Asymbiotic Germination and Low-temperature in Vitro Conservation of Cymbidium Dayanum

[Objective] The aim of the research was to establish asymbiotic germination and low-temperature in vitro conservation technique system of Cymbidium dayanum by using plant tissue culture technique to realize its rapid propagation and long-term conservation in vitro. [Method] With mature seeds of C. dayanum as explants, different media were selected to establish asymbiotic germination technique system. With protocorms as materials, conservation, resumptive proliferation and plant regeneration conditions were selected to establish low-temperature in vitro conservation technique system preliminarily. [Result] Mature seeds of C. dayanum could germinate after cultured 90 days on MS media as well as ＂Hyponex 1＂ media. The germination rate reached more than 98%. Protocorms inoculated in ＂Hyponex 1＂ media could be conserved continuously at 5 ℃ in dark for more than 18 months and the survival rate could reach 90%. Conserved protocorms could realize resumptive preliferation culture both on 1/2 MS and ＂Hyponex 1＂ media. The seed- ling-strengthening and rooting media were 1/2 MS media. [Conclusion] This research provided practical basis for in vitro conservation and rapid propagation of C. dayanum germplasm resource.

Comparative Transcriptome Analysis of Seed Germination of a Cotton Variety with High Tolerance to Low Temperature

Gossypium hirsutum L.is an important cash crop native to the subtropics and is widely cultivated around the world.Low temperature is an important stress that seriously affects seed germination and emergence during planting.In this study,transcriptomic profiles of low-temperature-and normal-temperature-germinated seeds of Xinluzao 25,a variety with low-temperature tolerance and high germination rates,were analyzed and compared.The following results were obtained.(1)A total of 81.06 Gb of clean data were obtained after transcriptome sequencing and assembly,and 76,931 non-redundant Unigene sequences were obtained after data consolidation and concatenation;of these,69,883 Unigene sequences were annotated.In addition,55,463 Unigene transcript sequences(72.2%)were annotated for Gene Ontology(GO)classification,and 26,629 genes were involved in 50 metabolic pathways identified by Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis.(2)Three main pathways related to low-temperature tolerance of seed germination were identified:starch and sucrose metabolism,phenylpropanoid biosynthesis,and cysteine and methionine metabolism.Their main molecular functions involve the regulation of abscisic acid and activities of enzymes such as amylase,peroxidase,and oxidoreductase.During germination at low temperature,more genes were down-regulated than up-regulated genes at the protrusion stage(2 mm),and more genes were up-regulated than down-regulated at the germination stage(30 mm)after protrusion.(3)The enzyme activities at the two stages showed that amylase,peroxidase,catalase,and glutathione reductase had higher activities when the seeds germinated at 15℃.In this study,high expression of amylase,peroxidase,catalase,and glutathione reductase genes may be the main cause of increased tolerance to low temperature.

Effects of Different-concentration EMS on Germination of Tarary Buckwheat [Fagopyrum tataricum(L.) Gaertn] Seeds

[Objective] This study aimed to determine the optimum ethyl methane sulfonate（EMS） concentration for germination of tarary buckwheat seeds so as to lay a solid foundation for obtaining excellent traits of tarary buckwheat and breeding new varieties that meet the requirements by EMS mutation breeding. [Method] The seeds of Jinqiaomai No.4, a local tarary buckwheat variety [Fagopyrum tataricum（L.） Gaertn] in Shanxi Province, were used as the material. They were mutagenized by different concentrations（0.3%, 0.5%, 0.7%, 1.0%, 1.5%, 1.7%） of EMS for different times（4, 8, 12 h）. Then the germination rate and germination vigor were analyzed. [Result] With the increase of EMS mutagenic agent concentration, the germination vigor, relative germination vigor, germination rate and relative germination rate are all trended to be decreased. When the EMS concentrations ranged from 0.3%to 1.0%, there were no significant differences between treatment and control groups（P〉0.05）. When the EMS concentrations were 1.5% and 1.7%, significant differences were shown between treatment and control groups（P〈0.01）. The 4 and 8 h treatment of EMS all had no significant effects on germination rate and relative germination rate of Jinqiaomai No.4, but the 12 h treatment of EMS showed significant effects. Among the three treatment times, there were still no significant differences in germination vigor and relative germination vigor between treatment and control groups. [Conclusion] The optimum median lethal dose and treatment time of EMS for mutagenizing Jinqiaomai No.4 were 1.7% and 12 h, respectively.

