Increased Germination Percentage Research Articles

植冠与土壤种子库储存种子的萌发特性及策略

PDF HTML阅读 XML下载 导出引用 引用提醒 植冠与土壤种子库储存种子的萌发特性及策略 DOI: 10.5846/stxb201608061617 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41371280，41501290）；黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金（A314021402-1512）；辽宁省博士启动基金（201601368）；辽宁工程技术大学第五批生产技术问题创新研究基金（20160046T） Seed germination characteristics and strategies of seeds stored in canopy and soil seed banks Author: Affiliation: 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:为明确黄土丘陵沟壑区植物种子库如何调控种子萌发来提高个体适合度，选择研究区7种具有种子库的主要物种为研究对象，以刚成熟和室内储存种子为对照，比较植冠宿存（5个宿存期）和土壤埋藏（5a埋藏期）对植物种子萌发特性的影响，探讨植冠种子库与土壤种子库储存下的种子萌发策略。结果表明：7种植物种子经过不同种子库储存后萌发特性表现出明显的种间差异，黄刺玫（Rosa xanthina）和水栒子（Cotoneaster multiflorus）种子萌发力表现为植冠宿存不变型、土壤储存增强型，土壤储存明显提高水栒子种子萌发速率；达乌里胡枝子（Lespedeza davurica）和狼牙刺（Sophora davidii）种子萌发力表现为植冠宿存增强型、土壤储存减弱型，种子萌发历时表现为植冠宿存延长型，土壤种子库储存还可加快达乌里胡枝子萌发速率、缩短萌发历时；茭蒿（Artemisia giralaii）和铁杆蒿（Artemisia gmelinii），种子萌发率随植冠宿存时间先升高后降低，随土壤储存时间先降低后升高，土壤储存可推迟其萌发，铁杆蒿种子萌发速率在植冠与土壤储存后均加快；紫丁香（Syringa oblata）种子萌发率随植冠宿存先升高后降低，土壤储存明显加快其种子启动萌发与速率。在黄土丘陵沟壑区，植物种子经过植冠或土壤种子库储存，或增加、加快、提早萌发充分利用有利条件提高占据性，或减少、减缓、推迟萌发分摊不利条件的风险；而且该区植物植冠与土壤储存后种子萌发特性间的关系，体现各自适应环境与应对干扰的分工与协作策略，主要表现为：单一主导型和相辅相成型。 Abstract:To determine how seeds improve their individual fitness by regulating their germination characteristics, we selected seven species with obvious canopy and soil seed banks in the hill-gully Loess Plateau. Effects of the duration of canopy storage (five storage periods) and soil storage (burial periods of five years) on seed germination were analyzed, which were compared with seeds of just matured or stored in laboratory as control. And the germination strategies of seeds after storage in canopy seed bank and soil seed bank were discussed. Our results indicated that the seed germination characteristics of the seven species were obviously different after storage. For Rosa xanthina and Cotoneaster multiflorus, storage improved the seed germination ability of the soil seed bank but had no effect on that of the canopy seed bank, and the seed germination rates of the soil seed bank of the C. multiflorus was considerably increased. For Lespedeza davurica and Sophora davidii, storage improved the seed germination ability of the canopy seed bank but weakened that of the soil seed bank. Meanwhile, the seed germination lasting times of the canopy seed bank were prolonged after storage, whereas the seed germination rate and seed germination lasting times of the soil seed bank were accelerated and shortened for L. davurica, respectively. For Artemisia giralaii and A. gmelinii, seed germination percentages initially increased but then declined as the duration of canopy storage increased, whereas the seed germination rate initially declined and then increased. Storage of the soil seed bank also delayed the seed germination for both species, whereas storage of both the canopy and soil seed banks increased the seed germination rates of A. gmelinii. For Syringa oblate, seed germination percentages initially increased but then declined as the duration of canopy storage increased, and storage of the soil seed bank both increased the germination rates and promoted seed germination. In conclusion, seeds from the hill-gully Loess Plateau either (1) took full advantage of favorable conditions to finish regeneration in right time quickly by increasing germination percentage, speeding up seed germination rate and germinating at high concentration during the early stages of storage or (2) shared the risk of unfavorable conditions by reducing germination percentage, slowing down seed germination rate and deferring seed germination through seed storage in the canopy or soil seed bank. In addition, the relationship between seed germination characteristics of the canopy storage and that of soil seed bank storage indicated that plant use the division and cooperation storages of canopy and soil seed bank to adapt environments and to respond disturbance, which strategies mainly presented as single-dominant and tow-complementary patterns. 参考文献 相似文献 引证文献

