镉对满江红(Azolla imbricata)-鱼腥藻(Anabaena azollae)共生体氮代谢的影响

在实验室条件下,研究了不同浓度(0、0.01、0.05、0.1、0.5mg/L)的Cd对满江红-鱼腥藻共生体异型胞频率,固氮酶、谷氨酰氨合成酶活性以及铵态氮、游离氨基酸、可溶性蛋白、总氮含量的影响。结果表明,在整个实验期间,0.01mg/LCd处理对上述指标均没产生显著影响,说明满江红-鱼腥藻共生体对Cd具有较强的耐性。当培养液中Cd浓度≥0.05mg/L时,随溶液中Cd浓度的增加和处理时间的推移,异型胞频率、固氮酶活性、谷氨酰氨合成酶活性、可溶性蛋白含量和总氮含量逐渐下降,而铵态氮含量在处理初期显著降低,随后迅速增加,游离氨基酸含量则逐渐增加。研究结果表明高浓度的Cd处理导致满江红-鱼腥藻共生体氮代谢的紊乱,最终造成氮素积累量的下降。

从“Azolla Event”论满江红在生态农业中的应用

从分析始新世满江红在地球气候从"温室效应"向"冰室效应"转变的过程所起的作用入手,指出满江红具有在未来生态农业应用的潜力,包括作为优质农产品的生产原料、作为控制农业生态环境和重金属污染的植物、作为外太空开发的先行植物等。并提出要加强满江红在节能、环保和有机肥源、外源基因导入和满江红孢子果生产技术的研究以充分发挥满江红在未来生态农业中的作用。

小叶满江红(Azolla microphylla)内生细菌多样性的T-RFLP分析

[目的]应用T-RFLP技术揭示小叶满江红内生细菌的多样性。[方法]将分离自实验室无菌培养的小叶满江红内生细菌进行16SrDNA-PCR扩增,产物用MspI、HhaI、HaeIII、HinfI 4种内切酶进行酶切,通过检测带荧光标记的片段,将所获得的数据用相关的软件工具Phylogenetic Assignment Tool(PAT)进行比对分析。[结果]通过比对获得10个科42个属的细菌菌种。[结论]T-RFLP技术配合生物信息学软件能较有效地揭示小叶满江红内生细菌的多样性。

满江红Azolla imbricata(Roxb.)Nak的生物学特征及其渔业利用

满江红(Azollaimbricata)天然资源丰富,产量高,渔业利用价值比较大。论文综述了近年来满江红的部分研究工作,介绍了满江红的生物学特征及其渔业利用,在前人的基础上,提出利用“鱼类—满江红”走生态养殖的模式。

高产高蛋白饲草满江红 (Azolla imbricata)放养技术研究初报

满江红属蕨类植物 ,以营养体的侧枝断离无性繁殖方式为主 ,粗蛋白、赖氨酸、磷、粗脂肪含量均高于紫花苜蓿。研究结果表明 ,群体延续时间为 7d时 ,繁殖系数最高 ,在西北地区 4～ 9月份的适宜生长季节 ,采用薄膜微水放养技术 ,每公顷水面生产鲜草约 450 t,折合干重 45t,粗蛋白 1 1 .2 5t。

Evaluation of Nitrogen and Phosphorus Wastes Produced by Nile Tilapia (<i>Oreochromis niloticus</i>L.) Fed <i>Azolla</i>-Diets in Earthen Ponds

Nitrogen (N) and phosphorus (P) wastes produced by Nile tilapia Oreochromis niloticus L. fed Azolla, an aquatic atmospheric nitrogen fixing fern, was evaluated for 90 days in pond experiment. Six isonitrogenous (29.2% crude protein) and isoenergetic (16.9 Kj·g–1) diets A0, A10, A20, A30, A40 and A50, containing 0%, 10%, 20%, 30%, 40% and 50% of Azolla meal (AM) respectively, as partial fishmeal (FM) substitutes, was provided to experimental fish. The Azolla-free diet A0 served as a control. Fish specific growth rate (SGR) was higher with the control diet, the lower values being obtained in A50-fed fish (P Azolla could be used in diet to sustain Nile tilapia growth and as “environmentally-friendly” ingredient to limit P loss, while providing N to the field, beneficially in tropical marshland pond where this nutrient is already limiting.

Eocene Cooling Through Sustained Growth of Azolla?

