Effects of osmotic priming and ageing on onion seed germination

Onion seeds were osmotically primed in polyethylene glycol solution (342 g/kg water) either for 14 days before accelerated ageing at 40°C. 18% m.c. for 0, 24, 48, 72 or 96 h, or for 10, 14 or 17 days after ageing. Priming improved the rate of germination compared with non-primed seed. Priming before ageing delayed the loss of viability due to ageing, but priming after ageing had no effect on viability. Primed and dried onion seed was stored for 18 months at 10°C, 9% m.c. with no effect on viability; improvements in germination rate due to priming were maintained over the storage period. Conductivity measurements of seed leachates were not a consistently reliable indicator of germination performance.     

Wet-dry cycling extends seed persistence by re-instating antioxidant capacity

Seeds in the field experience wet-dry cycling that is akin to the well-studied commercial process of seed priming in which seeds are hydrated and then re-dried to standardise their germination characteristics. To investigate whether the persistence (defined as in situ longevity) and antioxidant capacity of seeds are influenced by wet-dry cycling, seeds of the global agronomic weed Avena sterilis ssp. ludoviciana were subjected to (1) controlled ageing at 60% relative humidity and 53.5°C for 31 days, (2) controlled ageing then priming, or (3) ageing in the field in three soils for 21 months. Changes in seed viability (total germination), mean germination time, seedling vigour (mean seedling length), and the concentrations of the glutathione (GSH) / glutathione disulphide (GSSG) redox couple were recorded over time. As controlled-aged seeds lost viability, GSH levels declined and the relative proportion of GSSG contributing to total glutathione increased, indicative of a failing antioxidant capacity. Subjecting seeds that were aged under controlled conditions to a wet-dry cycle (to ?1 MPa) prevented viability loss and increased GSH levels. Field-aged seeds that underwent numerous wet-dry cycles due to natural rainfall maintained high viability and high GSH levels. Thus wet-dry cycles in the field may enhance seed longevity and persistence coincident with re-synthesis of protective compounds such as GSH.     

高温加速老化过程中甜菜种子线粒体小分

甜菜(BetavulgarisLcv.Loke)种子的人工老化(30℃,100％RH)导致种子的干重、生活力和活力逐渐丧失,线粒体的呼吸速率、细胞色素c氧化酶和苹果酸脱氢酶的活性下降。线粒体蛋白质随着种子老化而显著变化,小分子量热休克蛋白(LMWHSP)22从老化的0d到30d增加,然后从30d到90d下降。可以认为甜菜种子人工老化过程中线粒体活性和LMWHSP22的含量变化与种子活力密切相关。     

Effects of osmotic priming and ageing on the germination and emergence of carrot and leek seed

Carrot and leek seed was osmotically primed in polyethylene glycol solution (273 g/kg water and 342 g/kg water respectively) for 10, 14 or 17 days before accelerated ageing for 0, 24, 48, 72 or 96 h. Priming reduced the germination time compared with non-primed seed. Accelerated ageing increased germination and emergence times and decreased percentage germination and emergence to a greater extent for the primed seeds than for non-primed seeds in both species. Primed and dried but non-aged seed from both species was stored at 10°C for 12 months. There was no loss of viability and improvements in germination time due to priming were maintained throughout the storage period for all the priming treatments in leek, and for the 10 and 14 day priming treatments in carrot. Carrot seed primed for 17 days lost some viability after 12 months storage compared with non-stored seed.     

Storage Behaviour of Salix alba and Salix matsudana Seeds

Effects of dehydration, storage temperature and humidificationon germination of Salix alba andS. matsudana seeds were studied.Newly released seeds showed 100% germination before and afterdehydration to 11–12% moisture content. Germination ofthe high vigour lot (100% initial normal germination) was notaffected by dehydration to 6.7% moisture content but germinationdecreased with further dehydration to 4.3%. The lower vigourlot (75% initial normal germination) was more susceptible todehydration and germination decreased following dehydrationto 6.7% moisture content. Dry seeds of both species survivedimmersion in liquid nitrogen without loss of viability. Thegermination of seeds stored with 9% moisture content decreasedto 35–40% in 5 months at -20°C or in 2 months at 5°C.However, at 25°C seeds entirely lost viability within 2weeks. Seeds showed improved performance when stored at -70°C> - 20°C > 5°C > 25°C and tolerated dehydrationto a moisture content in equilibrium with 15% relative humidity.Results suggest that they are orthodox in storage behaviouralthough they are short-lived. Humidification treatment of lowvigour seed lots resulted in a remarkable increase in germinationpercentage. Copyright 2000 Annals of Botany Company Salix alba, Salix matsudana, willow, seed storage behaviour, dehydration, humidification, cryopreservation     

