Relative Germination Research Articles

Qualidade de sementes e mudas de Cedrela fissilis Vell. em função da biometria de frutos e sementes em diferentes procedências

Cedrela fissilis is a Brazilian native species with outstanding use in the timber sector and in the recovery of degraded areas. There is a need for a better understanding of the differences and genetic gains that may exist in relation to different origins and progenies. The objective of the study was to analyze the biometry of fruits and seeds of Cedrela fissilis as a function of different origins and matrices related to the initial growth of seedlings, besides evaluating the best photoperiod in germination. The seeds were collected in matrices from two sources (Fernandes Pinheiro and Lapa) for biometry and the weight of one thousand seeds per matrix. Seeds of the two provenances were submitted to different photoperiods (12, 16 and 24 hours of white light and 24 hours in the dark), the germination and the germination rate index (ORI) was evaluated. The initial growth of the seedlings was evaluated through the measurement of morphological characteristics after every 30 days. The experiments were performed in a completely randomized design and the data submitted to analysis of variance at the 5% level, the averages being compared by the Tukey test and/or polynomial regression. There were biometric differences between fruits and seeds between the matrices, with no relation to the origin. Regarding the germination rate and ORI among the provenances, Fernandes Pinheiro presented the best results. In relation to the photoperiod, there was no difference in germination in relation to light levels, and the ORI was higher for seeds germinated in the dark. Fernandes Pinheiro obtained higher initial growth of the seedlings in relation to the Lapa origin and this difference increases throughout the evaluations. In general, the experiments showed a difference between the provenances, having a relation with the quality of seeds and seedlings formed.

How to analyze germination of species with empty seeds using contemporary statistical methods?

ABSTRACT Statistical analysis is considered an important tool for scientific studies, including those on seeds. However, seed scientists and statisticians often disagree on the nature of variables addressed in germination experiments. Statisticians consider the number of germinated seeds to be a binomially distributed variable, whereas seed scientists convert it into a percentage and often analyze it as a normally distributed variable. The requirement for normal adjustment restricts the models of analysis of variance that can be used. Lack of fit requires nonparametric tests, but they are known by their inferential problems. Generalized Linear Models (GLM) can provide better fit to germination variables for any species, including Lychnophora ericoides Mart., because they allow wider probability distributions with fewer requirements. Here we suggest the use of relative germination besides absolute germination for species with seed development problems, such for L. ericoides and others from the campos rupestres. This paper introduces the most current statistical advancements and increases the possibilities for their application in seed science research.

Use of a germination bioassay to test compost maturity in Tekelan Village

Livestock waste from cattle farms in Tekelan village, Getasan Subdistrict, Semarang Regency can be grouped into three types, namely solid waste, slurry and waste water. Solid waste (cow dung) was processed into compost, while slurry and waste water were used to make liquid fertilizer. This compost was used as a component of planting media in horticultural crops and potted plants production. We evaluated the toxicity (phytochemical and ecotoxicological) test of compost by using germination index (GI). Vigna radiata seeds are sown on filter paper dampened with compost extract for different times. GI was calculated by relative germination (G) and relative radical length (L). The germination index (GI) = G / G0 x L / L0 x 100, where G0 and L0 are values obtained by distilled water as a control. The results showed that germination bioassay and radical length using aquades and groundwater in Tekelan village did not affect the radical length of Vigna radiata . Technically, groundwater in Tekelan village can be used as a germination bioassay control. The cow dung compost substrate appears to have a major influence on compost toxicity. Mature compost was produced on day 14 with a GI of 104.03.

