A practical method for overcoming the dormancy of <Emphasis Type="Italic">Taxus baccata</Emphasis> isolated embryos under <Emphasis Type="Italic">in vitro</Emphasis> conditions

Conditions for obtaining an efficient mass propagation procedure to overcome isolated Taxus baccata embryo dormancy were investigated. The protocol herein described was efficient for overcoming the dormancy of T. baccata isolated embryos under in vitro conditions, enabling the conservation and propagation of this species. T. baccata seeds were unable to germinate directly after collection under in vitro conditions. Very good sterility and germination was achieved by soaking seeds in distilled water at a low temperature (+4°C) at least for 48 h instead of leaching them for 7 d under running water, followed by maintaining isolated embryos on the Murashige and Skoog medium (MS) supplemented with 5 g l⁻¹ activated charcoal. That treatment allowed one to shorten the time of the experiment and gave almost 100% sterility. The best germination was observed in darkness, but to obtain worthy seedlings, it was necessary to place cultures in a 16-h photoperiod after a 2-wk incubation. There was no significant difference in germination between seeds collected from different populations of Southern Poland.     

Polyporus phyllostachydis sp. nov. with notes on other rhizophilic species of Polyporus (Basidiomycota,Polyporaceae)

Polyporus phyllostachydis is described and illustrated as a new species. This species is characterized by its occurrence on bamboo roots, the small and centrally stipitate basidiocarps, the white pileus, usually becoming darker from the center at maturity, and the cylindrical stipe with a distinct crust. Morphological characters of the present species were compared with those of P. cryptopus and P. rhizophilus, other rhizophilic species of the genus. Polyporus cryptopus and P. rhizophilus are morphologically distinct by contextual texture, basidiospores, and hyphae, and possibly represent two distinct species. Contribution no. 205, Laboratory of Plant Parasitic Mycology, Graduate School of Life and Environmental Sciences, University of Tsukuba, Japan     

Soil nutrient status after bamboo flowering and death in a seasonal tropical forest in western Thailand

We have examined the surface (0–10 cm) soil characteristics of sites after bamboo (Cephalostachyum pergracile) mass flowering and death (DB sites) in comparison with sites with living bamboo (Bambusa tulda) (LB sites) in a seasonal tropical forest in Thailand. One year after bamboo flowering the DB sites were acidic with lower concentrations of exchangeable Ca and Mg and soil nitrogen than the LB sites. Therefore, although leaf and root litter of the dead bamboo was deposited in the DB sites after bamboo flowering, soil nutrient status decreased.     

Biochar amendment to soils impairs developmental and reproductive performances of a major rice pest Nilaparvata lugens (Homopera: Delphacidae)

Biochar amendments to soils had aroused much interest for having potential for greenhouse gas mitigation, soil improvement and increased crop productivity. However, little attention had been focused on the influence of biochar amendments on herbivorous insect pests. This study investigated whether a biochar amendment affected developmental and reproductive performances of the rice brown planthopper (Nilaparvata lugens) feeding on rice plants. The biochar from the pyrolysis of wheat straw was used for treatments of soils (from a fallow rice field), and the treated soils were applied to grow rice seedlings in small vials, in which N. lugens life history was observed. The nymphal development time was delayed and nymph‐to‐adult survival decreased with a high level of 200 g/kg biochar application. Herbivore lifetime fecundity decreased with increasing amounts of biochar, from 256 eggs under the control down to 69 eggs under the high level (200 g/kg) of biochar application. Egg‐hatching rate significantly decreased at the highest biochar level (200 g/kg), compared to the other lower biochar levels. Our results suggest that biochar amendment to rice fields may have negative impacts on the rice brown planthoppers when applied at level of 200 g/kg of soil.     

Enhancing the combustible properties of bamboo by torrefaction

Bamboo has wide range of moisture content, low bulk energy density and is difficult to transport, handle, store and feed into existing combustion and gasification systems. Because of its important fuel characteristics such as low ash content, alkali index and heating value, bamboo is a promising energy crop for the future. The aim of this study was to evaluate the effects of torrefaction on the main energy properties of Bambusavulgaris. Three different torrefaction temperatures were employed: 220, 250 and 280 °C. The elemental characteristics of lignite and coal were compared to the torrefied bamboo. The characteristics of the biomass fuels tend toward those of low rank coals. Principal component analysis of FTIR data showed a clear separation between the samples by thermal treatment. The loadings plot indicated that the bamboo samples underwent chemical changes related to carbonyl groups, mostly present in hemicelluloses, and to aromatic groups present in lignin.     

Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation

An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo.     

