Seed vigor is a more promising seed quality character reflecting potential seed germination, field emergence and seed storage ability under different conditions than standard germination. Standard germination is influ...Seed vigor is a more promising seed quality character reflecting potential seed germination, field emergence and seed storage ability under different conditions than standard germination. Standard germination is influenced by genetic background and environmental effects during seed development and storage conditions. The latest research on physiological mechanism in seed vigor showed that at the late stage of seed development, the development of seed vigor involves some stress-resistant substances including late embryogenesis abundant (LEA) protein, oligosaccharides and abscisic acid (ABA). Whereas the loss of seed vigor, or seed aging and deterioration, could be attributed to lipid peroxidation, chromosome deformation and genes aberrance, and embryo protein degradation, etc. Seed vigor is a quantitative character controlled by multi-genes. Genetic and quantitative trait locus (QTL) analyses on seed-vigor trait in model plants, such as Arabidopsis and rice, are mostly concentrated on related morphology traits, whereas few physiological traits have been researched. It was concluded that, all of the QTL genetic characteristics of seed vigorincluding QTL quantities, its locus on chromosome, genetic effects, and interaction effects between genetic and environment, differed with plant species and used seed-vigor traits.展开更多
Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality.The purpose of this study was to assess the effect of mechanical threshing on the quality of maize see...Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality.The purpose of this study was to assess the effect of mechanical threshing on the quality of maize seed threshed at different moisture contents(MCs).Seeds of dent maize JK968 and flint maize DD2 were threshed at 12,15,18,21,and 24% MC.The damage degree was determined by iodine staining,and seed vigor was assessed by standard germination(SG),cold test germination(CTG),accelerated aging germination(AAG),seedling emergence rate,and seedling root and shoot length.The results showed that the damage percentage increased,and the seed vigor parameters decreased with increasing seed MC during threshing in both cultivars.For obtaining high seed quality,indicated by at least 90,85,and 80% of SG,AAG,and CTG,respectively,JK 968 and DD2 should be threshed at MC lower than 15 and 18%,respectively.Furthermore,the damage mainly occurred in the apical part of seeds,irrespective of the threshing MC in both cultivars.When the embryo was damaged,seedling emergence rates were significantly reduced with great influence on shoot length.Damage to the endosperm resulted in little effect on seedling performance.Flint maize DD2 was more tolerant to mechanical threshing than dent maize JK968.These results provided technical reference for the production and processing of high vigor maize seeds.展开更多
Oxygen sensing technology was employed to study the rapid methods for seed vigor assessment of Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana). Firstly, seeds of five lots were performed u...Oxygen sensing technology was employed to study the rapid methods for seed vigor assessment of Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana). Firstly, seeds of five lots were performed using accelerated aging (AA) into three vigor levels. Then, four oxygen sensing indices, including increased metabolism time (IMT), oxygen metabolism rate (OMR), critical oxygen pressure (COP), relative germination time (RGT) and the control indiees such as labora- tory germination indices, dehydrogenase activity (DA), and electrical conductivity (EC) were analyzed by the tests of 15 samples. The results of correlation analysis between these indices and field emergence per- formances based on two-year and two-spot data showed that RGT and OMR should be indicated as the optimal oxygen sensing indices to rap- idly and automatically evaluate seed vigor of Chinese fir and Masson pine, respectively. On the basis, one-variable linear regression equations were built to forecast their field emergence performances by the two oxygen sensing indices.展开更多
We analyzed the tolerance of Copaifera lucens seeds to sub- mersion in water to assess the use of this species for direct seeding in riparian forest restoration programs. Seeds were submerged in water for 2, 4, 8, 16 ...We analyzed the tolerance of Copaifera lucens seeds to sub- mersion in water to assess the use of this species for direct seeding in riparian forest restoration programs. Seeds were submerged in water for 2, 4, 8, 16 and 32 days or not submerged (control = 0 days of submer- gence). For the control and at the end of each period of submersion, germination and seedling vigor tests were carried out. For germination tests, seeds were sown in plastic pots containing sand and kept in labora- tory conditions. The percentage of seed germination, the germination rate and the average germination time were analyzed. For seedlings, total biomass, leaf area, leaf mass per area and leaf area ratio were analyzed. Submersion time drastically affected the dissolved oxygen content and seed germination. Between 4 and 8 days of submersion there was a de- crease from 83.8% to 15.6% in the germination percentage. No seed germination occurred after 16 days of submersion. Although there was a significant decrease in the percentage of seed germination between 4 and 8 days of submersion, seedling vigor was not affected. Seeds of this species were partially tolerant to submersion in water, suggesting that C. lucens is a promising species for direct seeding in riparian forest restora- tion projects.展开更多
By assay of accelerated aging germination, germination index, vigor index, seedling length, seedling weight, electric conductivity, dehydrogenase activity, ATP content and acid phosphoesterase activity during seed dev...By assay of accelerated aging germination, germination index, vigor index, seedling length, seedling weight, electric conductivity, dehydrogenase activity, ATP content and acid phosphoesterase activity during seed development of turf-type tall fescue, the seed vigor of tall fescue were studied. Combining with seed moisture content and yield, the optimal harvesting time of tall fescue was determined. The results indicated that the seed vigor increased continuously along with seed maturity, and the higher seed vigor was achieved at 19th day after perk anthesis and maintained continuously until 31st day after peak anthesis. At 25th day after peak anthesis, the highest yield of 3 533 kg ha-1 and the good quality of seeds of tall fescue were harvested with 32.19% moisture content. From 22nd to 31st day after peak anthesis, the seed yield of 3 300 kg ha-1 and the good quality seeds of tall fescue were harvested with 40 - 12. 43% moisture content, and the span was the optimal harvesting time.展开更多
