Representing Cumulative Germination. 1. A Critical Analysis of Single-value Germination Indices

Several single-value germination indices, including Kotowski'scoefficient of velocity, Maguire's speed of germination, Czabator'sgermination value, Diavanshir and Pourbiek's germination value,Timson's cumulative germination, Lehle and Putnam's Richardsfunction index, Smith and Millett's sprouting index, and Tuckerand Wright's regression index, were evaluated to test theirability to distinguish superior from inferior germination. Allexcept Timson's cumulative germination method were essentiallyno better for ranking germination responses than data on totalgermination; Kotowski's coefficient of velocity, Smith and Millet'ssprouting index, and Lehle and Putnam's Richards function indexwere markedly inferior. Because of the ambiguity inherent inany index that combines, into a single value, data about theonset, rate and extent of germination, none of the indices couldbe recommended as a way of summarizing germination. Cumulative germination, single-value germination indices, germination index, germination     

Comparative study of pressure- and nutrient-induced germination of Bacillus subtilis spores

Germination experiments with specific germination mutants of Bacillus subtilis, including a newly isolated mutant affected in pressure-induced germination, suggest that a pressure of 100 MPa triggers the germination cascades that are induced by the nutrient germinant alanine (Ala) and by a mixture of asparagine, glucose, fructose, and potassium ions (AGFK), by activating the receptors for alanine and asparagine, GerA and GerB, respectively. As opposed to germination at 100 MPa, germination at 600 MPa apparently short-cuts at least part of the Ala- and AGFK-induced germination pathways. Inhibitors of nutrient-induced germination (HgCl(2) and Nalpha-P-tosyl-L-arginine methyl ester) also inhibit pressure-induced germination at 600 MPa, suggesting that germination at 600 MPa involves activation of a true physiological germination pathway and is therefore not merely a physico-chemical process in which water is forced into the spore protoplast.     

Ultrahigh-Temperature Activation of a Low-Temperature Bacillus subtilis Spore Germination System

Exposure of Bacillus subtilis A spores to 115 to 125 C for several seconds activated a low-temperature germination system that remained dormant after a heat treatment that activated the normal l-alanine- and glucose-stimulated germination systems. The low-temperature germination system was characterized by an optimum temperature lower than that of the l-alanine or glucose germination systems (30 C versus 45 C), germination in the absence of exogenous germination stimulants, and the capacity for heat-induced deactivation and subsequent reactivation. The rates of activation at 115 to 125 C were exponential and were not influenced by a previous heat treatment that activated the l-alanine- or glucose-stimulated germination systems. Although activation of the low-temperature germination system was accompanied by suppression of l-alanine-stimulated germination, it did not appear to be a modification of the l-alanine germination system.     

欧洲榛子贮藏及萌发生理特性研究

对欧洲榛子(Corylus avellanaL.)在沙藏、萌发、幼苗生长阶段的种仁养分和保护酶活性动态变化特点进行了研究,结果表明:种子萌发后107 d营养耗尽;沙藏过程中种仁的干重、粗脂肪含量略下降,萌发后下降迅速且与时间呈线性负相关;可溶性糖在沙藏至萌发后12 d内下降而后上升,萌发24 d后上升迅速,72 d后进入高峰期;淀粉含量在沙藏过程中下降,萌发后上升并在萌发48 d取得11.12%的峰值后下降;游离氨基酸总量在沙藏期间下降,萌发前12 d开始升高,在萌发36~48 d达155.31 mg/100 g的高峰后降低;可溶性蛋白50.87 mg/g的峰值出现在萌发前12 d;SOD在萌发前12 d至萌发后12 d、CAT由萌发起24 d内、POD在萌发36 d后分别出现活性高峰,对种仁营养按测定时间进行的聚类分析结果与依据幼苗干重划分的幼苗生长阶段相吻合。     

三种植物生长调节剂对降香黄檀种子发芽的影响

采用三种植物生长调节剂GA3、IBA和6-BA不同浓度按正交设计方法,搭配处理组合,对降香黄檀种子进行处理,通过对种子发芽率、发芽势和发芽指数指标的测定,研究不同浓度的植物生长调节剂对珍贵用材树种降香黄檀种子萌发的影响。结果表明:3种植物生长调节剂浸种对降香黄檀种子萌发以6-BA的促进效果较好,GA3次之,而IBA对降香黄檀种子的发芽促进作用不明显,以处理组合6-BA50mg/L6h为最优,显著提高种子的萌发率。     

Biochemistry of L-proline-triggered germination of Bacillus megaterium spores.