Physiological potential of Oryza sativa seeds treated with growth regulators at low temperatures

The rapid and uniform establishment of rice crops is important for improving production. However, this condition is influenced by several factors, including the soil temperature when planting, which may delay seed germination and compromise the final stand. The aim of this study was to evaluate the behaviour of substances which have the effect of growth regulator when applied to the seeds of different rice cultivars under low-temperature conditions. The experiment was carried out in a completely randomised design with four replications in a bi-factorial scheme, where factor A was represented by the different products (gibberellic acid - AG3, tiamethoxam - TMX, Haf Plus® - HAF, and a control with water - TEST), and factor B by the irrigated rice cultivars (IRGA 424, IRGA 425, Puita INTA CL, and Avaxi CL). In addition, the experiment was repeated at temperatures of 17 °C and 25 °C in order to simulate low-temperature conditions. The results showed that AG3 is effective in increasing seed vigour in the rice cultivars at both temperatures, with the AG3, TMX and HAF responsible for increasing germination percentage only at the temperature of 17 °C. The effect of the products is more pronounced at low temperatures, and is dependent on the cultivar; in cultivars which are sensitive to cold there is no effect from the products used.

Seed dormancy and soil seedbank of the invasive weed Chenopodium hybridum in north‐western China

SummarySeed dormancy and persistence in the soil seedbank play a key role in timing of germination and seedling emergence of weeds; thus, knowledge of these traits is required for effective weed management. We investigated seed dormancy and seed persistence on/in soil of Chenopodium hybridum, an annual invasive weed in north‐western China. Fresh seeds are physiologically dormant. Sulphuric acid scarification, mechanical scarification and cold stratification significantly increased germination percentages, whereas dry storage and treatments with plant growth regulators or nitrate had no effect. Dormancy was alleviated by piercing the seed coat but not the pericarp. Pre‐treatment of seeds collected in 2012 and 2013 with sulphuric acid for 30 min increased germination from 0% to 66% and 62% respectively. Effect of cold stratification on seed germination varied with soil moisture content (MC) and duration of treatment; seeds stratified in soil with 12% MC for 2 months germinated to 39%. Burial duration, burial depth and their interaction had significant effects on seed dormancy and seed viability. Dormancy in fresh seeds was released from October to February, and seeds re‐entered dormancy in April. Seed viability decreased with time for seeds on the soil surface and for those buried at a depth of 5 cm, and 39% and 10%, respectively, were viable after 22 months. Thus, C. hybridum can form at least a short‐lived persistent soil seedbank.

Effect of Azospirillum lipoferum and Azotobacter chroococcum on germination and early growth of hopbush shrub (Dodonaea viscosa L.) under salinity stress

ABSTRACTReduced physiological efficiency as well as low and irregular germination rate under environmental stress conditions (e.g., salinity) are among the major factors affecting the propagation of numerous plants, in particular medicinal ones. A factorial experiment using a completely randomized design was employed to evaluate the effect of plant growth-promoting rhizobacteria (PGPR) on hopbush seed germination and seedling growth under salinity stress. After the seeds were inoculated with the Azospirillum lipoferum, Azotobacter chroococcum, and Azospirillum + Azotobacter and exposed to salinity stress at six levels, they were placed into a germinator at 20°C temperature and 65% relative humidity with a photoperiodic regime of 16 h light/8 h dark at 1,000 lux fluorescent light. The seeds inoculated with the bacterial strains could tolerate salinity levels of up to 50 dS/m and germinate. The combined treatment of Azospirillum + Azotobacter increased germination percentage at 20 and 50 dS/m levels by 21.67 and 10%, respectively. Also, A. chroococcum at 15 and 20 dS/m and Azospirillum + Azotobacter at 50 dS/m stress levels increased germination rate by 88, 316, and 155%, respectively, compared with the control. Furthermore, plant growth parameters—e.g., root and stem length, root and stem dry and fresh weights, as well as the ratios of root length and weight to the stem counterparts—were considerably enhanced by Azotobacter chroococcum treatment under elevated salinity stress (15 and 20 dS/m), relative to the control. Inoculation with A. chroococcum more favorably affected on and was also more compatible with Dodonaea viscosa seedlings leading to considerably improved seedlings growth parameters as well as seed germination under salinity stress.

