Photolysis of fluchloralin in aqueous methanol

The photodegradation of fluchloralin by UV irradiation or sunlight in aqueous methanolic solution has been examined. In the presence of titanium dioxide five photoproducts were obtained, but only four in its absence. One photoproduct, 2, 2'-azoxy-bis(alpha,alpha,alpha-trifluoro-6-nitro-p-toluidine) is reported for the first time as a metabolite of fluchloralin. In natural sunlight the rate of degradation was higher than in UV light and titanium dioxide had almost no effect on the rate of degradation.     

Commercial production of Cordyline terminalis (L) Kunth. from shoot apex meristem and assessment for genetic stability of somaclones by isozyme markers

Rapid multiplication of Cordyline terminalis (L) Kunth. was achieved from shoot apex explant on Murashige and Skoog's (MS) medium supplemented with 3% (w/v) sucrose and different concentration of growth regulators at various combinations. On MS medium supplemented with BA in combination with Adenine sulphate and IAA, shoot initiation and multiplication were obtained. Best elongations of shoots were found on 1/2 MS basal medium and shoots were rooted on 1/2 MS medium supplemented with IBA. Rooted plants passed through a hardening phase prior to ex vitro transfer. Clonal propagated plants established in garden soil were uniform and identical to mother plant in respect to growth characteristics and morphology. Isozymic profiles of different micropropagated clones were assessed for their genetic stability. Ten clones were tested for six isozymes. Only a few showed variation with respect to the banding pattern in esterase and superoxide dismutase. In superoxide dismutase, the two polymorphic isoforms (Rf 0.06 and 0.45) appeared in the clone C8 of the plants transferred to the field after 15 subcultural passages. Mobility and intensity of bands were monitored in other isozymes. Isozyme markers may be used as a tool for rapid screening of genetic stability in tissue cultured clones of C. terminalis.     

Effects of chromosome 5sh from Gossypium barbadense L. on flower production in G. hirsutum L.

Cotton (Gossypium spp.) yield is directly determined by mature bolls that developed from squares and flowers. The first four to six weeks of flowering accounts for the majority of lint yield in upland cotton (G. hirsutum L.) for most cultivated areas of the southern USA cotton belt. In this study, we evaluated 13 cotton chromosome substitution lines (CS-B) and their chromosome specific-F₂ hybrids, TM-1, 3–79, and six cultivars for the number of flowers produced during the first four weeks of flowering. Results showed that CS-B05sh produced more flowers than TM-1 and 3–79 from 10 July to 5 August. The results suggest that when the short arm of chromosome 5 was substituted from 3–79 (G. barbadense L.) into TM-1 (G. hirsutum) a positive genetic association with flower numbers during this flowering period was exhibited. CS-B05sh had comparable flower numbers with three cultivars, Deltapine 90, Phytogen 355, and Stoneville 474 and more flowers than, Sure Grow 747, Sure Grow 125, and Deltapine 5415. Different patterns for additive and dominance effects on cumulative flowers were observed across weeks of flowering. Dominance effects were more apparent during the early part of the flowering period while additive effects were more apparent towards the end of the flowering period.     

Microsatellite variability and its use in the characterization of cultivated clones of Hevea brasiliensis

Microsatellite markers were developed and evaluated in Hevea brasiliensis, an important crop species producing natural rubber of commercial utility. Of eight microsatellite markers, four were found to be highly informative, amplifying a total of 19 alleles when evaluated against 27 cultivated Hevea clones/genotypes. Power of discrimination of the microsatellite loci was in the range of 0.62‐0.89, with a mean of 0.76 indicating these microsatellites could be valuable genetic markers for diversity characterization. A combination of four microsatellite markers was successfully used to discriminate uniquely all the 27 Hevea clones and some clone‐specific allelic profiles were generated. Cross‐species amplification of the markers developed in H. brasiliensis had also been demonstrated with two other Hevea species, H. benthamiana and H. spruceana, indicating a high degree of sequence homology at the flanking regions. Sequence analysis of the repeat region at the 3′‐UTR of the hydroxymethylglutaryl‐coenzyme A reductase gene, containing clusters of AG repeats in 15 clones, revealed the existence of two alleles based on the repeat length polymorphisms. Homozygosity as well as heterozygosity for both the alleles had also been detected among the clones. Frequency of homozygotes for the smaller allele (allele‐1) was found to be lower than the larger allele (allele‐2) among the primary clones of H. brasiliensis.     

Combination of stem elongation ability with submergence tolerance in rice

Summary A study was conducted with six F₂ populations to test the possibility of combining submergence tolerance and stem elongation ability into a single genotype of rice (Oryza sativa L.). Submergence tolerance and stem elongation ability could be combined in the same genotype if strongly submergence tolerant genes are present in submergence tolerant parents.     