Influence of Temperature and Relative Humidity on Germinability of Mucor piriformis Spores

Studies were conducted to determine the influence of temperature and relative humidity (RH) on germinability and viability of Mucor piriformis spores. Spores did not survive when stored at 35 °C and their survival rate decreased rapidly at 30 °C; however, spores remained viable for more than 1 year at 0 °C. RH also significantly affected spore viability. Spores held at 26 °C and 100% RH no longer germinated after 35 days, while those held at 75 or 90% RH germinated for 65 days. At 20 °C, RH had little effect on spore germinability. The effect of temperature and RH on percentage spore germination also varied. At all temperatures studied, spore viability decreased more rapidly with time at 100% RH than at 75 or 90% RH. The least favorable, temperature-humidity combination, 30 °C and 100% RH, decreased spore germination from 100% to less than 1% in 14 days.     

Effect of post-irradiation ageing on onion seeds

Seeds of onion (Allium cepa) cv. Ailsa Craig were exposed to various doses of gamma radiation (0, 10, 20, 40, 80 and 100 krad) and subjected to accelerated ageing (RH 100%, 42°C) for 12 h. Radiation doses significantly affected the percentage of normal seedlings, abnormality types (%) and seedling growth. Seed viability, conductivities of seed leachates, final germination (%), germination speed and time to reach 50% germination (T ₅₀) were not affected by the seed irradiation. Accelerated ageing after irradiation had significant influence on seed viability, conductivities of seed leachates, final germination (%) and percentage of normal seedlings. Germination speed, T ₅₀ and seedling growth were not affected by the accelerated ageing. However, all the parameters studied were significantly influenced by the interaction of radiation doses and accelerated ageing. Accelerated ageing generally enhanced the damaging effects of irradiation on seeds. Therefore, it was concluded that onion seeds should not be exposed to adverse environmental conditions after irradiation.     

The deterioration of <Emphasis Type="Italic">Moringa oleifera</Emphasis> Lam. seeds in the course of storage involves reserve degradation

Seed deterioration in the course of storage may involve hydrolytic reactions. Hence, we aimed to evaluate viability, vigour, contents of reserves and metabolites, and activities of hydrolytic enzymes in Moringa oleifera Lam. seeds during storage under controlled conditions. Seeds were packaged in semipermeable plastic and maintained in a growth chamber (27 ± 2 °C and RH 60–65%) and under refrigeration (4 ± 2 °C and RH 20–25%) for 18 months. Samples were taken at the start of the experiment and every 3 months. During the first 12 months, water content, viability, and vigour remained almost unaffected, while the content of neutral lipids, starch, soluble sugars and free amino acids did not reduce in the seeds kept under refrigeration. After this period, the loss of viability and vigour was accompanied by the degradation of storage lipids, storage proteins, and non-reducing sugars associated with the increase of lipase and acid protease activity in both environmental conditions. As the seed water content remained below 8% in the course of the experiment, we suggest that non-enzymatic hydrolysis might play a role in the deterioration of M. oleifera seeds during storage. At least for planting, we recommend that M. oleifera seeds be kept at low relative humidity under refrigeration for up to 12 months.     

Cell death and reactive oxygen species metabolism during accelerated ageing of soybean axes

In this paper, Glycine max L. seeds under accelerated ageing condition (40°C and 100% relative humidity) were used as experimental material to study the relationships between seed viability and cell death, production and scavenging of reactive oxygen species (ROS) during accelerated ageing. Water content of seeds gradually increased, while the final germination percentage, germination rate of seeds and fresh weight of seedlings produced decreased with increasing accelerated ageing time. The accelerated ageing time (T ₅₀) when final seed germination decreased to 50% was about 10.5 days. During the period of accelerated ageing, the viability of root cells was lost gradually as manifested by the increase in staining with Evans blue. The respiration rate of seeds, ^·O₂ production rate, and H₂O₂ content of axes increased, peaked at the 10 days of accelerated ageing, and then decreased. Activities of superoxide dismutase, ascorbate peroxidase, catalase, and glutathione reductase of axes decreased; and malondialdehyde contents of axes markedly increased. A sceme to explain relationships between seed vigor, cell death, and production and scavenging of ROS during accelerated ageing was suggested. This text was submitted by the authors in English.     