Overexpression of PSK1, a SKP1-like gene homologue, from Paeonia suffruticosa, confers salinity tolerance in Arabidopsis.

Our study is the first to demonstrate that PSK1 , a SKP1 -like gene homologue, is involved in salinity tolerance. Our functional characterization of PSK1 provides new insights into tree peony development. A homologous gene of S-phase kinase-associated protein1 (SKP1) was cloned from tree peony (Paeonia suffruticosa) and denoted as PSK1. The 462-bp open reading frame of PSK1 was predicted to encode a protein comprising 153 amino acids, with a molecular mass of 17kDa. The full-length gene was 1,634bp long and included a large 904-bp intron. PSK1 transcription was detected in all tissues, with the highest level observed in sepals, followed by leaves. Under salinity stress, overexpression of PSK1 in Arabidopsis resulted in increased germination percentages, cotyledon greening, and fresh weights relative to wild-type plants. Furthermore, transgenic Arabidopsis lines containing 35S::PSK1 displayed increased expression of genes that would be essential for reproduction and growth under salinity stress: ASK1, LEAFY, FT, and CO involved in flower development and flowering time as well as P5CS, RAB18, DREB, and SOD1-3 contributing to salinity tolerance. Our functional characterization of PSK1 adds to global knowledge of the multiple functions of previously explored SKP1-like genes in plants and sheds light on the molecular mechanism underlying its role in salinity tolerance. Our findings also provide information on the function and molecular mechanism of PSK1 in tree peony flower development, thereby revealing a theoretical basis for regulation of flowering and conferral of salinity tolerance in tree peony.

Effects of fungicides and plant extracts on seed germination and seed associated mycoflora of Lens arietinum L. and Lathyrus sativus

Contexts: seed treatment reduced seed mycoflora. Evidences revealed that chemical fungicides and plant extracts were effectively controlled seed mycoflora and enhanced seed germination of pulse crops.Objectives: To determine the effects of chemical fungicides and plant extracts on seed germination and seed associated mycoflora on Lens arietinum L. (lentil) and Lathyrus sativus (khesari).Materials and Methods: All the samples were collected Rajshahi region during June - August 2012. The detection of seed mycoflora, seed germination and seed treatment with fungicides and plant extracts were carried out by using the blotter test (ISTA-1966).Results: Seed germination percentage was significantly (p?0.05) increased with both the treatments. Captan (1.2%) was more effective in comparison with Dithane M-45 (1.4%) and seed germination (%) was gradually increased with increase of the doses of fungicides. Seed associated mycoflora also significantly (p?0.05) varied with the treatments. Aspergillus flavus was the most dominant fungi in lentil and Fusarium oxysporum was in khesari for both the treatments and control. No fungi were recorded at 1.2 and1.4% doses of Captan and Dithane M-45 treated seeds of both pulses. Plant extracts increased germination percentage over control and showed different levels of antifungal activity against seed associated mycoflora (SAM) of both pulse seeds. Among the extracts, Allium sativum showed promising result in controlling of SAM of lentil and khesari. Besides this, A. flavus was remarkably eliminated with the all types of used extracts.Conclusion: From this study it had been clearly found that seed treatment with chemical fungicides and plant extracts were controlled seed mycoflora of lentil and khesari and increased seed germination.J. bio-sci. 22: 101-110, 2014

Characterization of β-amino- and γ-amino butyric acid-induced citrus seeds germination under salinity using nanoLC-MS/MS analysis.

