黑杨水培中营养液抑菌处理研究

水培条件下进行快速繁殖是大量生产黑杨种苗的途径之一 ,营养液的抑菌处理是水培的一个重要方面。该研究进行了二硫氰甲烷、中生菌素、敌磺钠、链霉素、青霉素等五种杀细菌剂和多菌灵、福美双、三唑酮等三种杀真菌剂的抑菌试验 ,结果表明 ,杀细菌剂对微生物生长的抑制率要高于杀真菌剂 ,二硫氰甲烷和中生菌素能较好地抑制营养液中微生物的生长 ,浓度分别为 2 0mg/L和 1 5mg/L时 ,抑制率分别为 75 .60 %和78 94%。杀真菌剂和杀细菌剂复配对营养液中微生物生长的抑制表现出较好的加和作用 ,其中以中生菌素(1 5mg/L)与福美双 (5mg/L)复配的效果最好 ,抑制率为 87.48%。     

Tolerance of rice to nickel in nutrient solution

For screening tolerance of six cultivars of rice (Oryza sativa) to different concentrations of nickel (0, 6, 12, 18, 24 and 30 μg dm3), growth parameters (root and shoot length, root and shoot dry matter production) and root and shoot tolerance indexes were tested after 7, 10 and 13 d of treatment. In presence of nickel in nutrient solution, root growth of cv. Nilgiri was enhanced, while in cvs. Subhadra, Khandagiri, Rudra, Sankar and Annapurna it decreased. The root tolerance index (RTI) and shoot tolerance index (STI) in cv. Nilgiri were high; cvs. Sankar and Khandagiri, however, showed a low RTI. Based on the standard growth parameters, six cultivars of rice were ranked in respect of their tolerance to nickel: Nilgiri > Annapurna > Subhadra > Khandagiri > Rudra > Sankar. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of temperature on rice growth in nutrient solution and in acid sulphate soils from Vietnam

Climatic and soil factors are limiting rice growth in many countries. In Vietnam, a steep gradient of temperature is observed from the North to the South, and acid sulphate soils are frequently devoted to rice production. We have therefore attempted to understand how temperature affects rice growth in these problem soils, by comparison with rice grown in nutrient solution. Two varieties of rice, IR64 and X2, were cultivated in phytotrons at 19/21°C and 28/32°C (day/night) for 56 days, after 3 weeks preculture in optimal conditions. Two soils from the Mekong Delta were tested. Parallel with the growing experiments, these two soils were incubated in order to monitor redox potential (E _h ), pH, soluble Al and Fe, soluble, and available P. Tillering retardation at 20°C compared to 30°C was similar in nutrient solutions and in soils. The effect of temperature on increasing plant biomass was more marked in solutions than in soils. The P concentrations in roots and shoots were higher at 20°C than at 30°C, to such an extent that detrimental effect was suspected in plants grown in solution at the lowest temperature. The translocation of Fe from roots to shoots was stimulated upon rising temperature, both in solutions and in soils. This led to plant death on the most acid soil at 30°C. Indeed, the accumulation of Fe in plants grown on soils was enhanced by the release of Fe²⁺ due to reduction of Fe(III)-oxihydroxides. Severe reducing conditions were created at 30°C: redox potential (E _h ) dropped rapidly down to about 0 V. At 20°C, E _h did not drop below about 0.2 V, which is a value well in the range of Fe(III)/Fe(II) buffering. Parallel to E _h drop, pH increased up to about 6–6.5 at 30°C, which prevented plants from Al toxicity, even in the most acid soil. Phosphate behavior was obviously related to Fe-dynamics: more reducing conditions at 30°C have resulted in enhancement of available P, especially in the most acid soil.     

