Proportion Of Dry Weight Research Articles

Comparison of soil improvement techniques on the development of efficient consolidation response

A comprehensive experimental program including two distinct series of consolidation tests was performed on clay specimens prepared at different dry weight proportions including 0%, 1%, 2.5%, 5%, 7.5%, 10% polypropylene fiber or lime by weight mixed with clayey soil. Fiber inclusion into clay resulted in enhancement of compressive strength characteristics, improvement of hydraulic properties that is an advantage for modification of stability and durability properties of clayey soil under loads. Similarly, the higher hydraulic conductivity of clay resulted that will shorthen duration of consolidation settlement, hence, eventually influence completion of plastic consolidation deformation favorably for soft clays. Lime-treatment on clay specimens showed that the compressibility properties are improved such that the strength of clay against loading enhances, exhibits less consolidation deformation under load owing to increase in lime content. On the other hand, clay becomes highly impermeable, displays substantially larger water-resistant properties because of increased lime mass proportion (i.e. time-extension) in clayey soil that results in prolongation of expulsion of excess porewater pressure from clay due to load application, relevant induced stresses. Fiber-inclusion resulted in exhibiting logarithmic decrement with a mild rate of decline while lime-treatment led to exponential reduction with a sharp rate of drop for compression index (Cc), compressibility coefficient (αv), volume compressibility coefficient (mv). Further, fiber-inclusion stimulated exponential and quadratical increment whereas lime-treatment induced exponential decrement for coefficient of consolidation (cv), hydraulic conductivity (k), respectively. As a result, the Cc, αv, mv enhanced on the order of within 10 at average of 80% to 90% with a minimum of 70% by value for both fiber-reinforcement and lime-stabilization soil-stabilization techniques. The cv, k improved on the order of within 10 at average of 75% to 85% by value for fiber-reinforcement whereas dis-improved on the order of within 10 at average of 70% to 80% by value for lime-stabilization.

Effect of growth promotors on morphogenesis, photosynthetic apparatus, productivity and residual substances content in sweet pepper (Capsicum annuum) fruits

The use of plant growth promoting substances in order to optimize crop performance is one of the leading tasks of modern plant physiology. The effect of 0.005% 1-naphthaleneacetic acid (1-NAA), 0.005% gibberellic acid (GA3), 0.005% 6-benzylaminopurine (6-BAP) foliar treatment on morphogenesis, leaf parameters, photosynthetic pigments content, photosynthetic apparatus activity indices, and residual amounts of the used substances in the sweet pepper Capsicum annuum L. variety Antey fruits was investigated. The field experiment was laid on plots of 32 m2. The treatment of plants was carried out at the budding stage. Morphometric indices were determined at the flowering and fruit formation stages. The mesostructure of the middle tier leaves was studied at the fruit formation stage. The content of the chlorophylls was determined in the fresh leaf tissue by the spectrophotometric method. Indices of photosystem II (PSII) activity were determined by registration of chlorophyll fluorescence induction, using a portable single-beam fluorimeter. The assay of the residual content growth of promotors in the fruits was carried out on a Shimadzu GC gas chromatograph with a mass spectrometric detector – GCMS-QP2020 EI. It was revealed that treatment with GA3 increased plant height. All substances increased the number of leaves on the plant, their fresh and dry weight, the leaf area, and the canopy leaf area index. All growth promoting substances thickened leaf laminas due to the growth of chlorenchyma. GA3 and 6-BAP increased the volume of columnar parenchyma cells, and 1-NAA and GA3 increased the size of leaf spongy parenchyma cells. 6-BAP increased the total chlorophyll (a + b) content in the leaves, and under the GA3 treatment this index tended to decrease. 6-BAP increased the chlorophyll index of plants at the fruit formation stage, and GA3 decreased it at the flowering stage. The net photosynthetic rate increased under the influence of 1-NAA and 6-BAP, and decreased under GA3 treatment. GA3 reduced photorespiration and transpiration in leaves, 6-BAP increased transpiration, and 1-NAA decreased it. All substances increased dark respiration. Treatment with GA3 and 6-BAP reliably increased the maximum quantum efficiency of PSII photochemical reactions. 1-NAA and 6-BAP increased the actual quantum efficiency of PSII photochemistry. The coefficient of chlorophyll fluorescence photochemical quenching significantly increased at flowering under the application of 1-NAA, and tended to increase at the stage of fruit formation under the treatment of 1-NAA and 6-BAP. When GA3 was applied, the rate of chlorophyll fluorescence photochemical quenching was significantly reduced. The index of PSII reaction centers fraction that do not reduce the QB acceptor did not change with the use of 1-NAA and GA3 and tended to decrease after the use of 6-BAP. All growth promotors increased the whole plant dry weight. They reduced the net photosynthetic efficiency at the flowering stage, and at the stage of fruit formation it significantly increased under the treatment with 6-BAP. The 6-BAP caused the redistribution of plastic substances into the fruits due to the decrease in the dry weight of vegetative organs. Treatment with 1-NAA increased the proportion of root dry weight. 1-NAA, GA3 and 6-BAP increased the yield of fruits from one plant by 17%, 22% and 20% respectively due to the increase in the number of fruits per plant. The residual amounts of 1-NAA and 6-BAP in ripe sweet pepper fruits did not exceed the maximum permissible sanitary standards.

