Agronomy - Study Mode

[#446] Germinating legume seed contains
Correct Answer

(D) Psidic acid

[#447] Oxygen evolving complex of PSII (Photosystem II) contains
Correct Answer

(D) All of the above

Explanation

Solution: The oxygen Evolving complex in Photosystem II contains a cluster of one calcium, four manganese atoms, and traces of chlorine. It is responsible for the oxidation of water to oxygen in plants, algae and cyanobacteria. This cluster of atoms serves as a model for the splitting of water by energy obtained from sunlight.

[#448] The total number of isotopes of elemental hydrogen is
Correct Answer

(B) 3

Explanation

Solution: Hydrogen has three isotopic forms which are hydrogen, Deuterium and tritium. All of them have one single proton but a different number of their neutrons. Hydrogen (Protium) contains one neutron, deuterium contains two neutrons whereas tritium contains 3 neutrons.

[#449] Downy Mildew of Bajra caused by
Correct Answer

(B) S. graminicola (Sclerospora)

Explanation

Solution: Downy mildew which is also known as 'Green Ear' is one of the destructive diseases of foliage like Bajra which is caused by fungus. The specific fungal organism responsible for its cause is Sclerospora graminicola . It is a soil-borne disease but spread through airborne spores of the fungus. Wet leaves in humid weather act as the most favorable spot for its infection.

[#450] The criteria of essentiality of nutrients in plants was given by
Correct Answer

(B) Arnon and Stout

Explanation

Solution: Essential nutrients are those that any organism is unable to produce within itself and need from outer environmental sources for its proper functioning of biochemical pathways. But there are some basic criteria to make any element essential for any plant type and these criteria were proposed by Arnon and Stout in 1939. And according to them, there are 16 elements essential for the proper growth and development of the plant.