To elucidate the role of flagella in biofilm formation by Erwinia carotovora subsp. carotovora EC1, we used a nonflagellate, nonmotile mutant (DfliC) and a flagellate, nonmotile mutant (DmotA). A biofilm-inducing medium, which contains the yeast peptone (YP) medium plus the salts of M-63 minimal medium, supported biofilm formation to a greater extent than either the YP or Luria Bertani (LB) medium alone. We demonstrated that both the DfliC and DmotA mutants greatly reduced their ability to form a biofilm on the surface of the wells of polyvinyl chloride (PVC) microtiter plates. The inability of both mutants to form biofilm on the PVC surface was further confirmed with phase-contrast microscopy. Both aflagellate (DfliC) and flagellate (DmotA) nonmotile mutants were equally defective in attachment to the PVC surface. The treatment of bacteria with the protonophore carbonyl cyanide mchlorophenylhydrazone (CCCP), which inhibits the motility of this organism, reduced greatly the biofilm formation. Based on these results, flagella-mediated motility may play an important role in biofilm formation of E. carotovora subsp. carotovora EC1.

No abstract

No abstract

The residual effect of eight herbicides (Pendimethalin, Pretilachlor, TriasulfuronEthoxysulfuron, Pyrazosulfuron Ethyl, Carfentrazone – ethyl, Carfentrazone – ethyl+ Isoproteuron, 2, 4 –D) used in wheat of Agronomy Field Laboratory during March to June 2014 was evaluated for the sunflower. The eighteen herbicide treatment combinations of the eight herbicides used in wheat. The experiment was conducted in Random Complete Block Design (RCBD) with three replications. The effect of herbicide residues on the sunflower was evaluated in terms of germination, the seedling root and shoot length, leaf chlorophyll content and seeding dry matter. The result showed that the seedling establishment of sunflower was not adversely affected by the herbicides applied to the previous wheat crop.

The residual effect of eight herbicides (Pendimethalin, Pretilachlor, Triasulfuron Ethoxysulfuron, Pyrazosulfuron Ethyl, Carfentrazone – ethyl, Carfentrazone – ethyl+ Isoproteuron, 2, 4 –D) used in wheat of Agronomy Field Laboratory during March to June 2014 was evaluated for mungbean. The eighteen herbicide treatment combinations of the eight herbicides were used in wheat. The experiment was conducted in Random Complete Block Design (RCBD) with three replications. The effect of herbicide residues on the mungbean was evaluated in term of germination, seedling root and shoot length, leaf chlorophyll content and seeding dry matter. The result showed that seedling establishment of mungbean was not adversely affected by the herbicides applied the previous wheat crop. Also, the residue of herbicides applied in strip-tilled wheat did not show any adverse effect on germination, shoot length and seedling dry matter of mungbean and even shoot growth of mungbean was not inhibited by the residue of those herbicides. The reason might be related to the half-life and rate of degradation of herbicides in soil. In addition, farmers can easily grow mungbean in a cropping pattern as a subsequent crop of wheat because the study ensures that tested herbicides did not show any adverse residual effect on the establishment of this succeeding crop. However, continuous use of same herbicide or different herbicides with same mode of action in the same land year after year is strictly prohibited. Also, the prudent use of chemical/herbicide is essential to fulfill the goals of conservation agriculture by having reducing detrimental environmental impact as well as reducing herbicide resistance development in crops.