The mechanism by which L-proline triggers germination in Bacillus megaterium QM B1551 spores was investigated. First, brief exposure of spores to L-proline, followed by dilution, was sufficient to trigger germination. Once germination was triggered, the spores continued initiation of germination and did not require high concentrations of L-proline. Triggering of germination was pH and temperature dependent. Second, enzymes for L-proline catabolism were absent in spores, and several non-metabolizable analogs of L-proline were effective trigger compounds. Third, triggering of germination occurred in the presence of inhibitors of proton motive force production, oxygen uptake, and metabolism. Fourth, uptake of L-proline occurred after the triggering of germination. These results argue that neither uptake nor metabolism of L-proline was necessary to trigger germination. Instead, L-proline probably causes a biophysical alteration in the spores that triggers the biochemical changes in germination.     

混合盐碱胁迫对芹菜种子萌发的影响

NaCl、Na2SO4、NaHCO3和Na2CO3按不同比例混合,模拟盐度和pH变化规律与天然盐碱地相似的15种盐碱条件,探讨混合盐碱胁迫对芹菜(Apium graveolens)种子萌发的影响.结果表明:芹菜种子的发芽率、发芽势、发芽指数和活力指数均随盐浓度的升高,pH的增大呈下降趋势.芹菜种子的萌发主要受盐浓度的影响,不同盐浓度间的影响差异大;当盐浓度为200 mmol/L时,基本不萌发.     

Seed germinating characteristics of 54 gramineous species in the alpine meadow on the eastern Qinghai-Tibet plateau

The germination experiment was started on March 3,2004,and seeds were collected from July to October in 2003.We analyzed the percentage of germination,days to first germination,germination period and days to 50% germination.Among the 54 examined species,26 species exceeded 80% germination,11 species exceeded 60%-80% germination,8 exceeded 40%-0%,5 exceeded20%-40%,and 4 showed less than 20%.A principalcomponent analysis revealed that the species were distributed along two statistically independent axes,the first primarily represented the germination rate and the second represented the time of germination process.Based on scores of germination characteristics,duster analysis of the 54 gramineous species could be divided into 4 distinct groups:rapid,slow,intermediate germinating (germination percentage＞ 50%),and low germinating (germination percentage＜ 50%).The meaning of different groups to the vegetation regeneration was discussed.     

A rapid staining technique for the detection of the initiation of germination of bacterial spores

AIMS: We propose to apply the Wirtz-Conklin staining technique to evaluate spore germination. METHODS AND RESULTS: Spores at different stages of germination were stained with modified spore stain (Wirtz-Conklin) and evaluated for staining properties. Bacillus spores suspended in deionized water, which does not support germination, stained greenish-blue. Spores suspended in germination enhancers that did not form bacilli stained pink, indicating the initiation of germination. Spores suspended in culture media, which promotes bacterial outgrowth, formed bacilli and were also stained pink. CONCLUSIONS: Modified spore stain (Wirtz-Conklin) was found to be useful to detect the initiation of spore germination as early as 30 min following incubation in a germination environment. SIGNIFICANCE AND IMPACT OF THE STUDY: This simple staining procedure is useful in detecting the initiation of germination of bacterial spores.     

不同条件下木兰科植物种子的保质期研究

在室温下测定10种木兰科植物种子的储藏时间及在室温、4 ℃、-18 ℃三种温度下测定其中5种木兰科植物种子的储藏时间。结果表明,10种木兰科植物种子在室温条件下的发芽率、发芽势和保存时间均差异较大。5种木兰科植物种子在4 ℃贮藏条件下发芽率最高,发芽率降低最慢,保存时间最长;其次是-18 ℃储藏,室温储藏最差;随着贮藏时间的延长,种子发芽率下降,但发芽所需天数减少,出土整齐度提高,表明其种子具有休眠现象。美丽紫玉兰和深山含笑均在4 ℃下发芽势最高,在室温下次之,在-18 ℃下最差;14 d是5种木兰科植物种子出土萌发最旺盛的时间,不同的温度对种子达到此时间的影响不大,因此,4 ℃低温贮藏和保证高发芽率是提高种子发芽势的有效途径。木兰科植物种子以随采随播的发芽率最高;其萌发前所需休眠时间因种类不同而不同;在不同保存条件下,种子保存时间差别较大。     

The effect of seed dormancy on percentage and rate of germination in Polygonum persicaria, and its relevance for crop-weed interaction

Changes in germination percentage and germination rate of Polygonum persicaria resulting from loss of primary dormancy during chilling of imbibed seeds were quantified. Both percentage and rate of germination increased with increasing loss of dormancy. It was concluded that retardation of germination caused by dormancy was not due to dormancy release prior to germination, but to retardation of the germination process itself. When evaluated in relation to competition between sugar-beet and P. persicaria, the effect of dormancy on the germination percentage was more important than the effect on germination rate, but for an accurate prediction of yield loss, the latter effect cannot be neglected.     

