Low Germination Percentage Research Articles

Mobilization of reserves and vigor of soybean seeds under desiccation with glufosinate ammonium

Abstract: The physiological quality of seeds depends on the cellular organization and their capacity to mobilize reserves. The goal of this study was to assess the germination and vigor of soybeans seeds of Benso1RR and NA 5909 RG cultivars from desiccated plants or not, by mobilizing reserves. Cultivars from desiccated plants or not, by mobilizing reserves. The plants were desiccated with glufosinate ammonium (GLA) in reproductive stage R7.1 or not (TST). The physiological seed quality was assessed by germination tests, accelerated aging and seedling length. For the mobilization of reserves were assessed within 48 hours of soaking: phytate, protein and soluble sugar contents. In 48 hours of soaking, seeds from desiccated plants in cultivar NA 5909 RG showed lower mobilization of soluble protein and soluble sugar, reflecting low vigor seedlings compared to their controls. For cultivar Benso1RR, in 48 hours of soaking, the application of GLA did not affect the mobilization of soluble protein when compared to control and did not differ as to vigor. It is concluded that the use of the desiccant has negatively influenced the mobilization of soluble protein and soluble sugar for cultivar NA 5909 RG, reflecting a low percentage of germination and low vigor.

Assessing the Potential of the Water Soluble Allelopaths of Marsilea minuta in Rice and Wheat

To investigate the allelopathic effect of Marsilea minuta against the germination and seedling growths of rice (Oryza sativa) and wheat (Triticum aestivum), germination bioassays were conducted in both Petri dish and soil cultures in laboratory conditions. Rice and wheat seeds were allowed to germinate in a 1, 2, 3, 4, and 5% (w/v) aqueous extract of whole plant and 2, 4, 6, and 8% (w/w) plant residue-incorporated soils of M. minuta. In Petri dish experiments, 5% (w/v) an aqueous extract of M. mimuta showed significantly lower germination percentages (18.8% and 56.3%), root lengths (0.9 and 4.5 cm), shoot lengths (3.3 and 12.4 cm), seedling lengths (4.1 and 25.0 cm), root dry weights (1.4 and 5.6 g), shoot dry weights (1.1 and 9.0 g), seedling biomasses (2.5 and 14.6 g), and seedling vigor indices (77.4 and 957.3) in rice and wheat, respectively. In pot experiments, the M. minuta residue infested soil, with 8% concentration, produced significantly lower germination percentages (25.3 and 37.5%), root lengths (2.7 and 6.1 cm), shoot lengths (6.2 and 16.5 cm), seedling lengths (8.9 and 22.6 cm), root dry weights (2.4 and 5.5 g), shoot dry weights (4.0 and 2.8 g), seedling biomasses (6.4 and 8.3 g), and seedling vigor indices (224.1 and 855.3) in rice and wheat, respectively. The highest phytotoxic action of 5% aqueous whole plant extract of M. minuta against test crops seem to be due to the presence of two potent phenolic compounds, namely p-coumaric acid (2.91 mg L-1) and m-coumaric acid (1.59 mg L-1) as determined by HPLC analysis.

PARENTAL LINE HAS MORE INFLUENCE ON SEED QUALITY THAN CONDITIONING PROCESS

Low germination percentage has been found in tomato F1 hybrid seed of male and female parent lines. Fermentation and drying steps were hypothesized to affect this issue. This study also investigated the effect of reciprocal parents on seed quality. The results showed that the maternal parent produced defect on seed but percentage of germination was influenced by parental lines. In the case of seed conditioning, chemical fermentation with HCl at 0.5-1% for 20-40 min and low temperature drying methods (heat pump dryer, silica gel or drying bead) were studied in comparison to conventional method (overnight juice fermentation and sun drying). The seed quality as determined by percentage of germination (% G), vigour – indicated by mean germination time (MGT), germination index (GI) and germination after accelerated aging (% AA) revealed that all fermentation methods had no effect on the seed appearance and % G (88-91%). HCl fermented seed at 1% for 30 min showed the lowest MGT (7.73) and the highest %AA (88.84%). All drying methods had no effect on F1 hybrid seed quality.

Lead tolerance and accumulation in initial sporophytes of Regnellidium diphyllum Lindm. (Marsileaceae).

