Althenia Filiformis Petit: Azione Della Temperatura e Dell'Acqua di Mare Sulla Germinazione

Abstract

Effects of temperature and sea water on germination behaviour of Althenia filiformis Petit seeds. - Germination capacity and energy of Althenia filiformis Petit seeds have been investigated, 90 and 180 days after ripening, to carry out a preliminary study on ecology of this species.

This species, halophite and hydrophyte, is spreaded along the coast shores of middle-west mediterranean sea and atlantic shores of Morocco, Spain, Portugal and France.

Seeds were soaked in the dark, at 10°, 20°, 30°C, in solutions at different salt concentration: sea water; sea water diluted in deionized water at ratios (v/v) 1: 2, 1: 4, 1: 8; sea water plus 26 gr/l NaCl; deionized water, as control.

The experimental results show that germination is reduced and delayed when seeds are soaked in progressively concentrated salt solutions; in sea water plus 26 gr/l NaCl seed germination is inhibited.

Seeds pretreated by soaking at 3°C for 10 days in sea water diluted (1:1) by deionized water did not show, when soaked in salt solution at weak and middle concentration, any delay in germination in comparison with unpretreated seeds. On the contrary, pretreated and unpretreated seeds sown in sea water at 30°C had shown, 180 days after ripening, a significant depression in germination values as compared with seeds sown at 20°C.     

A Nematicide Seed Treatment to Control Ditylenchus dipsaci on Seedling Alfalfa

Three nematicides were evaluated as seed treatments to control the alfalfa stem nematode (Ditylenchus dipsaci) on seedling alfalfa. Alfalfa seeds were soaked for 10 hours in a 0.5% (formulated by weight) concentration of either carbofuran, phenamiphos or oxamyl in acetone with no adverse effect on seed germination. All three treatments decreased nematode damage and increased survival of ''Ranger'' (susceptible) and ''Lahontan'' (resistant) alfalfa plants, when seeds were planted in soil infested with D. dipsaci. Mean live plant counts after 6 weeks in the untreated control, acetone alone, carbofuran, phenamiphos, and oxamyl treatments, respectively, were 4.3, 6.3, 19.0, 19.8, and 19.0 for Lahontan and 4.5, 1.5, 18.5, 19.3, and 18.0 for Ranger from 20 seeds/pot. Nematicide seed treatments resulted in significantly healthier Ranger alfalfa plants 4 months after planting. The combination of seed treatment and host resistance may provide a means of establishing alfalfa in an alfalfa monocropped system where soil populations of D. dipsaci are high.     

Reproductive and Damage Potential of Ditylenchus destructor on Peanut

The reproductive and damage potential of Ditylenchus destructor on peanut, Arachis hypogaea cv. Sellie, was determined in greenhouse tests. Final nematode population densities (Pf) in roots, hulls, and seeds increased (P = 0.01) as a function of increasing initial population (Pi). Final population densities were higher in hulls than in seeds and roots. Final densities in hulls and seeds were positively (P = 0.01) correlated. Fresh root and hull weight and number of pods and seeds per plant were not affected by D. destructor. Second generation germination and pod and seed disease severity increased (P = 0.01), whereas fresh seed weight decreased (P = 0.01) as a function of increasing Pi, and Pf in seeds and Pf in hulls. At Pi 250 and higher, 10-25% of seeds germinated into second generation seedlings before harvest. At Pi 250 and higher, fresh weight of harvested seed was suppressed 20-50%. At Pi 50 or Pf greater than 20 per seed, pod disease severity was 3-7 (on a scale of 1 to 10) and 15-80% of seeds were blemished or unsound.     

朱唇种子吸水特性及其在干旱胁迫下萌发特性

种子粘液质是植物在长期适应环境过程中形成的,该物质对于种子的扩散、定居、生存力的改善、萌发、幼苗生存乃至抵御有毒化学物质毒害等都具有重要的生态学意义。朱唇为唇形科鼠尾草属多年生草本植物,原产美洲热带地区,现已广泛栽植于世界各地。为了理解朱唇种子表面的粘液物质吸水特性和种子在干旱胁迫下的萌发特性,该研究以朱唇种子为材料,运用光学显微镜和扫描电子显微镜观察以及种子萌发试验的方法,对种子和粘液层的形态结构、粘液质对种子萌发的影响进行了研究。结果表明:朱唇种子为卵形,表面为负网状结构,千粒重为(1.611±0.0084)g,无粘液种子吸水倍数为3,粘液种子吸水倍数为25,粘液层吸水倍数为122。粘液和无粘液种子及粘液层的重量都随吸水时间的延长而增长,但脱水过程要远长于吸水过程。朱唇种子吸水2 h达到饱和,经过36 h可干燥失水恢复原重。不同浓度PEG对朱唇种子的萌发均有影响,发芽势随PEG浓度升高而显著降低。朱唇种子在5%PEG胁迫下发芽率最高达(90.00±8.66)%,20%PEG胁迫下发芽率最低为(76.67±10.41)%,低浓度PEG对朱唇种子萌发有一定促进作用。这说明朱唇种子为速萌型种子,其粘液质在种子吸水过程中起到举足轻重的作用,能保证短时间内有充足的水分供其萌发。     