Growth responses of rice in ammonium-based nutrient solution with variable calcium supply

It is commonly known that calcium promotes NO₃ ^- uptake in many crop species. However, calcium enhancement of NH₄ ⁺ uptake by plants has received little attention. This study aimed to evaluate the effect of Ca supplements on NH₄ ⁺ uptake and plant growth in solution cultured rice. Supplemental Ca applied at vegetative and reproductive phases of plant ontogeny tended to stimulate NH₄ ⁺ absorption, and accordingly resulted in a better straw and grain yield. However, excessively supplied Ca (400 ppm) was detrimental to plant growth. Increases in straw and grain yield observed at Ca levels up to 300 ppm were linked to the Ca-enhanced activities of glutamine synthetase (GS), glutamate synthase (GOGAT), and ribulose 1, 5-bisphosphate carboxylase/oxygenase (Rubisco).     

Effect of steaming on yield and nutrient content of tomatoes grown in three substrates and on physical properties of the substrate

Summary Steam sterilization increased the yield of tomatoes grown on peat over 3 years. The increase becomes more pronounced with time. The effect of steaming was greater in the summer crop which has a duration of 6 months than in the autumn crop which has a duration of 4 months. Similar yield patterns were evident in tomatoes grown in sand and soil. Manganese levels in the growing media and in the foliage rose as a result of steaming, but toxic levels were reached only in plants growing on steamed soil which caused yield reduction. Leaf nitrogen content was increased as a result of steaming. Steaming over three years did not cause a breakdown of the structure of the peat.     

An improved method for production of silica from rice hull ash

Biosorption of monovalent ions Na+ and K+, by deactivated protonated yeast (Saccharomyces cerevisiae) at controlled pH, was compared with biosorption of divalent ions Ca2+ and Mg2+ to help to understand the underlying bindingmechanisms. The adsorption for monovalent ions was accompanied by H+ release. Divalent ions were sorbed by proton displacement, and also an additional mode not accompanied by release of H+. The sorption uptake of both monovalent and divalent metal ions increased with pH in the range 3-7 peaking at 6.75. Equilibrium sorption isotherms at pH = 6.75 showed that the totalmaximum biosorptive capacity for metal ions decreased in the following order: Ca > Mg > Na > or = K.     

Pilot-scale production of carboxymethylcellulase from rice hull by Bacillus amyloliquefaciens DL-3

Optimal conditions for pilot-scale production of the carboxymethylcellulase (CMCase) by Bacillus amyloliquefaciens DL-3 were investigated. The best carbon and nitrogen sources for the production of CMCase by B. amyloliquefaciens DL-3 were found to be rice hull and peptone and their optimal concentrations were 5.0 and 0.20% (w/v), respectively. Optimal temperature and initial pH for the production of CMCase were 37°C and 6.8. Optimal agitation speed and aeration rate for the production of CMCase were 300 rpm and 1.0 vvm in a 7 L bioreactor, which were different from those for the cell growth of B. amyloliquefaciens DL-3. The highest productions of CMCase by B. amyloliquefaciens DL-3 from 5.0% (w/v) rice hull as a carbon source under optimal conditions in a 7 or 100 L bioreactor were 220 and 367 U/mL, respectively.     

Uptake of inorganic and organic nutrient species during cultivation of a Chlorella isolate in anaerobically digested dairy waste

A natural assemblage of microalgae from a facultative lagoon system treating municipal wastewater was enriched for growth in the effluents of an anaerobic digester processing dairy waste. A green microalga with close resemblance to Chlorella sp. was found to be dominant after multiple cycles of sub‐culturing. Subsequently, the strain (designated as LLAI) was isolated and cultivated in 20× diluted digester effluents under various incident light intensities (255–1,100 µmoles m^?2 s^?1) to systematically assess growth and nutrient utilization. Our results showed that LLAI production increased with increasing incident light and a maximum productivity of 0.34 g L^?1 d^?1 was attained when the incident irradiance was 1,100 µmoles m^?2 s^?1. Lack of growth in the absence of light indicated that the cultures did not grow heterotrophically on the organic compounds present in the medium. However, the cultures were able to uptake organic N and P under phototrophic conditions and our calculations suggest that the carbon associated with these organic nutrients contributed significantly to the production of biomass. Overall, under high light conditions, LLAI cultures utilized half of the soluble organic nitrogen and >90% of the ammonium, orthophosphate, and dissolved organic phosphorus present in the diluted waste. Strain LLAI was also found to accumulate triacylglycerides (TAG) even before the onset of nutrient limitation and a lipid productivity of 37 mg‐TAG L^?1 d^?1 was measured in cultures incubated at an incident irradiance of 1,100 µmoles m^?2 s^?1. The results of this study suggest that microalgae isolates from natural environments are well‐suited for nutrient remediation and biomass production from wastewater containing diverse inorganic and organic nutrient species. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1336–1342, 2016     