Regnellidium diphyllum Lindm. is a heterosporous fern which grows in shallow waters and wetlands, and water pollution contributes to its vulnerability. Environmental lead contamination is mostly caused by industrial and agricultural residues as well as domestic sewage. Given its persistence in the environment, lead can cause important toxicity in living organisms. Megaspore germination and the initial growth of R. diphyllum sporophytes were assessed in Meyer's solution with lead nitrate (Pb(NO3)2) concentrations of 0 (control), 1, 5, 10 and 50 mg L(-1). The study was conducted in a growth chamber at 25 ± 1°C and a 12 hour photoperiod with a nominal irradiance of 100 μmol m(-2) s(-1), for 28 days. Lead concentration in sporophytes was assessed using atomic absorption spectrometry. In the absence of lead, 74% of spores germinated, while significantly lower germination percentages were observed in Pb(NO3)2 concentrations of 1, 10 and 50 mg L(-1). The presence of lead did not significantly influence root growth. At 28 days, primary leaf development was significantly lower in Pb(NO3)2 concentrations of 5 mg L(-1) and higher in relation to the control. The length of secondary leaves did not significantly differ between sporophytes exposed to different concentrations of lead and those of the control at 28 days. Sporophytes exposed to 10 and 50 mg L(-1) Pb(NO3)2 accumulated 1129 mg kg(-1) and 5145 mg kg(-1) of Pb, respectively. The presence of high levels of lead in R. diphyllum sporophytes did not prevent initial development. Future studies should investigate the ability of the species to accumulate and tolerate high levels of lead in advanced stages of its development and in environmental conditions.

Tempo e Condição de Armazenamento das Sementes na Germinação e Desenvolvimento de Passiflora ligularis Juss

Passiflora ligularis Juss. é considerada apropriada ao consumo, tendo em vista, por exemplo, seus usos in natura, para sucos e sorvetes, mas não se conhecem pesquisas que obtiveram sucessos sobre o seu desenvolvimento e adaptação em território brasileiro. O custo alto da granadilla para o consumidor, aliado à dificuldade de ser adquirida, inclusive nos supermercados, justificam estudos com o objetivo de verificar a adaptabilidade desta espécie em algumas regiões do Brasil, com potencial produtivo. No presente ensaio, como contribuição às pesquisas sobre o comportamento da granadilla no Brasil, objetivou-se obter informações sobre o efeito do tempo e da condição de armazenamento na germinação das sementes e no desenvolvimento inicial das mudas. As sementes de granadilla foram obtidas de frutos provenientes da Colômbia. O ensaio constou da avaliação da qualidade das sementes com três diferentes períodos de armazenamento, obtendo-se o índice de velocidade de emergência (IVE); porcentagem de germinação e desenvolvimento das mudas. Os tratamentos foram: tratamento A – sementes armazenadas há 24 meses; tratamento B – sementes armazenadas há 3 meses; e tratamento C – sementes sem armazenamento. Utilizou-se o delineamento inteiramente casualizado com quatro repetições de 50 sementes, aplicando-se o teste Tukey a 1% de probabilidade. A obtenção de mudas deve ser feita a partir de sementes mantidas em câmara fria, por período superior a 101 dias. Sementes recém-retiradas de frutos possuem baixa porcentagem de germinação e menor crescimento em altura quando comparadas com plantas provenientes das sementes armazenadas por 24 meses. Storage Time and Conditions of Seeds in Germination and Development of Passiflora ligularis Juss ABSTRACT: Passiflora ligularis Juss. is highly consumed by people, especially in natura, as juice and ice-cream. However, no successful research is extant on its development and adaptation in Brazil. The high costs of granadilla and the difficulty to buy it, even in supermarkets, justify analysis to verify the adaptability of the species, with production potential, at least in some regions of the country. Current assay is a contribution for research on the behavior of granadilla in Brazil so that information on the effect of time and storage conditions may be obtained for seed germination and the early development stages of the seedlings. Granadilla seeds came from Colombian fruit and the assay focused on the evaluation of seed quality with three different storage periods, with emergence velocity index (EVI) and percentage of seedlings´ germination and development. Treatments comprised Treatment A – seeds stored for 24 months; Treatment B – seeds stored for 3 months; Treatment C – seeds without storage. Randomized design with four replications of 50 seeds was employed and comparisons made by Tukey´s test at 1% probability. Seedlings should be obtained from seeds kept in cold chambers for a period of more than 101 days. Seeds which had been only recently removed from the fruit have low germination percentage and small height growth when compared with plants from seeds stored for 24 months. KEYWORDS: Fruit Culture; Granadilla; Passifloraceae.

