Plant Pathology - Study Mode

[#331] Algae often float on surface of water during day but sink down during night due to
Correct Answer

(A) Evolution and trapping of oxygen bubbles during the day in their photosynthesis

Explanation

Solution: Algae often float on the surface of the water during the day but sink during the night due to the evolution and trapping of oxygen bubbles during the day in their photosynthesis. Algae produce oxygen during the day during photosynthesis. The oxygen that is released gets trapped between the filaments of the algae, making it lighter and causing it to float to the top of the pond or surface of water bodies.

[#332] Chlorophyll a has
Correct Answer

(D) No functional group

Explanation

Solution: Chlorophyll has no functional group. Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. The molecular structure of chlorophyll consists of a chlorin ring, whose four nitrogen atoms surround a central magnesium atom, and has several other attached side chains and a hydrocarbon tail formed by a phytol ester.

[#333] Glyricidia species is used as
Correct Answer

(C) Both A and B

Explanation

Solution: Gliricidia species is used as Green manure and Green leaf manure. Gliricidia is a genus of flowering plants in the legume family, Fabaceae and tribe Robinieae. The species G. sepium is a small, deciduous, ornamental tree, cultivated and used for a variety of purposes in tropical regions. Gliricidia is a fast-growing, nitrogen-fixing leguminous tree that is used in agroforestry to add nitrogen and organic matter to the soil.

[#334] A crop plant which can grow in nitrogen deficient soils without external supply of it is
Correct Answer

(A) Cajanus cajan

Explanation

Solution: A crop plant that can grow in nitrogen-deficient soils without an external supply of it is Cajanus cajan. The Cajanus cajan is a perennial legume from the family Fabaceae native to the Old World. The pigeon pea is widely cultivated in tropical and semitropical regions. Cajanus is a highly leguminous crop and can fulfill the need for nitrogen even in nitrogen-deficient soil by fixing atmospheric nitrogen itself.

[#335] Which of the following herbicides derived from urea?
Correct Answer

(A) Simazine

Explanation

Solution: Simazine from the following herbicides is derived from urea. Simazine is a selective herbicide C 7 H 12 N 5 Cl used to control weeds, especially among crop plants. It is a diamino-1,3,5-triazine that is N,N'-diethyl-1,3,5-triazine-2,4-diamine substituted by a chloro group at position 6. It has a role as a herbicide, a xenobiotic, and an environmental contaminant. It is used to control broad-leaved weeds and annual grasses in a field, berry fruit, nuts, vegetable and ornamental crops, turfgrass, orchards and vineyards.