BABA or GABA induces salinity acclimation during citrus seeds germination via alternation of specific proteins (e.g., citrin). The impact of four elicitors, namely hydrogen peroxide (H2O2), β-amino butyric acid (BABA), γ-amino butyric acid (GABA) and hydrogen sulfide (H2S) donor, sodium hydrosulfide (NaHS), in citrus seed germination under salinity (150mM NaCl) was tested. The germination potential was adversely affected by NaCl-alone treatment. Pretreatment with H2O2 or the NaHS-H2S donor prior to salinity had no significant effect in germination process, however, BABA and GABA substantially improved seed acclimation to salinity, as evidenced by increased germination percentage and radicle length. Total soluble proteins of radicle and cotyledons were separated by 1DE SDS-PAGE and proteins zones were analyzed by mass spectrometry. In total, 27 and 3 proteins were identified in radicle and cotyledons, respectively. The identified proteins mainly include redox-regulated enzymes (i.e., glutathione S-transferase, dehydroascorbate reductase, Mn-superoxide dismutase, glutathione peroxidase), energy-related proteins (i.e., isocitrate lyase, malate synthase, pyruvate decarboxylase), stress proteins (i.e., stress-related protein, miraculin, thaumatin, disulfide isomerase), storage proteins (i.e., vicilin, Pis v 1 allergen 2S albumin) and transcriptional regulators (i.e., MarR family transcriptional regulator, MADS544 protein). Pretreatments with BABA or GABA altered the accumulation of protein zones exclusively corresponding to citrin, indicating that this protein may serve as a marker for salinity acclimation in citrus seeds.

Trichoderma asperellum spore dose depended modulation of plant growth in vegetable crops

In the present study we bioprimed seeds of six vegetable crops (tomato, brinjal, chilli, okra, ridge gourd and guar) with different spore doses of Trichoderma asperellum BHUT8 ranging from 102 to 108 spores ml−1 and the effect of biopriming was seen on seed germination and development. The most effective spore dose for enhancement in seed germination and radicle length was found to be 103 spores ml−1 in tomato and ridge gourd, 104 spores ml−1 in brinjal and okra while 106 spores ml−1 in chilli and guar. At the most effective spore dose, the increase in germination percentage was 5, 146.15, 112.5, 5.4, 28.13 and 0% while increase in radicle length was 73.17, 50.83, 171.6, 107.35, 247.19 and 90.79% in tomato, brinjal, chilli, okra, ridge gourd and guar, respectively, compared to their controls. Higher spore dose i.e. 107–108 spores ml−1 and 106–108 spores ml−1 in tomato and brinjal, respectively, reduced seed germination percentage and radicle growth compared to their controls. Biopriming with T. asperellum BHUT8 also triggered various defense like responses such as high phenylpropanoid activities and lignifications in bioprimed tomato seedlings compared to the non-bioprimed tomato seedlings demonstrating possible use of BHUT8 against phytopathogens.

Positive effects of karrikin on seed germination of three medicinal herbs under drought stress

ABSTRACT- Improper seed germination is a serious challenge for medicinal herbs under drought stress conditions in semi-arid and arid regions. A new group of plant growth regulators known as karrikins have been proved useful to improve seed germination in some plants. In this regard, the effects of karrikin on seed germination and vigor of three medicinals under drought stress were examined. Seeds of Trachyspermum copticum (L.) Link, Foeniculum vulgare Miller, and Cuminum cyminum L. were sowed under drought treatments (-1, -1.5, -2 and -2.5 MPa of PEG 6000), with and without synthetic Karrikin GR24 (10µM). Results indicated increasing osmotic pressure seed germination characteristics were severely reduced; however, karrikin significantly increased the seed germination of the three herbs. The application of karrikin in all drought conditions significantly increased germination percentage, germination rate, germination index, seedling vigor, shoot length and radicle length of all herb seedlings. Ajwain (T. copticum) showed a greater drought tolerance compared to the other medicinal species.

Response of perennial woody plants to seed treatment by electromagnetic field and low-temperature plasma.