Seed size and capitulum position drive germination and dormancy responses to projected warming for the threatened dune endemic Cirsium pitcheri (Asteraceae)

Among coastal plant species at risk from rapid environmental changes is the North American Great Lakes dune endemic Cirsium pitcheri. Despite being listed as federally threatened, little is known about how C. pitcheri seed attributes influence germination and dormancy‐break patterns in the context of climate change. Following a previous work where we found differences in the number and weight of C. pitcheri seeds among capitulum positions and study sites, here we examine the effects of seed attributes (capitulum position, seed weight, and site of origin) on the proportion and timing of C. pitcheri seed germination under temperature treatments that simulate projected warming in the Great Lakes (20/10, 25/10, and 30/10°C day/night). Our results demonstrate that C. pitcheri produces diverse cohorts of seeds with seed attributes that significantly influence the timing and probability of germination over a 3‐year soil seed bank. Cirsium pitcheri seed germination proportions were highest at 20°C and decreased successively at 25 and 30°C. Seeds from terminal capitula also had higher germination proportions and took longer to germinate than those from secondary capitula. Lastly, the effect of seed weight on germination probability depended on site of origin and capitulum position, with all effects varying in size and significance over time. Ultimately, our results highlight the considerable differences in germination patterns exhibited by seeds from different capitulum positions and sites of origin and provide insight into the dormancy‐break patterns that C. pitcheri might experience under predicted temperature rise in the Great Lakes region of North America.     

Contamination control of microbe Ziziphus spina [christti] seed in vitro culture

Ziziphus spina [christti] is a naturally distributed tree in subtropical, arid and semi-arid parts of Iran. It is ecologically and economically important due to its tolerance to drought and salinity. Most tree seeds are infected with parasitic and saprophytic microorganisms which decrease the seed germination and seedling establishment. The goal of this paper was to evaluate the ability of selected chemical solutions to inhibit the growth of variety of microbial contaminants in Z. spina [christti] seeds and to enhance the seed germination. Different chemical treatments were used in surface sterilization of seeds: (Treatment 1) sodium hypochlorite (NaOCl) in concentrations of 1, 2 and 4% for 20 min. (Treatment 2) hydrogen peroxide (H₂O₂) in concentration of 4, 8, 12% treated for 10 min. (Treatment 3) 1% mercuric chloride (HgCl₂) at duration 10, 15, 20, 25 min. Seeds were scarified and aseptically, planted on agar Murashige and Skoog (MS) medium. Contaminants were identified according to their morphological and cultural characteristics. Bacterial contaminants included Xanthomonas sp. While Fungal isolates were Fusarium, Penicillium, Alternaria, Rhizopus, and Aspergillus. Our experiment reveals that 4% NaOCl followed by benomyl is the best sterilization treatment for Z. spina [christti] seeds, since the highest number of germination and highest number of sterilized seeds was observed after this treatment.     

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.     

野生药食两用植物青葙种子萌发的初步研究

测定青葙种子吸水和温度、光、暗、不同浓度GA,和0．2％KNO,影响其种子发芽的结果表明：青葙种子于25℃恒温下浸种8h后吸水达到饱和,其适宜发芽温度为30-35℃,萌发受光照抑制。10、50和100mg·L^-1GA3浸种的发芽率分别为61％、66％和72％,0．2％KNO3处理的发芽率达到81％。     