Study on nutrient stress tolerance of nine Taraxacum microspecies with a contrasting mineral ecology by cultivation in a low nutrient flowing solution

Growth and mineral status of 9 Taraxacum microspecies were studied under mineral stress conditions, using a flowing solution of low nutrient concentration. Relative growth rate of (whole) plant dry weight, leaf area, and (whole) plant tissue water were used to describe growth. For 4 microspecies, specific uptake rates of NO⁻₃, H₂PO⁻₄, K⁺, Mg²⁺ and Ca²⁺ were investigated.
The applied nutrient condition clearly discriminated between the studied Taraxacum microspecies. With respect to relative growth rate, 3 groups of microspecies could be distinguished: T. nordstedtii > T. lancidens, T. adamii, T. hollandicum, T. taeniatum > T. sellandii, T. eudontum, T. ekmanii, T. ancistrolobum . These categories coincided well with the mineral ecology of the microspecies, going from infertile to fertile sites.
T. nordstedtii , a microspecies of infertile sites, was most efficient in absorbing NO⁻₃, H₂PO⁻₄ and K⁺. T. sellandii and T. eudontum , both occurring in fertile grasslands, showed poor uptake performances for all studied ions. In all Taraxacum microspecies studied, except T. eudontum , internal N concentration appeared to limit growth. Efficiencies in N use, at sub-optimal internal N concentrations, varied with the mineral habitat of the microspecies studied. T. nordstedtii , from infertile sites, and T. sellandii , from fertile sites, were established as high and low extremes, respectively.     

Genetic control of a transition from black to straw-white seed hull in rice domestication

The genetic mechanism involved in a transition from the black-colored seed hull of the ancestral wild rice (Oryza rufipogon and Oryza nivara) to the straw-white seed hull of cultivated rice (Oryza sativa) during grain ripening remains unknown. We report that the black hull of O. rufipogon was controlled by the Black hull4 (Bh4) gene, which was fine-mapped to an 8.8-kb region on rice chromosome 4 using a cross between O. rufipogon W1943 (black hull) and O. sativa indica cv Guangluai 4 (straw-white hull). Bh4 encodes an amino acid transporter. A 22-bp deletion within exon 3 of the bh4 variant disrupted the Bh4 function, leading to the straw-white hull in cultivated rice. Transgenic study indicated that Bh4 could restore the black pigment on hulls in cv Guangluai 4 and Kasalath. Bh4 sequence alignment of all taxa with the outgroup Oryza barthii showed that the wild rice maintained comparable levels of nucleotide diversity that were about 70 times higher than those in the cultivated rice. The results from the maximum likelihood Hudson-Kreitman-Aguade test suggested that the significant reduction in nucleotide diversity in rice cultivars could be caused by artificial selection. We propose that the straw-white hull was selected as an important visual phenotype of nonshattered grains during rice domestication.     

Performance of olive mill solid waste as a constituent of the substrate in commercial cultivation of Agaricus bisporus

The feasibility of using olive mill waste (OMW) as an ingredient in the substrate used for cultivation of Agaricus bisporus (Lange) Sing. was studied in a large-scale cultivation trial, concerning 2500 m² of mushroom growing area, at a specialized mushroom farm. Standard commercial cultivation technique involving compost preparation, spawning, casing and harvesting was used. The performance indicators such as mushroom yield, biological efficiency, market quality as well as horticultural value of the spent compost showed that the compost prepared with OMW was superior to the control compost in all the categories. The OMW-amended substrate supported higher populations of beneficial microorganisms especially, actinomycetes which enabled the breakdown of the compost ingredients. It is suggested that OMW is a suitable ingredient for the preparation of mushroom substrate. We have demonstrated that conversion of OMW (a liability) into value-added mushroom substrate (an asset) is an effective waste management tool in oleaculture.     