Radiofrequency (5.28 MHz) electromagnetic radiation and low-temperature plasma were applied as short-term (2-15 min) seed treatments to two perennial woody plant species, including Smirnov's rhododendron (Rhododendron smirnowii Trautv.) and black mulberry (Morus nigra L.). Potential effects were evaluated using germination indices and morphometry. The results suggest that treatment with electromagnetic field stimulated germination of freshly harvested R. smirnowii seeds (increased germination percentage up to 70%), but reduced germination of fresh M. nigra seeds (by 24%). Treatment with low-temperature plasma negatively affected germination for R. smirnowii, and positively for M. nigra. The treatment-induced changes in germination depended on seed dormancy state. Longer-term observations revealed that the effects persisted for more than a year; however, even negative effects on germination came out as positive effects on plant morphometric traits over time. Treatments characterized as distressful based on changes in germination and seedling length increased growth of R. smirnowii after 13 months. Specific changes included stem and root branching, as well as increased leaf count and surface area. These findings imply that longer-term patterns of response to seed stressors may be complex, and therefore, commonly used stressor-effects estimates, such as germination rate or seedling morphology, may be insufficient for qualifying stress response. Bioelectromagnetics. 37:536-548, 2016. © 2016 Wiley Periodicals, Inc.

DIFFERENTIAL IMPACT OF MULTI-WALLED CARBON NANOTUBES ON GERMINATION AND SEEDLING DEVELOPMENT OF GLYCINE MAX, PHASEOLUS VULGARIS AND ZEA MAYS

In face of highly variable and so far largely unexplained plant responses after exposure to carbon nanomaterials, this study was designed to dissect the effects of a defined type of carbon nanomaterials (multi-walled carbon nanotubes, MWCNTs) under controlled conditions on three different plant species, depending on MWCNT dosage, treatment duration, and the plant-developmental stage, including imbibition, germination and seedling development. Germination experiments were conducted under standardized laboratory conditions according to the protocols of the International Seed Testing Association with aqueous MWCNT suspensions at a dosage of 0, 100 and 1000 mg L -1 applied as seed treatments during 36 h after sowing prior to radicle emergence, using soybean ( Glycine max (L.) Merr. cv. BR-16 Conquista) common bean ( Phaseolus vulgaris L. cv. Bohnen maxi) and maize ( Zea mays L. cv. Surprise) as test plants. The seed treatment with MWCNTs reduced the speed of water uptake particularly by soybean seeds. This was associated with an increased germination percentage and reduced development of abnormal seedlings, while mean germination time was unchanged. However, during later seedling development, negative effects on root growth, particularly affecting fine root development were recorded for all investigated plant species. In soybean, this effect was first detectable at 8 days after sowing and required a minimum MWCNT seed exposure of 36 h. Inhibition of root growth was associated with reduced metabolic activity of the root tissue as indicated by tetrazolium vitality staining. Also nitrate uptake was lower in MWCNT-treated plants, which could be mainly attributed to the smaller root system. The results demonstrated that even under standardized experimental conditions, largely excluding environmental factors and effects induced by the variable properties of carbon nanomaterials, plant responses to MWCNT exposure exhibit differences, depending on plant species but also on the physiological status and the developmental stage of individual plants.

Comparative Efficacy of Insecticidal Plants on the Management of Groundnut Bruchid (Caryedon Serratus)

Laboratory study was conducted to determine the efficacy of insecticidal plant extracts Azadirachta indica A. (Juss), Lantana camara L. (Verbenaceae), Eupatorium odoratum L. (Asteraceae), Tephrosia vogelii Hook, Afromomum melegueta K.M. (Schumann) and Ocimum gratissimum (L) leaves against groundnut bruchid beetle (Caryedon serratus), and a synthetic insecticide (Cypermethrin) (10EC)) under ambient condition of temperature and relative humidity (30°C and 72%). One hundred grams of shelled groundnut was weighed into jute bags and treated with powders of the insecticidal plants. Both treated and untreated bags of groundnut were then infested with newly emerged adult of C. serratus (20 per bag) and covered. The experiment was laid out in Completely Randomized Design (CRD) and replicated four times. Parameters assessed included number of egg oviposited, number of eggs hatched (eclosion) and number of adults that emerged from each treatment, total developmental period (egg – adult), sex ratio of the emerged adults and finally percentage germination of the treated seeds. Data collected were analyzed using analysis of variance and treatment means were separated using Duncan multiple range tests at P ≤ 0.05 level of significance. Results showed that A. indica, L. camara, T. vogelli, A. melegueta and O. gratissimum treated seeds significantly recorded lowest mean number of eggs, reduced damage by C. serratus and increased germination percentage compared with E. odoratum and control. In conclusion, A. indica, L. camara, T. vogelli, A. melegueta and O. gratissimum have the potentials as alternatives to synthetic insecticides in the management of C. serratus by resource poor farmers.

