Comparative Germination Responses of 28 Temperate Grassland Species

1998 ◽  
Vol 46 (2) ◽  
pp. 209 ◽  
Author(s):  
J. W. Morgan
Keyword(s):  
Temperature Regime ◽  
Seed Weight ◽  
Life Form ◽  
Percentage Germination ◽  
Light Conditions ◽  
Continuous Darkness ◽  
Plant Family ◽  
Grassland Plants ◽  
Single Temperature ◽  
Germination Speed

The comparative germination biology of 28 perennial species native to the temperate grasslands of southern Victoria was tested using a single temperature regime (20/10˚C) in either constant darkness or 12 h diurnal white-light conditions. This temperature regime was chosen because it corresponds to the temperature found to produce substantial or optimal germination in other germination studies of grassland plants. Four germination attributes—time to the beginning of germination (germination lag), time taken to achieve 50% of final germination (germination speed –t50), percentage germination in diurnal light conditions and percentage germination in continuous darkness—were calculated for each species and correlated to three plant attributes: plant family, life form and seed weight. Germination lag was short for many species: 50% had a lag of less than 7 days, whilst 96% of species had begun germinating within 28 days. Germination speed was moderately fast for most species: 75% of species had a t50 of less than 28 days. Total percentage germination in diurnal light or continuous darkness was variable (0–98%), but many species (64%) germinated readily (> 50%) in at least one treatment. Twenty-four percent of species had germination substantially inhibited by darkness (i.e. Acaena echinata, Bulbine bulbosa, Eryngium ovinum, Podolepis sp. aff. jaceoides, Velleia paradoxa and Wahlenbergia luteola). No species had its germination promoted by darkness. Few correlations between plant and germination attributes were detected. Seed weight was not correlated with any of the three germination attributes, nor was life form or plant family correlated with germination speed or percentage germination in the light or dark. Germination lag, however, was significantly associated with plant family and, in a related way, with life form: species from the Liliaceae (geophytes) took longer to begin germination than species from the Asteraceae (hemicryptophytes). The ecological implications of the observed germination biology on the potential formation of persistent soil seed banks and seedling recruitment dynamics are discussed.

scholarly journals Germination and seedling structure of Ruprechtia laxiflora Meissn. (Polygonaceae)

2017 ◽  
Vol 39 (2) ◽  
pp. 243
Author(s):  
Rafael Espanhol Müller ◽  
Luiz Antonio De Souza ◽  
Lindamir Hernandez Pastorini ◽  
Mariza Barion Romagnolo
Keyword(s):  
Experimental Design ◽  
Light Condition ◽  
Cotyledonary Node ◽  
Plant Anatomy ◽  
Light Conditions ◽  
Continuous Darkness ◽  
Germination Speed ◽  
Forest Remnants ◽  
Mean Time ◽  
Germination Parameters

Germination of diaspores and the seedling structure of Ruprechtia laxiflora Meissn. (Polygonaceae) which is a secondary species frequent in forest remnants are described. Seedlings were embedded in hydroxymethacrylate and sectioned in a rotary microtome according to usual techniques in plant anatomy. For bioassays of germination, the experimental design was completely randomized in a 3x2 bifactorial arrangement, corresponding to three temperatures (20, 25 and 30°C) and two light conditions (photoperiod and continuous darkness) for the diaspores newly harvested and in a 4x2 bifactorial arrangement, corresponding to four temperatures (15, 20, 25 and 30°C) and two light conditions (photoperiod and continuous darkness) for diaspores analyzed after storage. There was no interaction between the factors light condition and temperature for germination parameters analyzed. However, the temperature affected the germination and diaspores maintained at 25°C showed a shorter mean time and higher germination speed index. Seedlings are phanerocotylar and epigeal with tetrarch root, intermediate-low type of root-stem transition and trilacunar cotyledonary node.

Germination strategies of annual forbs from south-eastern Australian semiarid grasslands

2012 ◽  
Vol 60 (4) ◽  
pp. 340 ◽  
Author(s):  
Andrew J. Scott ◽  
John W. Morgan
Keyword(s):  
Temperature Regime ◽  
Environmental Conditions ◽  
Seed Banks ◽  
Constant Darkness ◽  
Continuous Darkness ◽  
Soil Seed Banks ◽  
South Eastern ◽  
Single Temperature ◽  
Risk Spreading ◽  
Main Strategy