甘蓝型油菜耐盐相关性状的主成分分析及综合评价

目的：通过对种子萌芽期盐胁迫下甘蓝型油菜耐盐相关指标的研究，筛选和鉴定甘蓝型油菜耐盐种质资源。方法：通过浓度梯度实验对中双11号油菜种子萌芽期进行盐胁迫培养，测定种子的发芽率，确定最佳盐胁迫浓度为1.2% NaC1。在此浓度下，对88份不同遗传背景的甘蓝型油菜在盐胁迫处理下进行发芽试验，同时以去离子水为对照，播种后7天测定种子的发芽率、根长、整株鲜重和发芽势，以盐胁迫下各性状相对指数作为衡量耐盐性指标，利用主成分分析、隶属函数分析及聚类分析对其进行耐盐性综合评价。结果：在1.2% NaC1胁迫下，根长受盐胁迫影响程度最大，而发芽率受盐胁迫影响最小。各耐盐指标间的相关性分析表明，除了根长与发芽率之间无显著相关外，其他指标两两之间均存在显著正相关。通过对各耐盐指标进行主成分分析，最终确定各主成分贡献率及各指标对耐盐综合指标的贡献率。进一步应用隶属函数分析法对88个材料各主成分进行了综合评估并进行聚类分析，将88个基因型划分为高度耐盐、中度耐盐、不耐盐和盐敏感型4类，其中高度耐盐基因型有8个，中度耐盐21个，低度耐盐33个，盐敏感型26。根据综合评价结果，筛选出最耐盐品种为SW190。结论：可利用主成分分析、隶属函数分析和聚类分析对甘蓝型油菜种子萌芽期耐盐性进行分类和综合评价，筛选甘蓝型油菜耐盐种质。 Objective: To identify and screen the salt tolerance resource in Brassica napus L., four indexes of salt tolerance related traits during seed germination stage were studied. Method: In this study, 1.2% NaCl was determined as the optimal salt stress concentration by the concentration gradient experiment on Zhongshuang 11. Subsequently, 88 Brassica napus varieties with different genetic background were evaluated for salt tolerance under the conditions of normal water supply and salt stress with 1.2% NaCl. Four indexes related to salt stress tolerance, including relative germination rate, relative root length, relative fresh weight and relative germination potential were measured. Principal component analysis, membership function value analysis and clustering analysis were used to evaluate the salt tolerance of 88 genotypes. Result: The results showed that salt stress has less influence on germination rate. However, it has larger influence on root length. By the principal component analysis on the four indexes, contribution rate of each principal component was obtained. The 88 materials were evaluated by membership function value analysis and for cluster analysis. Eighty-eight genotypes were clustered into 4 different levels of tolerance. 8, 21, 33 and 26 lines were classified as strong salt tolerant, medium tolerant, low tolerant and sensitive under salt stress during seed germination stage, respectively. Based on the results of comprehensive analysis, SW190 was determined to possess the strongest salt tolerance. Conclusion: It is feasible to comprehensively evaluate the salt tolerance of B. napus at the stage of seed germination by principal component analysis, membership function value analysis, and clustering analysis, which could be used to screen germplasm lines of B. napus for salt tolerance.

Thermal stress and physiological changes in watermelon seeds

ABSTRACT Given that watermelon is a crop widespread around the world, there is considerable interest in verifying how its seeds physiologically behave under unfavorable temperature conditions. This study aimed to evaluate the biochemical changes mobilization and reserves degradation, as well as the enzyme activity, during seed germination and initial growth of watermelon seedlings subjected to thermal stress, using temperature, germination percentage, germination rate and relative germination frequency over the incubation time as evaluation parameters. The experimental design was completely randomized, in a 5 x 3 factorial scheme, with five temperatures (17 ºC, 20 ºC, 25 ºC, 30 ºC and 35 ºC) and three cultivars (Charleston Gray, Fairfax and Crimson Sweet), with 4 replicates of 50 seeds. Germination, seedling growth, reserve degradation and stress protection system were evaluated. Thermal stress caused deleterious effects on watermelon seeds with germination capacity at well defined temperature limits, being 25 ºC the ideal temperature, with the highest percentage of normal seedlings. Sub- (17 ºC) and supra-optimal (30 ºC) temperatures presented more than 80 % of abnormal seedlings. The α-amylase enzyme activity is intense only at the beginning of germination. Under thermal stress, the proline contents increase mainly in the cotyledons.

Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Liquid Fertilizer on Plant Growth Characteristics and Nutrient Content of Komatsuna (<i>Brassica rapa</i> L. var. Wakana Komatsuna) Cultivated in Vermiculite

We conducted plant growth experiments in microbe-free vermiculite to study the effects of four types of fermented seaweed liquid fertilizer (SLF) made from nori (Pyropia yezoensis) seaweed on the germination, plant growth characteristics, SPAD value, and nutrient content and uptake of komatsuna (Brassica rapa L. var. wakana komatsuna). The four types of fermented nori SLF used in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). Komatsuna seeds treated with 200-, 300-, and 400-fold dilutions of SLFs exhibited improved relative germination ratios (RGRs) at 3 and 4 days after sowing (DAS). At 4 DAS, the RGRs of seeds treated with 10-, 100-, 200-, 300-, and 400-fold SLF dilutions showed no differential effect. Seeds treated with undiluted SLFs did not germinate by 4 DAS. SLF1 may promote komatsuna seed germination. The nitrogen (N), calcium, magnesium, sodium (Na), and iodine (I) contents of plants treated with SLF1 were significantly increased relative to plants treated with the other SLFs. Moreover, the I and Na contents of plants were significantly increased by foliar spray application of different dilutions of SLF1. However, SLF treatment markedly reduced the shoot dry weight compared with 1/2-strength modified Hoagland nutrient (MHN) solution, although the same amounts of N and K were applied. SPAD values of the plants treated with SLFs were significantly higher than those of plants treated with MHN. Foliar treatment with SLFs had no significant effect on plant growth, SPAD value, or uptake of nutrients (except Na) relative to the control, but the I content was increased. Plants treated with SLF1 and SLF2 exhibited the highest Na uptake. Foliar spray treatments with SLF1 resulted in the highest I contents in plants. Based on our results, SLF1 is suitable for use as a liquid fertilizer to promote germination and increase nutrient content in komatsuna. These results need to be followed up in soil experiments in the presence of microbes in the rhizosphere.

Influence of Microwave Irradiations on Germination, Seedling Growth and Electrolyte Leakage of Barley (Hordeum vulgare L.)

The introduction of telecommunication instruments, especially microwave, leads to a massive increase in electromagnetic pollution. The current research intends to assess the physiological effects of microwave radiations on barley (Hordeum vulgare L.). Barley seeds were exposed to eight different exposure periods of microwave from 0 to 600 seconds. Germination parameters were dose-dependents, the percentage of germinated seeds increased after short exposure periods to microwave recording 100% germination. Further the germination rate, relative germination coefficient were also increased after short exposure periods to microwave. Longer exposure periods reduced the percentage of germination, germination rates, and various germination indices. Morphological and growth traits showed a similar trend and were significantly decreased after longer exposure periods to microwave. Chlorophyll contents were significantly decreased with increasing exposure periods of microwave. Microwave-induced electrolyte leakage (%) was significantly increased (r=0.92*, p<0.001) following pretreatment with different exposure periods of microwave. Current research data gives spotlight on possible positive and negative effects of microwave on barley and recommended to minimize the exposure time to environmental microwave to safeguard recovering ability of biological systems. However, the positive effects of microwave are of considerable importance for improving crops.

Investigating of a wide range of concentrations of multi-walled carbon nanotubes on germination and growth of castor seeds (Ricinus communis L.)

Abstract Carbon nanotubes act as regulators of plant germination and growth and are able to change the morphology and physiology of plant cells. The castor plant (Ricinus communis L.) belongs to the Euphorbiaceae family and is a very important medicinal plant. The aim of this study was to investigate the effect of 10 different concentrations of multi-walled carbon nanotubes (MWCNTs) (2, 5, 10, 20, 50, 75, 100, 125, 250 and 500 μg · ml−1) alongside the control under laboratory conditions on the germination and growth of castor seedlings. The results demonstrated that the maximum percentage of germination (96.7%) and relative germination percentage (100%) were found in the concentrations of 50 and 100 μg · ml−1, respectively, and the highest germination rate (53.3%) and the mean germination time (4.6 days) was seen in the concentration of 75 μg · ml−1. However, no statistically significant differences were found between the different concentrations in any of the germination factors. In the concentration of 100 μg · ml−1, there was a significant increase in the seedling vigor index I (400) when compared with the concentrations of 5 and 10 μg · ml−1. The maximum seedling vigor index II (11.3) was found in the concentration of 100 μg · ml−1 and was significantly different from the control and all applied concentrations. The length of radicle in the 100 and 125 μg · ml−1 had a significant increase when compared with the control and the concentrations of 10 and 50 μg · ml−1. The maximum seedling length (4.6 cm) was seen in the concentration of 100 μg · ml−1 where there was a significant increase with 10 μg · ml−1. Moreover, in the 100 μg · ml−1 concentration, the largest number of rootlets (8.6) was seen and when compared with the control and concentrations of 5, 10 and 50 μg · ml−1, there was a statistically significant increase. The maximum wet weight (0.3 g) and dry weight (0.1 g) of seedlings were obtained in the concentration of 100 μg · ml−1 and when compared with the control, there was a significant increase. It was found that in all factors related to the growth of seedlings, the concentrations of 10 and 50 MWCNTs had an inhibitory effect on the response index. The MWCNTs concentration of 100 μg · ml−1 was considered as the optimum concentration in the growth stage of castor seedlings.