Complex dormancy in the seeds of Hypericum philonotis

Species of the genus Hypericum have elicited great interest in pharmacological research, therefore, their propagation is necessary. However, only a low germination percentage has been achieved to date. A population of Hypericum philonotis (Cham. & Schlecht.) grows every 2 or 5 years in the Parque Ecológico de la Ciudad de México (PECM). To understand seed germination and the population dynamics of H. philonotis in the PECM, we studied their seed germination to identify the dormancy type. We assessed the effect on germination of light, constant temperatures (5–35°C) and fluctuating (25/35°C, 18/6h, with the highest temperature at noon, photoperiod 12/12), cold stratification, scarification (with HCl); gibberellins and seed immersion in acetone or hexane. We also studied the morphology and structure of the seeds, and the allelopathic potential of the pigments present in the seed coat on its own seed germination and early seedling growth. Light, gibberellins, a combination of temperature with gibberellins, and immersion in acetone increased seed germination. Alternating temperatures replaced the effect of gibberellins. Immersion in acetone eliminated a pigment from the seed coat, enhancing full seed germination. The acetone extract from H. philonotis seeds partially inhibited seed germination and early growth. The endosperm was reduced, and the main reserve in cotyledons was proteins. The H. philonotis seeds exhibited physiological dormancy. Gibberellins increased the embryo growth potential, reducing the constraint of the thick seed cover and any inhibiting effect of the acetone extract. The requirement of light and temperature fluctuation acts as an environmental cue for the successful germination of these minuscule seeds (0.5–0.8mm in length).

A New Approach to Determine Time and Temperature Combination for Electrical Conductivity Test in Sorghum

This study was conducted to determine a suitable time and temperature combination for the electrical conductivity test to be used in sorghum seeds. Fifty seeds known initial seed moisture content and weight of fresh and dead seeds (105°C for 6h) of seven sorghum cultivars were used as material. The electrical conductivities of soaking water were measured using an EC meter in 20, 25 and 30°C for 4, 8, 12 and 24 h using 50 mL deionized water. The experimental design was three factor factorial (7 × 3 × 4) arranged in a completely randomized design; with four replications and 50 seeds per replicate. The results showed that increased time and temperature caused a remarkable increase in EC values of all of the cultivars. Temperature significantly affected the electrical conductivity values and the best results were obtained at 25°C. The cultivars with the lower germination percentage gave the higher electrical conductivity value. Dead seeds always gave higher electrical conductivity at 25°C for all periods. It was concluded that the temperature of 25°C and 24 h was the optimum combination for the electrical conductivity test in sorghum.

Seed germination of pot marigold (Calendula officinalis L.) as affected by physical priming techniques

Seed priming has been reported to enhance growth of plants. To evaluate the effect of some physical seed priming materials (ultrasonic, gamma, beta and laser irradiation, magnetic field and hydro-priming) on seed germination and growth of sunflower a laboratory experiment was conducted at Islamic Azad University of Tabriz branch, using completely randomized design, with three replicates. The results revealed that the highest germination rate (8.03) was due to seed treatment by laser irradiation 10 min. Lowest germination rate belonged to beta irradiation treaments (1.76 day). Mean comparisons for germination percentage also revealed that seeds treated with magnetic field for 5 min. resulted in higher germination percentage of (86.33). Lowest germination percentages (11.67%) were observed for exposure of seeds to beta irradiation. Higest seedling vigor index was obtained when seeds primed with magnetic field for 5 min. and lowest from beta irradiation seed treatment. It may be concluded that Pot Marigold producers could improve seed germination percent by priming the seed with magnetic field and laser and gamma.