An experiment was conducted to study the effects of different Pb concentrations on rice seed germination and seedling growth in three cultivars (Jiayu 293, Jiayu 948 and Xieyou 963). The method of qualitative traits...An experiment was conducted to study the effects of different Pb concentrations on rice seed germination and seedling growth in three cultivars (Jiayu 293, Jiayu 948 and Xieyou 963). The method of qualitative traits combining with quantitative traits by orthogonal polynomials was applied to analyze rice seed vigor by regression model. The seeds from different rice cultivars had different sensitivity to Pb poison. In the Pb concentration of 100-700 mg/L, Pb significantly decreased root length and shoot height, and the degree of the restraint would aggravate with the increasing of Pb concentration. However, Pb did not reduce root dry weight and shoot dry weight, which indicated that different physiological characteristics had different sensitive reactions to Pb. The predicting equations of regression were developed, which could be used to predict the effects of different Pb concentrations on rice seed vigor.展开更多
This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration...This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.展开更多
Improvement in seed vigor under adverse condition is an important object in maize breeding nowadays. Because the higher sowing quality of seeds is necessary for the development of the agriculture production and better...Improvement in seed vigor under adverse condition is an important object in maize breeding nowadays. Because the higher sowing quality of seeds is necessary for the development of the agriculture production and better able to resist all kinds of adversity in the seeds storage. So it is helpful for long-term preservation of germplasm resource. In our study, two connected recombinant inbred line (RIL) populations, which derived from the crosses Yu82 × Shen137 and Yu537A × Shen137 respectively, were evaluated for four related traits of seed vigor under three aging treatments. Meta-analysis was used to integrate genetic maps and detected QTL across two populations. In total, 74 QTL and 20 meta-QTL (mQTL) were detected. All QTLs with contributions (R2) over 10% were consistently detected in at least one of aging treatments and integrated in mQTL. Four key mQTLs (mQTL2-2, mQTL5-3, mQTL6 and mQTL8) with R2 of some initial QTLs > 10% included 5-9 initial QTLs associated with 2-4 traits. Therefore, the chromosome regions for four mQTLs with high QTL co-localization might be hot spots of the important QTLs for the associated traits. Twenty-two key candidate genes regulating four related traits of seed vigor mapped in 14 corresponding mQTLs. In particular, At5g67360, 45238345/At1g70730/At1g09640 and 298201206 were mapped within the important mQTL5-3, mQTL6 and mQTL8 regions, respectively. Fine mapping or construction of single chromosome segment lines for genetic regions of the three mQTLs is worth further study and could be put to use molecular marker-assisted breeding and pyramiding QTLs in maize.展开更多
As shown by the changes in physiological characteristics and seed vigor of three Medicago ruthenica samples during artificial aging process, the germination potential, germination rate, germination index, vigor index ...As shown by the changes in physiological characteristics and seed vigor of three Medicago ruthenica samples during artificial aging process, the germination potential, germination rate, germination index, vigor index and simple vigor index declined with the extension of aging time on the whole. After artificial aging for 6 min, the vigor was higher than that of the control. The conductivity, malondialdehyde content and soluble polysaccharide content of seed leachate increased with the aging time and negatively correlated ( P 〈 0.05) with the seed vigor indicators. The physiological indicators were very significantly correlated (P 〈 0.01 ) with the vigor indicators in the Medicago ruthenica sample from Dorbod Qi, UIanqab City(China).展开更多
Seed priming is a physiological seed enhancement method. Hydro- or osmotic priming can advance germination under adequate moisture conditions. During direct seeding on well-drained paddy and upland fields, rice seeds ...Seed priming is a physiological seed enhancement method. Hydro- or osmotic priming can advance germination under adequate moisture conditions. During direct seeding on well-drained paddy and upland fields, rice seeds occasionally encounter low soil moisture conditions. Under these conditions, rice seeds need to undergo rapid germination and secure emergence through improved water absorption capacity and seed bioactive. This study aims to clarify the effects of seed hydropriming on germination and seedling vigor in rice under different soil moisture conditions. The study employed three hydration conditions such as priming, soaking, and control. The seeds to be primed and soaked were submerged in tap water at 30℃ for 12 h. For priming, the seeds were subsequently dried to attain their initial seed weight, but the seeds for soaking were not dried before sowing, and the control seeds were untreated. In addition, different soil moisture conditions, such as 3%, 6%, 8%, 11%, 15%, and 20%, were set. Therefore, emergence time shortened with seed priming at 3%-11% soil moisture contents. In particular, at 8% soil moisture content, priming and soaking decreased emergence time by 26.8 h and 21.7 h, respectively compared with that of the control. At 8%-15% soil moisture contents, shoot elongation rate obtained with the priming seeds increased >1.2 times compared with that obtained with the control and soaking seeds. At >8% soil moisture content, shoot dry weight obtained with the priming seeds increased >1.3 times compared with that obtained with the soaking seeds. Furthermore, at declining soil moisture conditions, the increase in root dry weight is promoted by seed priming compared with that in the control seeds. These results suggest that increased root growth affects plant water absorption under low soil moisture conditions due to priming. This study demonstrates that seed priming facilitates rapid emergence and seedling vigor, unless extremely dry or flooded soil moisture conditions are present at seeding.展开更多