Yield and size of oyster mushroom grown on rice/wheat straw basal substrate supplemented with cotton seed hull

Oyster mushroom (Pleurotus ostreatus) was cultivated on rice straw basal substrate, wheat straw basal substrate, cotton seed hull basal substrate, and wheat straw or rice straw supplemented with different proportions (15%, 30%, and 45% in rice straw substrate, 20%, 30%, and 40% in wheat straw substrate) of cotton seed hull to find a cost effective substrate. The effect of autoclaved sterilized and non-sterilized substrate on growth and yield of oyster mushroom was also examined. Results indicated that for both sterilized substrate and non-sterilized substrate, oyster mushroom on rice straw and wheat basal substrate have faster mycelial growth rate, comparatively poor surface mycelial density, shorter total colonization period and days from bag opening to primordia formation, lower yield and biological efficiency, lower mushroom weight, longer stipe length and smaller cap diameter than that on cotton seed hull basal substrate. The addition of cotton seed hull to rice straw and wheat straw substrate slowed spawn running, primordial development and fruit body formation. However, increasing the amount of cotton seed hull can increase the uniformity and white of mycelium, yield and biological efficiency, and increase mushroom weight, enlarge cap diameter and shorten stipe length. Compared to the sterilized substrate, the non-sterilized substrate had comparatively higher mycelial growth rate, shorter total colonization period and days from bag opening to primordia formation. However, the non-sterilized substrate did not gave significantly higher mushroom yield and biological efficiency than the sterilized substrate, but some undesirable characteristics, i.e. smaller mushroom cap diameter and relatively long stipe length.     

基于稳定同位素比率及营养差异的双孢蘑菇不同栽培基质的溯源分析

双孢蘑菇是世界消费量最大的食用菌之一,不同于欧美国家的麦草栽培配方,我国双孢蘑菇栽培材料主要是以水稻秸秆为主.为了降低农业秸秆废弃物的焚烧和我国双孢蘑菇产业的持续发展,需因地制宜地开发和利用各地特色农业废弃物资源作为双孢蘑菇栽培的基质.为鉴别不同材料栽培的双孢蘑菇子实体的营养和产量差异,本研究以8种不同基质配方栽培的双...     

Integration of biological waste conversion and wastewater treatment plants by microalgae cultivation

In this study, growth performance and lipid content of two microalgae species Neochloris oleoabundans and Chlorella vulgaris are monitored by using three different types of sludge waste feedstocks obtained from the water treatment plants located in Bedonia, Borgotaro and Fornovo (Montagna2000 Spa, Province of Parma, Italy). The sludge waste is optimized in order to achieve microalgal growth media and dispose of the sewage sludge produced at the wastewater treatment facilities. Both photoautotrophic and heterotrophic growth conditions are applied to the microalgal cultivations. The growth parameters of microalgae strains such as cell concentration, growth rate, optical density, cell biovolume, photosynthetic pigments and lipid contents are monitored. The amounts of total dried lipid biomass, obtained by the biological conversion of the wet sludge waste, are determined. Lipid production of microalgal cells grown in the medium optimized from sludge waste from the Fornovo site provides the highest amount of microalgal lipid content for N. oleoabundans and C. vulgaris photoautotrophic cultivations, while sludge waste from the Bedonia site provides for N. oleoabundans heterotrophic cultivation.     

Utilization of modified silk cotton hull waste as an adsorbent for the removal of textile dye (reactive blue MR) from aqueous solution

Carbon prepared from silk cotton hull was used to remove a textile dye (reactive blue MR) from aqueous solution by an adsorption technique under varying conditions of agitation time, dye concentration, adsorbent dose and pH. Adsorption depended on solution pH, dye concentration, carbon concentration and contact time. Equilibrium was attained with in 60 min. Adsorption followed both Langmuir and Freundlich isotherm models. The adsorption capacity was found to be 12.9 mg/g at an initial pH of 2+/-0.2 for the particle size of 125-250 microm at room temperature (30+/-2 degrees C).     

