Development of high yielding early matured and shattering tolerant Brassica napus L. through interspecific hybridization between B. rapa L. and B. oleracea L.

Genetic Resources and Crop Evolution - Brassica napus L is an important oilseed crops grown throughout many parts of the world. It is well adapted to long day photoperiods. Synthetic B. napus was...     

棕榈在孟加拉乡村传统利用——一种可持续的生物多样性管理手段(英文)

采用多级采样的方法研究了孟加拉国农村耕作区内棕榈树的传统利用模式和当地的管理经验。农民管理棕榈主要为获取树液产品,生产以糖为主的次生品。树液可直接用作饮料,也可加工成糖蜜或酒精饮料。7块不同地块为棕榈提供生长环境,20.40%的棕榈种植在果园内。尽管中等级的农民拥有多数棕榈(33%),但是主要管理棕榈的是没有土地的农民,他们靠棕榈维持生计。这些农民将自己的智慧应用到棕榈管理当中,从种植到开孔取树液再到产品加工。如果能更科学地管理棕榈,加上农民的智慧,棕榈业将会对当地经济发展起到重要作用,也会丰富当地生物多样性。     

Role of active aluminum in the formation of water-stable macroaggregates

Soil structure is determined by the arrangement of particles in soil and the particles of sand, silt, and clay bind together into aggregates of various sizes by organic and inorganic materials. Structural stability which is the ability of the aggregates and pores to remain intact when subjected to stress, markedly affects crop production and soil erosion (Tisdall 1996). Since water, either directly as rainfall or as surface runoff is the main agent of aggregate breakdown, in the analyzes of stable soil aggregation, the term water-stable aggregation is generally used (Lynch and Bragg 1985). Water-stable aggregates have been divided into micro aggregates < 0.25 mm dia.) and macro aggregates (> 0.25 mm dia.) (Edwards and Bremner 1967; Tisdall and Oades 1982). Microaggregates show a relatively high stability against physical disruption (Edwards and Bremner 1967). On the other hand, macro aggregates are sensitive to soil management (Tisdall and Oades 1982).

There are many reports on the relationships between the aggregate stability and the soil physicochemical properties. For example, significant correlations were found between the aggregate stability and the amounts of organic C (Tisdall and Oades 1982), total N, and carbohydrates or the CEC (Chaney and Swift 1984). However, most of these studies were conducted in non-volcanic ash soils. Volcanic ash soils are widely distributed in Japan and are very important soils for crop production. The objective of this study was, therefore, to obtain more information on the relationship between the degree of macro aggregation and the soil physicochemical properties in non-volcanic and volcanic ash soils.     

Effects of all‐male,mixed‐sex and all‐female freshwater prawn in polyculture with major carps and molas in the fallow rice fields

This study was conducted to evaluate the effects of all‐male, mixed‐sex and all‐female freshwater prawn (Macrobrachium rosenbergii) in a polyculture with major carps (Catla catla and Labeo rohita) and self‐recruiting small fish molas (Amblypharyngodon mola) in the fallow rice fields of Bangladesh. There were three treatments with three replicates. All ponds were stocked with carps and molas plus either all‐male prawns (treatment MP), mixed‐sex prawns (MFP) or all‐female prawns (FP). Prawn, mola, catla and rohu were stocked 20 000, 20 000, 1750 and 750 ha^?1, respectively, in all treatments. The prawns were fed twice daily, starting at 8% body weight and gradually reduced to 3% body weight. The fish were fed in the morning with mustard oil cake and rice bran (1:2 ratios) at 3% body weight. Significantly higher production of prawns (697 kg ha^?1) was obtained in treatment MP, which yielded 34.7% and 56.2% more production than MFP and FP respectively. Significantly higher total production of 1620 kg ha^?1 and a higher benefit–cost ratio of 2.10:1 were also obtained in treatment MP. It can be concluded that an all‐male prawn culture is economically more viable than all‐female and mixed‐sex prawn cultures, along with other fish like major carps and the nutrient‐dense molas in the polyculture.     

Effects of iron ore tailings on growth and physiological activities of Tagetes patula L.

Purpose

Ornamentals can beautify the environment and resolve heavy metal pollution at the same time. Thus, the present study aimed at studying the growth and physiological response of Tagetes patula on iron ore tailings.

Materials and methods

Pot-culture experiments were conducted to investigate the effect of iron ore tailings both individually as well as in combination with soil (at different proportions) on the growth, pigment production as well as accumulation and translocation of various heavy metals from the tailings.

Results and discussion

The results suggested an increase in growth, chlorophyll content, as well as metal accumulation capacity of T. patula with increasing proportion of tailings in the soil. Furthermore, an increase in antioxidant activities in plants grown on tailings as compared to control was observed which suggests plant efficiency to overcome any stress generated due to excess of heavy metals. The order of accumulation of various heavy metals in the plant parts was observed to be Fe?>?Cr?>?Zn?>?Cu?>?Pb?>?Ni?>?Cd. Both bioaccumulation and translocation values were maximum for Fe and minimum for Ni and Cd, respectively.