Through analyses of unique microlaminated sediments recovered from the Lomonosov Ridge during Integrated Ocean Drilling Program(IODP) Expedition 302,it became evident that enormous blooms of the free floating freshwater fern Azolla occurred within the Arctic Basin during an extended period of～1.2 Ma in the Eocene.The timing of the Azolla

不同光照条件下4种满江红(Azolla)品系体内多酚氧化酶活性的变化

在生物学观察测定基础上，引入生化测定方法探讨不同光照条件下卡洲满江红３００１ 、小叶满江红４０１８ 、杂交萍９０４６ 和回交萍ＭＨ３１ 四个红萍品系体内多酚氧化酶（ＰＰＯ） 活性变化趋势。结果表明，光照影响各满江红品系的生长速率与抗霉腐病能力，随着光照强度减弱，各品系的生长速率和抗霉腐病能力都下降。在低光下，供试的满江红品系生物量与体内ＰＰＯ 活性的相关性显著（ｒ＝ ０ ．９５６０） 。低光下满江红各品系生长速率、抗霉腐病能力和体内ＰＰＯ 活性的从高到低依次为卡洲满江红３００１ 、杂交萍９０４６ 、小叶满江红４０１８ 和回交萍ＭＨ３１ 。从生理、生化角度讨论了满江红耐荫性与体内多酚氧化酶活性的关系。

Approximate Compositional Values and Tissue Fatty Acid Profiles of Nile Tilapia (<i>Oreochromis niloticus</i>L.) Fed <i>Azolla</i>-Diets in Earthen Ponds

The approximate general composition and the fatty acid profile of Nile tilapia fed Azolla-diets in ponds were studied for 90 days. Six isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g>sup>-1) diets were formulated to contain 0% (A0), 10% (A10), 20% (A>sub>20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM), as partial fish meal (FM) substitutes. Diet A0 without AM served as a control. Fish growth decreased as AM level exceeded 20% in diets (P 0.05). Crude lipid was significantly lower in fish fed A50 and significant differences were also found in crude ash (P 20, A30 and A50. High level of the fern reduces growth without negatively affecting fatty acid in fish. Fish PUFA, especially the (n - 3) fatty acids, are affected positively, even when fed 50% AM, which is good for the quality of the fish produced in regard to the benefits for the health of consumers.

2,4-D Hyper Accumulation Induced Cellular Responses of Azolla pinnata R. Br. to Sustain Herbicidal Stress

In the present experiment with ongoing concentration(0µM,100µM,250µM,500µM and 1000µM)of 2,4-D,the responses of Azolla pinnata R.Br.was evaluated based on cellular functions.Initially,plants were significantly tolerated up to 1000µM of 2,4-D with its survival.This was accompanied by a steady decline of indole acetic acid(IAA)concentration in tissues with 78.8%over the control.Membrane bound H^(+)-ATPase activity was over expressed within a range of 1.14 to 1.25 folds with activator(KCl)and decreased within a range of 57.3 to 74.6%in response to inhibitor(Vanadate)application.With regards to IAA metabolism,plants recorded a linear increase with wall bound oxidase activity up to maximum concentration of 2,4-D.The variations were more moderated when wall bound IAA-oxidase recorded a linear increase proportionate to the 2,4-D concentrations.This was more extended with the presence of different isoforms of IAA-oxidase which was much more pronounced with distinct polymorphisms of expressed proteins,however,not independent to the 2,4-D concentrations.Polyamines like spermine,spermidine and putrescine(spm,spd and put)were not consistent in concentration with the dosages of 2,4-D.Besides these,plants were induced to apoplastic NAD(P)H oxidase activity maximally by 1.6 folds under 500µM 2,4-D over control.Still,putrescine responded more or less consistently and recorded maximally 11.9 folds at 500µM 2,4-D as compared to the control.NAD(P)H oxidase activity recorded maximally 1.6 folds against control and remain consistent throughout the concentrations of 2,4-D.GPX along with APX were more linear in responses through the concentration of 2,4-D except CAT as compared to control.On enzymatic antioxidative activity,peroxidases(GPX and APX)were overexpresed in a similar manner except for catalase with a non-significant rise.In stabilization of cellular redox,glutathione reductase attended maximum value by 2.45 folds at 1000µM evidenced with significant variations in protein polymorphism.The sensitivity of 2,4-D also appeared in Azolla with a maximum loss of nucleic acids as documented by the comet assay.Moreover,the Azolla might have some DNA damage protective activity as evident using frond extract with plasmid nick assay.Therefore,Azolla plants with its cellular responses is evident to sustain against the 2,4-D herbicidal stress and may be granted in bio remediation process for the contaminated soil.