Effect of Seed Treatment on Seedling Health of Chili

Effect of seed treatment on seedling health of chili (BARI Morich 1) was studied at Bangladesh Agricultural University (BAU), Mymensingh, Bangladesh. BAU Bio-fungicide (3% of seed weight), chitosan (1% solution), thiovit (0.3% of seed weight), compressed moist heat (54ºC for 15 minutes), neem leaf extract (1:1 w/v), garlic clove extract (1:3 w/v), ginger extract (1:2 w/v) and allamonda leaf extract (1:1 w/v) were employed as seed treating agents. The treated seeds were placed on moistened blotter paper. Data were recorded on percent germination, production of percent healthy seedling and seedling vigour of chili. The results of seed health testing showed that, five different seed borne fungi viz. Colletotrichum capsici, Curvularia lunata, Rhizopus stolonifer, Aspergillus flavus and Fusarium moniliforme were found to be associated with the tested chili seed samples. Among these fungi, Curvularia lunata was the most prevalent one which was followed by Rhizopus stolonifer, Colletotrichum capsici, Fusarium moniliforme and Aspergillus flavus. All the seed treating agents were found to be effective compared to control in controlling seed borne fungi for the blotter method. The highest percentage of germination (93.33%) was recorded when the seeds of BARI Morich 1 were treated with BAU Bio-fungicide, whereas the lowest percentage of germination (61.33%) was recorded in case of untreated seeds. The highest percentage of healthy seedling (95.33%) was recorded when the seeds were treated with BAU Bio-fungicide and allamonda leaf extracts, whereas the lowest percentage of healthy seedling (59.00%) was recorded in case of untreated seeds. The highest vigour index (681.59) was recorded when the seeds were treated with neem leaf extracts, whereas the lowest vigour index (214.66) was recorded in case of untreated seeds.DOI: http://dx.doi.org/10.3329/jesnr.v7i1.22167 J. Environ. Sci. & Natural Resources, 7(1): 177-181 2014

Seed Germination and Seedling Survival Percentage of Shorea robusta Gaertn.f. in Buffer Areas of Similipal Biosphere Reserve, Odisha, India

Seed germination and seedling survival percentage of Shorea robusta was studied in Similipal Biosphere Reserve (SBR) from 2010 to 2011. During the investigation period it was found that larger seeds (12 to 14 mm diameter) exhibited higher germination percentage (70 ± 6.5%) and all the seedlings survived. On the other hand, smaller seeds showed a very low percentage of germination (25 ± 4.24%) and none of the seedlings survived. It was also noticed from the study that the growth phase of the parent tree has a prominent effect on the germination potential of seeds. Juvenile trees with Girth at Breast Height (GBH) 75 to 80 cm as well as over mature (GBH: 91 to105 cm) or senile trees (GBH: 106 to 150 cm) produce seeds with a lesser germination capacity. However, young trees (GBH: 81 to 90 cm) produce seeds with a higher germination potential. Not only these aspects but also the orientation of seeds showed a peculiar phenomenon during natural germination. Maximum percentage (85 ± 12.75%) of seed germination was marked in case of seeds fallen on the forest floor in inverted position in comparison to other seed orientation types i.e. upright and horizontal. The uprightly falling seeds on the forest floor exhibited the minimum percentage (32 ± 6.84%) of germination, while horizontally falling seeds showed an intermediate range of germination percentage. Percentage survival of seedlings also followed the same pattern.

Evaluation of the viability and germination of tempisque [Sideroxylon capiri (A.DC.) Pittier Sapotaceae

The tempisque (Sideroxylon capiri) is a tree native to Mexico used by the rural population for housing construction, poles and hedges, as fuel (wood) and also for fodder and ornamental purposes, among others. It is considered an endangered species. In order to contribute to its preservation and sustainable management, it was considered important to determine the proportion of viable seeds, the loss of viability due to storage period and the germination process by applying pregerminative treatments. We found that freshly collected seeds showed 100% viability, which decreased to 0% after 5 months of storage. According to the cumulative germination significant differences between treatments (p≤0.01) were found. It was observed that seeds can accelerate their time of germination with the previous exposure of 24 h in water at room temperature. The soaking treatment in water for 24 h at room temperature obtained final germination of 55%, while with the control 39% was reached. Soaking in hydrogen peroxide and scarification were the treatments with lower germination percentage (33 and 23%, respectively). To get a higher percentage of germinated seeds in a short time, it is necessary to give a soaking treatment in water for 24 h before sowing.

