Effects of gamma rays irradiation on seed germination and growth of hard wheat

The effects of irradiation with low doses (0, 10, 20 and 30 Gy) of radioactive cobalt (⁶⁰Co) γ rays on seed germination, shoot and epicotyl growth of hard wheat (Triticum durum Desf.) were investigated under laboratory and glasshouse conditions. Irradiated wheat seeds kept their germination speed and capacity levels compared to the control. However, improvements of +18 and +32% were, respectively obtained in root number and root length at the 20-Gy dose. Moreover, the 20-Gy-irradiation dose generated an increase of +33% in epicotyl length. The 20-Gy-irradiation dose improved the root length by +32% and root number by +75% in plants grown on liquid medium. A lower root length increase of +23% was obtained with the same treatment under glasshouse growing conditions. These results show that the in depth development stimulation of hard wheat roots following gamma ray treatment may be used for drought control.     

Response of peroxidase and catalase to acid rain stress during seed germination of rice, wheat, and rape

Seed germination of plants with various acid-resistance display different responses to acid rain. To understand the reason why such differences occur, the effects of simulated acid rain (pH 2.5–5.0) on the activities of peroxidase (POD) and catalase (CAT) during seed germination of rice (O. sativa), wheat (T. aestivum), and rape (B. chinensis var. oleifera) were investigated. Results indicated that the maximum change in activities of CAT and POD by acid rain treatment with different acidity and time in relation to the referent treatment without acid rain, was in the order: rice (28.8%, 31.7%) < wheat (34.7%, 48.3%) < rape (79.3%, 50.0%). The pH level for which the treatment with acid rain did not cause significant difference (p < 0.05) was in the order: rice (3.5).wheat (4.0).rape (5.0). Moreover, the change in activity of POD was higher than that of CAT, which showed that POD was more sensitive to acid rain stress than CAT. The difference in the ability of POD and CAT in removing free radicals was one reason why the germination indexes of these three species behaved differently.     

两种四环素类兽药抗生素对白菜种子发芽与根伸长抑制的毒性效应

采用土培和水培相结合的方法,在预试验研究的基础上,研究砖红壤中不同质量分数金霉素（0～4 000 mg·kg-1）、土霉素（0～25 000 mg·kg-1）和水溶液中不同质量浓度金霉素（0～150 mg·L-1）和土霉素（0～150 mg·L-1）污染对白菜（Brassica pekimensis）种子发芽的抑制与毒性效应。结果表明：（1）当土壤中添加外源土霉素时,白菜种子发芽率总体呈下降趋势。而当添加金霉素时,白菜种子发芽率在85%附近波动,与对照相比,并无显著差异（P〉0.05）。而在水培条件下,金霉素对白菜发芽的抑制作用大于土霉素,但并未达显著差异水平（P〉0.05）。（2）白菜根伸长量随着土壤、水溶液中土霉素和金霉素质量分数或质量浓度的增加而缩短,生长均受到抑制。且与两种抗生素的质量分数或质量浓度均表现为极显著的相关性（P〈0.01）。（3）同一质量分数或质量浓度水平下,发芽率、根伸长、芽伸长对金霉素和土霉素的生态毒性敏感顺序依次为根伸长〉芽伸长〉发芽率。根伸长抑制率可作为诊断土霉素、金霉素对土壤毒性的敏感指标,反映土壤被四环素类抗生素污染的状况。（4）金霉素和土霉素在水培条件下对白菜的IC50值分别为20.32和287.52 mg·L-1。而在土壤中,白菜对金霉素和土霉素的IC50值分别为851.08和14 045.75 mg·kg-1。说明在土霉素对白菜的毒性作用小于金霉素,并且2种抗生素在土壤中对白菜根伸长的抑制效应明显低于水溶液中的抑制效应,这与土壤对抗生素污染有重要的缓冲作用有关。     