Variations of intact phospholipid compositions in the digestive system of Antarctic krill, Euphausia superba, between summer and autumn.

The biochemical composition of Antarctic krill, Euphausia superba, is largely determined by their feeding behaviour. As they supply energy for animals of a higher trophic level and are also commercialized for human consumption, the interest in research on the species is high. Lipids, especially phospholipids, make up a high proportion of dry weight in krill. Seasonal changes are well documented in the fingerprint of free fatty acids analysed after hydrolysis of phospholipids, but the underlying intact polar lipids are rarely considered. In this study, we evaluated the compositions of intact phospholipids (IPLs) in the stomach, digestive gland and hind gut of Antarctic krill caught in summer and autumn at the Antarctic Peninsula region. Using high-resolution mass spectrometry, the fatty acid composition of 179 intact phospholipids could be resolved. Most IPLs were phosphatidylcholines, followed by phosphatidylethanolamines. Several very long chain polyunsaturated fatty acids up to 38:8, which have not been reported in krill before, were identified. The composition shifted to higher molecular weight IPLs with a higher degree of unsaturation for summer samples, especially for samples of the digestive gland. The data supplied in this paper provides new insights into lipid dynamics between summer and autumn usually described by free fatty acid biomarkers.

Increase of the morpho-physiological responses of sugarcane plants in vitro (Saccharum spp. hybrids) using sodium silicate

Sugarcane (Saccharum spp. hybrids) is used as raw material in the agri-food and bioenergy industries. Plant tissue culture (PTC) allows production of many propagules in a relatively short time and limited space. Silicon (Si) is considered a non-essential element, and studies have demonstrated a positive impact on the development of plants obtained through PTC. This study aimed to evaluate the bio-stimulant effect of sodium silicate (Na2SiO3) on the in vitro propagation of sugarcane (CP 72-2086 and Mex 69-290). Plant tips were established for each variety. The shoots obtained were then cultivated in an MS medium supplemented with different concentrations of Na2SiO3 (0, 2.5, 5.0, and 10.0 mg L−1). After 30 d, morphometric analysis, quantification of photosynthetic pigments, and stomatal index measurements were performed. The results showed that 10.0 mg L−1 of Na2SiO3 had a positive effect on the morphology of both varieties. The CP 72-2086 variety had a 0.5 number of shoots, 6.36 leaves and 5.8 roots more compared to the control. In contrast, the Mex 69-290 variety had more sizable proportion of shoot length (1.42 times), root length (2.20 times), and dry weight (1.33 times) compared to the control. However, 2.5 and 5.0 mg L−1 of Na2SiO3 decreased the responses of variables evaluated in both varieties compared to the highest concentration. While the addition of Na2SiO3 in both varieties had a bio-stimulant effect on the content of photosynthetic pigments. Results obtained suggest that Na2SiO3 can be used as a bio-stimulant agent during the commercial micropropagation of sugarcane hybrids.