Application of solid waste from anaerobic digestion of poultry litter in Agrocybe aegerita cultivation: mushroom production, lignocellulolytic enzymes activity and substrate utilization

The degradation and utilization of solid waste (SW) from anaerobic digestion of poultry litter by Agrocybe aegerita was evaluated through mushroom production, loss of organic matter (LOM), lignocellulolytic enzymes activity, lignocellulose degradation and mushroom nutrients content. Among the substrate combinations (SCs) tested, substrates composed of 10–20% SW, 70–80% wheat straw and 10% millet was found to produce the highest mushroom yield (770.5 and 642.9 g per 1.5 kg of substrate). LOM in all SCs tested varied between 8.8 and 48.2%. A. aegerita appears to degrade macromolecule components (0.6–21.8% lignin, 33.1–55.2% cellulose and 14–53.9% hemicellulose) during cultivation on the different SCs. Among the seven extracellular enzymes monitored, laccase, peroxidase and CMCase activities were higher before fruiting; while xylanase showed higher activities after fruiting. A source of carbohydrates (e.g., millet) in the substrate is needed in order to obtain yield and biological efficiency comparable to other commercially cultivated exotic mushrooms.     

Modeling methane emissions from irrigated rice cultivation in China from 1960 to 2050

Rice paddy is a major source of anthropogenic terrestrial methane (CH₄). China has the second‐largest area of rice cultivation in the world, accounting for ca. 19% of the world's rice‐producing area. Recognizing the significance of China's rice cultivation in the global CH₄ budget, we estimated the CH₄ emissions resulting from irrigated rice cultivation in China from 1960 to 2050 using a CH4MOD model. The model estimates suggest that the annual CH₄ emissions decreased from 5.62 Tg yr^?1 in 1960 to 4.13 Tg yr^?1 in 1970, and this decrease was attributed to changes in water management from continuous flooding to mid‐season drainage irrigation. Since the early 1970s, the amount of CH₄ emissions gradually increased to 6.85 Tg yr^?1 by 2009 because of significant improvements in crop production that led to high‐crop residue retention. Higher levels of CH₄ emissions occurred in southern China, where double rice cropping systems are most common. For the A1B and B1 scenarios of the IPCC Special Report on Emissions Scenarios (SRES), the amount of CH₄ emissions from 2010 to 2050 is predicted to increase at an average rate of 1.2 kg ha^?1 yr^?1 in response to global warming. Compared to 2009, the CH₄ flux is predicted to increase by ca. 14% by the late 2040s, and the increase in these emissions in northeastern China is estimated to become more significant than in the other rice‐growing regions of the country. Under the assumptions that the rice‐producing land area will remain the same, decrease by 25% or increase by 38% by the late 2040s, the CH₄ emissions are projected to be 7.8, 5.6 or 11.7 Tg yr^?1, respectively.     