Background: Although emerging research is demonstrating the potential health impact of exergaming,investigations have primarily been conducted in laboratory settings among small samples with short-term interventions.I...Background: Although emerging research is demonstrating the potential health impact of exergaming,investigations have primarily been conducted in laboratory settings among small samples with short-term interventions.Information on the effectiveness of exergaming in underserved children's objective physical activity(PA) in population-based settings is also scarce.Moreover,most empirical studies have only included 1 type of exergame in the intervention.Therefore,this study's purpose was to investigate the long-term impact of a multigame exergaming intervention among underserved children integrated within school curricula.Specifically,this study examined the effect of exergaming on children's accelerometer-determined sedentary behavior(SB),light PA,moderate-to-vigorous PA(MVPA),and energy expenditure(EE) over 2 years as compared with regular physical education(PE) classes.Methods: A total of 261 second-and third-grade children(134 girls,127 boys; mean age 8.27 years) were recruited from 2 Texas elementary schools.Children's pre-test 3-day SB,light PA,MVPA,and EE at school were assessed in the fall of 2012.Participants were assigned to 1 of 2groups:(1) exergaming/PE group(125 min weekly of exergaming-based PA program) and (2) comparison group(125 min weekly of PE).PA(SB,light PA,and MVPA) and EE outcome variables were assessed again in 2013(post-test) and 2014(follow-up).Results: Significant time effects were observed for SB(F(1,162)=25.0,p<0.01,η~2= 0.14),light PA(F(1,162)=9.6,p<0.01,η~2= 0.06),and MVPA(F(1,162)=6.2,p=0.01,η~2= 0.04) but not for EE(F(1,162)=0.63,p>0.05,η~2= 0.004).Subsequent pairwise comparisons revealed significant increases from pre-to post-test for light PA(p<0.01),MVPA(p<0.01),and EE(p=0.02) with no changes in SB(p>0.05).Conversely,significant decreases occurred in light PA(p<0.01) from post-test to follow-up with no differences seen in MVPA(p=0.08) and EE(p=0.06) over the same time period.A significant increase was seen,however,for SB from post-test to follow-up.Conclusion: Exergaming PE can have the same positive effect on children's light PA,MVPA,and EE as regular PE.More research is necessary to discern how to promote long-term PA participation after conclusion of the intervention.展开更多
Background: Evidence suggests involvement in youth sport does not guarantee daily guidelines for moderate-to-vigorous physical activity(MVPA) are met, and participation may not mitigate the risks associated with physi...Background: Evidence suggests involvement in youth sport does not guarantee daily guidelines for moderate-to-vigorous physical activity(MVPA) are met, and participation may not mitigate the risks associated with physical inactivity. The need to promote higher habitual MVPA engagement amongst children active in the youth sport context has therefore been underlined. Framed by self-determination theory, the aim of the present study was to examine the implications of the motivational climate created in youth sport, for children's daily engagement in MVPA and associated adiposity. Specifically, we sought to test a motivational sequence in which children's perceptions of an empowering coach-created motivational climate were related to autonomous and controlled motivation, which in turn predicted sport-related enjoyment. Finally, enjoyment was assumed to predict accelerometer assessed daily MVPA and, following this, adiposity.Methods: Male and female youth sport participants aged 9–16 years(n = 112) completed multi-section questionnaires assessing their perceptions of the motivational climate created in youth sport(i.e., autonomy supportive, task involving, socially supportive), autonomous and controlled motivation, and sport-related enjoyment. Daily MVPA engagement was determined via 7 days of accelerometry. Percent body fat(BF%) was estimated using bio-electrical impedance analysis.Results: Path analysis revealed perceptions of an empowering motivational climate positively predicted players' autonomous motivation, and in turn, sport-related enjoyment. Enjoyment was also significantly negatively related to players' BF%, via a positive association with daily MVPA.Conclusion: Fostering more empowering youth sport environments may hold implications for the prevention of excess adiposity, through encouraging higher habitual MVPA engagement. Findings may inform the optimal design of youth sport settings for MVPA promotion, and contribute towards associated healthy weight maintenance amongst youth active in this context. Longitudinal and intervention studies are required to confirm these results.展开更多
Agave durangensis propagates basically by seeds. This species is economically important because it supports a mescal industry in Durango, Mexico. At present, its exploitation is overall by collecting plants from the w...Agave durangensis propagates basically by seeds. This species is economically important because it supports a mescal industry in Durango, Mexico. At present, its exploitation is overall by collecting plants from the wild populations. In order to reduce the negative impact of the collection in the natural populations of A. durangensis and to improve the mescal industry, it is necessary to establish plantations with selected seeds for a high vigor. In this paper, the variation in morphological features, physiological behavior of germination, and biochemical indicators of seed vigor among three natural populations of A. durangensis was assessed. Variation was found in the seed weight (0.68 to 1.15 mg/seed), seed dimensions (3.51 × 5.29 to 4.62 × 5.92 mm), germinability reduction at 15°°C related to 25°C (4% to 51%), germination rate at 25°C (44.0 to 48.5 seeds/day) and at 15°C (5.17 to 6.77 seeds/day), development reduction at 15°C related to 25°C (86.66% to 91.99%), levels of seed accumulated phenols (71 to 85 μg/seed), antioxidant potential (42% to 50% reduction of DPPH*), seed alcohol dehydrogenase activity (ADH) (180 to 1100 μmol NAD+/mg protein/min), highest ADH activity after imbibitions at 25°C (310.24 to 520.2 μmol NAD+/mg protein/min), and highest ADH activity after imbibitions at 15°C (170.74 to 440.71 μmol NAD+/mg protein/min). The variation in the seed vigor was revealed by a principal component analysis (PCA) based on all the parameters evaluated. PCA clearly discriminated among the three populations.展开更多
Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorte...Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorter growing season experienced by a maternal jointed goatgrass plant similarly affected seedling vigor in the progeny. Seed mass, percent germination, emergence, seedling height and biomass, including roots, were recorded or evaluated on progeny that were produced from three jointed goatgrass populations grown under a long or short growing season in a common garden experiment in eastern Oregon, an area where jointed goatgrass is known to commonly infest natural resources, including winter wheat. Seeds produced under a shorter growing season weighed less, were slower to germinate, and displayed lower percent germination compared with seeds produced under a long growing season. Seedlings from a short growing season were slower to emerge, and produced less shoot biomass compared to seedlings produced under a long growing season. Seedling roots and shoots were shorter when seeds were produced under a short growing season. A shorter growing season negatively affected jointed goatgrass seedling vigor. If resources for jointed goatgrass management are limited, strategies should focus on controlling plants that emerge in the fall, because they have the potential to produce more vigorous seedlings compared to plants that emerge in late winter or early spring.展开更多