盐胁迫对蓝蓟种子萌发及早期幼苗的影响

研究了不同浓度盐(NaCl)处理对蓝蓟种子发芽势、发芽率及幼苗生长的影响。结果表明:(1)不同盐胁迫处理对蓝蓟种子的萌发具有显著影响。随着盐处理浓度的增加,发芽率呈下降趋势,蓝蓟在无盐环境(蒸馏水)和低盐环境中(0.05 mol/L)长势最好、发芽率最高、发芽速度最快。(2)将不同盐溶液处理5 d的未萌发种子转移到蒸馏水后,蓝蓟种子的萌发能力均可恢复,原来较高盐浓度(0.3 mol/L～0.5 mol/L)下的种子在恢复后,其萌发恢复率均在75%以上,发芽率基本上随着原浓度的升高呈上升的趋势。研究表明,NaCl处理对蓟种子没有造成伤害,其抑制萌发是通过渗透效应而不是离子毒害。     

种皮和环境温度对橡胶树种子萌发的影响

在人工气候箱控制的条件下,研究了种皮和环境温度对橡胶树(Hevea brasiliensis)种子萌发的影响.结果表明,种皮对橡胶树种子的吸水和萌发具有明显的机械限制作用;去除种皮后种子萌发速率加快,萌发指数增大,但萌发率从83.8%下降到47.8%,幼苗活力指数从332.3下降到187.9.15℃以下的温度明显推迟种子萌发,且萌发率下降.去除种皮后的种仁萌发率、萌发指数和幼苗活力指数均随着温度的升高而增大;有种皮种子的萌发率、萌发指数和幼苗活力指数分别在20℃(94.7%)、30℃(1.86)和25℃(374.4)时最大,而萌发速率系数随着温度的升高先增大后减小.在橡胶树栽培和胶园建设中,可利用种皮对种仁水分散失的限制作用以及对低温的不敏感性,有效延长橡胶树种子的贮藏时间,提高萌发率和籽苗质量.     

Glucose-induced inhibition of seed germination in Lotus japonicus is alleviated by nitric oxide and spermine

Seed germination is sensitive to glucose (Glc), nitric oxide (NO) and polyamine (PA). To elucidate whether cross-talk among Glc, NO and PAs occurs in mediation of seed germination, effects of Glc, NO and spermine on seed germination of Lotus japonicus were studied. Glc retarded seed germination in a concentration-dependent manner. NO donor sodium nitroprusside (SNP) alleviated Glc-induced inhibition of seed germination, whereas the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO) diminished the SNP-dependent alleviation of seed germination. These observations indicate that Glc may inhibit seed germination by interacting with NO signaling pathways. Exogenous spermine enhanced and the inhibitor of the spermine synthase, methylglyoxal-bis-guanyl hydrazone (MGBG), inhibited seed germination, respectively. Like SNP, spermine alleviated the Glc-induced inhibition of seed germination, whereas MGBG exaggerated the Glc-induced inhibition of seed germination. These results suggest that Glc may inhibit the spermine synthesis, leading to reductions in seed germination. NO scavenger and spermine synthase inhibitor diminished the SNP-induced alleviation of Glc-induced inhibition of seed germination. These findings reveal that both NO and spermine participate in the Glc-induced inhibition of seed germination in L. japonicus.     

加快棕种子萌发和幼苗生长的研究

棕种子萌发和幼苗生长十分缓慢 ,为了探索加快种子萌发和幼苗生长的方法 ,对棕种子进行不同处理、不同时间催芽和催芽后不同处理等试验 ,结果表明 :(1)生长调节剂 3号 ABT生根粉、吲哚丁酸和 2 ,4 - D可提高种子萌发率 ,促进幼苗生长。 (2 )播种前催芽可促使种子提前萌发 ,延长幼苗生长期 ,使当年生苗更粗壮 ;贮藏 3个月后催芽可提高 10 %～ 15%的发芽率。 (3)催芽后用 50 mg/ L和 10 0 mg/ L的 3号 ABT生根粉、或者 10 0 mg/ L的萘乙酸浸泡都可以提高幼苗出土率 ,但对幼苗生长没有明显影响。     

不同前处理条件对薄荷种子萌发的影响

研究了不同质量浓度(10～250 mg·L~(-1))赤霉素(GA_3)以及清水浸种不同时间(6～36 h)、层积不同时间(5～20 d)和超声波处理不同时间(5～25 min)对薄荷(Mentha haplocalyx Briq. )种子萌发的影响. 结果表明, 用100～200 mg·L~(-1) GA_3处理6 h, 薄荷种子的发芽启动时间缩短且发芽率和发芽势均显著高于对照, 其中, 用150 mg·L~(-1)GA_3浸种,薄荷种子的发芽率最高(57.3%).用清水浸种6～36 h后,薄荷种子的发芽启动时间和发芽持续时间与对照无显著差异,但浸种12 h的薄荷种子发芽率极显著高于对照.于10 ℃层积5～15 d后,薄荷种子的发芽率和发芽势极显著高于对照,发芽启动时间也与对照差异显著,其中层积5～10 d的种子发芽率较高,达47.8%～52.4%.用功率50 W、频率40 kHz超声波处理5～20 min后,薄荷种子发芽率较对照有极显著提高,其中用超声波处理10 min的薄荷种子发芽率最高,达到68.3%.研究结果显示,使用功率50 W、频率40 kHz的超声波处理10 min是打破薄荷种子休眠的最佳方法,可显著提高薄荷种子的发芽率.     