两种集合繁殖体形态及间歇性萌发特性——以蒺藜和欧夏至草为例

PDF HTML阅读 XML下载 导出引用 引用提醒 两种集合繁殖体形态及间歇性萌发特性——以蒺藜和欧夏至草为例 DOI: 10.5846/stxb201405090928 作者: 作者单位: 新疆农业大学,新疆农业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31360100,40761002) Morphology and intermittent germination characteristics of two types of synaptospermy: a case study of Tribulus terrester and Marrubium vulgare Author: Affiliation: Xinjiang Agricultural University,Xinjiang Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:集合繁殖体(synaptospermy)是荒漠植物为适应恶劣环境条件而演化出的关键性特征,其作为植物生活史特性之一,有助于了解在荒漠环境下集合繁殖体植物的适应策略。蒺藜(Tribulus terrestris)和欧夏至草(Marrubium vulgare)分别为一年生及多年生草本植物,蒺藜扩散单位由一朵花发育而成的集合繁殖体组成,欧夏至草扩散单位由多朵花发育的集合繁殖体和种子组成,以这两种植物为材料,对其集合繁殖体形态、活力、吸水及萌发特性进行初步研究。结果显示:(1)蒺藜集合繁殖体依照发育成熟先后位置在质量、附属物刺的长度、附属物占质量百分比、种子数、活力、吸水量、萌发率及萌发速率均存在显著差异;欧夏至草集合繁殖体质量及吸水量明显大于种子,而活力、萌发率及萌发速率不存在显著差异。(2)萌发位置上,蒺藜集合繁殖体仅在长刺端位置的种子萌发,属非随机萌发,而欧夏至草集合繁殖体萌发不具有规律性,属随机萌发;萌发时间上,蒺藜和欧夏至草集合繁殖体在当季下均只萌发部分种子,具间歇性萌发特性。(3)对不同生活型植物而言,其集合繁殖体附属物对种子的保护、保水、扩散及萌发行为的功能相同,但一年生草本植物的萌发行为侧重于种群繁衍,因此蒺藜集合繁殖体在当季萌发率及萌发速率较高;多年生草本植物的萌发行为侧重于种群扩散,因此欧夏至草扩散单位多样化,且萌发率及萌发速率较低。 Abstract:Female plants protect and adjust their offspring through the morphology of synaptospermy after withering. This adjustment provides elasticity and guarantees heredity and reproduction for a given species. Synaptospermy is a critical characteristic of desert plants that evolved as an adaptation to harsh environmental conditions, and may have important ecological significance for the protection of seed function and cross-pollination between plants. Knowledge about this characteristic of the plant life cycle would increase our understanding about the adaptation strategies of synaptospermic plants in desert environments. Synaptospermy involves the joining of two or more seeds or one-seeded fruit to form a compound dispersal unit. This adaptation is common throughout the plant kingdom, but is largely restricted to arid regions. Out of the many morphological-ecological types that have been distinguished among synaptospermic plants, only a few are mentioned here. Synaptospermy is primarily derived from monospermy. Thus, this adaptation represents an advanced evolutionary stage associated with (1) the degeneration of separation tissues in pods, legumes, loments, and capsules, (2) the formation of abscission tissue in the joints of peduncles and pedicels, and (3) a series of other characteristics. In fact, synaptospermic species are found in genera belonging to phylogenetically advanced groups within their respective families, such as the Brassicinae, Galegeae, Hordeae, and Paronychieae. Fruit that contains synaptospermic seeds are able to establish physiological gradients;thus, spreading germination over time (a major advantage). The dispersal and spreading of germination over time (polyphenic germination) allows a mother plant to reduce competition among its offspring. Polyphenic germination is especially pronounced in synaptospermic seeds. Synaptospermy may be divided into two morphologically different types: (1) diaspores develop from the joined seeds of the carpels of one flower, and (2) diaspores develop from the units of different flowers. None of these dispersal units, which contain up to several seeds in a single diaspore, develops more than two seedlings in one season, indicating that all seeds remain together in the dispersal unit, but are ready to germinate in different years;this phenomenon is called intermittent germination. The annual Tribulus terrestris and the perennial Marrubium vulgare are synaptospermic plants with dispersal units belonging to the two morphologically different diaspore types;M. vulgare also disperses using seeds. Here, we conducted preliminary comparisons and observations on the morphology, vigor, water absorption, and germination characteristics of each dispersal unit. The results showed that mass, length of burs, percentage of appendages accounting for mass, number of seeds, vigor, and water absorption all significantly differed among the synaptospermies of T. terrestris. Conversely, while mass and water absorption significantly differed among M. vulgare dispersal units, no significant differences were observed for vigor, germination, and germination rate. The position of germination in synaptospermy differed between plants. For instance, seeds only germinated on the long thorns of synaptospermids in T. terrestris, indicating nonrandom germination, but no regularity in germination was observed for M. vulgare, indicating random germination. In addition, under the conditions with the highest germination percentage, only part of the seeds germinated in one season for both species, indicating intermittent germination. For different plant life forms, the synaptospermic appendage has the same functions, e.g., protecting seeds, retaining water, dispersing, and germinating. However, the germination behavior of annual plants focuses on population reproduction;therefore, the germination percentage of synaptospermy was high over the season for T. terrestris. Conversely, the germination behavior of perennial plants focuses on population dispersal;therefore, the dispersal units of M. vulgare showed diverse characteristics, with a low germination percentage for the dispersal units over the season. 参考文献 相似文献 引证文献