[Objectives] The aim was to investigate the effects of corona field and dielectric separation on the seed vigor of hybrid rice.[Methods] The seeds of 6 hybrid rice varieties were processed with corona field, dielectri...[Objectives] The aim was to investigate the effects of corona field and dielectric separation on the seed vigor of hybrid rice.[Methods] The seeds of 6 hybrid rice varieties were processed with corona field, dielectric separation and corona field + dielectric separation.[Results] When the field intensity was 200 km/m and the processing time was 4 min, the seed vigor was significantly increased. The seed vigor of Y Liangyou 9918 (2014) increased the most, and the germination potential and the germination rate increased by 17 and 12 percentage points respectively compared to the control. Corona field reduced seed conductivity, and for seedlings, it decreased their MDA content, increased proline content, improved peroxidase activity, and enhanced root activity. When the rotating speed of the drum was 30 r/min, the dielectric separation voltage of 4 500 V could achieve good separation effect, and the vitality of seeds at different grades was significantly different. Under the optimized corona field combined with optimized voltage processing of dielectric separation, the seed vigor at all grades from the separation was significantly higher than that of the dielectric separation processing alone. The combined separation processing separated no seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of lower than 60%, yet it could effectively separate the seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of 65%-70%. After the combined processing, the germination rates of separated Grade I seeds of Wangliangyou 6 (2015), N Liangyouhuazhan (2015), Wangliangyou 6 (2016) increased by 20, 15, 20 percentage points from the germination rates of the control, while the germination rates of N Liangyouhuazhan (2016) and Y Liangyou 9918 (2016), which had the germination rates of higher than 80%, increased by 3 and 9 percentage points from the control, suggesting insignificant separation effect.[Conclusions] This study provided a new technical approach for the processing of hybrid rice seeds.展开更多
<b><span>Background</span></b><b><span>: </span></b><span>Bisphosphonate abuse is associated with atypical femur fractures, which despite different fixation method...<b><span>Background</span></b><b><span>: </span></b><span>Bisphosphonate abuse is associated with atypical femur fractures, which despite different fixation methods have increased non-union, delayed union, and re-operation rates. Therefore, there is a need for a surgical technique that may enhance union in such cases. Herein we are introducing a novel technique of sequential multiple vigorous reaming across the fracture site to introduce reaming debris/endosteal bone graft around the fracture site.</span><span> </span><b><span>Materials and Methods</span></b><b><span>: </span></b><span>We present a retrospective analysis of five prospectively treated patients with atypical diaphyseal femur fracture who presented to us from January 2015 to August 2019.</span><span> </span><span>All the patients were followed up at regular intervals and assessed both clinically and radiologically.</span><span> </span><b><span>Results</span></b><b><span>: </span></b><span>All 5 cases operated with our technique showed union at a mean follow-up of 16 weeks (12</span><span> </span><span>-</span><span> </span><span>20 weeks). There were no complications reported in our study at the last mean follow-up of 25 months (12</span><span> </span><span>-</span><span> </span><span>51 months).</span><span> </span><b><span>Conclusion</span></b><b><span>: </span></b><span>This technique of multiple vigorous reaming at and around the fracture site provides a new paradigm in the management of AFF. The autograft around the outer cortex promotes the formation of bridging callus and results in the early union.</span>展开更多
THE wallets of the locals are bulging, there is much laughter, people are vigorous and energetic, cultural activities have become enriched, and the lifestyle has become increasingly modernized. A walk through the sout...THE wallets of the locals are bulging, there is much laughter, people are vigorous and energetic, cultural activities have become enriched, and the lifestyle has become increasingly modernized. A walk through the southern part of Xinjiang Uygur Autonomous Region will enable visitors to spot the varied changes happening in the lives of people of all local ethnic groups.展开更多
Voices are growing louder and louder,calling for vigorously carryingout the foreign trade agency system in China’s foreign economic andtrade field.Vice Premier Li Lanqing in charge of foreign trade andeconomic cooper...Voices are growing louder and louder,calling for vigorously carryingout the foreign trade agency system in China’s foreign economic andtrade field.Vice Premier Li Lanqing in charge of foreign trade andeconomic cooperation has pointed out many times recently that theoperational mode of foreign trade should be transferred from thetraditional purchase system to service-type agency system.This isimportant to deepening the reform of the foreign trade system.展开更多
文摘Seed vigor is a more promising seed quality character reflecting potential seed germination, field emergence and seed storage ability under different conditions than standard germination. Standard germination is influenced by genetic background and environmental effects during seed development and storage conditions. The latest research on physiological mechanism in seed vigor showed that at the late stage of seed development, the development of seed vigor involves some stress-resistant substances including late embryogenesis abundant (LEA) protein, oligosaccharides and abscisic acid (ABA). Whereas the loss of seed vigor, or seed aging and deterioration, could be attributed to lipid peroxidation, chromosome deformation and genes aberrance, and embryo protein degradation, etc. Seed vigor is a quantitative character controlled by multi-genes. Genetic and quantitative trait locus (QTL) analyses on seed-vigor trait in model plants, such as Arabidopsis and rice, are mostly concentrated on related morphology traits, whereas few physiological traits have been researched. It was concluded that, all of the QTL genetic characteristics of seed vigorincluding QTL quantities, its locus on chromosome, genetic effects, and interaction effects between genetic and environment, differed with plant species and used seed-vigor traits.