Accelerated ageing and subsequent imbibition affect seed viability and the efficiency of antioxidant system in macaw palm seeds

Accelerated ageing is an accurate test indicator of seed vigor and storability that helps to understand the mechanisms of cellular and biochemical deterioration that occur during seed ageing. This study was carried out to elucidate the mechanisms of ageing in macaw palm embryos. Seeds were artificially aged during 4, 8 and 12 days at 45 °C and 100% relative humidity. After ageing, seeds were tested for viability (tetrazolium), electrical conductivity, lipid peroxidation (MDA) and hydrogen peroxide (H₂O₂) content. Part of the aged seeds was imbibed for 8 days and then determined the hydrogen peroxide content and the activity of antioxidant system enzymes (superoxide dismutase, catalase and glutathione reductase). Ageing reduced the embryo viability from 8 days of treatment and increased malondialdehyde content (MDA) and solute leakage. Hence, membrane permeability correlated with both loss of viability and lipid peroxidation. Imbibition after ageing significantly increased H₂O₂ content along with superoxide dismutase activity. Catalase activity was significantly higher than control in embryos aged from 8 days and imbibed, and glutathione reductase activity did not change. Our results suggest that macaw palm seed deterioration during accelerated ageing is closely related to lipid peroxidation, and that enzymatic antioxidant system is not completely efficient in reducing reactive oxygen species after imbibition, a critical phase to germination. Moreover, accelerated ageing test can be used as a reliable model to understand the mechanisms involved in palm seeds deterioration.     

Viability of rape (Brassica napus L.) seeds following selection on the basis of newly-emerged radicles then subsequent drying and storage

Germinating rape seeds selected on the basis of newly-emerged radicles (1 ± 0.5 mm) were dried to an equilibrium moisture content (c. 11%) in air at 20°C and 80% relative humidity without loss of viability. Storage life of these low-moisture-content germinating (LMCG) seeds at 15°C was limited to 7 days before viability was significantly reduced. However, viability of LMCG seeds was maintained for 84 days in storage at -20°C. Longer periods in store reduced viability, but 96% of seeds still remained viable after 336 days at - 20°C. Increasing periods of storage at -20°C reduced the subsequent seed longevity at 15°C, indicating a reduction in vigour during storage. Storage under reduced pressure or in a nitrogen atmosphere had little significant effect on seed longevity. Reduction of moisture content below 11% using vacuum drying at a range of temperatures reduced seed vigour.     

Factors influencing the storability of Fagus sylvatica L. seeds after release from dormancy

Seeds of beech (Fagus sylvatica L.) that have been subjected to dormancy breaking consisting of 10 weeks of prechilling at 3 °C and 34 % water content (WC) and then desiccation to 10 % WC, are non-dormant (ND). ND seeds are characterised by greater sensitivity to storage conditions, than no prechilled, dormant (D) seeds. The aim of the present work was to investigate factors affecting the loss of seed viability during storage of D and ND beech seeds at different temperatures (4 and 20 °C) and humidity levels (45 and 75 % RH) for 3 weeks. In general, both D and ND seeds maintained a high germination capacity after storage at 4 °C. At 20 °C and 45 and 75 % RH the germination capacity of D seeds diminished to 80 and 28 %, respectively. Under the same conditions, ND seeds lost germination capacity to a greater degree, with only 62 and 7 % germinated seeds, respectively. At 20 °C, an increase in production of reactive oxygen species was observed, and the increase was significantly higher in ND seeds. The loss of germination capacity was coincident with an increase in electrolyte leakage and accumulation of free fatty acids, which suggests that membrane deterioration was the cause of the decline in germinability. ND seeds stored at 20 °C and 45 and 75 % RH showed a greater decrease than D seeds in contents of the primary phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) as well as in polyunsaturated fatty acids (18:2 and 18:3). ND seeds possessed more unsaturated fatty acids, especially 18:3, than D seeds in the phospholipid fraction before storage. D seeds were characterised by a significantly higher level of α-tocopherol and UV-absorbing phenols. The level of ascorbate was similar in D and ND seeds. D seeds contained glutathione in both reduced (GSH) and oxidised (GSSG) forms, and GSSG dominated GSH. ND seeds contained more GSSG form than D seeds. We concluded that the membranes of ND seeds are exposed to greater oxidative stress during storage due to higher levels of unsaturation and lower levels of α-tocopherol, the main antioxidant that protects membranes against free radical attack.     