Growth and fatty acid composition of Nile tilapia <i>Oreochromis niloticus</i>L. fed Azolla-diets, in tanks and in earthen ponds: A comparative study

Two 90-day experiments were conducted in the same period in tanks and in earthen ponds to study the effects of culture systems on growth and fatty acid (FA) of Nile tilapia (Oreochromis niloticus L.) fingerlings (mean weight: 16.3 g) fed Azolla, as partial replacement for fish meal (FM). Diets were isonitrogenous (29.2% CP) and isoenergetic (16.9 kJ·g-1) containing 0% (A0), 10% (A10), 20% (A20), 30% (A30), 40% (A40) and 50% (A50) of Azolla meal (AM) respectively. Diet A0, without AM, acted as a control. In both experiments, fish growth decreased as AM level increased in diets (P P 30-A50). Interestingly, those fish were rich in eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Consequently, the n-3/n-6 values decreased in tanks, whereas an increasing trend was found in ponds, and values were significantly higher in ponds than in tanks (0.35 - 0.53 vs. 0.08 - 0.17). The results suggest raising Nile tilapia with Azolladiets in ponds to improve growth and produce fish with a better FA composition, for the wellbeing of consumers.

Effects of Various Environmental Factors on Biological Characteristics of Azolla

This study was conducted to screen and breed Azolla varieties with strong resistance.Four Azolla samples( CD,XT,HY,YZ) were collected from Hunan Province,and the growth characteristics such as propagation coefficient,temperature,light intensity,pH value and humidity were analyzed using artificial culture method.The results showed the four Azolla varieties all had the largest reproduction coefficients after cultured for 21 d,and the optimum culture conditions were temperature at 24-28 ℃,illumination intensity of 15 000-20 000 lx,pH 6.0,and humidity of 60%-80%.Among the four Azolla varieties,YZ has strong reproductive performance and high temperature resistance,and XT has strong acid resistance.

The Growth of Rice(Oryza sativa L.)on Non Tidal Lowland Soil through Enrichment of Azolla and Different Level Fertilization Dosage(N and P)

Rice can grow in the non tidal lowland despite its limited soil fertility.One of the biofertilizers that can be used to improve fertility is azolla.This research aims to evaluate the growth of rice in non tidal lowlands using azolla to enrich the soil and different dosage of N(Nitrogen)and P(Phosphate)fertilization.A FCRD(Factorial Completely Randomized Design)was adopted consisting of 3 treatment factors,namely concentrations of N with doses of N1:46 kg/ha;N2:69 kg/ha;N3:92 kg/ha;P with P1:34 kg/ha;P2:68 kg/ha;and the application of azolla(A0:without azolla and A1:with 100 g/m2 azolla).The result showed that enriching the soil with azolla,fertilization dosage N and P,has a significant effect on plant height in the 4th WAP(Week After Planting).Furthermore,the interaction between azolla and N significantly influences panicle number,grain weight,and plant height at 2nd,4th,and 8th WAP.Conclusively,the application of azolla,N,and P fertilization supplied nutrients to rice crops in the non tidal lowland.

RE-ESTABLISHMENT OF SYMBIOSIS TO Anabaena-FREE Azolla

Symbiosis to Anabaena-free Azolla has been re-established by placing indusium containing Anabaena onto the Anabaena-free megasporocarps. Anabaena-free megasporocarps were obtained by removing the indusium and the apical membrane of the megaspore apparatus of normal Azolla. The recovery of symbiosis in artificially reconstituted Azolla-Anabaena association was confirmed using the scanning electron microscope, monoclonal antibody test (McAb-C16), and nitrogen fixation capacity （ARA）.Laboratory-grown Anabaena azollae cells inoculated subsequently to the decapitated megaspore apparatus were observed to have entered the leaf cavities of sporophyte, although some portions of Anabaena filaments were found outside the leaf cavity. Plants invaded by artificially inoculated Anabaena did not have sufficient N2-fixing activity to allow the growth in the N-free medium.