Lactic acid bacteria mediated induction of defense enzymes to enhance the resistance in tomato against Ralstonia solanacearum causing bacterial wilt

The biocontrol agent Lactic acid bacterium (LAB) was used against the bacterial wilt caused by Ralstonia solanacearum. The present investigation focuses on the role of defense related enzymes in imparting resistance to tomato plants against R. solanacearum. The LAB isolate was tested for its ability to induce the production of defense-related enzymes in treated tomato seedlings. Tomato seedlings were raised from LAB pretreated seeds, were challenge inoculated with R. solanacearum, harvested at different time intervals (0–72h) and assayed for defense enzyme activity. The LAB treated seeds showed increase in germination percentage (6%) and seedling vigour index (259) compared with control. Treatment of tomato seedlings with LAB isolate induced a significant amount of Peroxidase (POX), Polyphenol oxidase (PPO), Phenylalanine ammonialyase (PAL), total phenolics and β-1,3-glucanase activities. The activities of PAL, POX, PPO and β-1,3-glucanase reached maximum at 24h, 24h, 32h and 24h respectively after challenge inoculation. Increased accumulation of phenolics was noticed in plants pre-treated with LAB. Native PAGE analyses of POX and PPO were carried out for the time course of enzyme activities and the isoforms of POX and PPO were examined. In field study, ten isolates of R. solanacearum treated plots yielded an average of 32.4–50kg/m2 and LAB treated plots an average of 153.5kg/m2. As compared to the control, LAB increased the yield by 15.3% (8.2kg/m2) and the pathogen infected plants and pre-treated with LAB gave an average of 55% (28.3kg/m2 compared to the infected plots). Field experiment results indicated that LAB exhibited 61.1% of disease reduction of bacterial wilt in tomato.

Effect of Foliar Application of Micronutrients on Plant Growth and Seed Germination of Four Okra Cultivars

In the present study, the effect of foliar application of micronutrient fertilizers on okra plants was examined. Four okra cultivars (‘Boyiatiou’, ‘Veloudo’, ‘Clemson’ and ‘Pylaias’) were sprayed weekly throughout the duration of the cultivation with two commercial micronutrient fertilizers (F1 and F2) [e.g. M1= control (0 ml); M2= 40 ml (20 ml of each fertilizer); M3 = 80 ml (40 ml of each fertilizer). From the results of the present study, it was observed that plant height of ‘Boyiatiou’ and ‘Pylaias’ was increased by application of M2 whereas plant height of ‘Clemson’ and ‘Veloudo’ was either unaffected or reduced. Flower induction increased at both micronutrient levels (M2 and M3) only in ‘Pylaias’. Pod set was higher in treatment M3 in ‘Veloudo’ and ‘Pylaias’ and resulted in higher seed yield. Pod length and diameter were not affected by micronutrient application, as well as 100-seed mean weight and moisture content; however the number of seeds per pod in ‘Pylaias’ was significantly lower in M2 and M3 than in M1, whereas the percent seed germination of all cultivars was higher following micronutrient application. Germination differed between the control and the micronutrient treatments at all times of harvest and plant parts. In conclusion, the main value of foliar application of micronutrients was to increase germination percentage and reduce hardseedness, especially for cv. ‘Veloudo’, since the occurrence of hard seeds in susceptible cultivars reduces germination, and therefore seed quality. In some cultivars (‘Pylaias’ and ‘Veloudo’ here) micronutrients may also increase seed yield by increasing pod set.