PEG模拟干旱胁迫对栓皮栎种子萌发及生长生理的影响

为了阐明栓皮栎种子萌发期对水分胁迫的耐受性,以当年采集的栓皮栎种子为材料,采用培养皿滤纸萌发的方法研究了不同浓度（0%、5%、10%、20%、30%）PEG-6000溶液对其种子萌发、生长、保护酶活性和有机渗透调节物质的影响,并对种子萌发率、胚根生长速率等与PEG浓度进行了回归分析。结果表明:（1）随着干旱胁迫程度的加剧,栓皮栎种子的发芽率、发芽指数、胚根长度、胚根生长速率和活力指数均呈先升高后下降趋势,说明低浓度（5%、10%）PEG胁迫可以促进栓皮栎种子萌发及生长,而高浓度（20%、30%）则具有抑制作用。（2）建立水分胁迫条件下种子萌发率、胚根生长速率等与PEG浓度的回归方程发现,栓皮栎种子在PEG胁迫下的萌发临界值和极限值分别为32.01%和36.99%,胚根生长速率的临界值和极限值分别为30.1%和33.35%。（3）随着PEG浓度的升高,栓皮栎种子中3种保护酶（SOD、POD、CAT）活性和3种有机渗透调节物质（可溶性蛋白、脯氨酸、可溶性糖）含量呈现不同的变化,但均有不同程度升高趋势。由此可见,栓皮栎种子可通过增加保护酶活性和体内渗透调节物质来适应水分胁迫环境,使自身萌发和生长受抑制程度降到最低。     

Precocious Germination during In Vitro Growth of Soybean Seeds

Immature Glycine max (L.) Merrill seeds were grown and matured in liquid medium at 25°C under fluorescent light. In standard medium containing minerals, 146 millimolar sucrose and 62.5 millimolar glutamine (osmolality 0.24), precocious germination seldom occurred with a starting seed size of less than 300 milligrams fresh weight. Frequency of precocious germination increased with increased starting seed size. Sucrose concentration strongly affected precocious germination while glutamine concentration had no effect. Starting with 300 to 350 milligrams fresh weight seeds, treatments which reduced the sucrose concentration or lowered the osmolality of the culture medium stimulated precocious germination, and increased the fresh weight growth but not the dry weight growth of seeds. Increasing the osmolality to 0.38 with sucrose or mannitol prevented precocious germination without reducing dry weight accumulation in seeds. In medium with initially low osmolality, precocious germination was inhibited by addition of 1 to 100 micromolar abscisic acid to the medium without a reduction in seed growth. During growth and maturation of large soybean seeds in vitro, precocious germination and other abnormal tissue growth can be prevented by high sucrose or mannitol concentrations in the medium or by addition of abscisic acid.     

Polyploidy and polyembryony in Anemopaegma (Bignonieae, Bignoniaceae)

Polyploidy is a key process in plant evolution, with the asexual formation of embryos representing a way through which polyploids can escape sterility. The association between polyploidy and polyembryony is known to occur in Bignoniaceae. In this study, we investigate polyembryony in four polyploid species of Anemopaegma: A. acutifolium, A. arvense, A. glaucum and A. scabriusculum as well as in one diploid species, A. album. Polyembryony was observed only in polyploid species. We used seed dissection and germination tests to compare the number of polyembryonic seeds. We tested how the pollen source influences the number of polyembryonic seeds and the number of embryos per seed and tested the correlation between the number of viable seeds per fruit and mean number of embryos per seed. The number of polyembryonic seeds observed by seed dissection was higher than the number of polyembryonic seeds determined by the germination test, with the number of embryos produced per seed being higher than the number of seedlings. The dissection of seeds of A. glaucum indicated that a higher number of polyembryonic seeds and a higher number of embryos were present in seeds from cross-pollination than in seeds from self-pollination. On the other hand, germination tests indicated that a higher number of polyembryonic seeds were present in fruits from self-pollination than from cross-pollination. The mean number of embryos per seed was not influenced by the number of viable seeds per fruit in fruits from open pollination. These results indicate a positive relationship between polyembryony and polyploidy in Anemopaegma.     