Germination is a key process driving the composition and dynamics of annual-forb communities and soil seed banks. We tested the germination biology of 20 annual forbs from semiarid grasslands in southern Australia, under a single temperature regime (20/10°C) in either constant darkness or 12-h diurnal light, to assess whether their laboratory germination responses are consistent with transient seed banks and rapid field emergence. Germination in the light was generally moderate to high, with most (70%) species achieving >35% final germination. Additionally, most (90%) species began germinating within 5 days, and all species achieved at least 50% of final germination within 10 days, suggesting that rapid and synchronous germination is the main strategy of annual forbs in this region. However, several species had seeds that continued to germinate for a prolonged period, and in most species, a fraction of seeds did not germinate, demonstrating risk-spreading strategies. Additionally, the germination of most (79%) species was significantly inhibited by continuous darkness. Despite the potential for the formation of large persistent seed banks through low germination in some species and dark inhibition in most, rapid germination and prevailing environmental conditions apparently prevent this in the field.

scholarly journals SUPERAÇÃO DA DORMÊNCIA EM SEMENTES DE Plathymenia reticulata Benth.

Nativa ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 317
Author(s):  
Cássio Do Prado Borges ◽  
Cheila Deisy Ferreira ◽  
Daniela Pereira Dias
Keyword(s):  
Electrical Conductivity ◽  
Germination Percentage ◽  
Lateral Side ◽  
Detergent Solution ◽  
Sodium Hypochlorite Solution ◽  
Percentage Germination ◽  
Dormancy Breaking ◽  
Germination Speed ◽  
Mean Germination Time ◽  
T1 And T2

Este trabalho objetivou avaliar a germinação e vigor de sementes de Plathymenia reticulata Benth. submetidas a diferentes tratamentos para superação de dormência. Os tratamentos testados foram: controle - sementes intactas (T0), escarificação mecânica com lixa d’água nº 60 (T1), desponte na região lateral do tegumento (T2), imersão em água fervente por 10 min (T3), em hipoclorito de sódio por 15 min (T4) e em solução com detergente por 15 min (T5). Foram determinados: peso de mil sementes, grau de umidade, porcentagem de germinação, índice de velocidade de germinação (IVG), tempo médio de germinação (TMG), curva de embebição, teste da condutividade elétrica e comprimento da radícula. A porcentagem de germinação das sementes submetidas ao T1 e T2 foi estatisticamente igual (respectivamente, 90 e 88%) e superiores aos outros tratamentos testados (12%). As sementes expostas aos T1 e T2 apesentaram porcentagem de absorção de água superiores e em menor tempo, assim como maiores IVG e menores TMG, comparadas aos demais tratamentos. O comprimento das radículas não variou entre os tratamentos testados. A condutividade elétrica da solução com as sementes do T0 foi superior aos outros tratamentos testados. Sementes de P. reticulata expostas ao T1 e T2 apresentam maior germinação e vigor.Palavras-chave: germinação, índice de velocidade de germinação, teste de condutividade elétrica, vigor, vinhático. DORMANCY BREAKING OF Plathymenia reticulata Benth. SEEDS ABSTRACT:This study aimed to evaluate the germination and vigor of Plathymenia reticulata Benth. seeds submitted to different dormancy breaking treatments. Testing treatments were: control - intact seeds (T0); mechanical scarification with sandpaper n. 60 (T1), coating cutting in the lateral side of tegument (T2), immersion in boiling water during 10 min (T3), in sodium hypochlorite solution during 15 min (T4), and in detergent solution during 15 min (T5). Moisture content, 1000-seed weight, germination percentage, germination speed index (GSI), mean germination time (MGT), imbibition curve, electrical conductivity test, and radicle length were determined. Germination percentage to T1 and T2 were statistically equal (90 and 88 %, respectively) and higher than others treatments tested (12%). Seeds exposed to T1 and T2 also presented higher and faster water absorption percentage, when compared to the others treatments, as well as higher GSI, and lower MGT. The rootlets length did not vary among treatments tested. Electrical conductivity of intact seeds was higher than others treatments. P. reticulata seeds expose to T1 e T2 had highest germination percentage and vigor.Keywords: germination, germination speed index, electrical conductivity test, vigor, vinhático.

scholarly journals SEED GERMINATION AND PLANT DEVELOPMENT IN Escobedia grandiflora (OROBANCHACEAE): EVIDENCE OF OBLIGATE HEMIPARASITISM?