Modeling available 2,4-dichlorophenoxyacetic acid in a tissue culture medium containing activated carbon

Clonal propagation of high-value forest trees by somatic embryogenesis can help meet industry needs for uniform and high quality raw materials. Low embryogenic tissue initiation frequencies for loblolly pine (Pinus taeda L.) pose a limitation in work towards commercialization of this technology. At the time our research began most work on somatic embryo culture initiation in loblolly pine reported success in the range of 1–5%. Activated carbon (AC) has been reported to improve many tissue culture systems including embryogenic tissue initiation in Douglas-fir. To improve initiation frequencies in loblolly pine, the development of an AC-containing system was explored. In order to better understand the availability of 2,4-dichlorophenoxyacetic acid (2,4-D) in initiation medium, we tracked media surface concentrations of free or available 2,4-D. Media containing 1/2 modified P6 salts, 1.5% maltose, 2% myo-inositol, case amino acids, glutamine, vitamins, and 0.4% Gelrite were modified to include 0.625 – 2.5 g l^–1 of activated carbon (Sigma C-9157, acid washed) and 110 –440 mg l^–1 2,4-D. Adsorption and availability of 2,4-D in AC-containing medium was tracked by C¹⁴ labeled 2,4-D present in surface moisture absorbed into filter paper. High correlations were found between–available 2,4-D and time when AC and initial 2,4-D concentrations were held constant,–available 2,4-D and AC concentration when initial added 2,4-D and time were held constant, and–available 2,4-D and initial 2,4-D when AC and time were held constant.All of these relationships were exponential, not linear. Multiple regression models inputting initial 2,4-D added to medium in mg l^–1, activated carbon added to medium in %, and time in days, were able to explain 85–88% of the variability in available 2,4-D. These models can be used to achieve target levels of available 2,4-D by adjustment of initial 2,4-D levels or AC content.     

活性炭对苦荞幼苗根系和叶片生理特性的影响

以山西省主栽苦荞品种‘黑丰1号’温室盆栽幼苗为材料,设置土壤活性炭含量分别为0(CK)、2.5(B2.5)、5.0(B5.0)、7.5(B7.5)、10(B10)g/kg共5个水平,研究土壤中施加活性炭后对苦荞幼苗根系及碳氮代谢、保护酶活性等指标的影响.结果显示:(1)随着活性炭施用比例的增加,苦荞幼苗根系生长指标和根系活力指标均呈先增后减的趋势,根平均直径呈先减后增的趋势,其中B5.0、B7.5处理的幼苗根系总长度、总表面积、总体积、活跃吸收面积、根尖数均显著高于对照,但B10处理的根系发育减弱.(2)随活性炭施用比例的增加,苦荞幼苗叶片蔗糖酶活性变化呈先增后减的趋势,同一处理水平条件下随苦荞的生长而逐渐下降;B2.5、B5.0处理苦荞幼苗叶片蔗糖酶活性和可溶性糖含量均比CK极显著增加,B7.5处理略有提高,B10处理差异不显著.(3)苦荞幼苗叶片谷氨酰胺合成酶(GS)活性随活性炭的增加基本呈上升趋势,而同一处理水平下随苦荞的生长而下降;叶片GS活性在B5.0、B7.5处理时比CK极显著提高,可溶性蛋白质含量在B7.5处理时也显著提高.(4)叶片保护酶SOD、POD、CAT活性随活性炭浓度的升高呈先升后降的变化趋势,而同一处理水平下各时期间变化不大;B2.5处理叶片的SOD、POD和CAT活性比对照显著增强.研究发现,适量施用活性炭(2.5～7.5g/kg)能有效促进苦荞幼苗碳氮代谢和保护酶活性,增强其根系活力.     

城市绿化竹种综合选择

针对城市绿化材料选择的需求,对福建华安竹种园79个丛生竹和121散混生竹分别测定分析,运用集对分析方法对竹子生态适应性、观赏性和放氧量等方面13个指标进行综合评价选择,结果表明:花竹、小叶琴丝竹、黄竹、糯竹、乡土竹、泰竹、青皮竹等为城市绿化优良丛生竹种;实心竹、衢县苦竹、黄槽毛竹、毛竹、鸟哺鸡竹、高节竹、红哺鸡竹、毛环水竹为城市绿化优良散混生竹种.     

Molecular Genotyping of Macrophomina phaseolina Isolates: Comparison of Microsatellite Primed PCR and Repetitive Element Sequence-based PCR

Seventy isolates of Macrophomina phaseolina recovered from different host plants were assessed for DNA polymorphism using two molecular techniques: microsatellite primed polymerase chain reaction (MSP‐PCR) under both touchdown (T) and non‐touchdown (NT) PCR conditions and primers corresponding to disperse repetitive sequence‐based polymerase chain reaction (rep‐PCR). Fingerprints obtained by rep‐PCR were compared with those of MSP‐PCR. Even though these methods yielded intraspecific polymorphisms, yet different levels of discrimination could be obtained. A partial correlation was apparent between the molecular techniques used. Some of the genetic groups/genotypes were supported by both the molecular markers employed in the study, thus confirming their relationship. Thirty nine MSP (T), 55 MSP (NT) and 53 rep‐PCR genotypes were identified with discrimination indices of 0.962, 0.993 and 0.99, respectively. Our results have shown that rep‐PCR is a rapid, inexpensive technique that is highly reproducible and almost as discriminatory as MSP‐PCR for genotyping M. phaseolina isolates and is highly suitable for understanding disease epidemiology at molecular level. Suggesting, thereby, that it is a robust technique employed for genotypical and phylogenetic studies for determining taxonomical diversity and phylogenetic structure of the economically important fungal pathogen of cluster bean. The data presented here will help researchers to design effective strategies for deployment of resistant germplasm in cluster bean (Cymopsis tetragonoloba) growing regions in the country and worldwide.