Diet selection of sheep shifted from quality to quantity characteristics of forages as sward availability decreased

Understanding the dynamic inter-relationship between grazing animals and the pasture sward is critical for sustainable grazing management. A field study was conducted to investigate the relationships between the quantity and quality characteristics of forages and diet selection of 30-kg Mongolian ewes in different seasons in Bromus inermis improved meadow steppe. Using a residual herbage mass method (1 000 kg/ha in spring, 800 kg/ha in summer and 600 kg/ha in autumn) to adjust stocking rate, three seasonal rest grazing strategies (spring rest, summer rest and autumn rest) combined with continuous grazing were studied. In each season, diet selection of sheep, quantified by diet composition and selectivity index, was estimated using a plant wax marker technique. Quantity (dry weight proportion, coverage, frequency, density and height) and quality (CP, NDF, ADF and DM digestibility) characteristics of forages consumed by sheep were determined simultaneously. Our results showed that in spring with the highest sward availability (herbage mass), diet selection of sheep could be predicted by the positive linear relationship between quality characteristics of forages and their selectivity index. In summer, the diet selection could be predicted by both positive linear relationship between quality characteristics and selectivity index, and the relationship between quantity characteristics and diet composition. While in autumn with the lowest sward availability, it could be predicted by the positive linear relationship between quantity characteristics and diet composition. During the whole grazing season, the diet composition of B. inermis (40.4%) and Leymus chinensis (35.1%) were larger than that of Potentilla bifurca (9.5%) and Carex (15.1%) and the selectivity index of P. bifurca was the highest (0.62), followed by Carex (0.17) and B. inermis (0.05), and L. chinensis (−0.29) was the lowest. The two parameters of diet selection above were positively related to their quantity and quality characteristics, respectively. These results suggested that the influence of quality characteristics on diet selection of sheep decreased gradually as a result of the decline in sward availability, while the influence of quantity characteristics increased. This study provides a comprehensive understanding of diet selection of sheep examining the trade-offs between quantity and quality characteristics of forages. The knowledge of diet selection of sheep and the corresponding prediction regressions acquired in this study could give the basis for designing appropriate grazing management strategies.

Shear response and frictional properties of soil mixtures at different dry weight proportions

On a specific purpose to investigate and evaluate an important mechanical property of natural soil mixtures being shear response and frictional characteristics, an extensive laboratory experimental program has been conducted that consisted of a series of direct shear tests on various soil mixtures, including sand (S), silt (M) and clay (C), at different dry weight proportions [(i) S:100% – M:0% – C:0%; (ii) S:50% – M:50% – C:0%; (iii) S:50% – M:0% – C:50%; (iv) S:50% – M:25% – C:25%]. The experimental findings of the testing program have shown that the measured values of two crucial engineering design parameters such as the peak (τpeak) as well as the residual (τresidual) shear strengths for the soil mixtures are strongly influenced by the present soil type such that the detected values of τpeak, τresidual increase with an increase in sand content in the mixture whereas the attained values of τpeak, τresidual decrease with an increase in clay content in the mixture. Further, adding silt into sand-clay mixture improves strength characteristics such that the values of τpeak, τresidual become greater. On the other hand, adding silt into pure sand diminishes frictional resistance such that the values of τpeak, τresidual become lower. Consequently, it is seen that soil particle size (i.e. grain size) plays an important role on the shear strength behavior of the natural soil mixtures. Moreover, the displacement (δpeak) required to reach peak shear strength (τpeak) was also determined as a result of the direct shear tests. As such, the detected values of δpeak become larger with higher clay content available in the mixture, while the obtained values of δpeak become smaller with higher sand content existing in the mixture. Therefore, it is concluded that the higher the clay content, the mixture exhibits relatively more ductile shear behavior, whereas the higher the sand content, the mixture displays relatively more brittle shear response.

Characterizing the potential and suitability of Ethiopian variety Jatropha curcas for biodiesel production: Variation in yield and physicochemical properties of oil across different growing areas