Investigation of Coffee Seed Physical Purity, Seed Health and Effect of Storage Time on Viability

High seed quality is essential for optimum stand establishment in Coffee. As a result, it is necessary to have seed physical, germination percent, physiological and health tests that permit rapid, objective and accurate evaluation of seed quality. This study evaluated the effect of storage time on physical, physiological, germination percent and health quality of seed lots of five coffee varieties obtained from research and commercial company. This test is conducted under ideal laboratory conditions and in the nursery site. After sample collected pure, pea-beery, cracked and shriveled seeds were measured before determining standard germination and vigor. The highest pea berry was recorded at JARC on the variety 75227(18.63), and the lowest was at LCP on the variety 74165 (8.81). In parchment coffee seed, the percentage of physical defects during seed processing affects germination and seedling viability. The standard germination test in the moisten-soft paper continues to be the most common measure of seed quality in coffee. In addition, this test requires more than two weeks before a determination of seed germination was possible. Ideally, seed quality tests efficiently differentiate between poor and good seed lots in a short period. There was high germination percent in the first planting time were recorded after one month storage than other two consecutive storage time. Normal germinated seedling reduced with in increases seed storage time and the incidence of seed/ soil -born pathogenic fungi. The germination test of seeds from laboratory under petri-dish with moist soft paper and at the nursery site also had low vigour and did not produce suitable seedlings for planting evaluated after three month storage. If after one month storage time of coffee seeds germinated more than older seeds (as our study indicates), then seedlings derived from younger may have a competitive advantage over seedlings derived from older one. In the present study, pre-emergence seedling mortality (Rotten) was greater in third month storage than in first month old seeds. This mortality partially accounted for the lower germination percentage in three month old seeds because only seeds that emerged above the soil surface were considered to have germinated is an indication of reduced vigor. In my study, in coffee seeds, seedlings from relatively low stored seeds were generally better able to withstand environmental stress than those from old seeds. Coffee seed sample from two sources stored safely to optimize coffee seedling production at the appropriate time and season with ideal climatic conditions for planting in the field.

ATR-FTIR spectroscopy reveals involvement of lipids and proteins of intact pea pollen grains to heat stress tolerance.

With climate change, pea will be more frequently subjected to heat stress in semi-arid regions like Saskatchewan during flowering. The pollen germination percentage of two pea cultivars was reduced by heat stress (36°C) with an important decrease in cultivar ‘CDC Golden’ compared to ‘CDC Sage.’ Lipids, protein and other pollen coat compositions of whole intact pollen grains of both pea cultivars were investigated using mid infrared (mid-IR) attenuated total reflectance (ATR)–Fourier transform infrared (FTIR) spectroscopy. Curve fitting of ATR absorbance spectra in the protein region enabled estimation and comparison of different protein secondary structures between the two cultivars. CDC Sage had relatively greater amounts of α-helical structures (48.6–43.6%; band at 1654 cm-1) and smaller amounts of β-sheets (41.3–46%) than CDC Golden. The CDC Golden had higher amounts of β-sheets (46.3–51.7%) compared to α-helical structures (35.3–36.2%). Further, heat stress resulted in prominent changes in the symmetrical and asymmetrical CH2 bands from lipid acyl chain, ester carbonyl band, and carbohydrate region. The intensity of asymmetric and symmetric CH2 vibration of heat stressed CDC Golden was reduced considerably in comparison to the control and the decrease was higher compared to CDC Sage. In addition, CDC Golden showed an increase in intensity at the oxidative band of 3015 cm-1. These results reveal that the whole pollen grains of both pea cultivars responded differently to heat stress. The tolerance of CDC Sage to heat stress (expressed as pollen germination percentage) may be due to its protein richness with α-helical structures which would protect against the destructive effects of dehydration due to heat stress. The low pollen germination percentage of CDC Golden after heat stress may be also due to its sensitivity to lipid changes due to heat stress.