Changes in Lipids of Bean Seeds (Phaseolus vulgaris) and Corn Caryopses (Zea mays) Aged in Contrasting Environments

Seeds of French bean (Phaseolus vulgaris L. cv. The Prince)and caryopses of sweet corn (maize; Zea mays L.F1 hybrid Firstof All) were stored in environments of 79% relative humidityand 25 °C, 80% r.h. and 40 °C or 100% r.h. and 45 °C,giving ageing (loss of gcrminability and vigour) over periodsof months, weeks or days, respectively. The relationship betweenchanges in lipids and changes in germinability or vigour wasunaffected in general by the speed of ageing. In the corn caryopsesthere was no evidence of hydrolysis of phospholipids or peroxidationof fatty acids during ageing. In the bean seeds phosphatidicacid increased during the ageing period and phosphatyl cholinedeclined. The percentage of fatty acids as hnolenic acid initiallyfell during bean ageing, but in the slower ageing conditionsit rose again as germination reached zero. In bean, the presenceof phosphatidic acid could be a sensitive indictator of lossof vigour, but relative proportions of the different fatty acidswould be a misleading indicator of quality. Rapid artificialageing may be an adequate model, in some species, of ageingat moderate speeds and of ageing under some ambient conditions. French bean (Phaseolus vulgaris L. cv. The Prince), sweet corn (maize, Zea mays L., Fl hybrid First of All), seed ageing, phospholipids, fatty acids     

Free radical scavenging as affected by accelerated ageing and subsequent priming in sunflower seeds

Lipid peroxidation resulting from loss of free radical scavenging is thought to be involved in deterioration of sunflower (Helianthus annuus L.) seeds during accelerated ageing. In other respects, presoaking of seeds in a solution of low water potential (osmopriming) has been demonstrated to reinvigorate aged seeds. The aim of the present work was to study the effect of osmopriming on the germination of aged sunflower seeds and to investigate whether this effect was associated with the restoration of antioxidant defence systems. Seeds were aged for 5 days at 45°C and 100% relative humidity and then primed for various durations up to 7 days at 15°C in a solution of polyethylene glycol 6000 at ?2 MPa. Lipid peroxidation was estimated by measuring malondialdehyde (MDA) and conjugated diene contents, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) were measured throughout the treatments. Accelerated ageing resulted in a marked decrease in the germination rate, and was associated with an increase in the levels of MDA and conjugated dienes, thus indicating lipid peroxidation. Ageing was also characterized by a decrease in the activities of CAT and GR. The activities of SOD and DHAR were much less altered. No APX activity was detected whatever the seed treatment. Priming of aged seeds progressively restored the initial germinative ability and resulted in a marked decrease in the levels of MDA and conjugated dienes, indicating a fall in lipid peroxidation processes. These effects of priming were also well correlated to the recovery of SOD, CAT and GR activities. Priming treatment for 7 days led to full restoration of the cell detoxifying mechanisms which were strongly altered during ageing. Glutathione content showed the same changes as GR activity. There existed a clear-cut relationship between seed germinative energy, expressed as the germination rate, and the efficiency of free radical scavenging systems, in particular CAT and GR activities and glutathione content. The results suggest that the antioxidant defence systems might play a key role in seed vigour.     

A continental-scale study of seed lifespan in experimental storage examining seed,plant, and environmental traits associated with longevity

Management of seed banks conserving the biodiversity of phylogenetically diverse species requires insight into seed longevity. This study determined the seed longevity of 172 species sourced from across the mega-diverse flora of the Australia continent. Seeds were aged via a controlled ageing experiment through storage at 45 °C and 60 % RH, or 60 °C and 60 % RH, and regularly tested for germination. Relative seed longevity between species was determined by comparing the time to 50 % viability loss (p ₅₀), calculated via probit analysis of seed survival curves. Seed, plant, and environmental traits were examined for associations with longevity. The p ₅₀ values varied between species from 3.0 to 588.6 days. Serotinous species, and woody trees and shrubs, had significantly longer-lived seeds than geosporous species, and species of herbaceous habit. Seeds that possess physical dormancy, and seeds with large embryos with little endosperm, were also long-lived. There was a weak, but significant, positive correlation between seed mass and longevity. Seeds sourced from regions of higher mean annual temperature and rainfall were significantly longer-lived than seeds from cooler and drier regions, although both environmental factors were weakly associated with longevity. Compared with species from other regions of the world, prolonged longevity is a feature of many Australian species. Nevertheless, seed life-spans vary substantially between species and close consideration of seed traits along with biotic and abiotic components of the plants and their environment can assist to differentiate between potentially long- and short-lived seeds.     