The increased cost of biodiesel production from edible oils has motivated the researchers to find alternative non-edible oil feedstocks. Jatropha curcas has been identified as a promising tropical and subtropical perennial energy crop for biodiesel production. However, securing adequate J. curcas oil for sustainable biodiesel production is not achieved yet. Therefore, the present study sought to investigate the potential and suitability of J. curcas grown at different areas of Ethiopia for biodiesel production using analytical, instrumental, and empirical methods. The dry weight proportion of J. curcas seeds, seed coats, and kernels were significantly varied across growing ecologies. The oil contents of kernels were reneged between 47.10–59.32%, while the free fatty acid content of all sampled oils was less than 2.7%. The estimated iodine and saponification values were ranged between 99.6–112.6 mg I2 and 180.9–202.0 mg KOH per gram of oil, respectively. Oleic (34.2–42.2%) and Linoleic (34.8–41.8%) acids dominated the fatty acid composition of J. curcas oil. The biodiesel fuel properties such as kinematic viscosity, density, cold filter plugging point, and cetane numbers predicted from the fatty acid composition of oils were agreed with EN-14214 standards. The k-means cluster revealed that kernels harvested from different geographic locations were grouped in the same cluster, which indicates that the effect of altitudinal variation on the oil content of J. curcas was not significant. However, at too lower and higher altitudes, the kernel’s oil content has significantly declined. In conclusion, Ethiopian variety J. curcas oil showed suitable physicochemical properties for biodiesel production. However, its yield, composition, and physicochemical properties were significantly varied across growing areas.

Manufacture of a bio-tissue based on nanocrystalline cellulose from chilean bamboo Chusquea quila and a polymer matrix using electrospinning

Polymers of renewable origin have aroused great interest among researchers due to their sustainable, environmentally friendly nature. This work presents a biopolymer called bio-tissue, as it is created by electrospinning. This bio-tissue was formed with a polymer matrix of cellulose acetate (CA) reinforced with crystalline cellulose (NCC) derived from an autochthonous Chilean bamboo species of no commercial value which is considered a pest, Chusquea quila or quila. Bio-tissues were produced with three concentrations of NCC (1, 5 and 10% as a dry weight proportion of cellulose acetate) and their technological potential as an interior coating in small constructions was assessed. The morphology of the bio-tissues showed that the CA nanofibers containing NCC were of better quality and more uniform diameter than pure CA. The thermal profile showed that the highest concentration of NCC (10% as a dry weight proportion of cellulose acetate) induced earlier degradation; it was less thermally stable and decomposed at lower temperatures. The bio-tissue with 5% as a dry weight proportion of cellulose acetate showed the greatest resistance to traction with a break-point of 30 MPa and an elasticity module of 1.597 MPa. Finally, it was shown that the permeability to water vapour, oxygen and carbon dioxide was low, allowing regulated passage of these molecules. These results show the feasibility of using cellulose nanofibers as a reinforcement in polymer matrices; this could have various applications in fields ranging from the construction industry to food packaging.

The root-layer regulation based on the depth of phosphate fertilizer application of summer maize improves soil nitrogen absorption and utilization

Favorable root phenotypes can promote crops to obtain soil nutrients efficiently. The root-layer regulation technology based on the depth of phosphate fertilizer application can optimize the spatial and temporal distribution of summer maize root system and promote its spatial matching with soil water and nutrients to supply, providing a theoretical and technical support for realizing fertilizer saving and efficiency improvement by tapping potential of maize root system. In the present study, there were five treatments including CK (no P applied), P5 (phosphorus placement depth of 5 cm), P10 (phosphorus placement depth of 10 cm), P15 (phosphorus placement depth of 15 cm), and P20 (phosphorus placement depth of 20 cm). The effect of phosphorus application depth on root distribution, plant growth and yield formation, as well as nitrogen uptake, accumulation and transport in summer maize was analyzed. The suitable application depths of phosphate fertilizer promoted the growth of summer maize roots and increased root dry weight, root length density, root surface area and root volume significantly totally showing a trend of P15 > P10 > P20 > P5 > CK. With the increase of phosphate fertilizer application depth, the deep corn roots increased significantly. The proportion of root dry weight in P15 and P20 treatments was 12.3% and 12.1% in the 20–40 cm soil layer, and 6.7% and 6.9% in the 40–60 cm soil layer, respectively. The increase of root distribution depth promoted the absorption of nitrogen in the soil, and the nitrogen content in each soil layer, especially below 20 cm, was reduced significantly by the deep application of phosphate fertilizer. The optimization of root distribution promoted the accumulation and transportation of nitrogen in plants. Compared with P5 treatment, the averaged nitrogen fertilizer absorption efficiency, accumulation amount, accumulation rate, partial factor productivity and the grain yield in two years of P15 treatment increased by 14.5 kg kg–1, 19.2%, 48.9%, 6.4 kg kg–1, and 16.4% respectively, showing that under the conditions of the present study, concentrated application of phosphate fertilizer in −15 cm treatment can significantly promote the growth of deep soil roots, expand the space of nutrient utilization for root system, increase the absorption of nitrogen in deep soil, promote the accumulation and transportation of plant nitrogen, improve the productivity and ultimately yield in summer maize.