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

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

金丝李果实、种子形态分化及外源物质对种子萌发和幼苗生长的影响

通过采集3个天然种群的金丝李(Garcinia paucinervis)果实,观察果实和种子的形态性状,分析其种群内和种群间的形态分化,观察不同种群种子萌发和幼苗生长的规律;采用四种植物生长调节剂和两种化学药剂,研究浸种对金丝李种子萌发和幼苗生长的影响。结果表明:金丝李种子长2.48~3.08 cm、宽1.49~1.67cm、百粒重392.50~438.18 g;3个种群果实和种子已产生明显的形态分化,胡润种群多数表型性状值在3个种群中最小,安宁种群的果实和种子偏圆,弄岗种群偏窄;在种群内部,果实和种子重量的分化较显著,整体形态较稳定;在萌发过程中,种子留存,不定根逐渐取代胚根成为主根;3个种群的萌发过程均缓慢,中间阶段几乎停滞,出苗极不整齐,萌发率表现为安宁种群(78.33%)弄岗种群(55%)胡润种群(48.33%),种子存在休眠;从种子萌发来看,以80 mg·L~(-1)的6-BA浸种24 h处理效果最好,萌发时滞最短、萌发率最高、平均萌发时间最短;结合幼苗生长情况来看,10~50 mg·L~(-1)的6-BA和500 mg·L~(-1)的GA_3处理均适宜,以50 mg·L~(-1)的6-BA效果最佳。低浓度的KNO_3和NH_4NO_3能提高萌发率,但未显著加快萌发进程,IAA和NAA对种子萌发和幼苗生长有抑制作用。该研究结果为金丝李的遗传多样性提供了形态学资料,为更好地保护、开发和利用这一珍贵树种提供了科学依据。     

Seed germination and seedling growth of Zostera marina L. (eelgrass) in the chesapeake bay

Seed germination and seedling growth of Zostera marina L. were monitored in the Chesapeake Bay in 1979 and 1980. Harvested seeds were placed in small acrylic tubes at several sites representing the salinity range of Z. marina distribution. Seed germination was observed first in late September and continued through May, with peaks in the fall and spring. The majority of seeds that germinated (66%) did so between December and March when water temperatures ranged from 0–10°C. There was no correlation between sites (different salinity regimes) and frequency of germination rates, indicating that salinity was not a major factor in the germination process in this study. Additional information on seed germination was available for seeds collected in 1977 and 1980 and subsequently monitored for germination at only one site. These data were similar to germination frequency recorded in 1979–1980.Seedling growth was measured from individuals collected from an existing Zostera marina bed. Seedlings were collected from November through May, at which time we could no longer distinguish seedlings from existing vegetative stock. Growth was characterized by the increased length of the primary shoot, number of leaves per shoot and numbers of shoots per plant. Seedling growth was slow during the winter months (water temperature ? 10°C) but rapidly increased in the spring (temperatures > 10°C). The size range of the harvested seedlings indicated that seed germination in the field probably occurred from October through April, corroborating evidence from the seed germination experiments.     

Effect of seaweed liquid extract on growth and yield of <Emphasis Type="Italic">Triticum aestivum</Emphasis> var. Pusa Gold

The effect of seaweed liquid extract (SLE) of Sargassum wightii on germination, growth and yield of Triticum aestivum var. Pusa Gold was studied. Application of a lower concentration (20%) of SLE enhanced the percentage of seed germination, growth and yield, as measured by kernel number and seed dry weight. All growth and yield parameters were found to be highest at the 20% concentration SLE treatment. Total (100%) seed germination was observed for the 20% concentration SLE treatment, an 11% increase over the control. The present study demonstrated that seaweed liquid extract could serve as an alternative biofertilizer as is eco-friendly, cheaper, deliver substantial economic and environmental benefits to farmers.     

北柴胡和狭叶柴胡的萌发试验研究

目的：提高北柴胡和狭叶柴胡种子的发芽率,加大黑龙江省道地药材的开发力度。方法：采用40℃温水浸种8h后,流水冲洗4h;150w微波辐射25s（北柴胡）、20s（狭叶柴胡）;柳枝浸出液为萌发剂;浓H2SO4浸种2s,同时培养未经处理的种子作为对照组。结果流水组两种柴胡的发芽率分别为82%、86%;微波组发芽率分别为77%、75%;柳浸组发芽率分别为67%、72%;浓硫酸组发芽率分别为45%和35%;对照组发芽率41%、47%。结论：大规模播种可采用40℃温水浸种8h,流水冲洗4h,150w微波辐射25s（北柴胡）、20s（狭叶柴胡）,采用柳枝浸出液为萌发剂均可提高发芽率。     

Submergence Tolerance and Germination Dynamics of Roegneria nutans Seeds in Water-Level Fluctuation Zones with Different Water Rhythms in the Three Gorges Reservoir