Influence of Microwave Irradiations on Germination, Seedling Growth and Electrolyte Leakage of Barley (Hordeum vulgare L.)

The introduction of telecommunication instruments, especially microwave, leads to a massive increase in electromagnetic pollution. The current research intends to assess the physiological effects of microwave radiations on barley (Hordeum vulgare L.). Barley seeds were exposed to eight different exposure periods of microwave from 0 to 600 seconds. Germination parameters were dose-dependents, the percentage of germinated seeds increased after short exposure periods to microwave recording 100% germination. Further the germination rate, relative germination coefficient were also increased after short exposure periods to microwave. Longer exposure periods reduced the percentage of germination, germination rates, and various germination indices. Morphological and growth traits showed a similar trend and were significantly decreased after longer exposure periods to microwave. Chlorophyll contents were significantly decreased with increasing exposure periods of microwave. Microwave-induced electrolyte leakage (%) was significantly increased (r=0.92*, p<0.001) following pretreatment with different exposure periods of microwave. Current research data gives spotlight on possible positive and negative effects of microwave on barley and recommended to minimize the exposure time to environmental microwave to safeguard recovering ability of biological systems. However, the positive effects of microwave are of considerable importance for improving crops.

Establishment of evaluation procedure for soybean seed-flooding tolerance and its application to screening for tolerant germplasm sources

The experiments concluded 48hrs for germination testing as most appropriate stress duration. Using paper roll for recording the traits was the best method than petri dish and towel method. Among the traits relative germination rate (RGR), relative seedling length (RSL), relative root length (RRL), relative root fresh weight (RRFW) and relative root dry weight (RRDW) were proved to be flooding-responsive. RSL was chosen as the major seed-flooding indicator due to higher heritability (h2), genotypic coefficient of variation (GCV), correlation with other indicators and easier measuring procedure, while RRL was considered as the subsidiary indicator. Thus, the RSL in paper roll after 48hrs seed-flooding was recognized as standard seed-flooding testing procedure and used to evaluate breeding materials. Among the 11 cultivars, the superior seed-flooding-tolerant ones were M8206, NN1138-2 and ZXD, while ten best lines were evaluated from one hundred breeding lines.

Phytotoxicity test applied to sewage sludge using Lactuca sativa L. and Lepidium sativum L. seeds

Sewage sludge from wastewater treatment plants (WWTPs) has increased in recent years in Spain and Europe in general. Agriculture seems a viable solution when seeking alternatives for its final disposal. Sewage sludge reuse can, however, pose risks given presence of heavy metals, pathogen microorganisms or toxic compounds, which must be controlled to minimize risks for human health and the environment. In the present study, the phytotoxicity of sewage sludge from the Alcazar de San Juan WWTP using two types of seeds (Lactuca sativa L. and Lepidium sativum L.) in bioassays was analyzed. The relative germination rates (RGP), relative radicle growth (RRG) and germination index were determined for both species. Hypocotyl length was measured in lettuce. Negative (distilled water) and positive (zinc sulfate) controls were prepared. Depending on the biological material and residue phytotoxicity dose, analyses can be modified given the different sensitivities of plants. Lepidium sativum L. was more sensitive to phytotoxic compounds than Lactuca sativa L. Hypocotyl measurements provide complementary toxicity information. A general agreement between authors and researchers to standardize this type of analysis would be useful to make criteria uniform.

UV-B radiation-related effects on conidial inactivation and virulence against Ceratitis capitata (Wiedemann) (Diptera; Tephritidae) of phylloplane and soil Metarhizium sp. strains.