塑料地膜对小麦种子萌发及幼苗抗氧化酶系统的影响

研究了中国北方地区常用的塑料地膜对小麦Triticum aestivum L.种子发芽率,芽长根长及幼苗抗氧化酶系的影响以探明塑料地膜的毒性。结果显示500~2 500 mg.kg-1两种质量分数的塑料地膜处理对小麦种子的发芽率几乎不产生影响,在高质量分数（≥5 000 mg.kg-1）处理下小麦的发芽率有所下降。500~5 000 mg.kg-1的塑料地膜能促进小麦叶和根的伸长,但在高质量分数情况下则显著抑制了根和芽的延伸,其中15 000 mg.kg-1添加量下,叶和根的抑制率分别达到了16.70%和15.07%。小麦根系抗氧化酶活性对两种塑料地膜的敏感程度大于叶片。在高质量分数条件下,根系中超氧化物歧化酶（SOD）活性随暴露时间的延长明显受到了抑制。在经地膜1和地膜2处理后,小麦叶片中过氧化物酶（POD）及过氧化氢酶（CAT）活性在不同暴露时间和不同质量分数下没有显著差异,但地膜1处理后的小麦根系中的POD随暴露时间的延长呈先降低后增加的趋势,而CAT活性变化不大。地膜2处理后的小麦根系中的POD和CAT活性随暴露时间的延长而降低。结果表明,高质量分数塑料地膜的处理会对小麦早期幼苗的抗氧化酶系统产生毒害作用。     

Activity of insect juvenile hormone III: seed germination and seedling growth studies

Summary. Juvenile hormones are sesquiterpenoids that regulate developmental processses such as metamorphosis and reproduction in insects. Insect juvenile hormone III (JH III), methyl-10R,11-epoxy-3,7,11-trimethyl-2E,6E-dodecadienoate, has also been identified in two sedge species, Cyperus iria and C. aromaticus (Toong et al. 1988). Potential allelopathic activity of this compound and the structurally related sesquiterpenoid farnesol was investigated using seed germination and seedling growth assays with radish, lettuce and rice. Treatment of seeds with JH III delayed lettuce seed germination and potently inhibited rice shoot growth. Both farnesol and JH III inhibited the growth of C. iria seedlings. The antimicrobial activity of JH III was also tested on a taxonomic and ecologically diverse range of fungi. Using the classic cytotoxic disk assay, JH III did not effect growth of the fungal species tested. We believe that JH III may contribute to the aggressive nature of this invasive weed species. Received 11 October 1999; accepted 26 February 2000     

Possible cause of inhibition of seed germination in two rice cultivars by heavy metals Pb2+ and Hg2+

Seeds of two rice cultivars (Oryza sativa) cv. PR-116 and Pant Dhan-12 subjected to heavy metal lead (Pb²⁺) and mercury (Hg²⁺) exposure showed an inhibition in germination percentage, shoot and root length, and lower fresh and dry weight after 7 days. Both Pb²⁺ and Hg²⁺ inhibited the solubilization process of starch due to reduction in α-amylase activity, which is also evident from greater starch content and reduced soluble carbohydrate content of endosperms of treated seeds of the two cultivars. Mercury was more tolerated by Pant Dhan-12 when grown under in vitro culture medium containing 2% sucrose. The inhibitory effect of Pb²⁺ on embryo growth was not only abolished but also accelerated by 2% sucrose. The inhibitory effect, however, was not significantly blocked in Hg²⁺-treated embryos grown in vitro in sucrose containing medium. Embryos did not grow normally in a medium devoid of sucrose in either case. Data indicated that Pb²⁺ inhibited germination and seedling growth by impairing the solubilization of endosperm starch without markedly affecting the embryo, while Hg²⁺ inhibited germination and seedling growth by damaging the embryo itself.     

Effects of organic matter on Leymus chinensis germination,growth, and urease activity and available nitrogen in coastal saline soil

ABSTRACT

The present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J₀V₀Y₀, J₁V₀Y₀, J₀V₁Y₀, J₀V₀Y₁, J₁V₁Y₀, J₁V₀Y₁, J₀V₁Y₁, J₁V₁Y₁. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J₀ – no straw powder, J₁ – 0.2 kg straw powder, Y₀ – no manure, Y₁ – 0.3 kg manure, V₀ – no microbial fertilizer, V₁ – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments.     