Modelling the germination of Stellaria media using the concept of hydrothermal time

The germination characteristics of Stellaria media (common chickweed) were investigated over a range of constant temperatures and degrees of moisture stress in order to assess the suitability of hydrothermal time as a basis for modelling germination under field conditions. Maximum percentage germination occurred over a much narrower temperature range around the optimum temperature than previously seen for cultivated crop seed. The entire final percentage germination response to temperature in water was well described by two probit curves, and this model was extended to describe the data at all water potentials at a temperature close to the optimum. The implications of the reduction in germination at nonoptimal temperatures are discussed with respect to the interpretation of germination progress curves and conditional dormancy. After adjusting for maximum percentage germination, a hydrothermal time model was found to fit the data set well within the conditions normally encountered in horticultural seedbeds. This separation of the final percentage germination presents a flexible modelling approach that allows for the different levels of dormancy typically expressed within weed populations. By contrast with many previously reported species, S. media had a synchronous germination rate within the population at any given temperature/water potential combination. This synchronous germination of at least a proportion of the population over a wide range of temperature and water potentials might have ecological significance for the opportunistic germination behaviour of this weed species.     

风箱果种子催芽技术研究

以风箱果自然种群成熟的种子为研究对象,对种子的生活力和催芽方法进行了研究,结果表明：TTC染色法测得风箱果种子的生活力达到94.44%;清水浸种处理的发芽势和发芽率均较低,以浸种48 h的效果较好,发芽率为28.33%;不同化学药剂处理均能不同程度的提高发芽率,其中50 mg·L^-1 GA₃+4%KNO₃的混合药剂处理72 h的萌发效果最好,发芽率达到90%;100和200 mg·L^-1 GA₃能极显著提高发芽势（P<0.01）;低温处理28 d能显著提高发芽势和发芽率（P<0.05）。     

Characterization of the germination of Bacillus megaterium spores lacking enzymes that degrade the spore cortex

Aims:  To determine roles of cortex lytic enzymes (CLEs) in Bacillus megaterium spore germination.
Methods and Results:  Genes for B. megaterium CLEs CwlJ and SleB were inactivated and effects of loss of one or both on germination were assessed. Loss of CwlJ or SleB did not prevent completion of germination with agents that activate the spore's germinant receptors, but loss of CwlJ slowed the release of dipicolinic acid (DPA). Loss of both CLEs also did not prevent release of DPA and glutamate during germination with KBr. However, cwlJ sleB spores had decreased viability, and could not complete germination. Loss of CwlJ eliminated spore germination with Ca²⁺ chelated to DPA (Ca-DPA), but loss of CwlJ and SleB did not affect DPA release in dodecylamine germination.
Conclusions:  CwlJ and SleB play redundant roles in cortex degradation during B. megaterium spore germination, and CwlJ accelerates DPA release and is essential for Ca-DPA germination. The roles of these CLEs are similar in germination of B. megaterium and Bacillus subtilis spores.
Significance and Impact of the Study:  These results indicate that redundant roles of CwlJ and SleB in cortex degradation during germination are similar in spores of Bacillus species; consequently, inhibition of these enzymes will prevent germination of Bacillus spores.     

Quantitative analysis of spatial-temporal correlations during germination of spores of Bacillus Species

Bacteria of Bacillus species sporulate upon starvation, and the resultant dormant spores germinate when the environment appears likely to allow the resumption of vegetative growth. Normally, the rates of germination of individual spores in populations are very heterogeneous, and the current work has investigated whether spore-to-spore communication enhances the synchronicity of germination. In order to do this work, time-lapse optical images of thousands of individual spores were captured during germination, and an image analysis algorithm was developed to do the following: (i) measure the positions and germination rates of many thousands of individual spores and (ii) compute pairwise correlations of their germination. This analysis showed that an individual spore''s germination rate was dependent on its distance from other spores, especially at short distances. Thus, spores that were within a few micrometers exhibited an increased synchronicity in germination, suggesting that there is a mechanism for short-range communication between such spores during germination. However, two molecules known to be germinants that are released during germination, l-alanine and the 1:1 chelate of Ca²⁺ and dipicolinic acid, did not mediate spore-to-spore communication during germination.