Recent studies have demonstrated the presence of Metarhizium species on the epigeal areas of weeds and woody plants in various Mediterranean ecosystems, and the question arises whether isolates from the phylloplane, which experiences greater exposure to environmental UV-B radiation than soil isolates do, could have better UV-B radiation tolerance. The in vitro response of 18 Metarhizium strains isolated from phylloplane and soil of several Mediterranean ecosystems to UV-B radiation and the in vitro and in vivo effects of UV-B radiation on the viability and virulence of a selected M. brunneum strain against C. capitata were determined. The conidial germination, culturability and colony growth of these strains exposed to 1200mWm-2 for 2, 4 or 6h were evaluated. Germination rates below 30% and poor conidia recovery rates were observed for all strains. However, no relationship between the Metarhizium species or isolation habitat and the effect of UV-B radiation was found. Strain EAMa 01/58-Su, which showed a high tolerance to UV-B inactivation in terms of relative germination, was subsequently selected to investigate the UV-B related effects on virulence toward C. capitata adults. In a series of bioassays, the virulence and viability was determined using pure dry conidia, which were irradiated with 1200mWm-2 for 6h prior or after adult flies were inoculated, which resulted in a significant 84.7-86.4% decrease in conidial viability but only a slightly significant reduction of virulence, with 100.0% and 91.4% adult mortality rates and 4.6 and 5.9days average survival time for the no UV-B and UV-B treatments, respectively. A second series of experiments was performed to determine whether the UV-B effects on strain EAMa 01/58-Su were dose- or exposure time-dependent. Adult flies were inoculated with five doses (1.0×104-1.0×108conidiaml-1) and then irradiated at 1200mWm-2 for 6h, and similar LC50 values, 3.8×107 and 4.3×107conidiaml-1, were determined for the UV-B and no UV-B treatments, respectively. However, the LT50 values for flies inoculated with 1.0×108conidiaml-1 and with1.0×107conidiaml-1 were 15.1% and 30.8% longer for UV-B treatments than no UV-B treatments, respectively. Next, adult flies were treated with 1.0×108conidiaml-1 and then exposed to 1200mWm-2 for 0, 6, 12, 24, 36 and 48h, and the relationships among exposure time and conidia viability and fly mortality losses were determined. The exposure time for adult flies at 1200mWm-2 to achieve a 50% reduction in fly mortality was 47.2h, which was longer than that of 5.6h required for a 50% reduction in conidia viability. Our results show that the UV-B radiation significantly affected the virulence of EAMa 01/58-Su strain against C. capitata adults, with this effect being dependent on the exposure time but not related to fungal dosage.

Seed Biology of the Weed Maryland Meadowbeauty (Rhexia mariana L.) in Blueberry (Vaccinium spp.)

ABSTRACTStudies were conducted at three locations across the North Carolina coastal plain region to determine sexual reproductive potential, seedbank density, frequency of seed dormancy, and effect of temperature on Maryland meadowbeauty seed germination. Seed capsule density ranged from 500 per m2 to 1124 per m2 across locations. Each capsule contained an average of 74 seeds. Seeds germinated only in the 35/20 °C temperature regime, which represents the hottest month (August) of the growing season in southeastern North Carolina. Total number of germinated seeds differed across locations and ranged from 30% to 57%. The percent (average) of viable (66) and nonviable (26) meadowbeauty seeds was not different across locations. Relative germination and seed dormancy percentages were calculated based on the number of viable seeds. The percent relative germination and seed dormancy were different across locations and ranged from 47% to 86% and 14% to 55%, respectively. The highest number of germination resulted from 90 days of stratification. On average, 27 seeds germinated among soil samples, which is equivalent to 989 seeds per m2. The data indicate that the populations of meadowbeauty in blueberry fields have the potential to sexually reproduce and contribute 5 × 106 to 1.1 × 107 seed capsules/ha and 3.7 × 108 to 8.3 × 108 seeds/ha of infestation. Freshly mature seeds can germinate and contribute 1.79 × 108 to 7.14 × 108 seedlings/ha in the year the seeds are produced and 5.18 × 107 to 4.4 × 108 seeds/ha can be dormant and incorporated into the seed bank on an annual basis. Approximately 9.89 × 106 seeds/ha are dormant and viable in the soil and have the potential to germinate following adequate stratification.