基金supported by the earmarked fund for China Agriculture Research System(CARS-02-10)the Special Fund for Agro-scientific Research in the Public Interest,China(201303002)the National Natural Science Foundation of China(31771891)
文摘Mechanical threshing used when preparing maize seeds for planting subjects seed to damage and reduces seed quality.The purpose of this study was to assess the effect of mechanical threshing on the quality of maize seed threshed at different moisture contents(MCs).Seeds of dent maize JK968 and flint maize DD2 were threshed at 12,15,18,21,and 24% MC.The damage degree was determined by iodine staining,and seed vigor was assessed by standard germination(SG),cold test germination(CTG),accelerated aging germination(AAG),seedling emergence rate,and seedling root and shoot length.The results showed that the damage percentage increased,and the seed vigor parameters decreased with increasing seed MC during threshing in both cultivars.For obtaining high seed quality,indicated by at least 90,85,and 80% of SG,AAG,and CTG,respectively,JK 968 and DD2 should be threshed at MC lower than 15 and 18%,respectively.Furthermore,the damage mainly occurred in the apical part of seeds,irrespective of the threshing MC in both cultivars.When the embryo was damaged,seedling emergence rates were significantly reduced with great influence on shoot length.Damage to the endosperm resulted in little effect on seedling performance.Flint maize DD2 was more tolerant to mechanical threshing than dent maize JK968.These results provided technical reference for the production and processing of high vigor maize seeds.
基金supported by National Natural Science Foundation of China (No. 30800890)
文摘Oxygen sensing technology was employed to study the rapid methods for seed vigor assessment of Chinese fir (Cunninghamia lanceolata) and Masson pine (Pinus massoniana). Firstly, seeds of five lots were performed using accelerated aging (AA) into three vigor levels. Then, four oxygen sensing indices, including increased metabolism time (IMT), oxygen metabolism rate (OMR), critical oxygen pressure (COP), relative germination time (RGT) and the control indiees such as labora- tory germination indices, dehydrogenase activity (DA), and electrical conductivity (EC) were analyzed by the tests of 15 samples. The results of correlation analysis between these indices and field emergence per- formances based on two-year and two-spot data showed that RGT and OMR should be indicated as the optimal oxygen sensing indices to rap- idly and automatically evaluate seed vigor of Chinese fir and Masson pine, respectively. On the basis, one-variable linear regression equations were built to forecast their field emergence performances by the two oxygen sensing indices.
基金the Foundation for Research Support of the State of Bahia (FAPESB)
文摘We analyzed the tolerance of Copaifera lucens seeds to sub- mersion in water to assess the use of this species for direct seeding in riparian forest restoration programs. Seeds were submerged in water for 2, 4, 8, 16 and 32 days or not submerged (control = 0 days of submer- gence). For the control and at the end of each period of submersion, germination and seedling vigor tests were carried out. For germination tests, seeds were sown in plastic pots containing sand and kept in labora- tory conditions. The percentage of seed germination, the germination rate and the average germination time were analyzed. For seedlings, total biomass, leaf area, leaf mass per area and leaf area ratio were analyzed. Submersion time drastically affected the dissolved oxygen content and seed germination. Between 4 and 8 days of submersion there was a de- crease from 83.8% to 15.6% in the germination percentage. No seed germination occurred after 16 days of submersion. Although there was a significant decrease in the percentage of seed germination between 4 and 8 days of submersion, seedling vigor was not affected. Seeds of this species were partially tolerant to submersion in water, suggesting that C. lucens is a promising species for direct seeding in riparian forest restora- tion projects.
基金The study was supported by“948”Project of the Ministry of Agriculture of China.