Effect of Foliar Application of Micronutrients on Plant Growth and Seed Germination of Four Okra Cultivars

In the present study, the effect of foliar application of micronutrient fertilizers on okra plants was examined. Four okra cultivars (‘Boyiatiou’, ‘Veloudo’, ‘Clemson’ and ‘Pylaias’) were sprayed weekly throughout the duration of the cultivation with two commercial micronutrient fertilizers (F1 and F2) [e.g. M1= control (0 ml); M2= 40 ml (20 ml of each fertilizer); M3 = 80 ml (40 ml of each fertilizer). From the results of the present study, it was observed that plant height of ‘Boyiatiou’ and ‘Pylaias’ was increased by application of M2 whereas plant height of ‘Clemson’ and ‘Veloudo’ was either unaffected or reduced. Flower induction increased at both micronutrient levels (M2 and M3) only in ‘Pylaias’. Pod set was higher in treatment M3 in ‘Veloudo’ and ‘Pylaias’ and resulted in higher seed yield. Pod length and diameter were not affected by micronutrient application, as well as 100-seed mean weight and moisture content; however the number of seeds per pod in ‘Pylaias’ was significantly lower in M2 and M3 than in M1, whereas the percent seed germination of all cultivars was higher following micronutrient application. Germination differed between the control and the micronutrient treatments at all times of harvest and plant parts. In conclusion, the main value of foliar application of micronutrients was to increase germination percentage and reduce hardseedness, especially for cv. ‘Veloudo’, since the occurrence of hard seeds in susceptible cultivars reduces germination, and therefore seed quality. In some cultivars (‘Pylaias’ and ‘Veloudo’ here) micronutrients may also increase seed yield by increasing pod set.

Efecto de la luz y de la escarificación en la germinación de las semillas de cinco especies de árboles tropicales secundarios

We studied the effect of light and scarification of the seed coat on the germination of seeds of five tree species which are characteristic of secondary growth: Apeiba membranacea, A. tibourbou, Luehea seemannii, Trichospermum mexicanum and Guazuma ulmnifolia. The seeds were scarified in sulfuric acid or hot water for 2 or 10 minutes, then germinated in a screened growing house in sunlight and shade.The seeds were not light sensitive. In the controls, germination was very low in both light and shade except in L. seemannii. A requirement for light did not develop after scarification.Scarification increased percent germination in all species by either softening the seed coat or providing a high temperature cue. In L. seemannii, the species with the softest seed coat, hot water increased germination while acid decreased it.

Prevention of collar rot disease in germinating peanut seedlings by Azotobacter sp. RA2

Use of plant growth promoting rhizobacteria (PGPR) to increase the production and decrease disease occurrence is a useful, ecofriendly method in agriculture. A rhizospheric bacterial culture named RA2 was isolated from peanut rhizosphere from Junagadh region of Gujarat, India and showed different direct and indirect plant growth promoting activity like indole acetic acid, gibberellic acid, siderophore, hydrogen cyanide, Ammonia and (1‐Aminocyclopropane‐1‐Carboxylate) deaminase production, N2 fixation, phosphate and potassium solubilization in vitro. RA2 was able to protect peanut germinating seedling from A. niger infection and reduce collar rot disease incidence from 72–60% to 41–35% and increase germination percentage from 75–70% to 97–82% in two varieties GG20 and GG2 of peanut. RA2 was found to induce resistance in A. hypogaea L. seedlings via induction of different defense related enzyme like phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, lipoxygenase and pathogenesis related protein like chitinase and β– 1, 3‐ glucanase. Jasmonic acid, one of the major signaling molecules during induce systemic resistance, was also found to induce due to RA2 treatments. RA2 bacterium also promoted peanut growth and reduced A. niger infection in pot studies. 16S rDNA sequence of RA2 showed 99 % homology to Azotobacter species.Support or Funding InformationAuthors are thankful to BRD School of Biosciences, Sardar Patel University for providing infrastructure and all necessary facilities. Authors are also grateful to University Grant commission (UGC Major Research Project F.No. 39‐247/ 2012 (SR)) for providing financial aid.

