Biochemical Oxygen Demand (BOD) in a river water
remains unchanged when algal bloom occurs
has no relationship with the concentration of oxygen in the water
gives a measure of Salmonella in the water
gives a measure of Salmonella in the water
D.
gives a measure of Salmonella in the water
Biochemical Oxygen Demand (BOD) is the amount of oxygen used for biochemical oxidation by micro-organisms in a unit volume of water. Polluted water has high BOD. Thus, when sewage gets mixed with river water, BOD will increase.
A common biocontrol agent for the control of plant diseases is
Baculovirus
Bacillius thuringiensis
Glomus
Glomus
D.
Glomus
Trichoderma is a genus of fungi that is present in all soils, where they are the most prevalent culturable fungi. Many species in the genus can be characterised as opportunistic avirulent plant symbionts. Several strains of Trichoderma have been developed as biocontrol agents against the fungal disease of plants. The various mechanisms include antibiosis, parasitism inducing host-plant resistance and competition. Most biocontrol agents are from the species. T.harzianum, T. varied and T. hamatum. The biocontrol agent generally grows in its natural habitat on the root surface and so affects root disease in particular but can also be effective against the foliar disease.
Which of the following is not used as a biopesticide?
Trichoderma harzianum
Nuclear Polyhedrosis virus (NPV)
Nuclear Polyhedrosis virus (NPV)
D.
Nuclear Polyhedrosis virus (NPV)
The bacterium Xanthomonas campestris is the causative agent of plant disease, black rot of cabbage.
Bacillus thuringiensis, T. harzianum and NPV are biopesticides.
The common nitrogen -fixer in paddy field is
Rhizobium
Azopirillum
Oscillatoria
Oscillatoria
B.
Azopirillum
Azopirillum is a nitrogen-fixing bacterium in paddy fields. It is very useful soil and root bacterium. It is an associative symbiotic N2 -fixing bacteria. When it is added to the soil, it multiplies in millions and can supply 20-40 kg of nitrogen per hectare per season. It also produces growth promoting substance like Indole Acetic acid (IAA). Gibberellins and promotes root proliferation. These substances improve the plant growth and yield.
A person likely to develop tetanus is immunised by administering
dead germs
preformed antibodies
wide spectrum antibiotics
wide spectrum antibiotics
B.
preformed antibodies
In passive immunity, the antibodies are produced in some other organism (eg, horse) in response to the given antigen,.These antibodies are then injected into the human body at the time of need. This is known as inoculation, eg, persons infected by tetanus, rabies, Salmonella and snake venom are given the sufficient amount of antibodies, so that they can survive.