文摘By assay of accelerated aging germination, germination index, vigor index, seedling length, seedling weight, electric conductivity, dehydrogenase activity, ATP content and acid phosphoesterase activity during seed development of turf-type tall fescue, the seed vigor of tall fescue were studied. Combining with seed moisture content and yield, the optimal harvesting time of tall fescue was determined. The results indicated that the seed vigor increased continuously along with seed maturity, and the higher seed vigor was achieved at 19th day after perk anthesis and maintained continuously until 31st day after peak anthesis. At 25th day after peak anthesis, the highest yield of 3 533 kg ha-1 and the good quality of seeds of tall fescue were harvested with 32.19% moisture content. From 22nd to 31st day after peak anthesis, the seed yield of 3 300 kg ha-1 and the good quality seeds of tall fescue were harvested with 40 - 12. 43% moisture content, and the span was the optimal harvesting time.
文摘An experiment was conducted to study the effects of different Pb concentrations on rice seed germination and seedling growth in three cultivars (Jiayu 293, Jiayu 948 and Xieyou 963). The method of qualitative traits combining with quantitative traits by orthogonal polynomials was applied to analyze rice seed vigor by regression model. The seeds from different rice cultivars had different sensitivity to Pb poison. In the Pb concentration of 100-700 mg/L, Pb significantly decreased root length and shoot height, and the degree of the restraint would aggravate with the increasing of Pb concentration. However, Pb did not reduce root dry weight and shoot dry weight, which indicated that different physiological characteristics had different sensitive reactions to Pb. The predicting equations of regression were developed, which could be used to predict the effects of different Pb concentrations on rice seed vigor.
基金funded by the National Natural Science Foundation of China(Grant No.31770769)the National Key Research and Development Program of China(No.2017YFC0504403)the Fundamental Research Funds for the Central Universities(No.2015ZCQ-GX-03).
文摘This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis seeds.Four thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm estimates.The Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise impact.The successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed vigor.Finally,a model for seed vigor classifi-cation of Q.variabili s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was developed.The results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection methods.The combination SG second derivative-LS-SVM provided the best classification model for Q.variabilis seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.
文摘Improvement in seed vigor under adverse condition is an important object in maize breeding nowadays. Because the higher sowing quality of seeds is necessary for the development of the agriculture production and better able to resist all kinds of adversity in the seeds storage. So it is helpful for long-term preservation of germplasm resource. In our study, two connected recombinant inbred line (RIL) populations, which derived from the crosses Yu82 × Shen137 and Yu537A × Shen137 respectively, were evaluated for four related traits of seed vigor under three aging treatments. Meta-analysis was used to integrate genetic maps and detected QTL across two populations. In total, 74 QTL and 20 meta-QTL (mQTL) were detected. All QTLs with contributions (R2) over 10% were consistently detected in at least one of aging treatments and integrated in mQTL. Four key mQTLs (mQTL2-2, mQTL5-3, mQTL6 and mQTL8) with R2 of some initial QTLs > 10% included 5-9 initial QTLs associated with 2-4 traits. Therefore, the chromosome regions for four mQTLs with high QTL co-localization might be hot spots of the important QTLs for the associated traits. Twenty-two key candidate genes regulating four related traits of seed vigor mapped in 14 corresponding mQTLs. In particular, At5g67360, 45238345/At1g70730/At1g09640 and 298201206 were mapped within the important mQTL5-3, mQTL6 and mQTL8 regions, respectively. Fine mapping or construction of single chromosome segment lines for genetic regions of the three mQTLs is worth further study and could be put to use molecular marker-assisted breeding and pyramiding QTLs in maize.
基金funded by National Key Technology R & DProgram during the 11th Five-Year Plan Period (2008BADB3B01)Crops Germplasm Resource Conservation Project of Ministry of Agriculture (NB08-2130135-43)
文摘As shown by the changes in physiological characteristics and seed vigor of three Medicago ruthenica samples during artificial aging process, the germination potential, germination rate, germination index, vigor index and simple vigor index declined with the extension of aging time on the whole. After artificial aging for 6 min, the vigor was higher than that of the control. The conductivity, malondialdehyde content and soluble polysaccharide content of seed leachate increased with the aging time and negatively correlated ( P 〈 0.05) with the seed vigor indicators. The physiological indicators were very significantly correlated (P 〈 0.01 ) with the vigor indicators in the Medicago ruthenica sample from Dorbod Qi, UIanqab City(China).
文摘Seed priming is a physiological seed enhancement method. Hydro- or osmotic priming can advance germination under adequate moisture conditions. During direct seeding on well-drained paddy and upland fields, rice seeds occasionally encounter low soil moisture conditions. Under these conditions, rice seeds need to undergo rapid germination and secure emergence through improved water absorption capacity and seed bioactive. This study aims to clarify the effects of seed hydropriming on germination and seedling vigor in rice under different soil moisture conditions. The study employed three hydration conditions such as priming, soaking, and control. The seeds to be primed and soaked were submerged in tap water at 30℃ for 12 h. For priming, the seeds were subsequently dried to attain their initial seed weight, but the seeds for soaking were not dried before sowing, and the control seeds were untreated. In addition, different soil moisture conditions, such as 3%, 6%, 8%, 11%, 15%, and 20%, were set. Therefore, emergence time shortened with seed priming at 3%-11% soil moisture contents. In particular, at 8% soil moisture content, priming and soaking decreased emergence time by 26.8 h and 21.7 h, respectively compared with that of the control. At 8%-15% soil moisture contents, shoot elongation rate obtained with the priming seeds increased >1.2 times compared with that obtained with the control and soaking seeds. At >8% soil moisture content, shoot dry weight obtained with the priming seeds increased >1.3 times compared with that obtained with the soaking seeds. Furthermore, at declining soil moisture conditions, the increase in root dry weight is promoted by seed priming compared with that in the control seeds. These results suggest that increased root growth affects plant water absorption under low soil moisture conditions due to priming. This study demonstrates that seed priming facilitates rapid emergence and seedling vigor, unless extremely dry or flooded soil moisture conditions are present at seeding.