Removal of methyl orange from aqueous solution by Azolla filicoloides:Synthesis of Fe_3O_4 nano-particles and its surface modification by the extracted pectin of Azolla

The modified Fe3O4 nanoparticles with the extracted pectin from the cell wall of Azolla filicoloides（FNEP） can remove methyl orange as a watersoluble azo dye from waste water better than Azolla and the extracted pectin from Azolla（EPA）,alone.It could be due to more crowding the main functional groups of uptake after binding pectin with nanoparticles.Thermodynamic studies showed that adsorption equilibrium constant（KL） and maximum adsorption capacities（Q（max）） were increased with decreasing temperature（exothermic）.The maximum uptake capacity（Q（max）） of dye by FNEP in a batch reactor was 0.533,0.498 and 0.446 mmol/g at 5,25 and 50℃,respectively.The enthalpy change（△H） and entropy change（△S） were 15.31 kJ/mol and 0.02434 kJ/mol K,respectively.

Azolla-A Model Organism for Plant Genomic Studies

The aquatic ferns of the genus Azolla are nitrogen-fixing plants that have great potentials in agricultural production and environmental conservation. Azolla in many aspects is qualified to serve as a model organism for genomic studies because of its importance in agriculture, its unique position in plant evolution, its symbiotic relationship with the N2-fixing cyanobacterium, Anabaena azollae, and its moderate-sized genome. The goals of this genome project are not only to understand the biology of the Azolla genome to promote its applications in biological research and agriculture practice but also to gain critical insights about evolution of plant genomes. Together with the strategic and technical improvement as well as cost reduction of DNA sequencing, the deciphering of their genetic code is imminent.

Poultry litter biochar application in combination with chemical fertilizer and Azolla green manure improves rice grain yield and nitrogen use efficiency in paddy soil

Poultry litter biochar is known to improve crop productivity.However,its beneficial interactions with chemical fertilizer and/or organic manure on rice yield and nitrogen(N)use efficiency(NUE)are not well studied.The objective of this study was to co-apply poultry litter biochar(hereinafter biochar)and chemical fertilizer and/or Azolla as organic manure(herein N fertilizer sources)to improve the productivity of rice and NUE.Eight treatments-no amendments(control),chemical fertilizer(NPK),Azolla as green manure(Azolla),and NPK+Azolla without and with biochar amendment-were evalu-ated in a pot trial.Selected rice plant growth components,yield,and NUE were determined.Compared to the treatments without biochar,co-application of biochar and N fertilizer sources significantly improved grain N uptake by 23.9%and NUE by 34.3-246.9%.These treatments also significantly improved rice growth components(5.6-18.2%)and grain yield(32.4%).Significant changes in soil properties including increases in pH,electrical conductivity(EC),total N,organic car-bon,and available phosphorus were observed following biochar application.Except for the soil pH and EC parameters,no significant synergistic interactions between biochar and N fertilizer sources were observed for any parameters in the present study.Notably,compared to other treatments,the co-application of biochar and Azolla offers a feasible approach to improve rice productivity and NUE and reduce chemical fertilizer use,thereby reducing agricultural pollution and production costs.

Application of Microwave Treatment for Cell Lysis in Screening of Transformed Colony of Anabaena azollae by in situ Hybridization

In our experiment, the method of in situ hybridization with some modification was used to quickly screen out the transformed colonies of dinitrogen fixing filamentous cyaobacteria Anabaena azollae. In order to effectively complete lysis of A. azollae cells, which can cause colonies on nitrocellulose membrane over agar plate, several physical methods, such as freeze-thawing with liquid nitrogen, microwave treatment and incubation

A green chemistry approach for the synthesis and characterization of bioactive gold nanoparticles using Azolla microphylla methanol extract

This article reports the environmentally benign synthesis of gold nanoparticles （GNPs） using methanol extract of Azolla microphylla as the stabilizing and reducing agent. The GNPs were characterized by UV-vis spectrophotometry and FTIR, and the morphological characteristics were analyzed by XRD, FESEM-EDX and HRTEM. The GNPs could be formed in very short time, even in less than 30 min. The nanoparticles measured by UV-spectrophotometer demonstrated a peak at 540 nm corresponding to surface plasmon resonance spectra, and the peaks showed by FTIR suggested the presence of organic biomolecules on the surface of the GNPs. XRD results confirmed the crystalline nature of the GNPs, and FESEM-EDX and HRTEM analyses had been performed in the size ranges of 17-40nm and 1.25-17.5nm respectively. The synthesized GNPs showed excellent antioxidant activity. This study shows the feasibility of using plant sources for the biosynthesis of GNPs.