Localization of sulfate reduction in planted and unplanted rice field soil

Rates of in situ sulfate reduction (SRR) in planted and unplanted rice fieldsoil were measured by the ³⁵SO^2– ₄-radiotracermethod using soil microcosms. The concentration of ³⁵SO^2– ₄ decreased exponentially with time.However, time course experiments indicated that incubation times of10–30 min were appropriate for measurements of SRRusing a single time point in routine assays. Unplanted microcosmsshowed high SRR of 177 nmol cm^-3 d^-1 inthe uppermost centimeter where average sulfate concentrations were<33 µM. Fine scaled measurements (1 mmresolution) localized highest SRR (<100 nmol cm^-3d^-1) at the oxic/anoxic interface at 2–5 mmdepth. In planted rice field soil, SRR of <310 nmolcm^-3 d^-1 were observed at 0–2cm depth. Sulfate reduction rates were determined at a millimeter-scalewith distance to a two dimensional root compartment. The SRR was highestat 0–1.5 mm distance to the root layer with rates up to500 nmol cm^-3 d^-1, indicating a highstimulation potential of the rice roots. SRR seemed to be mainlydependent on the in situ sulfate porewater concentrations. At thesoil surface of unplanted microcosms sulfate concentration decreasedfrom <150 µM to <10 µM within the first 8 mm of depth. In planted microcosmssulfate concentration varied from 87–99 µMsulfate at the 0–3 mm distance to the root layer to48–62 µM sulfate at a root distance>4 mm from the roots.The depth distribution of inorganic sulfur compounds was determinedfor planted and unplanted rice field soil. Sulfate, acid volatilesulfide (AVS) and chromium reducible sulfide (CRS) were up to 20 foldhigher in planted than in unplanted microcosms. CRS was the majorinsoluble sulfur fraction with concentrations >1.7µmol cm^-3. Organic sulfur accounted for25–46% of the total sulfurpresent (269 µg/g dw) in an unplanted microcosm.The biogeochemical role of sulfate reduction forshort-term accumulation of inorganic sulfur compounds(FeS, FeS_{_2} and S°) in rice soil wasdetermined in a time course experiment with incubationperiods of 5, 10, 20, 30 and 60 min. The relativedistribution of CRS and AVS formation showedlittle depth dependence, whereas the formation of³⁵S° seemed to be the highest in themore oxidized upper soil layers and near the root surface.AV³⁵S was the first major product of sulfatereduction after 20–30 min, whereas CR³⁵Swas formed, as AV³⁵S and ³⁵S°decreased, at longer incubation periods of >30 min.     

Model estimates of methane emission from irrigated rice cultivation of China

A model developed by the authors ( Huang et al. 1998 ) was further validated against field measurements from various regions of the world and calibrated to estimate methane emission from irrigated rice cultivation of China. On the basis of available information on rice cultivated area, growth duration, grain yield, soil texture and temperature, methane emission from Chinese rice paddies was estimated for 28 rice cultivated provinces in mainland. The calculated daily methane emission rates, on a provincial scale, ranged from 0.15 to 0.86 g m^–2 with an average of 0.32 g m^–2. Five of the top six locations with higher daily methane emissions are located at a latitude between 28° and 31° N. A total amount of 9.66 Tg (1 Tg = 10¹² g) CH₄ per year, ranging from 7.19 to 13.62, was estimated to be released from Chinese rice paddy soils. Of the total, 45% is emitted from the single-rice growing season, and 19% and 36% are from the early-rice and the late-rice growing seasons, respectively. Approximately 70% of the total is emitted in the region located at latitude between 25° and 32° N. The emissions from rice fields in Sichuan and Hunan Province were calculated to be 2.85 Tg y^–1, accounting for ≈ 30% of the total. Comparisons of the estimated and the observed emission rates show that the estimates were, in general, close to the measurements at most locations.     

不同水稻栽培模式下小麦秸秆腐解特征及对土壤生物学特性和养分状况的影响

采用尼龙网袋法于2007-2008年连续2a在水稻常规栽培和节水灌溉栽培模式下,研究小麦秸秆腐解特征、养分释放规律及对土壤微生物数量、酶活性和养分状况的影响.结果表明:秸秆还田后,在0-30d腐解较快,后期腐解速率逐渐变慢.90d时累计腐解率达到了48.9％-61.3％.秸秆中养分释放速率表现为K＞P＞N≈C.节水栽培模式下小麦秸秆还田腐解率和养分释放率均显著高于常规栽培.秸秆还田后,土壤微生物数量以及土壤脲酶、碱性磷酸酶和蔗糖酶活性均呈现“前期迅速增加,中期急剧减少,后期缓慢减少”的变化特征,而纤维素酶活性呈现“前期剧升、中期缓增、后期骤降”的变化趋势.小麦秸秆在节水栽培模式下还田土壤微生物数量和酶活性均显著高于常规栽培.适当增加秸秆用量可以提高微生物数量和酶活性,用量过高对细菌和放线菌数量有负效应.秸秆还田可显著提高土壤有机碳和养分含量.土壤有机碳、全氮、碱解氮和速效磷含量在整个试验期间均呈增加趋势.速效钾含量在秸秆还田30 d时达到最高,而后则逐渐降低.节水栽培模式下秸秆还田后土壤有机碳和养分含量的提高效应显著高于常规栽培.提高秸秆用量对土壤养分含量有显著的正效应.