基金funded by a grant from the National Institute of Child and Human Development(1R15HD071514-01A1)
文摘Background: Although emerging research is demonstrating the potential health impact of exergaming,investigations have primarily been conducted in laboratory settings among small samples with short-term interventions.Information on the effectiveness of exergaming in underserved children's objective physical activity(PA) in population-based settings is also scarce.Moreover,most empirical studies have only included 1 type of exergame in the intervention.Therefore,this study's purpose was to investigate the long-term impact of a multigame exergaming intervention among underserved children integrated within school curricula.Specifically,this study examined the effect of exergaming on children's accelerometer-determined sedentary behavior(SB),light PA,moderate-to-vigorous PA(MVPA),and energy expenditure(EE) over 2 years as compared with regular physical education(PE) classes.Methods: A total of 261 second-and third-grade children(134 girls,127 boys; mean age 8.27 years) were recruited from 2 Texas elementary schools.Children's pre-test 3-day SB,light PA,MVPA,and EE at school were assessed in the fall of 2012.Participants were assigned to 1 of 2groups:(1) exergaming/PE group(125 min weekly of exergaming-based PA program) and (2) comparison group(125 min weekly of PE).PA(SB,light PA,and MVPA) and EE outcome variables were assessed again in 2013(post-test) and 2014(follow-up).Results: Significant time effects were observed for SB(F(1,162)=25.0,p<0.01,η~2= 0.14),light PA(F(1,162)=9.6,p<0.01,η~2= 0.06),and MVPA(F(1,162)=6.2,p=0.01,η~2= 0.04) but not for EE(F(1,162)=0.63,p>0.05,η~2= 0.004).Subsequent pairwise comparisons revealed significant increases from pre-to post-test for light PA(p<0.01),MVPA(p<0.01),and EE(p=0.02) with no changes in SB(p>0.05).Conversely,significant decreases occurred in light PA(p<0.01) from post-test to follow-up with no differences seen in MVPA(p=0.08) and EE(p=0.06) over the same time period.A significant increase was seen,however,for SB from post-test to follow-up.Conclusion: Exergaming PE can have the same positive effect on children's light PA,MVPA,and EE as regular PE.More research is necessary to discern how to promote long-term PA participation after conclusion of the intervention.
基金supported by the European Commission under the Seventh Framework Programme-Health (No. 223600) as part of the PAPA project (www.projectpapa.org)
文摘Background: Evidence suggests involvement in youth sport does not guarantee daily guidelines for moderate-to-vigorous physical activity(MVPA) are met, and participation may not mitigate the risks associated with physical inactivity. The need to promote higher habitual MVPA engagement amongst children active in the youth sport context has therefore been underlined. Framed by self-determination theory, the aim of the present study was to examine the implications of the motivational climate created in youth sport, for children's daily engagement in MVPA and associated adiposity. Specifically, we sought to test a motivational sequence in which children's perceptions of an empowering coach-created motivational climate were related to autonomous and controlled motivation, which in turn predicted sport-related enjoyment. Finally, enjoyment was assumed to predict accelerometer assessed daily MVPA and, following this, adiposity.Methods: Male and female youth sport participants aged 9–16 years(n = 112) completed multi-section questionnaires assessing their perceptions of the motivational climate created in youth sport(i.e., autonomy supportive, task involving, socially supportive), autonomous and controlled motivation, and sport-related enjoyment. Daily MVPA engagement was determined via 7 days of accelerometry. Percent body fat(BF%) was estimated using bio-electrical impedance analysis.Results: Path analysis revealed perceptions of an empowering motivational climate positively predicted players' autonomous motivation, and in turn, sport-related enjoyment. Enjoyment was also significantly negatively related to players' BF%, via a positive association with daily MVPA.Conclusion: Fostering more empowering youth sport environments may hold implications for the prevention of excess adiposity, through encouraging higher habitual MVPA engagement. Findings may inform the optimal design of youth sport settings for MVPA promotion, and contribute towards associated healthy weight maintenance amongst youth active in this context. Longitudinal and intervention studies are required to confirm these results.
文摘Agave durangensis propagates basically by seeds. This species is economically important because it supports a mescal industry in Durango, Mexico. At present, its exploitation is overall by collecting plants from the wild populations. In order to reduce the negative impact of the collection in the natural populations of A. durangensis and to improve the mescal industry, it is necessary to establish plantations with selected seeds for a high vigor. In this paper, the variation in morphological features, physiological behavior of germination, and biochemical indicators of seed vigor among three natural populations of A. durangensis was assessed. Variation was found in the seed weight (0.68 to 1.15 mg/seed), seed dimensions (3.51 × 5.29 to 4.62 × 5.92 mm), germinability reduction at 15°°C related to 25°C (4% to 51%), germination rate at 25°C (44.0 to 48.5 seeds/day) and at 15°C (5.17 to 6.77 seeds/day), development reduction at 15°C related to 25°C (86.66% to 91.99%), levels of seed accumulated phenols (71 to 85 μg/seed), antioxidant potential (42% to 50% reduction of DPPH*), seed alcohol dehydrogenase activity (ADH) (180 to 1100 μmol NAD+/mg protein/min), highest ADH activity after imbibitions at 25°C (310.24 to 520.2 μmol NAD+/mg protein/min), and highest ADH activity after imbibitions at 15°C (170.74 to 440.71 μmol NAD+/mg protein/min). The variation in the seed vigor was revealed by a principal component analysis (PCA) based on all the parameters evaluated. PCA clearly discriminated among the three populations.