ROCKET PRODUCTION IN A LOW COST HYDROPONIC SYSTEM USING BRACKISH WATER

ABSTRACT The production of vegetables in communities of family farmers in semiarid regions is limited due to rudimentary cultivation practices and systems, water scarcity, and excess salts in the water and soil. Thus, the objective of this work was to evaluate the production of rocket (Eruca sativa L. cv. Folha Larga) in a low cost hydroponic system, considering strategies for the use of brackish water in the nutrient solution. The experiments were conducted in complete randomized designs, in 6×2 factorial arrangements, with five replications, using rocket plants grown in different nutrient solutions, consisting of six salinity levels (1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 dS m -1) and two circulation frequencies of the nutrient solution (twice a day, at 8:00h, and 16:00h; and three times a day, at 8:00h, 12:00h, and 16:00h). In Experiment I, the nutrient solution lost by evapotranspiration was replenished with the respective brackish water used in its preparation; and in Experiment II it was replenished with public water (0.12 dS m -1). The shoot and root fresh and dry biomass of the plants and their respective dry weight proportions, and biometric variables were evaluated. Replenishing of the nutrient solution with public water resulted in lower losses in biomass and plant growth. The increases in circulation frequency of the nutrient solution did not affect the biometric variables, however, the plants prioritized shoot biomass development to the detriment of the root when using high circulation frequencies.

Exogenous trehalose improves growth under limiting nitrogen through upregulation of nitrogen metabolism

BackgroundThe trehalose (Tre) pathway has strong effects on growth and development in plants through regulation of carbon metabolism. Altering either Tre or trehalose 6-phosphate (T6P) can improve growth and productivity of plants as observed under different water availability. As yet, there are no reports of the effects of modification of Tre orT6P on plant performance under limiting nutrition.ResultsHere we report that nitrogen (N) metabolism is positively affected by exogenous application of Tre in nitrogen-deficient growing conditions. Spraying foliage of tobacco (Nicotiana tabacum) with trehalose partially alleviated symptoms of nitrogen deficiency through upregulation of nitrate and ammonia assimilation and increasing activities of nitrate reductase (NR), glycolate oxidase (GO), glutamine synthetase (GS) and glutamine oxoglutarate aminotransferase (GOGAT) with concomitant changes in ammonium (NH4+) and nitrate (NO3−) concentrations, glutamine and amino acids. Chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased compared to nitrogen-deficient plants without applied Tre. Total plant biomass accumulation was also higher in Tre -fed nitrogen-deficient plants, with a smaller proportion of dry weight partitioned to roots, compared to nitrogen-deficient plants without applied Tre. Consistent with higher nitrogen assimilation and growth, Tre application reduced foliar starch. Minimal effects of Tre feeding were observed on nitrogen-sufficient plants.ConclusionsThe data show, for the first time, significant stimulatory effects of exogenous Tre on nitrogen metabolism and growth in plants growing under deficient nitrogen. Under such adverse conditions metabolism is regulated for survival rather than productivity. Application of Tre can alter this regulation towards maintenance of productive functions under low nitrogen. This has implications for considering approaches to modifying the Tre pathway for to improve crop nitrogen-use efficiency and production.

Environmental Improvement in Use of Fine Fraction Recycled Aggregates as a Raw Material in Masonry Mortar Fabrication

Background: Great use of raw material and natural resources as well as generation of huge amount of waste make the construction and building sector one of the less sustainable human activities. Objective: The main aim of this research is to study both technical feasibility and environmental sustainability of fine fraction recycled aggregates (RA) use in masonry mortar fabrication. Method. The tests were developed using the binder CEM IV/B (V) 32.5 N and two types of RA: ceramic RA and concrete RA. The substitution percentages were 50%, 75% and 100% and cement-to-aggregate by dry weight proportions were 1:3 and 1:4. Results: Performed tests show that cement-based mortars fabricated with CEM IV/B (V) 32. 5 N can incorporate concrete and ceramic recycled aggregates, using both cement-to-aggregate proportions, complying with the limits established by the Spanish standards. On the other hand, carbon footprint calculation of one of the RA used in the research and a comparative study with natural aggregate (NA) carbon footprint were carried out to analyze environmental sustainability of fine fraction RA. Conclusion. The results show that the amount of kgCo2eq released into the atmosphere as a result of RA fabrication is significantly lower compared with the emissions from NA fabrication, and therefore the use of this type of waste reduces greenhouse gas emissions.