2015 ◽  
Vol 20 (3) ◽  
pp. 133-140 ◽  
Author(s):  
Edison CARDONA-MEDINA ◽  
Sandra Bibiana MURIEL RUIZ
Keyword(s):  
Dry Matter ◽  
Parasitic Plants ◽  
Paspalum Notatum ◽  
Percentage Germination ◽  
Critical Stage ◽  
Stage Of Development ◽  
Medicinal Use ◽  
Germination Speed ◽  
Total Plant ◽  
Root Parasitic Plants

<p>Root parasitic plants can be facultative or obligate. Facultative parasites are able to complete their life cycle and their seeds can germinate without a host. <em>Escobedia</em> <em>grandiflora</em> is a poorly studied species in spite of its ancestral importance as dye of foods and medicinal use. The present study evaluates the states of seed, seedlings and mature plants, under presence and absence of possible hosts, for inferring the type of parasitism exhibited by <em>E. grandiflora</em>. Seeds were evaluated using two conditions each of light (12 and 0 hours) and temperature (20 ºC and 25 ºC); percentage germination, and germination speed were determined. The seeds did not require a host to germinate, as is typical of facultative parasitic plants.  Percentage of germination varied between 66 % and 85.3 % and was not affected by light or temperature although germination speed was greater at 25 ºC. Larger seeds had a higher percentage of germination and produced larger seedlings. The seedlings planted without a host did not survive, while those planted with <em>Paspalum notatum</em> had a 45 % survival rate, demonstrating that this is a critical stage of development, even with a host. <em>Escobedia grandiflora</em> plants sowed with grasses began the reproductive stage at the 28<sup>th </sup>week, and those planted with <em>Pennisetum</em> <em>purpureum</em> showed better performance, expressed in more haustoria, higher dry matter of total plant, rhizome and aerial stems. Plants sowed alone lived for more than six months, but they did not produce flowers or fruits. According to the behavior of seedlings and plants, <em>E. grandiflora</em> is an obligate parasite. </p><p><strong>Germinación de semillas y desarrollo de plantas en <em>Escobedia</em> <em>grandiflora</em> (Orobanchaceae): ¿Evidencia de hemiparasitismo obligado?</strong></p><p> </p><p>Las plantas parásitas de raíces pueden ser facultativas u obligadas, las primeras pueden completar su ciclo de vida y sus semillas pueden germinar sin un hospedero. <em>Escobedia</em> <em>grandiflora</em> es una especie poco estudiada, a pesar de su importancia ancestral como colorante de alimentos y uso medicinal. Este estudio evaluó los estados de semilla, plántula y planta adulta, en presencia y ausencia de posibles hospederos para inferir sobre su tipo de parasitismo. En las semillas se evaluaron dos condiciones de luz (12 y 0 horas) y temperatura (20 ºC y 25 ºC), el porcentaje y velocidad de germinación. Las semillas no requirieron la presencia del hospedero para germinar. El porcentaje de germinación osciló entre 66 y 85,3 %  y no fue afectado por la luz o la temperatura, aunque la velocidad de germinación fue mayor a 25 ºC. Las semillas con mayor tamaño presentaron mayor porcentaje de germinación y produjeron plántulas más grandes. Las plántulas sembradas sin hospedero no sobrevivieron, mientras que las sembradas con <em>Paspalum notatum</em>, tuvieron una sobrevivencia del 45 %, evidenciando que este estado es crítico, aún con hospedero. Las plantas de <em>Escobedia grandiflora</em> sembradas con pastos, iniciaron la etapa reproductiva en la semana 28, y aquellas sembradas con <em>Pennisetum</em> <em>purpureum</em> presentaron más haustorios, y mayor materia seca en la planta total, rizoma y tallos aéreos. Las plantas sembradas solas vivieron más de seis meses, pero ellos no desarrollaron flores y ni frutos. Según el comportamiento de las plántulas y las plantas, <em>E. grandiflora</em> es parásita obligada.</p>

Factors affecting germination of horseweed (Conyza canadensis)

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 898-902 ◽  
Author(s):  
Vijay K. Nandula ◽  
Thomas W. Eubank ◽  
Daniel H. Poston ◽  
Clifford H. Koger ◽  
Krishna N. Reddy
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Conyza Canadensis ◽  
Light Conditions ◽  
Complete Darkness ◽  
Continuous Darkness ◽  
Factors Affecting ◽  
Nacl Concentration ◽  
Alkaline Conditions ◽  
Ph Range

The influence of environmental factors on germination and emergence of horseweed was examined in growth chamber experiments. Germination was highest (61%) under 24/20 C day/night temperature under light. Horseweed seed germination was observed under both light (13 h photoperiod) and complete darkness (24 h), but germination under continuous darkness was only 0 to 15% compared with 0 to 61% under light. All other experiments were conducted under 24/20 C and 13-h light conditions. Germination was 19 to 36% over a pH range from 4 to 10, with a trend toward higher germination under neutral-to-alkaline conditions. Horseweed germination was > 20% at < 40 mM NaCl concentration and lowest (4%) at 160 mM NaCl. These data suggest that even at high soil salinity conditions, horseweed can germinate. Germination of horseweed decreased from 25% to 2% as osmotic potential increased from 0 (distilled water) to −0.8 MPa, indicating that germination can still occur under moderate water stress conditions. Horseweed seedling emergence was at its maximum on the soil surface, and no seedlings emerged from seeds placed at a depth of 0.5 cm or higher.