Seed germination studies of tree species: Radermarchera xylocarpa and Dolicandrone falcata

Seeds of Radermarchera xylocarpa and Dolicandrone falcata were soaked overnight in water and germinated in different substrates. In both the plants, the highest percent of germination was recorded in cocopeat (Radermarchera xylocarpa:62%; Dolicandrone. falcata: 41%) followed by MS basal medium (Radermarchera xylocarpa: 46%; Dolicandrone falcata:20%), cocopeat: sand (Radermarchera xylocarpa:30%; Dolicandrone. falcata: 8%) and least being in filter paper (Radermarchera xylocarpa: 23%; Dolicandrone falcata: 0%).Prior to germination in optimised substrate, seeds were soaked overnight in distilled water (control) and in gibberllic acid (GA3) (5 & 10 ?M). In both the plants GA3 treated seeds failed to increase percent germination and the growth of seedlings. In control the seedling growth was better with respect to all the parameter for both the species. Seedlings which were grown in cocopeat, rapidly developed into healthy plants after transfer to field Bangladesh J. Sci. Ind. Res. 51(1), 41-46, 2016

Halophilic bacteria mediated phytoremediation of salt-affected soils cultivated with rice

Salinity is a most important ecological constraint for cereal crop including rice nowadays. Phytoremediation has been used to remediate salt affected soil but the use of halophilic bacteria is limited. In this study, the salt resistant Thalassobacillus denorans (NCCP-58) and Oceanobacillus kapialis (NCCP (National Culture Collection of Pakistan) -76), halophilic bacteria isolated from salt mines near Karak, Pakistan were used to evaluate its effect on rice variety (Basmati-385)in soil contaminated with different concentrations (control, 50, 100 and 150mM) of NaCl. It has been observed that significant increase in germination percentage and germination rate occurred in seeds primed with bacterial strains as compared to non-primed seeds. Root and shoot lengths were more in plants raised from primed seeds than non-treated seeds. Plants raised from inoculated seeds showed a significant increase in fresh and dry weight of seedling after 15days. Significant increase in photosynthetic pigment; chlorophyll a (Chl a), chlorophyll b (Chl b) and carotenoid contents occurred in 28days old plants inoculated with bacterial strains under different saline conditions. Similarly significant increase occurred in total nitrogen and protein contents in inoculated plants. Ca+2 and K+ ion concentration significantly increased while Na+ ion concentration decreased in plants inoculated with bacterial strains as compared to non-inoculated plants under different saline conditions. Bacterial strains O. Kapialis (NCCP-76) was more responsive in term of physiological and biochemical parameters than T. denorans sp. (NCCP-58). The corresponding strains have a positive effect in alleviating the salt stress in plants growing in saline condition.

Role of short-term cold stratification on seed dormancy break and germination of alien species in southeastern China

Do short periods of relatively low temperatures during winter in subtropical zones promote seed dormancy break and germination of alien species and thus facilitate their spread? To help answer this question, we tested the germination responses to moist storage at low temperatures of seeds of 21 alien species from southeastern China. For each species, fresh seeds and seeds stored dry at room temperature and wet at 15 °C and wet at 4 °C for 30 days were tested for germination at 25 and 25/15 °C in a 12-h daily photoperiod. Fresh seeds of Bidens pilosa,Eclipta prostrata, Hyptis suaveolens, and Talinum paniculatum germinated to 89–96.7 % at both test temperatures, those of Ageratum conyzoides, Mikania micrantha, and Wedelia trilobata to 53–83 % at one or both temperatures, and those of the other 14 species to 0–39 % at one or both temperatures. A 30-day cold stratification pretreatment at 4 °C increased the germination percentage of seeds of Lantana camara and Solanum torvum, but they germinated to only 10.7–21.3 % and 2–30.7 %, respectively. However, germination speed of seeds of five species increased following moist storage at 4 °C, and that of four species increased following storage at 15 °C. Seeds of 14 species began germinating during wet storage at 15 and/or 4 °C. B. pilosa germinated to 87.3 and 57 % at 15 and 4 °C, respectively, and the other 13 species to 0.3–22.3 % at 15 °C. Thus, the short periods at 4 and/or 15 °C increased germination percentages of two species and the rate of six species and permitted early germination of 14 species, leading to the conclusion that the short cool periods during winter in the subtropical zone of China may contribute to the success of alien plant species in this region.