连续两年紫外线-B辐射增强对玉米种子发芽及幼苗生长的影响

研究了在紫外线 (UV -B)辐射增强条件下与自然光下生长的玉米种子的发芽和幼苗生长特性以及对UV -B反应的变化。结果表明 :与自然光下生长的玉米种子相比 ,UV -B辐射增强条件下生长的玉米种子的发芽率和幼苗生长指标有不同程度的下降 ,但在连续两年UV -B强度增加条件下 ,其种子发芽和幼苗生长指标受高强度UV -B影响的程度显著下降。在连续两年UV -B辐射增强条件下生长的玉米种子萌发的幼苗叶片类黄酮含量显著高于在自然光下生长的玉米种子萌发的幼苗 ,这可能是在UV -B辐射增强条件下生长的玉米对UV -B辐射增强产生适应性的重要原因之一。     

不同pH与重金属Cd胁迫对紫穗槐萌发和幼苗生长的影响

为了探索紫穗槐修复酸性矸石山的机制,研究了含有0—20μmol.L-1CdCl2的不同pH(3.0—7.5)溶液对紫穗槐种子萌发和幼苗生长的影响.种子萌发结果表明,不同pH溶液处理对紫穗槐萌发率(约62%)和发芽势(约48%)无显著影响;当在不同pH(3.0—7.5)溶液中添加10—20μmol.L-1CdCl2时,10μmol.L-1Cd2+可促进种子萌发,20μmol.L-1Cd2+则抑制种子萌发.萌发露白的紫穗槐种子在不同pH溶液处理10 d时,幼苗的根长和株高在pH 4.5—5.0的酸性溶液最大,而在pH 3.0溶液中最小.添加CdCl2后,幼苗的根长变化趋势与单一pH结果一致,但均低于相应的pH.紫穗槐幼苗在单一pH与pH+10μmol.L-1CdCl2联合处理20 d时,株高和根长在pH 4.5—5.0溶液中最大,Cd可显著抑制幼苗根的生长.研究结果说明,pH 3.0—5.0酸性水不影响紫穗槐种子萌发,20μmol.L-1Cd显著抑制种子萌发;紫穗槐幼苗能耐pH 3.5—5.0酸性和10μmol.L-1Cd胁迫,为紫穗槐修复酸性矸石山提供了理论依据.     

Impact of fertilizer factory effluent on seed germination, seedling growth and chlorophyll content of gram (Cicer aeritenum)

In the present study effect of fertilizer factory effluent on seed germination, seedling growth and chlorophyll content of gram (Cicer aeritenum) has been carried out, at different concentration of the effluent and time intervals. The effluent is alkaline in nature with strong ammonia odour. The germination percentage of seed, seedling growth and chlorophyll content showed a gradual decline with increase in effluent concentration. At 25% concentration of the effluent, growth promotion in terms of root, shoot length and increase in chlorophyll content recorded at 21 days. However, at higher concentrations of the effluent toxic effects were observed at 21 days. The study suggests that the effluent can be used safely for Cicer aeritenum cultivation, only after proper treatment and dilution.     

Population structure of the widely dispersing marine bryozoan Membranipora membranacea (Cheilostomata): implications for population history, biogeography, and taxonomy

Morphologically plastic, cryptic, or geographically widespread species pose similar challenges to the evolutionary biologist: their taxonomic status is often unclear yet must be known to study almost any aspect of their biology, ecology, evolution, or biogeography. The marine bryozoan Membranipora membranacea (L.) is morphologically plastic and geographically widespread in temperate oceans of the Northern and Southern Hemispheres, and its taxonomy is unclear. This study examined genetic relationships among allopatric populations and sympatric morphs of this species, or species complex. Colonies were collected from 1992 to 1995. Allozymes were used to elucidate the relationships among four widely separated populations, two in the North Atlantic and two in the North Pacific Ocean. Allozymes and mtDNA sequencing were used to clarify the genetic relationships among three sympatric morphs that might correspond to the species M. villosa Hincks and M. membranacea in the northeastern Pacific (Washington State). Populations in the North Atlantic and North Pacific had no fixed allelic differences at the loci tested but were separated by an average Nei's genetic distance of 0.581, suggesting their near-sibling species status. Populations from Friday Harbor (Washington) and Catalina Island (California) were not significantly differentiated, which was attributed to high gene flow. Populations on either side of the North Atlantic were genetically indistinguishable, which is most likely due to the recent establishment of the West Atlantic populations from European founders. At Friday Harbor, sympatric morphs varying in their spination and spine inducibility were genetically indistinguishable, supporting the hypothesis that M. villosa is an induced phenotype of M. membranacea and not a distinct species in the northeastern Pacific. Since such phenotypic plasticity is common in cheilostome bryozoans, the morphospecies concept must be used with caution. Received: 31 August 1998 / Accepted: 10 August 1999     