Water Relations of Seed Development and Germination in Muskmelon (Cucumis melo L.): VII. INFLUENCE OF AFTER-RIPENING AND AGEING ON GERMINATION RESPONSES TO TEMPERATURE AND WATER POTENTIAL

The effects of storage conditions on the germination of developingmuskmelon (Cucumis melo L.) seeds were tested to determine whetherafter-ripening is required to obtain maximum seed vigour. Seedswere harvested at 5 d intervals from 35 (immature) to 60 (fullymature) days after anthesis (DAA), washed, dried, and storedat water contents of 3·3 to 19% (dry weight basis) at6, 20, or 30°C for up to one year. Germination was testedin water and in polyethylene glycol 8000 solutions ( –0·2to –1·2 MPa osmotic potential) at 15, 20, 25 or30°C. Germination percentages and rates (inverse of meantimes to radicle emergence) were compared to those of newlyharvested, washed and dried seeds. For 40 and 60 DAA seeds,one year of storage at 20°C and water contents <6·5%significantly increased germination percentages and rates at20°C, but had little effect on germination at 25 and 30°C.Storage reduced the estimated base temperature (T_b) and meanbase water potential (_b) for germination of both 40 and 60 DAAseeds by approximately 5°C and 0·3 MPa, respectively.Immature 35 DAA seeds showed the greatest benefit from storageat 3 to 5% water content and 30°C, as germination percentagesand rates increased at all water potentials (). Storage underthese same conditions had little effect on the germination ofmature seeds in water, but increased germination percentagesand rates at reduced 's. Accelerated ageing for one month at30°C and water contents from 15 to 19° increased germinationrates and percentages of mature seeds at reduced 's, but longerdurations resulted in sharp declines in both parameters. Immatureseeds lost viability within one month under accelerated ageingconditions. An after-ripening period is required at all stagesof muskmelon seed development to expand the temperature andwater potential ranges allowing germination and to achieve maximumgerminability and vigour. Post-harvest dormancy is deepest atthe point of maximum seed dry weight accumulation and declinesthereafter, both in situ within the ripening fruit and duringdry storage. Key words: Muskmelon, Cucumis melo L., seed, development, dormancy, germination, vigour, after-ripening     

Biochemical changes induced in seeds of <Emphasis Type="Italic">Brassicaceae</Emphasis> wild species during ageing

The aim of the present study was to determine whether the loss of seed germination capacity and vigour in seeds of four wild Brassicaceae species (Brassica repanda, Moricandia arvensis, Rorippa nasturtium-aquaticum and Sinapis alba) during ageing at 45°C and 90% relative humidity was related to changes in lipid peroxidation and membrane integrity. For all of the species, ageing reduced the final germination percentage and increased the length of time required to reach 50% of final germination (T ₅₀). Large differences in longevity were observed among the species. The times required for viability to be reduced to 80 and 50% of maximum germination (P80 and P50) were the lowest for B. repanda, and these values were two times longer for M. arvensis and R. nasturtium-aquaticum and five times longer for S. alba compared with B. repanda. A loss of seed viability was not associated with malondialdehyde accumulation, suggesting that lipid peroxidation did not cause seed deterioration under these conditions. However, the conductivity test effectively detected seed deterioration in these wild Brassicaceae species, and membrane permeability correlated with both germination and vigour loss. This correlation may provide a valuable mean for early detection of seed viability in wild Brassicaceae species.     

Seed germinability and longevity influences regeneration of <Emphasis Type="Italic">Acacia gerrardii</Emphasis>