Effects of Specific Gravity-based Seed Grading on Seed Germination, Seedling Emergence and Grain Yield of Hybrid Rice

Using the commercial seeds of two hybrid rice varieties including Lu- liangyou 996 and Liangyoupeijiu as the materials, four specific gravity-based seed grading treatments, Le., the specific gravity of 〈1.0 （T1）, 1.0-1.09 （T2）, 1.1-1.19（T3） and ≥1.2 （T4）, by selection with different saline solutions, and the control without seed grading （CK） were designed to study the effects of seed grading on seed germination, seedling emergence, seedling quality and grain yield. The results showed that the treatments of T2, T3 and T4 had higher or significantly higher seed germination rate, germination index and vigor index, seedling emergence rate and adult seedling rate than the CK, while T1 had significantly lower values of these traits than the CK. Compared with the CK, the number of spikelets per pani- cle was found to be the main reason for the yield increase of these treatments with high seed viability.

Effects of Induced Concentration and Time of EMS on Seed Germination of Common Buckwheat

[Objective] This study aimed to investigate the effects of induced concen- tration and time of EMS on seed germination of common buckwheat. [Method] The seeds of Jinqiaomai No.3, a common buckwheat cultivar, were used as the test material, and their germination was induced by different concentrations of EMS un- der different induced times. The germination rate, germination vigor, relative germi- nation rate and relative germination vigor of Jinqiaomai No.3 were measured. [Re- sult] With increased induced concentration and time of EMS, the germination rate, germination vigor, relative germination rate and relative germination vigor of Jinqiao- mai No.3 were all trended to be decreased. For Jinqiaomai No.3, the optima in- duced concentration and time of EMS was 1.0% and 4 h, respectively, and the lethal concentration was 1.7%. [Conclusion] The induced concentration and time of EMS all showed significant effects on seed germination of Jinqiaomai No.3.

Germination and early seedling growth of Pinus densata Mast.provenances

We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were col- lected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distri- bution of P. densata in China to assess variation in ger- mination traits and early seedling growth, and to examine the relationships among these traits. Results showed that seeds from all populations germinated and seedlings established successfully. There were significant differences among populations in 13 of 14 traits evaluated. Seed germination and early seedling growth were strongly related to seed size and seed weight. Bigger seeds germi- nated earlier and faster than small seeds, and seedling size was positively correlated with seed size. Some germination traits were strongly and significantly correlated with cli- matic variables associated with the provenance of the studied populations. Based on these observations, we conclude there were large, significant, and biologically important differences among P. densata populations in seed germination and seedling growth traits. The observed variability probably reflects a high degree of adaptive dif- ferentiation among populations that is likely to be relevant for future afforestation.

Combining Ability and Genetic Effects of Germination Traits of Brassica napus L.Under Waterlogging Stress Condition

Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.

Effects of sludge on germination and initial growth performance of Leucaena leucocephala seedlings in the nursery

A study was carried out to determine the influence of different types of sludges （municipal, industrial and residential） on field germination, growth and nodulation of L. leucocephala seedlings in the nursery. Before sowing of seeds, different combinations of sludges were incorporated with the nutrient deficient natural forest soils. Field germination, nodulation status and physical growth parameters of seedlings （shoot and root length, vigor index, collar diameter, leaf number, fresh and dry weight of shoot and root and total dry biomass increment） were recorded after three and six months of seed sowing. Field germination, nodulation status and growth parameters were varied significantly in the soil amended with sludges in comparison to control. The highest number of nodule was recorded from soil amended with residential sludge （ 1：1 ） and highest fresh and dry nodule weight was also found from the same combination in both three and six month old seedlings. In case of growth parameters, the highest growth was recorded from soil and residential sludge （ 1：1 ） combination compared to control. From the study, it can be recommended that soil amended with residential sludge （ 1：1 ） provide better field germination, growth and nodule formation of L. leucocephala in degraded soil.