Response of sunflower (Helianthus annuus L. var. Hyson) under laboratory condition to priming techniques

Seed priming has been reported to enhance growth of plants. To evaluate the effect of some physical seed priming materials (ultrasonic, gamma, beta and laser irradiation, magnetic field and hydro-priming) on seed germination and growth of sunflower a laboratory experiment was conducted at Islamic Azad University of Tabriz branch, using completely randomized design, with three replicates. The results revealed that the highest germination rate (8.4) was due to seed treatment by magnetic field 10,15 min. (Table 2). Lowest germination rate belonged to beta irradiation treaments (3.13 day) and control (3.16 day). Comparion of means indicated that highest seedling dry weight belonged seed treatments by magnetic field for 5 min. (9.46 mg) and gamma irradiation 15 min. (9.16 mg) respectively. Lowest germination percentages (40%) were observed for exposure of seeds to ultrasonic irradiation, beta irradiation and hydro-priming respectively. Comparison of means indicated that priming of sunflower seed with laser irradiation for 10 min. increased seedling vigor index by 173% against control. It may be concluded that sunflower producers could improve seed germination percent by priming the seed with magnetic field and laser and gamma.

Efeito da temperatura, extração e embebição de sementes na germinação de Bactris maraja Mart. (Arecaceae)

Bactris maraja Mart., palmeira nativa da Amazônia, ocorre em solos arenosos tipicamente às margens de lagos e igarapés. Apresenta grande importância ecológica, podendo ser propagada vegetativamente (touceiras) ou através de sementes. A propagação das palmeiras por meio de sementes geralmente apresenta germinação lenta, irregular e em baixa porcentagem. Dessa forma, a pesquisa teve como objetivo estudar os efeitos de diferentes temperaturas, períodos de secagem do pireno e extração da semente e períodos de embebição da semente na germinação. Foram realizados três experimentos: 1) Sementes foram submetidas a dois níveis de beneficiamento (sem remoção e com remoção do endocarpo) e seis diferentes temperaturas (20, 25, 30, 35, 40 e 26-40 ºC); 2) Pirenos foram submetidos a 0, 1, 2, 3, 5, 7, 9, 11 e 15 dias de secagem, em que em cada período foi feita a extração da semente; e 3) Sementes foram submetidas a 0, 1, 2, 3, 4 e 5 dias de embebição. As sementes submetidas à temperatura alternada de 26-40 ºC apresentaram maior porcentagem de germinação (acima de 60%), não diferindo entre os níveis de beneficiamento. A secagem dos pirenos facilitou a extração das sementes. Contudo, a secagem e a extração das sementes reduziram a germinação e o vigor. Assim, o beneficiamento não é recomendado. A embebição das sementes por dois dias favoreceu a porcentagem e a velocidade de germinação.

Essential Oil Compositions and Natural Herbicide Activity of Four Denaei Thyme (Thymus daenensis Celak.) Ecotypes

Denaei Thyme (Thymus daenensis Celak.) is a perennial plant from Lamiaceae family. The plant's leaves possess biological attributes that provide it with the potential to be used for medicinal purposes and newly for suppressing the growth of herbaceous plants. In this study essential oil (EO) compositions and phytotoxic effects of four T. deanensis ecotypes (ECTPs) of T. deanensis were evaluated on Amaranthus retroflexus, Avena fatua, Datura stramonium and Lepidium sativum germination and related growth traits.For this purpose, thyme plants were collected from different ecological locations of Fars Province, Iran to identify EOs content and compositions and also their phytotoxic activity. Gas chromatography (GC) and GC-Mass spectrometry (GC-MS) analysis of the EOs showed that thymol (20 - 60.5 %) and carvacrol (20.1 - 63.4 %) were the two major oil components found in the studied ECTPs. For evaluating phytotoxic activity, the concentrations, 0, 200, 400, 600, 800 and 1000 µl l-1 of the EOs were tested in vitro against seeds and their effect on germination percentage and rate, root and shoot length, fresh and dry weight of seedlings were determined. In general, higher EO concentration resulted in lower germination percentage and/or rate in all studied species. The overall results of germination test represent a reduction in germination percentage of most species at concentration of 200 µl l-1. The results reported herein suggest that herbicidal properties of the four ECTPs could be due to their EO concentrations and have potential as natural herbicides.

Biogenic nanoparticle-mediated augmentation of seed germination, growth, and antioxidant level of Eruca sativa mill. varieties.