Acacia gerrardii is the only native tree species of the Kuwaiti desert ecosystem. However, anthropogenic disturbances and harsh arid climate have contributed towards the disappearance of this keystone species from its habitat. In this study, effects of different seed pretreatments to break dormancy, water entry pathway, and ecology (seasonal timing) of dormancy loss and germination of A. gerrardii were investigated. Effects of mechanical scarification, hot water treatment (30 s, 1, 2, and 5 min), and concentrated acid scarification (10, 20, and 30 min) on germination percentage and rate (time to 50% germination and final germination) were also examined. Pretreatment with mechanical scarification produced the highest germination in the least time and 20 °C, 40% RH with 12 h of light (2370 Lux) were found to provide the best germination environment. Seeds were rapidly aged at 60% RH and 45 or 50 °C to determine longevity, and the results were analyzed using probit analysis. Times taken for viability of A. gerrardii seeds aged at 45 and 50 °C to fall to 50% (p₅₀) were 38.6 and 9.3 days, respectively, and therefore the seeds can be considered to have medium longevity. Experiments to find the water entry pathway in A. gerrardii indicated that the micropyle region was the primary point of water entry into the seed. Seed burial experiments indicated that though seed retention decreased over time, there was no significant decrease in number of viable seeds after 31 weeks. The findings of this study are important to nursery managers, seed banks, and those involved in conservation and restoration activities.     

The influence of aerated hydration seed treatment on seed longevity as assessed by the viability equations

Aerated hydration (AH) treatments of cauliflower seeds for 12 h (12AH) and 28 h (28AH) at 20 degrees C resulted in improved or reduced storage potential of low or high vigour seeds, respectively. Seeds were stored at their initial seed moisture content (mean 5.5% mc) or at 12% mc at 10 degrees C for 12 months and at 20 degrees C for 4 months. The improved longevity of low vigour seeds was associated with increased K(i) (initial seed viability) and a reduced rate of deterioration (1/sigma) whereas the K(i) of high vigour seeds fell after 28AH and the rate of deterioration increased such that the time to lose one probit of viability decreased from 28.7 to 5.3 months at 10 degrees C and from 10.4 to 1.2 months at 20 degrees C. The improved K(i) of low vigour seeds could be explained by the reduction in the extent of deterioration after AH, as indicated by the increase in germination after cotrolled deterioration (CD), and the possible activation of metabolic repair during treatment. In contrast the reduced germination after CD of AH-treated high vigour seeds was indicative of deterioration as a result of treatment. Both high and low vigour seeds contained constitutive levels of ss-tubulin which increased during AH treatment, the increase being greater in high vigour seeds. High vigour seeds also showed an increase in the proportion of nuclear DNA present as 4C DNA, from 3% (untreated seeds) to 26% (28AH), indicative of germination advancement from the G(1) to G(2) phase of the cell cycle during treatment. This higher proportion of 4C DNA is correlated with the increased sensitivity of seeds to drying and/or storage after AH, leading to their reduced K(i) and storage potential. In contrast, there was little change in %4C in low vigour seeds. Priming in polyethylene glycol (PEG, -1.0 MPa) for 5 d or 13 d also improved the longevity of low vigour seeds stored at their initial and 12% mc at 10 degrees C for 8 months, as reflected in their laboratory and CD germination. In this case, however, the improved longevity of the low vigour seeds following 13 d priming was associated with an increase in 4C DNA from 4% (dry control) to 56% after treatment. The germination of both untreated and primed high vigour seeds remained high throughout the storage period. Increases in the rate of germination (decreased mean germination time) observed after all AH and PEG treatments were not consistently associated with an increase in the proportion of nuclei containing 4C DNA.     

Changes in germinability,lipid peroxidation,and antioxidant enzyme activities in pear stock (<Emphasis Type="Italic">Pyrus betulaefolia</Emphasis> Bge.) seeds during room- and low-temperature storage

The aim of this study was to determine if loss of germinability in Pyrus betulaefolia seeds stored at 4°C and at room temperature is associated with a loss of membrane lipid peroxidation or changes in antioxidant enzyme activities. The results indicated that germination percentage clearly decreased when seeds were stored at room temperature rather than at 4°C from 6 to 12 months. Room-temperature storage of the pear stock seed for 12 months decreased germination to 15.52%, but germination percentage was not changed when seed was stored at 4°C for 12 months. MDA, a marker for membrane lipid peroxidation, increased significantly under room-temperature storage conditions. Antioxidant enzyme (SOD, POD, and CAT) activities were a good indicator of germination percentage in pear stock seeds. Antioxidant enzyme activities of pear stock seeds at 4°C were higher than antioxidant enzyme activities in seeds stored at room temperature from 6 to 12 months. Antioxidant enzyme activities of the pear stock seed decreased markedly under conditions of room-temperature storage from 6 to 12 months. The results of this study showed that long-term room-temperature storage was detrimental for maintaining the vigor of P. betulaefolia seeds. The mechanisms responsible for this outcome are a higher level of membrane lipid peroxidation and a lower level of activity of antioxidant enzymes.