Effect of Low Temperature on Germination Characteristics of Rice Cultivars

The effects of low temperature on germination characteristics of rice seeds were studied,using three rice varieties as materials.The results showed that the germination rate,germination energy,germination index,vigor index,shoot length and root length all reduced with the decrease of temperature.When the treatment temperature was 10 ℃,whether or not cold-resistant varieties,the values of all parameters showed an extremely significant difference from the control's.When the stress temperature was 15 ℃,compared with the normal condition,the parameter values of the non-tolerant variety( Changbai 9) had an extremely significant difference and the germination rate,germination potential,seedling length and root length of two cold-tolerance varieties( Jisheng 202 and Tongjing 9) had little difference from the control.Therefore,the above four indicators at 15 ℃ can be considered as the evaluation indices of cold tolerance at early stage.

Effects of Cashew Seeds Storage Duration on Germination and Performance of Seedlings in Tanzania

A field trial was set in 2018/2019 season to investigate the capacity of cashew seeds to germinate and its vegetative performance with respect to the storage period at Agricultural Research Institute-(TARI-Naliendele), Mtwara-Tanzania. The variable investigated was the duration of the cashew seeds storage period. Cashew seeds were harvested at polyclonal seed gardens (PSG) for three harvesting seasons 2016, 2017 and 2018 consecutively;seeds were sorted, weighed and soaked before sowing to test viability in respective to storage time. Using a randomized complete block design obeying factorial approach the experiment was laid with three replications. The observed growth parameters were height (cm), number of leaves, leaf length (cm), leaf width (cm), leaf area (sq cm), leaf area index (LAI), canopy diameter (cm) and seedlings canopy ground area (sq cm). The analysis was done by using GenStat under Duncan Multiple Range Test (DMRT) on seed germination. The findings indicated that cashew seeds harvested in 2018 were the superior in both germination and growth vigor differing significantly (p < 0.05) from other seeds harvested in the previous years. Cashew seeds harvested in 2017 were weak and those harvested in 2016 were the worse such that no seeds were able even to germinate. Thus, it is recommendable to sow cashew seeds harvested at the current season for sowing than those stored for more than a year.

Effect of Plant Derived Smoke on Germination and Post Germination Expression of Wheat (Triticum aestivum L.)

Smoke produced from burning of plant material elicits a striking increase in seed germination in various plant species. In present work, effect of plant derived smoke exposure on wheat (Triticum aestivum L.) seeds germination and post germination response has been studied in laboratory. Plant derived smoke was generated by burning of plant material (leaf, straws etc.) in a special designed furnace. Non-imbibed and imbibed seeds of wheat were exposed to plant derived smoke for 1 hr time duration. Best results were observed in non-imbibed seeds treated with plant derived smoke while imbibed seeds showed poor response to germination percentage, germination index, seedling vigor index and root shoot length. It has been proved from present study that plant derived smoke has stimulatory effect on germination & post germination response of non-imbibed seeds while it may cause inhibitory effect in imbibed seeds of wheat.

Effects of Cold Atmospheric Plasma Jet Treatment on the Seed Germination and Enhancement Growth of Watermelon

The current study was carried out to reveal the possible impacts of non-thermal plasma on water uptake by seeds, seed germination and vigor of seedlings of watermelon seeds using cold plasma jet at atmospheric pressure and room temperature. Cold atmospheric plasma jet with nitrogen gas sources was employed in this study. Five treatment doses and one control were used to conduct germination parameters. The effects of the different duration time of cold atmospheric plasma on the germination of treated watermelon seeds were studied. The cold plasma operated at 3 Kv and 14 l/min as a fixed input voltage and a fixed flow rate respectively. Cold atmospheric plasma increased the germination percentage of watermelon as well as the growth parameters (root and shoot length, dry weight), and the vigor of seedlings. The effects of cold plasma during this study depended on exposure time. The operation time of 4 min considered as an appropriate plasma dose to promote the germination parameters.