Effects of Water-Nitrogen Coupling on Dry Matter and Nutrient Accumulation of Flue-Cured Tobacco

In order to explore the effects of water-nitrogen coupling on dry matter and nutrient accumulation of flue-cured tobacco, 9 treatments with different lowest limits and nitrogen fertilizer amount were designed, and the distribution and accumulation of dry matter and nutrient (N, P and K) of flue-cured tobaccos under water-nitrogen coupling treatments were observed. Results showed that: (1) High irrigation amount could not certainly increase the dry matter accumulation of tobacco root, but which was beneficial to the dry matter accumulation of whole tobacco plant. (2) Dry weight proportion of flue-cured tobacco leaves was highest, which was above 55% among the treatments. (3) Higher water and nitrogen promoted the nutrient accumulation of flue-cured tobaccos, nutrient content of W3N3, W3N2 and W2N2 was higher compared to other treatments.

Fibrous Root Distribution in Blood Red Sweet Orange Trees under Semi- arid Irrigated Ecosystem

Fibrous root distribution pattern of mature trees of sweet orange cultivar Blood Red budded on rough lemon with her cleoptera and troyer citrange rootstocks were studied by root excavation method. The roots excavated from four radial distances i.e.0–75,75–150, 150–225 and 225–300 cm from the tree trunk and three depths i.e.0–15, 15–30 and 30–60 cm from the ground level indicated that fibrous root dry weight density and proportion of dry weight differed significantly at various depths and radial distances. Cleoptera has more feeder roots as compared to rough lemon and troyer. Feeder root dry weight density and dry weight proportion was almost the same between 0–15 & 15–30 cm depth and at deeper horizon there was significant decrease in all the root stocks. Approximately 70% of the total feeder roots in all rootstocks were within 0–30 cm depth i.e. intensive vertical development. The highest feeder root dry weight density was recorded at 0-75cm radial distance after that there was a sharp decrease. Troyer citrange, cleoptera and rough lemon contain about 65, 61 and 50% feeder roots up to 150 cm radial distance from the trunk. Hence, feeder roots, in troyer citrange and cleoptera may be exemplified as intensive lateral development. Rough lemon bears extensive lateral development as it has substantial amount of feeder roots at 150-225cm radial distance.

GA-responsive dwarfing gene Rht12 affects the developmental and agronomic traits in common bread wheat.

Opportunities exist for replacing reduced height (Rht) genes Rht-B1b and Rht-D1b with alternative dwarfing genes, such as the gibberellin-responsive gene Rht12, for bread wheat improvement. However, a comprehensive understanding of the effects and mode of action of Rht12 is lacking. In the present study, the effects of Rht12 were characterized by analyzing its effects on seeding vigour, seedling roots, leaf and stem morphology, spike development and carbohydrate assimilation and distribution. This was carried out in the four genotypes of F2:3 lines derived from a cross between Ningchun45 and Karcagi (12) in two experiments of autumn sowing and spring sowing. Rht12 significantly decreased stem length (43%∼48% for peduncle) and leaf length (25%∼30% for flag leaf) while the thickness of the internode walls and width of the leaves were increased. Though the final plant stature was shortened (40%) by Rht12, the seedling vigour, especially coleoptile length and root traits at the seedling stage, were not affected adversely. Rht12 elongated the duration of the spike development phase, improved the proportion of spike dry weight at anthesis and significantly increased floret fertility (14%) in the autumn sowing experiment. However, Rht12 delayed anthesis date by around 5 days and even the dominant Vrn-B1 allele could not compensate this negative effect. Additionally, grain size was reduced with the ability to support spike development after anthesis decreased in Rht12 lines. Finally, grain yield was similar between the dwarf and tall lines in the autumn sowing experiment. Thus, Rht12 could substantially reduce plant height without altering seeding vigour and significantly increase spikelet fertility in the favourable autumn sowing environment. The successful utilization of Rht12 in breeding programs will require careful selection since it might delay ear emergence. Nonetheless, the potential exists for wheat improvement by using Rht12.