A study was undertaken to examine the influence of biogenic nanoparticles synthesized from Tridax procumbens on different parameters of seed germination, seedling growth, and various biochemical parameters in four Eruca sativa varieties having low percentage of germination. Seeds were treated with different concentrations (30 and 40 ppm) of biogenic nanoparticles, of which 30 ppm was found to be the most effective and was therefore used for subsequent studies. Initially, the effect of biogenic nanoparticles on germination percentage, speed of germination, coefficient of germination, mean germination time, shoot and root length, fresh and dry matter, and vigor index was studied. From the experiments performed and the results obtained, it was evident that the treatment with biogenic nanoparticles decreased the electrolyte leakage and level of malondialdehyde as compared to control. The treatment with biogenic nanoparticles enhanced the levels of proline and ascorbic acid and stimulated the antioxidant enzyme activities resulting in the reduced level of reactive oxygen species. These activities were found to be variety-dependent. The possible involvement of biogenic nanoparticles in the production of new pores in seed coat during their penetration, resulting in the influx of the nutrients inside the seed, is suggested. This accelerated seed germination is followed by rapid seedling growth. The present findings indicated that biogenic nanoparticles promote seed germination in E. sativa by overcoming the detrimental effects of reactive oxygen species (ROS) and improving the antioxidative defense system which finally result in increased seedling growth.

In vitro propagation of Gentiana scabra Bunge - an important medicinal plant in the Chinese system of medicines.

BackgroundGentiana scabra Bunge commonly known as ‘Long dan cao’ in China has been used in traditional Chinese medicines for more than 2000 years. Dry roots and rhizome of the herb have been used for the treatment of inflammation, anorexia, indigestion and gastric infections. Iridoids and secoiridoids are the main bioactive compounds which attribute to the pharmacological properties of this plant. The species is difficult to mass propagate by seed due to the low percentage of germination and limited dormancy period. Wild populations in some locations are considered to be in the endangered category due to over exploitation.ResultsIn the present study, we report an efficient micropropagation system. Shoot apices of six weeks old in vitro grown G. scabra plants were used as explants for the in vitro propagation. Induction of multiple shoots (9.1/explant) was achieved on the culture of shoot apices on half strength Murashige and Skoog’s basal medium (MSBM) containing 2.0 mg/L−1 6-benzylaminopurine (BA), 3% sucrose and 0.9% Difco agar. In vitro shoots induced profuse rooting on half strength of MSBM supplemented with 0.1 mg/L−1 1-naphthaleneacetic acid (NAA), 3% sucrose and 0.3% gelrite. A two-stage ventilation closure procedure during the in vitro culture, and transparent sachet technique enhanced the survival rate of G. scabra plantlets to 96% in the greenhouse. Tissue culture plants flowered after 5 months of transfer to pots.ConclusionsA simple and an efficient in vitro propagation protocol of Gentiana scabra Bunge by optimizing the medium composition and ventilation closure treatments has been developed. The protocol can be very useful in germplasm conservation and commercial cultivation of G. scabra plants.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0056-4) contains supplementary material, which is available to authorized users.

Effects of great bustard (Otis tarda) gut passage on black nightshade (Solanumnigrum) seed germination

AbstractBirds are important seed dispersers for fleshy fruits through their transportation of ingested seeds. The seeds of many species germinate faster and in greater proportions after passing through a digestive tract, although the effects of this passage vary amongst bird and plant species. Many factors determine the germination success of ingested seeds, such as seed scarification during the digestion process, the fertilizing effect of droppings and the removal of pulp surrounding the seeds. In central Spain, the great bustard (Otis tarda) may act as a disperser of European black nightshade (Solanum nigrum). We analysed the germination success of ingested and non-ingestedS. nigrumseeds. The fertilizing effect of bustard droppings and the disinhibition effect of the removal ofSolanumpulp on final germination percentage, germination speed and viability were also assessed. Although ingested seeds germinated faster than non-ingested seeds, the former showed a lower germination percentage than the latter: 80–87% versus 99%. Droppings and fruit pulp showed no effect on germination enhancement, except in one aspect: the germination speed of non-ingested seeds decreased when they were sprayed with a fruit extract. We confirm that seeds ingested by great bustards had lower germination success than non-ingested seeds. Although seed ingestion by great bustards reduced seedling emergence, the number of emerged seedlings was still quite large. Thus, great bustards may play a role as aS. nigrumseed dispersal vector.