不同美味猕猴桃花粉萌发活力及形态学研究

为探究猕猴桃花粉萌发活力和花粉萌发前后的形态变化,以15份美味猕猴桃花粉为样本,采用离体培养方法测定花粉的萌发活力,利用扫描电镜观察离体培养前后5份雌株花粉和10份雄株花粉的形态变化。结果表明:15份花粉样本萌发率差异较大,5份雌株花粉均不萌发;10份雄株花粉中8号花粉样本的萌发率最高,为79.27%;9号花粉样本的萌发率最低,仅为22.85%。15份花粉样本离体培养前后扫描电镜观察发现:极面观基本相同,均为三裂圆形;赤道面观有差异,5份雌株花粉离体培养前后花粉形态不发生改变,均为近球形,而10份雄株花粉在萌发前为超长球形或长球形,萌发后均为近球形,极轴长度略有变小、赤道轴长变大、极轴长度与赤道轴长度比值变小、萌发沟宽度增宽,但萌发后的雄株花粉样本间各项形态学指标值差异较小。

中波紫外线辐照对甜玉米种子萌发的影响及转录组分析

【目的】研究中波紫外线(UV-B)辐照处理对甜玉米种子萌发及相关基因表达的影响,为解析UV-B辐照促进种子活力的分子机理奠定基础。【方法】以甜玉米自交系T28种子为材料,设置0(CK),0.5,1,2,4和8 h共6个不同时长的UV-B辐照处理,对处理和对照(CK)种子萌发相关的表型指标、生理指标进行分析,同时借助转录组测序技术筛选促进玉米种子萌发的差异表达基因。【结果】UV-B辐照处理1 h时甜玉米自交系T28种子的发芽率最高,发芽势、发芽指数和活力指数随着UV-B处理时间的延长均呈先上升后下降的趋势,且在UV-B辐照处理1 h时达到最高。UV-B辐照处理1和2 h的甜玉米种子萌发72 h后,萌发种子的CAT、POD活性和游离脯氨酸含量均高于CK。对0(CK),1和2 h辐照处理下的差异表达基因进行趋势表达分析,获得8个不同趋势的基因集profile(0-7),其中profile2中1 716个转录本表达量呈先下降后上升趋势,profile5中919个转录本表达量呈先上升后下降趋势。GO富集分析表明,在生物过程、细胞组分、分子功能类别中,profile2基因集中富集最显著的分别为蛋白磷酸化、膜整体组件、转移酶活性和转移己糖基,profile5基因集中富集为翻译、核糖体、核糖体的结构组分。KEGG富集分析发现,profile2基因集中显著富集的通路主要注释在苯丙素类生物合成、次生代谢物的生物合成、代谢途径等;profile5基因集中显著富集的通路为淀粉和蔗糖代谢、氧化磷酸化及蛋白酶体。淀粉和蔗糖代谢通路中13个基因与各样本表达量聚类分析表明,在处理1 h样本中这些基因的表达显著上调。【结论】UV-B处理可以提高甜玉米种子的活力,处理时长1 h的效果最显著,推测不同时长处理下的差异表达基因与种子活力密切相关。

苦荞种子活力测定方法与其田间成苗率的相关性

为确定与田间成苗率相关性较好的室内苦荞种子活力测定方法,以活力水平不同的4个苦荞品种:六苦1号、品苦1号、黑米15、额曲木耳薏为试验材料。采用标准发芽试验、低温发芽试验和高温发芽试验3种室内发芽方法测定种子活力,并将其结果与田间成苗率进行相关性分析。结果表明标准发芽试验中,苗鲜重和活力指数与四月份田间出苗率表现出显著相关性,低温发芽试验中苗鲜重和活力指数与七月份田间出苗率表现出显著相关性,高温发芽试验中苗鲜重活力指数与四月和七月田间出苗率均表现出显著相关性。高温发芽试验中发芽势、发芽率、苗鲜重、发芽指数、活力指数与七月份田间成苗率均表现出显著相关性,其中发芽势和发芽率与七月份田间成苗率相关系数最高(0.993、0.907)。研究结论:在使用标准发芽试验检测苦荞种子活力时,苗鲜重和活力指数与田间出苗率表现出显著相关性,可作为预测田间成苗率的有效指标,逆境试验中的高温发芽试验结果与田间出苗率表现出显著相关性,可作为预测田间成苗率的有效方法。

