germination was closely associated with an increasing endo-β-mannanase and β-mannosidase activity; which have provided new knowledge to decrease the harm of E.crus-galli on production of cereal crop plant.
基金the National 863 Program of China (2001AA247041)
文摘The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. nectariana cv. Shuguang） and involved three treatments： a short day treatment （8 h）, a long day treatment （16 h）, and the normal condition as the control. The dormancy status was determined with the growth of shoot and the sprouting ability, and the respiratory rate was mensurated with oxygen electrode. Short day treatment could induce the growth stopping of peach shoots ahead, promote the development of dormancy, and induce buds into dormancy with 21 d previous to control. Long day treatment postponed the growth stopping and the induction and development of dormancy. The respiratory rate decreased according to the development of dormancy induction. The minimum respiratory rate appeared about 7 days after the start of dormancy induction. Bud respiratory rate increased during this period and then declined and remained at low level during dormancy period. Long day reduced buds respiratory rate slightly. Short day could induce dormancy obviously, and long day postponed dormancy induction. The changes of respiratory rate were correlated with the development of dormancy induction, and the bud respiratory rate was also affected by photoperiod.
文摘For improving seed germination of Prosopis koelziana and Prosopis juliflora, different treatments of seeds were conducted, including scarification with sulfuric acid 98% for 10 and 15 min, sandy paper, hot water for 5 and 10 min, potasium nitrate 0.1%, gibberellic acid at 250 mg·L^-1 and 500 mg·L^-1 and combinational treatment of scarification with gibberellic acid of 250 mg·L^-1 and 500 mg·L^-1. The results show that scarifications with sandy paper and sulfuric acids 98% were the most effective treatments on breaking seed dormancy and seed germination induction. Scarification with sulfuric acid 98% for 15 min was the best treatment. According to the positive effect of scarification and lack of reaction of seeds against KNO3 and gibberellic acid, the kind of seed dormancy was determined as exogenous.
文摘Cupressus atlantica Gaussen （Cupressaceae） is an endemic and endangered coniferous tree geographically restricted to the N＇Fis valley in South-Western Morocco. Like many forest species, C. atlantica exhibits dormancy which delays and reduces germination. To improve seed germination, different pre-treatments were conducted on C. atlantica seeds after storage for different periods （one, two and five years） including： scarification with sandy paper; soaking seeds in hot distilled water at 60℃ and 80℃ for 15 min and soaking seeds for 48 h in a gibberellic acid （GA3） at 1,000 and 2,000 mg·L-1. Results showed that scarification with sandy paper increased the germination rate of Atlas cypress by up to 67%, indicating that the species possess essentially an exogenous dormancy （physical dormancy） due to the hard seed coat （hardseededness）. Exogenous application of gibberellic acid （GA3） at 1,000 mg.L-1 was also effective in breaking seed dormancy and germination induction. These two treatments induced faster speed germination expressed by low number of days to first germination （8-10 days） and low values of mean germination times （MGT）. However, germination rate, under any treatment, is greatly dependent on the year of seed collection. Seeds collected in year 2004 gave the highest value, suggesting that even after five years of storage, the germination capacity of C. atlantica seeds could remain high. This observation is very interesting in the ex-situ conservation of such endemic and endangered species where the production of seeds is irregular over the years.