TiO2@palygorskite composite for the efficient remediation of oil spills via a dispersion-photodegradation synergy

• A novel and multi-functional clay-based oil spill remediation system was constructed. • TiO₂@PAL functions as a particulate dispersant to break oil slick into tiny droplets. • Effective dispersion leads to the direct contact of TiO₂ with oil pollutes directly. • TiO₂ loaded on PAL exhibits efficient photodegradation for oil pollutants. • TiO₂@PAL shows a typical dispersion-photocatalysis synergistic remediation. Removing spilled oil from the water surface is critically important given that oil spill accidents are a common occurrence. In this study, TiO₂@Palygorskite composite prepared by a simple coprecipitation method was used for oil spill remediation via a dispersion-photodegradation synergy. Diesel could be efficiently dispersed into small oil droplets by TiO₂@Palygorskite. These dispersed droplets had an average diameter of 20–30 mm and exhibited good time stability. The tight adsorption of TiO₂@Palygorskite on the surface of the droplets was observed in fluorescence and SEM images. As a particulate dispersant, the direct contact of TiO₂@Palygorskite with oil pollutants effectively enhanced the photodegradation efficiency of TiO₂ for oil. During the photodegradation process, •O₂⁻and •OH were detected by ESR and radical trapping experiments. The photodegradation efficiency of diesel by TiO₂@Palygorskite was enhanced by about 5 times compared with pure TiO₂ under simulated sunlight irradiation. The establishment of this new dispersion-photodegradation synergistic remediation system provides a new direction for the development of marine oil spill remediation.     

Rice straw ash extract, an efficient solvent for regioselective hydrothiolation of alkynes

Environmental Chemistry Letters - Herein, we describe a simple and inexpensive protocol for the hydrothiolation of alkynes. In this context, water extract of rice straw ash (WERSA) has been proven...     

Changes in seed dispersal processes and the potential for between-patch connectivity for an arid land daisy

Dispersal is a major and critical process in population biology that has been particularly challenging to study. Animals can have major roles in seed dispersal even in species that do not appear specifically adapted to animal-aided dispersal. This can occur by two processes: direct movement of diaspores by animals and modification of landscape characteristics by animals in ways that greatly influence dispersal. We exploited the production of large, persistent dispersal structures (seed heads, henceforth) by Erodiophyllum elderi (Asteraceae), a daisy from arid Australia, to further understand secondary dispersal. Seed head dispersal on and off animal tracks in eight E. elderi patches was monitored for 9.5 months by periodically recording the location of marked seed heads. Sites were located inside a reserve that excludes sheep but not kangaroos, and in a nearby area with both kangaroos and sheep. The distance moved and likelihood of seed head movement was higher in areas with sheep, and especially along animal tracks. There was clear evidence that seed heads were channeled down animal tracks during large rainfall events. Seed head dispersal away from patches occurred to a limited extent via their physical contact with sheep and potentially via wind dispersal. Thus, the advantages of this study system allowed us to demonstrate the two postulated effects of herbivores on dispersal via direct movement of seed heads, and two distinct indirect effects through landscape modification by herbivores from the creation of animal tracks and the denudation of vegetation.     

Distillery effluent effect on seed germination,early seedling growth and pigment content of sugarbeet (Beta vulgaris Linn. var. mezzanau-poly)

Bioassay studies were carried out to assess the toxicity of distillery effluent on seed germination, seedling growth and pigment contents. Higher concentrations (> 5%) of effluent were found to be toxic but however, can be used for irrigational purpose after proper dilution.     

Detoxification of 4-chlorophenol in TiO2 sunlight system: effect of raw and treated solution on seed germination and plants growth of various sensitive vegetables

The mineralization and detoxification of 4-chlorophenol (4-CP) were studied using a TiO₂-paper/sunlight system. The possibility of reusing the photocatalyst was examined to determine the cost effectiveness of the method. Experiments were performed to establish optimum conditions for 4-CP removal. Phytotoxicity of photo-treated and raw 4-CP (100 mg L^?1) solutions on seed germination and plant growth were carried out with the aim of water reuse and environment protection. The seeds irrigated with raw 4-CP solution showed lower sprout length while increase in sprout length was observed with the photo-treated solution for tomato (Lycopersicon esculentum), lettuce (Lactuca sativa), onion (Allium cepa), and turnip (Brassica rapa). Plant growth tests with the photo-treated 4-CP solution did not affect the leaf numbers compared to those irrigated with tap water. Photo-treated 4-CP solution can be used for irrigation in agriculture.     