Study on Vigor of Kenaf Seeds Stored with Different Packaging Methods for 31 Years

This study was conducted to investigate the effects of different packaging methods on seed germination and vigor under a long-term bank storage condition, selecting suitable packaging materials and methods, and comprehensively estimate changes in seed vigor of seeds stored with different packaging materials. Hibiscus cannabinus L. seeds were stored in aluminium box, seed box, glass bottle, POlyethylene film bag, sack and kraft paper bag as packaging materials in a, long-term bank and tested for their seeds germinability, electrical conductivity and field seedling rate after 31 years. The results showed that the kenaf seeds with an initial germination rate of 88% exhibited the germination rates over 79.7% after being stored in the 6 packaging materials for 31 years, the germination rates of seeds packaged with paper bag and sack and of those sealed in film bag and aluminium box showed significantly decreased germination rates, while the seeds sealed in seed boxes and glass bottles exhibited non-significant decreases in seed germination rate, and their germination rates were still above 85%. Seed box and glass bottle were the packaging materials most suitable for long-term safe storage of kenaf seeds with a safe storage period long than 31 years.

PAW及其与LTP的联合作用对小麦种子萌发及幼苗生长的影响

以济麦22、百农307为材料,研究等离子体活化水(PAW,制备时间分别为5.0、7.5、10.0 min,分别命名为PAW-5、PAW-7.5、PAW-10)及其与低温等离子体(LTP)联合处理(LTP+W-5、LTP+W-7.5、LTP+W-10)对小麦种子萌发及幼苗生长的影响,以期为PAW、LTP在小麦种子活力提高方面的应用提供理论依据。结果表明,2个小麦品种种子均于LTP处理9 s时的发芽率及发芽指数达到最佳,因此选用LTP处理时间9 s进行PAW与LTP联合作用效果研究。PAW、PAW与LTP联合处理均能提高小麦种子的发芽率、株高、幼苗鲜质量和干质量,并显著提高种子的活力指数,总体以LTP+W-7.5处理效果最好;未经LTP处理的种子与蒸馏水之间的接触角最大,表明其润湿性能最弱,相较之下,未经LTP处理的种子与PAW之间的接触角有所下降,而经LTP处理后的种子与蒸馏水或PAW之间的接触角极显著下降;与蒸馏水处理相比,PAW及其与LTP联合处理的小麦幼苗中的活性氧氮(RONS)含量总体上显著增加,而仅LTP处理的小麦幼苗中RONS含量无显著变化。综上,PAW及其与LTP联合处理均有效地促进了小麦种子萌发及幼苗生长,其中LTP+W-7.5处理的促进效果最佳。

冷等离子体处理对番茄种子发芽特性的影响

为探明冷等离子体处理对番茄种子发芽的影响,利用冷等离子体种子处理仪,以空气为真空室环境介质,在真空室绝对压力150 Pa条件下分别以40、50、60、70、80和90 W处理功率对浙砧1号(2018)、浙杂205(2019)、浙粉716(2023)和浙粉202(2019)番茄种子进行冷等离子体处理15 s,放置7 d后进行发芽试验。结果表明,当处理功率≤40 W时,冷等离子体对不同品种番茄种子萌发影响较小;浙砧1号(2018)、浙杂205(2019)、浙粉716(2023)和浙粉202(2019)番茄种子较佳的冷等离子体处理功率50 W,处理后发芽势分别提高4.00%、6.75%、11.25%和5.00%,发芽率分别提高2.50%、3.00%、6.75%和4.75%;随着处理功率的增加,冷等离子体处理对番茄种子萌发的促进作用降低,因此处理功率不宜>80 W。

Effect of mechanical threshing on damage and vigor of maize seed threshed at different moisture contents

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.

Seed Vigor Variation of <i>Agave durangensis</i>Gentry (Agavaceae)

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.