Ethion degradation and its correlation with microbial and biochemical parameters of tea soils

Ethion, a highly persistent insecticide in soil, is extensively used in tea cultivation in the tropics. The studies on the environmental impact of ethion in tea soil ecosystems are scanty. Silty loam and sandy loam soils from tea fields of Dooars (Typic Uderthents) and Hill (Typic Dystrudepts), respectively, were investigated for the degradation and effect of ethion application on soil microbial and biochemical variables under controlled laboratory conditions. Ethion degraded faster in the Hill soil than in the Dooars soil. Higher temperature (30°C) aided in faster degradation due to the increased microbial activity in the soils. Ethion application at field rate (FR) had lower half-lives (70 days at 20°C and 42.3 days at 30°C for Dooars soil; 65.4 days at 20°C and 39 days at 30°C for Hill soil) than at ten times FR (10FR; 75.2 days at 20°C and 44.2 days at 30°C for Dooars soil; 70 days at 20°C and 41.8 days at 30°C for Hill soil). Soil microbial biomass carbon, ergosterol content, fluorescein diacetate hydrolyzing and β-glucosidase activities declined in all the treatment combinations up to day 60 for both FR and 10FR doses at 20°C, irrespective of the soil types. At 30°C, the decreasing trend was observed up to day 30 for both the soils. The toxicological effect of ethion on microbiological and biochemical parameters persisted till their corresponding half-lives. The microbial metabolic quotient and microbial respiration quotient were altered, but was short-lived, indicating ethion induced disturbances. The recovery of the depressive action at 10FR ethion spiking on the studied variables was of slightly longer duration than noticed at FR application, although the depressive effect was overcoming after the respective half-lives of ethion. The microbial and biochemical soil parameters were negatively correlated with application of ethion up to day 60 of incubation.     

A phosphatase associated with metastasis of colorectal cancer

To gain insights into the molecular basis for metastasis, we compared the global gene expression profile of metastatic colorectal cancer with that of primary cancers, benign colorectal tumors, and normal colorectal epithelium. Among the genes identified, the PRL-3 protein tyrosine phosphatase gene was of particular interest. It was expressed at high levels in each of 18 cancer metastases studied but at lower levels in nonmetastatic tumors and normal colorectal epithelium. In 3 of 12 metastases examined, multiple copies of the PRL-3 gene were found within a small amplicon located at chromosome 8q24.3. These data suggest that the PRL-3 gene is important for colorectal cancer metastasis and provide a new therapeutic target for these intractable lesions.     

Effects of inoculation of cyanobacteria on nitrogen status and nutrition of rice (Oryza sativa L.) in an Entisol amended with chemical and organic sources of nitrogen

A field experiment was conducted with wetland rice (Oryza sativa cv. IR-36) in a sandy clay loam soil (Entisol) to study the effect of inoculation with a soil-based mixed culture of four diazotrophic cyanobacteria,Aulosira fertilissima, Nostoc muscorum, N. commune andAnabaena spp., on the N-flux in inorganic NH₄ ⁺+NO₃ ^–+ NO₂ ^–), easily oxidizable, hydrolysable and non-hydrolysable forms of N in soil during vegetative growth periods of the crop. Effects on grain and straw yield and N uptake by the crop were estimated. The effects of applying urea N and N as organic sources, viz.Sesbania aculeata, Neem (Azardirachta indica) cake and FYM, each at the rate of 40 kg N ha^–1, to the soil were also evaluated. Inoculation significantly increased the release of inorganic N, evidenced by its increased concentrations either in soil or in soil solution. However, such increases rarely exceeded even 4% of total N gained in different froms in the soil system by inoculation during the vegetative growth stages of the rice plant, when the nutritional requirement of the plants is at a maximum. Most of the N₂ fixed by cyanobacteria remained in the soil as the hydrolysable form (about 85%) during this period. Inoculation caused an insignificant increase in grain (8%) and straw (11%) yield, which was, however, accompanied by a significant increase in N uptake by the grain (30%) and an increase in total uptake of 15.3 kg N ha 1. Such beneficial effects of inoculation varied in magnitude with the application of organic sources, with farmyard manure (FYM) being the most effective. Application of urea N, on the other hand, markedly reduced such an effect.     

Characterization of plant and animal based natural fibers reinforced polypropylene composites and their comparative study

Natural fibers are largely divided into two categories depending on their origin: plant based and animal based. Plant based natural jute fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated by compression molding. Bending strength (BS), bending modulus (BM), tensile strength (TS), Young’s modulus (YM), and impact strength (IS) of the composites were found 44.2 MPa, 2200 MPa, 41.3 MPa, 750 MPa and 12 kJ/m², respectively. Animal based natural B. mori silk fiber reinforced polypropylene (PP) matrix composites (20 wt% fiber) were fabricated in the same way and the mechanical properties were compared over the silk based composites. TS, YM, BS, BM, IS of silk fiber reinforced polypropylene composites were found 55.6 MPa, 760 MPa, 57.1 MPa, 3320 MPa and 17 kJ/m² respectively. Degradation of composites in soil was measured upto twelve weeks. It was found that plant based jute fiber/PP composite losses its strength more than animal based silk fiber/PP composite for the same period of time. The comparative study makes it clear that mechanical properties of silk/PP composites are greater than those values of jute/PP composites. But jute/PP composites are more degradable than silk/PP composites i.e., silk/PP composites retain their strength for a longer period than jute/PP composites.