Spatial and temporal patterns of seed dispersal: an important determinant of grassland invasion.

We measured spatial and temporal patterns of seed dispersal and seedling recruitment for 58 species in a grassland community to test whether seed dispersal could predict patterns of invasion after disturbance. For the 12 most abundant grasses, recruitment of native species was dependent on the propagule supply of both native and exotic species. Variability in seed rain on small spatial (1-10 m) and temporal (within season) scales led to qualitative differences in the outcome of disturbance colonization such that native species dominated disturbances when exotic seed supply was low but failed to establish when exotic seed supply was high. Local dispersal and spatial heterogeneity in species composition promoted coexistence of native and exotic species by creating refuges from high exotic seed supply within native dominated patches. Despite this, copious exotic seed production strongly limited recruitment of native species in exotic dominated patches. Most grasslands in California are presently dominated by exotic species, suggesting that competition at the seedling stage is a major barrier to native species restoration.     

Microalgae binary culture for higher biomass production,nutrients recycling,and efficient harvesting: a review

Environmental Chemistry Letters - Microalgae are photosynthetic cell factories of global interest for fuels, food, feed, bioproducts, carbon sequestration, waste mitigation, and environmental...     

Towards the development of an operational tool for oil spills management in the Algarve coast

Portugal is strongly vulnerable to sea hazards due to intense vessel traffic and sea conditions. The southwest region off the Iberian Peninsula lies in the main route from the Mediterranean and Southern Hemisphere to the Northern Europe, causing a ship concentration in a narrow band off Cape S?o Vicente. Tankers represent a significant part of the vessel traffic and the occurrence of oil spills cannot be disregarded. Cape S?o Vicente region is part of a Natural Park with 110 Km of coastline, integrated in the European Natura 2000 network and its socio-economic context is closely related with sea resources exploitation, particularly fishing and tourism. Recognizing the importance of accurate information systems for the decision making process in an oil spill situation, this work presents the development of an integrated tool to support the process in the Algarve coast. The system relies in a regional operational mathematical model based on the MOHID modelling system. The system core is composed by three models (3D hydrodynamics, wave and Lagrangian transport) all linked in the same system and exchanging information in real time. Oil advection and weathering processes are coupled to the Lagragian transport model. The overall operational system includes external operational data products as inputs, to ensure a successful validation of the results. The system is linked to stakeholders and response authorities using a geographic referenced database based on Mapserver technology that will include relevant information for oil spill management.     

Short-term effects of an oil spill on the West coast of the Cape Peninsula, South Africa

In 1994, the sinking of the ‘Apollo Sea’ off the West coast of South Africa led to the deposition of ca. 2 500 tons of heavy fuel oil over 150 km of coastline. The impact of the spill on rocky shore invertebrates, rock-pool fish fauna and rock lobsters was assessed by conducting surveys shortly after the spill, and again two months later. Where possible, results of these surveys were compared with existing data from before the sinking of the Apollo Sea. Among the fish fauna of rock-pools, changes in total density of fishes were largely due to changes in the abundance ofClinus superciliosus and were within the range of natural variation for the species and the community as a whole. Community structure of the rock-pool fish fauna also remained unaffected. At three of four impacted rocky shore sites no changes could be detected in overall benthic community structure, although the winkleNodilittorina africana was affected. At the fourth site, a boulder beach, statistical analysis showed distinct differences in community structure between heavily and lightly contaminated areas, as well as between all areas compared with previously existing data. There were also significant changes in the lightly oiled areas between the first and second surveys after the spill. Oil-fouled lobster were found at one of three sites investigated. Ca. 7 % of the seabed in this particular area was polluted. Antennae and forelegs of almost all lobsters in the vicinity of the oil were fouled. Examination of the gut-contents confirmed that oil inhibits the ability of lobster to feed. Although there was no evidence that mortalities of lobster were caused by the spill, growth rates may be reduced by the decreased feeding rate. Overall, the impact of the spill was strikingly less than might have been predicted from the effects of other oil spills. Nomenclature: Names of fish species follow Smith & Heemstra (1986).