EFFECTS OF BRACHYPTEROLUS PULICARIUS (L.) (COLEOPTERA: NITIDULIDAE) ON FLOWERING AND SEED PRODUCTION OF COMMON TOADFLAX

1992 ◽  
Vol 124 (4) ◽  
pp. 631-636 ◽  
Author(s):  
A.S. McClay
Keyword(s):  
Seed Production ◽  
Seed Weight ◽  
Shoot Biomass ◽  
Percentage Germination ◽  
Linaria Vulgaris ◽  
Potted Plants ◽  
Delayed Onset ◽  
Adult Feeding ◽  
Viable Seeds ◽  
Total Seed

AbstractImpact of the flower- and shoot-tip-feeding beetle, Brachypterolus pulicarius (L.), on growth, flowering, and seed production of common toadflax, Linaria vulgaris (L.) Mill., was investigated using potted plants. Brachypterolus pulicarius had no effect on root or shoot biomass of attacked plants. Adult feeding by B. pulicarius delayed onset of flowering by 27 days relative to controls. Flowering of attacked plants was suppressed from mid-June until mid-July, but by mid-August flowering was similar to that of control plants. Total seed weight, individual seed weight, and percentage germination were all reduced significantly on attacked plants, resulting in a 74% reduction in number of viable seeds produced. Brachypterolus pulicarius is univoltine in Alberta, overwintering mainly as pupae.

scholarly journals Effect of gibberellic acid and temperature on germination of Vitex montevidensis Cham

CERNE ◽  
2011 ◽  
Vol 17 (2) ◽  
pp. 203-207 ◽  
Author(s):  
Marlene de Matos Malavasi ◽  
Glaucia Bravo Dias ◽  
Ubirajara Contro Malavasi
Keyword(s):  
Gibberellic Acid ◽  
Tree Species ◽  
Germination Percentage ◽  
Fruit Tree ◽  
Light Conditions ◽  
Adult Trees ◽  
Germination Speed ◽  
Dark Conditions

This work aims to evaluate treatments that may help improve speed and uniformity of germination in fruit tree species tarumã. Data were obtained from pyrenes (stones) of ripe fruits which in turn were picked from adult trees in the municipality of Vera Cruz do Oeste-PR. Treatments consisted of applying GA3 solutions at various concentrations (zero, 50 mg L-1, 100 mg L-1 or 200 mg L-1) to pyrenes via immersion for 47 hours, and thermoperiods of alternate 20ºC and 30ºC (8 hours at 20ºC in light conditions, and 16 hours at 30ºC in dark conditions) and constant 30ºC with the same photoperiod. The combination of alternate temperatures of 20ºC and 30ºC with a 200 mg L-1 GA3 solution resulted in an increase both in germination percentage, from 19.2% to 56.2%, and in the germination speed index, from 0.19 to 3.12, with resulting normal, uniform seedlings.

scholarly journals Origin and temperature on the germination of beggartick seeds

2017 ◽  
Vol 21 (7) ◽  
pp. 448-453 ◽  
Author(s):  
Renato T. de Barros ◽  
Cibele C. Martins ◽  
Givanildo Z. da Silva ◽  
Dagoberto Martins
Keyword(s):  
Seed Germination ◽  
Seed Weight ◽  
Bidens Pilosa ◽  
Invasive Behavior ◽  
Randomized Design ◽  
Germination Speed ◽  
Seed Origin ◽  
Completely Randomized Design ◽  
Entre Rios ◽  
Seeds Germination

ABSTRACT The invasive behavior of beggarticks (Bidens pilosa L.) in cropped areas is due to its ecological adaptation and aggressive regeneration, which is dependent on seed germination. The objective of this research was to verify the effects of B. pilosa seed origin and temperature on seed germination. The seeds were collected in Entre Rios do Oeste, PR, Botucatu, SP, Capão Bonito, SP, São Joaquim da Barra, SP, Sertãozinho, SP, Selvíria, MS, Barra do Garças, MT, Areia, PB and Manaus, AM. The seeds were evaluated regarding moisture content, 1000-seed weight, germination speed index and germination at 60 days (normal seedlings, dormant seeds and dead seeds) at the temperatures of 10, 15, 20, 25, 30, 35, 40, and 45 ºC. The replicates were distributed according to a completely randomized design in a 9 x 8 factorial arrangement (seed origin x temperature) with four replicates. The means were compared by the Scott-Knott test. B. pilosa seeds germination depends on seed origin. Temperatures higher than 35 ºC are lethal to the seeds. The temperature of 15 ºC allows maximum germination in the shortest time whichever the seed origin.