文摘Seed production and percent germination in jointed goatgrass were negatively affected by a shorter vernalization period in field studies conducted at Oregon State University. Our objective was to determine if a shorter growing season experienced by a maternal jointed goatgrass plant similarly affected seedling vigor in the progeny. Seed mass, percent germination, emergence, seedling height and biomass, including roots, were recorded or evaluated on progeny that were produced from three jointed goatgrass populations grown under a long or short growing season in a common garden experiment in eastern Oregon, an area where jointed goatgrass is known to commonly infest natural resources, including winter wheat. Seeds produced under a shorter growing season weighed less, were slower to germinate, and displayed lower percent germination compared with seeds produced under a long growing season. Seedlings from a short growing season were slower to emerge, and produced less shoot biomass compared to seedlings produced under a long growing season. Seedling roots and shoots were shorter when seeds were produced under a short growing season. A shorter growing season negatively affected jointed goatgrass seedling vigor. If resources for jointed goatgrass management are limited, strategies should focus on controlling plants that emerge in the fall, because they have the potential to produce more vigorous seedlings compared to plants that emerge in late winter or early spring.
基金Supported by the National Key Technology R&D Program of China(2014BAD06B07)the Innovation Project of Hunan Province,China(SCX1634)
文摘[Objectives] The aim was to investigate the effects of corona field and dielectric separation on the seed vigor of hybrid rice.[Methods] The seeds of 6 hybrid rice varieties were processed with corona field, dielectric separation and corona field + dielectric separation.[Results] When the field intensity was 200 km/m and the processing time was 4 min, the seed vigor was significantly increased. The seed vigor of Y Liangyou 9918 (2014) increased the most, and the germination potential and the germination rate increased by 17 and 12 percentage points respectively compared to the control. Corona field reduced seed conductivity, and for seedlings, it decreased their MDA content, increased proline content, improved peroxidase activity, and enhanced root activity. When the rotating speed of the drum was 30 r/min, the dielectric separation voltage of 4 500 V could achieve good separation effect, and the vitality of seeds at different grades was significantly different. Under the optimized corona field combined with optimized voltage processing of dielectric separation, the seed vigor at all grades from the separation was significantly higher than that of the dielectric separation processing alone. The combined separation processing separated no seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of lower than 60%, yet it could effectively separate the seeds with germination rate of higher than 80% from the hybrid rice seeds with germination rate of 65%-70%. After the combined processing, the germination rates of separated Grade I seeds of Wangliangyou 6 (2015), N Liangyouhuazhan (2015), Wangliangyou 6 (2016) increased by 20, 15, 20 percentage points from the germination rates of the control, while the germination rates of N Liangyouhuazhan (2016) and Y Liangyou 9918 (2016), which had the germination rates of higher than 80%, increased by 3 and 9 percentage points from the control, suggesting insignificant separation effect.[Conclusions] This study provided a new technical approach for the processing of hybrid rice seeds.
文摘<b><span>Background</span></b><b><span>: </span></b><span>Bisphosphonate abuse is associated with atypical femur fractures, which despite different fixation methods have increased non-union, delayed union, and re-operation rates. Therefore, there is a need for a surgical technique that may enhance union in such cases. Herein we are introducing a novel technique of sequential multiple vigorous reaming across the fracture site to introduce reaming debris/endosteal bone graft around the fracture site.</span><span> </span><b><span>Materials and Methods</span></b><b><span>: </span></b><span>We present a retrospective analysis of five prospectively treated patients with atypical diaphyseal femur fracture who presented to us from January 2015 to August 2019.</span><span> </span><span>All the patients were followed up at regular intervals and assessed both clinically and radiologically.</span><span> </span><b><span>Results</span></b><b><span>: </span></b><span>All 5 cases operated with our technique showed union at a mean follow-up of 16 weeks (12</span><span> </span><span>-</span><span> </span><span>20 weeks). There were no complications reported in our study at the last mean follow-up of 25 months (12</span><span> </span><span>-</span><span> </span><span>51 months).</span><span> </span><b><span>Conclusion</span></b><b><span>: </span></b><span>This technique of multiple vigorous reaming at and around the fracture site provides a new paradigm in the management of AFF. The autograft around the outer cortex promotes the formation of bridging callus and results in the early union.</span>
文摘THE wallets of the locals are bulging, there is much laughter, people are vigorous and energetic, cultural activities have become enriched, and the lifestyle has become increasingly modernized. A walk through the southern part of Xinjiang Uygur Autonomous Region will enable visitors to spot the varied changes happening in the lives of people of all local ethnic groups.
文摘Voices are growing louder and louder,calling for vigorously carryingout the foreign trade agency system in China’s foreign economic andtrade field.Vice Premier Li Lanqing in charge of foreign trade andeconomic cooperation has pointed out many times recently that theoperational mode of foreign trade should be transferred from thetraditional purchase system to service-type agency system.This isimportant to deepening the reform of the foreign trade system.