Relationship between seed quality and changes in conjugated polyamine in plasma membrane purified from wheat embryos during grain ripening

In order to explore the relationship between seed quality and changes in conjugated polyamine in plasma membrane purified from wheat embryos during grain ripening. Plasma membrane (PM) vesicles were isolated from the embryos of ripening wheat (Triticum aestivum L.) grains by the gradient centrifugation method. The contents of polyamines conjugated (covalently and non-covalently) to the PM vesicles were investigated. Results showed that after pollination, from the 22nd to the 32nd day, the embryos of wheat grains underwent dehydration, as judged by the decrease of embryo relative water content (ERWC). During embryo ripening, non-covalently conjugated (NCC)-Spd and NCC-Spm, covalently conjugated (CC)-Put and CC-Spd contents increased markedly, while relative embryo cell vigor (RECV) decreased slightly. The treatment with methylglyoxyl-bis (guanylhydrazone) (MGBG), an inhibitor of S-adenosylmethionine decarboxylase (SAMDC), inhibited the increases of the NCC-Spd and NCC-Spm contents, enhanced the decrease of RECV simultaneously, and decreased mature seed relative germination potential (RGP). The effects of MGBG were reversed by exogenous Spd and Spm. Phenanthrolin (o–Phen), an inhibitor of transglutaminase (TGase), inhibited the increases of CC-Put and CC-Spd contents, enhanced the decrease of RECV simultaneously, and decreased mature seed RGP. These results suggest that during embryo ripening, the levels of NCC-Spd, NCC-Spm, CC-Put, and CC-Spd increase, and these increases might affect embryo cell vigor and seed germination potential.

Genotypic variability in salt tolerance of Vicia faba during germination and early seedling growth

Salt tolerance of four Egyptian Vicia faba L. cultivars – Nubaria 1, Nubaria 2, Sakha 1 and Giza 3 – was investigated at germination in relation to seed size. The variability in seed size was wide as seed index of Giza 3 was about half that of Nubaria 1. The four investigated cultivars can withstand up to 150mM NaCl; with marginal reductions in germination capacity but with marked reductions in speed of germination and embryo growth. The vague genotypic variability among the four cultivars in germination parameters emerged more clearly under salt stress. The response of early emergence of the embryo to salt stress seems to differ from that of the subsequent extension of embryonic axis; since based on magnitude and speed of germination Nubaria 1 was the most salt sensitive cultivar but exhibited relatively high salt tolerance on the basis of embryo growth. The salt-sensitive Nubaria 1 produced smaller embryo, with shorter and thicker radicles than the other three cultivars. Germination speed and embryo growth were maximum but lag period was minimum for the medium-sized seeds. Length and thickness of the emerging radicles were affected more by the genotype than by salinity stress and nutrient supply during germination. The beneficial effects of nutrients on seed germination and embryo growth were more evident in the salt-tolerant Nubaria 2 than in the salt-sensitive Nubaria 1.

Seed germination in relation to the invasiveness in spiny amaranth and edible amaranth in Xishuangbanna, SW China.

Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor) are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C), and at lower water potential (below -0.6 MPa). It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions—excellent seed traits for crops and for many invasive species—might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

Phytotoxicity of Rosmarinus officinalisL. and Salvia officinalis L. to Control the Noxious Weed, Panicum turgidum Forssk.

PETRI-DISH experiments were applied to investigate thepotential allelopathic effects of cold and hot aqueous extracts ofRosmarinus officinalis and Salvia officinalis on germinationpercentage, relative germination percentage, and inhibition percentageas well as plumule and radicle lengths of Panicum turgidum. Theresults indicate that the degree of inhibition of seed germination andthe growth of the recipient species was largely dependent on theconcentration of the extracts of both donor species. The effect wasstatistically significant at p ≤ 0.05 for most treatments. The p resentthe study recommends the use of the two donor species for the biocontrolof weeds like Panicum turgidum.

Effect of industrial effluents on seed germination and seedling growth of rice

An experiment was conducted during T. Aman 2010 and Boro 2010-11 seasons to determine the effect of industrial effluents on seed germination and seedling growth of rice. In both the seasons, all the effluents and city waste water (CWW) had no effect on rice seed germination except pharmaceutical effluent. Pharmaceutical effluent showed the lowest seed germination. City waste water gave the highest shoot length (8.40 and 5.38 cm) and root length (8.06 and 6.35 cm) in the T. Aman and Boro seasons, respectively. Pharmaceutical effluent gave the highest shoot-root ratio of 10.49 while tannery effluent gave lowest ratio of 0.91. In both T. Aman and Boro seasons, seedling weight with and without endosperm, seedlings dry weight, seedling strength were found higher with CWW. During T. Aman and Boro seasons, relative germination ratio showed higher with a beverage effluent but relative shoot and root elongation ratio were found higher with CWW managed treatment.&#x0D; Dhaka Univ. J. Biol. Sci. 26(1): 59-68, 2017 (January)

Germination, Physiological Responses and Gene Expression of Tall Fescue (Festuca arundinacea Schreb.) Growing under Pb and Cd.