Bacillus cereus UW85 inoculation effects on growth, nodulation, and N accumulation in grain legumes: Controlled-environment studies

2002 ◽  
Vol 82 (2) ◽  
pp. 282-290 ◽  
Author(s):  
J. Kevin Vessey ◽  
Terry J. Buss
Keyword(s):  
Bacillus Cereus ◽  
Common Bean ◽  
Temperature Regime ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Controlled Environment ◽  
N Accumulation ◽  
Positive Effects ◽  
Whole Plant ◽  
Single Temperature

Treating seed with Bacillus cereus strain UW85 stimulates nodulation in soybean, but the underlying mechanisms of this stimulation are poorly understood. In this study we assessed the effects of inoculation on nodulation, nitrogenase activity and dry matter partitioning in soybean (cv. Maple Ridge), common bean (cv. OAC Rico) and pea (cv. Express) under controlled, gnotobiotic conditions. Plants were grown for 34 d under controlled-environment conditions without a mineral N source, at low two levels of (brady)rhizobia inoculation. Soybean and common bean were grown at a single temperature regime and pea was grown at two temperature regimes. Each trial consisted of five treatments (noninoculated control, low (brady)rhizobia inoculation, low (brady)rhizobia plus UW85 inoculation, high (brady)rhizobia inoculation, and high (brady)rhizobia plus UW85 inoculation) with six plants as replicates per treatment in a completely randomized design. Inoculation of soybean with UW85 increased growth of roots, shoots, and nodules across both levels of bradyrhizobia inoculation and increased plant N accumulation by 12%. In oculation with UW85 also increased whole-plant nodulation (nodules plant-1) by 16%, but there were no effects on specific nodulation [nodules g-1 root dry weight (DW)], individual nodule DW, nitrogenase activity (μmol H2 g-1 nodule DW h-1) or N2 fixation efficiency (g plant-N g-1 nodule DW). Inoculation of pea with UW85 at the low temperature regime increased whole-plant nodulation by 19%, but had no positive effects on any other growth parameters. Inoculation of common bean with UW85 had no positive effects on any aspects of growth, nodulation or nitrogenase activity. Our data indicate that under gnotobiotic conditions, UW85 inoculation increases nodulation in soybean indirectly by increasing root growth and not stimulating the nodulation process per se. The bacterium had little to no positive effects on pea and common bean symbioses. Key words: Bacillus cereus UW85, Glycine max, growth-promotion, nodulation, Phaseolus vulgaris, Pisum sativum

scholarly journals Improving Germination Rate of Coastal Glehnia by Cold Stratification and Pericarp Removal

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 944
Author(s):  
Moon-Sun Yeom ◽  
Thi Kim Loan Nguyen ◽  
Ju-Sung Cho ◽  
Myung-Min Oh
Keyword(s):  
Mass Production ◽  
Germination Rate ◽  
Germination Percentage ◽  
Cold Stratification ◽  
Percentage Germination ◽  
Breaking Dormancy ◽  
Glehnia Littoralis ◽  
Germination Speed ◽  
Germinating Seeds ◽  
Inhibited Water

The medicinal plant, coastal glehnia (Glehnia littoralis F. Schmidt ex Miq.), belongs to the Apiaceae, which is known to exhibit morpho-physiological seed dormancy (MPD). In this study, we aimed to determine the dormancy type of this plant, along with the conditions for breaking dormancy, and how to increase its germination rate for mass production. Initially, the seeds of coastal glehnia had undeveloped embryos, which gradually developed following cold (5 °C) stratification over eight weeks. The embryo to seed (E:S) ratio increased to 66.7%, confirming that the seeds had the MPD type. Coastal glehnia seeds with pericarp did not show inhibited water uptake, and the germination inhibitory chemicals were not detected. However, removal of the pericarp improved the final germination percentage, germination speed, and T50 of coastal glehnia seeds compared with those of seeds with pericarp at 20 °C, which showed the highest value compared with other temperature treatments. Thus, cold stratification at 5 °C for eight weeks and removing the pericarp of germinating seeds maintained at 20 °C is efficient ways to break dormancy and improve the germination rate for the mass production of coastal glehnia.

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