Conclusions

The overall study clearly suggests plant ability to grow well on the tailings and survive excess of heavy metals present in the tailings. Thus, the plant qualifies well as a potential tool for phytostabilization of iron ore tailings and probably a source of income generation from wasteland owing to its multiple commercial values.     

Assessment of natural regeneration status and diversity of tree species in the biodiversity conservation areas of Northeastern Bangladesh

A study was conducted at two-biodiversity conservation areas of Northeastern Bangladesh (a part of Sylhet Forest Division) to assess the species composition, diversity and density of natural regeneration of tree species both indigenous and exotic species. Data were collected by stratified random quadrate method during January 2010 to July 2010. Totally 200 circular plots of 2 m×2 m in size had 5 different habitat types of plants namely; forest, roadside, homestead (surrounding forest dwellers house), fallow land and others (canals, streams and tea gardens side), which included a total of 55 regenerating species belonging to 28 families. Meliaceae is the dominant family and shows the highest family importance value (26.3), having six species, followed by Moraceae (24.24). Among the five habitat types, forest (43 species) possess the highest number of species, followed by roadside (23 species). Total 15 exotic species among 9 families and 40 indigenous species with 24 families were recorded. For exotic species, Tectona grandis possess the highest relative density (11.7%) and relative frequency (10.5%); Senna siamea had highest relative abundance (7.83%). In case of indigenous species, Chickrassia tabularis possess the highest relative density (4.23%) and relative frequency (4%); Dipterocarpus turbinatus had the highest relative abundance (3.92%). Tectona grandis (29.66) and Chickrassia tabularis (10.8) had the highest IVI for exotic and indigenous species respectively. Different diversity indices such as Shanon-Winner diversity index, species diversity index, species richness index, species evenness index, Simpson index and species dominance index, etc. were applied to quantify definite diversity. The regeneration of species associated with low levels of disturbance was in the exotic species. Study suggests that proper protection from human disturbances and scientific management of natural regeneration of two-study forests may lead a rich biodiversity site in the country.     

Analysis of methanogenic archaeal communities of rumen fluid and rumen particles from Korean black goats

Molecular diversity of methanogens in the rumen of Korean black goats was investigated with 16S rRNA gene clone libraries using methanogen‐specific primers. The libraries were composed of rumen fluid‐associated methanogens (FAM) and rumen particle‐associated methanogens (PAM) from rumen‐fistulated Korean black goats. Among the 141 clones of the FAM library, the sequences were mostly related to two phyla, the Methanobacteriaceae family (77.3%) and the Thermoplasmatales family (22.7%); and among the 68 clones of the PAM library, sequences were also mainly clustered in the two phyla, the Thermoplasmatales family (63.24%) and the Methanobacteriaceae family (35.29%). Most of the sequenced clones in the two libraries were closely related to uncultured methanogenic archaeon. Quantitative real‐time PCR revealed that PAM (8.97 log 10) had significantly higher (P < 0.01) density of methanogens by the methanogenic 16S rRNA gene copies than FAM (7.57 log 10). The two clone libraries also showed difference in Shannon index (FAM library 1.70 and PAM library 1.59) and Chao 1 estimator (FAM library 18 and PAM library 17 operational taxonomic units). Apparent differences found in the microbial community from the two 16S rRNA gene libraries could be a result of such factors as the chemical and physical nature of the target material surface, types or component of diets, the interaction between the methanogens and other microbes, and age of the experimental goats.     

Optimization of Compatible Mixed Cultures for Liquid State Bioconversion of Municipal Wastewater Sludge

The filamentous fungal strains such as Penicillium corylophilum (P), Aspergillus niger (A), Trichoderma harzianum (T) and Phanerochaete chrysosporium (PC) isolated from its relevant sources (wastewater, sewage sludge and sludge cake) were selected for compatible/incompatible mixed cultures. Six combinations of P. corylophilum and A. niger (P/A); P. corylophilum and P. chrysosporium (P/PC); P. corylophilum and T. harzianum (P/T); A. niger and T. harzianum (A/T); A. niger and P. chrysosporium (A/PC); T. harzianum and P. chrysosporium (T/PC) were used to evaluate their potential performance as compatible/incompatible mixed culture for the treatment of municipal wastewater sludge in a bioconversion process. The results of the present study showed that the combinations of P/A, P/PC and A/PC showed compatible growth and the rest of the combinations (P/T, A/T and T/PC) were incompatible cultures. A maximum production of dry biomass and dry filter cake were recorded in the compatible mixed culture of P. corylophilum and A. niger (P/A). A maximum reduction of COD (90%) and a decreased filtration time of treated sludge was observed in the case of P/A microbial mixed culture. The pH value was also affected by the fungal cultures. Effective results were observed by using microbial mixed culture after four days of treatment compared to other treatments (2 and 6 days).