Using Diets to Reveal Overlap and Egg Predation among Benthivorous Fishes in Lake Michigan

AbstractEcological stability in the Laurentian Great Lakes has been altered by nonindigenous species, such as the Round Goby Neogobius melanostomus and dreissenid mussels, and by declines in native amphipods Diporeia spp. We evaluated whether these changes could influence diet overlap between three benthivorous fishes (Slimy Sculpin Cottus cognatus, Deepwater Sculpin Myoxocephalus thompsonii, and Round Goby) and whether predation on eggs of native species was occurring. We examined diets of fish collected at depths of 69–128 m in Lake Michigan offshore of Frankfort and Muskegon, Michigan, and Two Rivers and Sturgeon Bay, Wisconsin, during January–May 2009 and 2010. Important prey (by dry weight proportion and by percent frequency of occurrence) for Slimy Sculpin were Mysis (0.34; 45%), Diporeia (0.16; 34%), and Limnocalanus macrurus (0.22; 68%); important prey for Deepwater Sculpin were Mysis (0.74; 92%) and Diporeia (0.16; 54%). Round Goby consumed mainly bivalves (i.e., dreissenids: 0.68; 95%) and Mysis (0.15; 37%). The two sculpin species consumed the eggs of Bloaters Coregonus hoyi (Slimy Sculpin: 0.04, 11%; Deepwater Sculpin: 0.02, 7%) and the eggs of Deepwater Sculpin (Slimy Sculpin: 0.03, 13%; Deepwater Sculpin: 0.05, 16%) during February–May at all sites. Round Goby also consumed eggs of these species but at lower levels (≤0.01; <1%). Diet overlap was identified between sculpin species at Frankfort and Sturgeon Bay, suggesting possible interspecific competition, but their diets did not overlap at Two Rivers; diet overlap was never observed between Round Goby and either sculpin species. Given that (1) diet overlap varied by site and (2) diet proportions varied spatially more than temporally, benthivores appear to be exhibiting localized responses to recent ecological changes. Overall, these results reveal that egg predation and interspecific competition could be important interactions to consider in future examinations of the population dynamics of these species or in ecosystem models that forecast how fisheries will respond to possible perturbations or management scenarios.

Wastewater polishing by a channelized macrophyte-dominated wetland and anaerobic digestion of the harvested phytomass

Constructed wetlands (CW) offer a mechanism to meet increasingly stringent regulatory standards for wastewater treatment while minimizing energy inputs. Additionally, harvested wetland phytomass subjected to anaerobic digestion can serve as a source of biogas methane. To investigate CW wastewater polishing activities and potential energy yield we constructed a pair of secondary wastewater-fed channelized CW modules designed to retain easily harvestable floating aquatic vegetation and maximize exposure of water to roots and sediment. Modules that were regularly harvested averaged a nitrate removal rate of 1.1 g N m−2 d−1; harvesting, sedimentation and gasification were responsible for 30.5%, 8.0% and 61.5% of the N losses, respectively. Selective harvesting of a module to maintain dominance of filamentous algae had no effect on nitrate removal rate but lowered productivity by one-half. The average monthly productivity for unselectively harvested modules was 9.3 ± 1.7 g dry wt. m−2 d−1 (±SE). Cessation of harvesting in one module resulted in a significant increase in nitrate removal rate and decrease in phosphate removal rate. Compared to the influent, the effluent of the harvested module had significantly lower levels of estrogenic activity, as determined by a quantitative PCR-based juvenile trout bioassay, and significantly lower densities of E. coli. In mixed vertical-flow reactors anaerobic co-digestion of equal dry weight proportions of harvested aquatic vegetation, wine yeast lees and dairy manure was greatly improved when the manure was replaced with the crude glycerol by-product of biodiesel production. Remaining solids were vermicomposted for use as a soil amendment. Our results indicate that incorporation of constructed wetlands into an integrated treatment system can simultaneously enhance the economic and energetic feasibility of wastewater and organic waste treatment processes.