The Three Gorges Dam features two water-level fluctuation zones (WLFZs): the preupland drawdown zone (PU-DZ) and the preriparian drawdown zone (PR-DZ). To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ), PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness rate and >91% germination rate. The final seed germination rate and germination dynamics were consistent with those of the controls. Meanwhile, the PU-DZ seeds submerged at 5 m, 10 m, 15 m, and 20 m exhibited intactness rates of 70.5%, 79.95%, 40.75%, and 39.87%, respectively, and >75% germination. Furthermore, the PR-DZ seeds exhibited intactness rates of 22.44%, 61.13%, 81.87%, and 15.36% at 5 m, 10 m, 15 m, and 17 m, respectively, and 80% germination. The germination rates of the intact seeds submerged >10 m were >80%. Finally, the intact seeds germinated quickly in all WLFZs. The high proportion of intact seeds, rapid germination capacity, and high germination rate permit R. nutans seeds to adapt to the complicated water rhythms of the PU-DZ and PR-DZ and indicate the potential for their use in vegetation restoration and recovery. Thus, perennial seeds can be used for vegetation restoration in the WLFZs of large reservoirs and in other regions with water rhythms similar to the Three Gorges Reservoir.     

The effects of ripening and drying of carrot seed (Daucus carota) crops on germination

Carrot seeds taken from the parent plant were capable of germinating before the stage when maximum seed dry weight was reached but even after this stage, when the seed moisture content had fallen below 20%, improvement in seed germination characteristics continued. In the latter stages of seed growth losses by shedding were 12–20 kg/ha/day. For low density crops (10 plants/m²) the yield of viable seed was at a maximum in crops whose seed was harvested with a moisture content of between 20 and 40% but no consistent relationship could be established for high density crops (80 plants/m²). There were no effects of umbel order or plant density on mean germination time or spread of germination. At any early harvest, percentage germination was highest for primary-umbel-seeds and seeds from low density crops but the differences between the seed origins diminished with later harvests. Drying the seeds on the umbels improved the percentage germination, reduced the mean germination time and the spread of germination particularly at the early harvests compared with seeds removed from the umbels and germinated immediately without drying.     

Seed flotation and germination of salt marsh plants: The effects of stratification, salinity, and/or inundation regime

We examined the effects of cold stratification and salinity on seed flotation of eight salt marsh species. Four of the eight species were tested for germination success under different stratification, salinity, and flooding conditions. Species were separated into two groups, four species received wet stratification and four dry stratification and fresh seeds of all species were tested for flotation and germination. Fresh seeds of seven out of eight species had flotation times independent of salinity, six of which had average flotation times of at least 50 d. Seeds of Spartina alterniflora and Spartina patens had the shortest flotation times, averaging 24 and 26 d, respectively. Following wet stratification, the flotation time of S. alterniflora seeds in higher salinity water (15 and 36 ppt) was reduced by over 75% and germination declined by more than 90%. Wet stratification reduced the flotation time of Distichlis spicata seeds in fresh water but increased seed germination from 2 to 16% in a fluctuating inundation regime. Fresh seeds of Iva frutescens and S. alternflora were capable of germination and therefore are non-dormant during dispersal. Fresh seeds of I. frutescens had similar germination to dry stratified seeds ranging 25-30%. Salinity reduced seed germination for all species except for S. alterniflora. A fluctuating inundation regime was important for seed germination of the low marsh species and for germination following cold stratification. The conditions that resulted in seeds sinking faster were similar to the conditions that resulted in higher germination for two of four species.     

Effect of temperature and light on seed germination of Erysimum naxense and Erysimum krendlii

Seed germination of two local Greek endemics was studied (Erysimum naxense, Erysimum krendlii). Seed viability was determined by using the tetrazolium method and germination was studied in synchronized cycles of five and four alternating temperatures [10/5 (for E. naxense only) and 15/10, 20/15, 25/20, and 30/25°C for both species, in cycles of 16 h day/8 h night], and in five light regimes (red, blue, green, white, and dark). Germination of E. naxense and E. krendlii seeds was determined daily for six and five weeks, respectively, with the data analyzed as viability adjusted accumulative seed germination at the end of each week. E. naxense’s seed viability was higher (90%) than that of E. krendlii (64%); seed germination (%) of both increased at low alternating temperatures (10/5°C, 15/10°C, 20/15°C). Germination of E. naxense seeds at low temperatures was light-independent, whereas at high temperatures it was increased with red light. Germination of E. krendlii seeds was inconsistently affected by light at the temperatures studied. Percentages of seed germination of both species were higher in experimental conditions similar to the ones of their natural habitats during autumn and/or spring (facilitated with Geographic Information Systems). These conclusions provide guidelines for species-specific propagation protocols and ex situ conservation.