Cadmium (Cd) and lead (Pb) are recognized as the most toxic metal ions due to their detrimental effects not only to plants, but also to humans. The objective of this study was to investigate the effects of Cd and Pb treatments on seed germination, plant growth, and physiological response in tall fescue (Festuca arundinacea Schreb.). We employed six treatments: CK (nutrient solution as control), T1 (1000 mg L-1 Pb), T2 (50 mg L-1 Cd), T3 (150 mg L-1 Cd), T4 (1000 mg L-1 Pb+50 mg L-1 Cd), T5 (1000 mg L-1 Pb+150 mg L-1 Cd). Antagonistic and synergistic actions were observed in tall fescue under Pb and Cd combined treatments. Under low Cd, plants exhibited higher relative germination rate, germ length, VSGR, catalase (CAT) and peroxidase (POD) activities. Additionally, in the shoots, the gene expression level of Cu/Zn SOD, FeSOD, POD, GPX, translocation factors, MDA, EL, and soluble protein contents were reduced under Pb stress. Conversely, under high Cd level, there was a decline in NRT, Pb content in shoots, Pb translocation factors, CAT activity; and an increase in VSGR, Pb content in roots, gene expression level of Cu/ZnSOD and POD in tall fescue exposed to Pb2+ regimes. On the other hand, tall fescue plants treated with low Cd exhibited lower relative germination rate, germination index, germ length, NRT, Cd content in roots. On the other hand there was higher Cd content, Cd translocation factor, CAT and POD activities, and gene expression level of Cu/Zn SOD, FeSOD, POD, GPX under Pb treatment compared with single Cd2+ treatment in the shoots. However, after high Cd exposure, plants displayed lower NRT, Cd content, CAT activity, and exhibited higher Cd contents, Cd translocation factor, MDA content, gene expression level of Cu/ZnSOD and GPX with the presence of Pb2+ relative to single Cd2+ treatment. These findings lead to a conclusion that the presence of low Cd level impacted positively towards tall fescue growth under Pb stress, while high level of Cd impacted negatively. In summary, antioxidant enzymes responded to Cd and Pb interaction at an early stage of exposure, and their gene expression profiles provided more details of the activation of those systems.

Germination Capacity of Porophyllum Ruderale (JACQ.) Cass (Asteraceae) A Food Crop Weed in Côte d’Ivoire

Germination Capacity of Porophyllum Ruderale (JACQ.) Cass (Asteraceae) A Food Crop Weed in Côte d’Ivoire Kpla Christine F; Touré A, Ipou Ipou J Abstract Porophyllum ruderale is a weed present in all the regions of Côte d’Ivoire. It is a weed that rapidly colonizes agricultural parcels. A comparative study of its seed germination in relation to agro ecological areas was carried out. Selected seeds were sown in three different environments to test their germinative capacity. These are a closed environment and two opened environment in the south and central western Côte d’Ivoire. To determine the effect of sowing depth on the germination capacity, six sowing depths were tested: 0 cm, 0.5 cm, 1 cm, 2.5 cm, 5 cm and 10 cm. The results showed that the germination rate in the open environment is significantly different from that of the closed environment. We have 40-70% in natural environments and 10% in closed environments. For the depth test, the highest germination rate was obtained with seeds sowed at soil surface (0 cm) and the smallest one at 2.5 cm. These are 84% and 2.5% respectively. Our work has shown that Porophyllum ruderale is a heliophilic species because the presence of light activates its germination capacity. In a closed environment, the absence of this factor delays the growth of the weed until preventing flowering. It therefore fails to complete its life cycle, which is about six months. Thus, deep plowing cold prevent the development of Porophyllum ruderale. Full Text: PDF DOI: 10.15640/jaes.v6n2a13