Bioprospecting the thermal waters of the Roman baths: isolation of oleaginous species and analysis of the FAME profile for biodiesel production

The extensive diversity of microalgae provides an opportunity to undertake bioprospecting for species possessing features suited to commercial scale cultivation. The outdoor cultivation of microalgae is subject to extreme temperature fluctuations; temperature tolerant microalgae would help mitigate this problem. The waters of the Roman Baths, which have a temperature range between 39°C and 46°C, were sampled for microalgae. A total of 3 green algae, 1 diatom and 4 cyanobacterial species were successfully isolated into ‘unialgal’ culture. Four isolates were filamentous, which could prove advantageous for low energy dewatering of cultures using filtration.Lipid content, profiles and growth rates of the isolates were examined at temperatures of 20, 30, 40°C, with and without nitrogen starvation and compared against the oil producing green algal species, Chlorella emersonii. Some isolates synthesized high levels of lipids, however, all were most productive at temperatures lower than those of the Roman Baths. The eukaryotic algae accumulated a range of saturated and polyunsaturated FAMEs and all isolates generally showed higher lipid accumulation under nitrogen deficient conditions (Klebsormidium sp. increasing from 1.9% to 16.0% and Hantzschia sp. from 31.9 to 40.5%). The cyanobacteria typically accumulated a narrower range of FAMEs that were mostly saturated, but were capable of accumulating a larger quantity of lipid as a proportion of dry weight (M. laminosus, 37.8% fully saturated FAMEs). The maximum productivity of all the isolates was not determined in the current work and will require further effort to optimise key variables such as light intensity and media composition.

A high proportion of blue light increases the photosynthesis capacity and leaf formation rate of Rosa × hybrida but does not affect time to flower opening

Alterations in light quality affect plant morphogenesis and photosynthetic responses but the effects vary significantly between species. Roses exhibit an irradiance-dependent flowering control but knowledge on light quality responses is scarce. In this study we analyzed, the responses in morphology, photosynthesis and flowering of Rosa × hybrida to different blue (B) light proportions provided by light-emitting diodes (LED, high B 20%) and high pressure sodium (HPS, low B 5%) lamps. There was a strong morphological and growth effect of the light sources but no significant difference in total dry matter production and flowering. HPS-grown plants had significantly higher leaf area and plant height, yet a higher dry weight proportion was allocated to leaves than stems under LED. LED plants showed 20% higher photosynthetic capacity (Amax ) and higher levels of soluble carbohydrates. The increase in Amax correlated with an increase in leaf mass per unit leaf area, higher stomata conductance and CO2 exchange, total chlorophyll (Chl) content per area and Chl a/b ratio. LED-grown leaves also displayed a more sun-type leaf anatomy with more and longer palisade cells and a higher stomata frequency. Although floral initiation occurred at a higher leaf number in LED, the time to open flowers was the same under both light conditions. Thereby the study shows that a higher portion of B light is efficient in increasing photosynthesis performance per unit leaf area, enhancing growth and morphological changes in roses but does not affect the total Dry Matter (DM) production or time to open flower.

Effect of abscisic acid on the maturation of olive trees cv. Arbequina

Interventions which accelerate the fruit maturation of olives planted in cold climates are necessary to advance the harvest and not allow the fruit to be exposed to early freezes which may have negative effects on the quality of the oil. In Autumn (28 April) 2006 we applied 0, 100, 200, 300 and 400 mg-L-1 abscisic acid (ABA) to trees of the variety of Arbequina at the beginning of veraison in an orchard in Melipilla, Metropolitan Region, Chile, in order to evaluate its effect on the acceleration of fruit maturation. The experimental design was completely randomized; the means of the treatments were compared by ANOVA and Tukey's test (p<0.05). The application of ABA produced a strong defoliation of the trees, together with a marked fruit fall, especially at 300 and 400 mg-L-1. Fruit maturation was retarded, expressed as a delay in the development of color for trees treated with 400 mg-L-1 ABA. The treatments did not produce an effect on the oil content measured as a proportion of dry weight. The following year (2007), those trees treated with 300 and 400 mg-L-1showed a significant reduction in fruit harvested per tree, which may be due to an effect of the ABA applied on the processes of induction or initiation of bud differentiation