SEEDLING GROWTH TOLERANCE OF CUCURBITS CROPS TO HERBICIDES STOMP AND ACETOCHLOR
Summary. Several species from the Cucurbitaceae family including muskmelon, watermelon, cucumber, pumpkin, and squash were used to evaluate their tolerance in a laboratory test to two herbicides (Stomp and Acetochlor) widely used in crop cultivation. The effects of concentration and site of herbicide action on the length of primary roots and hypocotyls as well as seedling fresh weight were studied. The results showed that the cultivars differed greatly in their sensitivity to the herbicide action. The difference in the growth responses was not only species-, but also cultivar-specific. In addition, there was a difference in the herbicide acting site on plants which depended on the kind of cucurbits crops. Based on the tolerance to the action of both herbicides the studied species can be classified as follows: watermelon, squash, pumpkin, muskmelon, cucumber. The tolerance differences of the studied cucurbits crops can be used in cultivation practice.
Summer squash production using conservation tillage
Three summer squash (Cucurbita pepo L.) cultivars were grown using conventional tillage and no-till soil management practices during 1991 and 1992 in the mountain regions of Georgia. Soil bulk density and N content as well as crop dry weight, leaf area, and yield were monitored to assess the potential for using conservation tillage in squash production. Soil bulk density of the surface (0 to 10 cm) layer under no-till exceeded that under conventional tillage at planting by 0.25 Mg.m -3 , and 1 month after planting by as much as 0.16 Mg.m -1 . However, growth-limiting bulk densities (>1.45 Mg.m -3 ) did not occur [...]
Toluene degradation via a unique metabolic route in indigenous bacterial species
Tanneries are the primary source of toluene pollution in the environment and toluene due to its hazardous effects has been categorized as persistent organic pollutant. Present study was initiated to trace out metabolic fingerprints of three toluene-degrading bacteria isolated from tannery effluents of Southern Punjab. Using selective enrichment and serial dilution methods followed by biochemical, molecular and antibiotic resistance analysis, isolated bacteria were subjected to metabolomics analysis. GC–MS/LC–MS analysis of bacterial metabolites helped to identify toluene transformation products and underlying pathways. Three toluene-metabolizing bacteria identified as Bacillus paralicheniformis strain KJ-16 (IUBT4 and IUBT24) and Brevibacillus agri strain NBRC 15538 (IUBT19) were found tolerant to toluene and capable of degrading toluene. Toluene-degrading potential of these isolates was detected to be IUBT4 (10.35 ± 0.084 mg/h), IUBT19 (14.07 ± 3.14 mg/h) and IUBT24 (11.1 ± 0.282 mg/h). Results of GC–MS analysis revealed that biotransformation of toluene is accomplished not only through known metabolic routes such as toluene 3-monooxygenase (T3MO), toluene 2-monooxygenase (T2MO), toluene 4-monooxygenase (T4MO), toluene methyl monooxygenase (TOL), toluene dioxygenase (Tod), meta- and ortho-ring fission pathways. But additionally, confirmed existence of a unique metabolic pathway that involved conversion of toluene into intermediates such as cyclohexene, cyclohexane, cyclohexanone and cyclohexanol. LC–MS analysis indicated the presence of fatty acid amides, stigmine, emmotin A and 2, 2-dinitropropanol in supernatants of bacterial cultures. As the isolated bacteria transformed toluene into relatively less toxic molecules and thus can be preferably exploited for the eco-friendly remediation of toluene.