Plant Pathology - Study Mode

[#91] Miximum photosynthesis occurs in
Correct Answer

(D) White light

Explanation

Solution: Maximum photosynthesis occurs in White light. Most organisms that use oxygenic photosynthesis use visible light for the light-dependent reactions, although at least three use shortwave infrared or, more specifically, far-red radiation. Photosynthesis range from 400 to 700 nm, and it absorbs the Violet, Blue and Red colour of Light. In white light all the colour spectrum energies are involved so, maximum photosynthesis is taken place in white light.

[#92] Bacteria leaf blight of rice caused by Xanthomonas oryzae is commonly controlled by seed treatment and foliar spray of the chemical in India
Correct Answer

(A) Streptocycline

Explanation

Solution: Bacteria leaf blight of rice caused by Xanthomonas oryzae is commonly controlled by seed treatment and foliar spray of the Streptocycline chemical in India. Bacterial leaf blight of rice (BB) is a disease caused by the Gram-negative bacterium Xanthomonas oryzae. It causes wilting of seedlings and yellowing and drying of leaves. Spray Streptomycin sulphate + Tetracycline combination 300 g + Copper oxychloride 1.25 kg/ha. If necessary repeat 15 days later. The application of bleaching powder @ 5 kg/ha in the irrigation water is recommended in the kresek stage.

[#93] Which plant shows chloroplast dimorphism?
Correct Answer

(D) Sugarcane

Explanation

Solution: Sugarcane plant shows chloroplast dimorphism. The occurrence of two different types of chloroplasts in the leaves of C 4 plants is referred to as chloroplast dimorphism. It is a characteristic feature of C 4 plants like sugarcane. The vascular bundle sheath cells of sugar cane contain starch-storing chloroplasts lacking grana, whereas the adjacent mesophyll cells contain chloroplasts that store very little starch and possess abundant grana.

[#94] The gummosis disease of citrus which is caused by Phytophthora palmivora is identified by observing
Correct Answer

(D) Oozing of gum

Explanation

Solution: The gummosis disease of citrus which is caused by Phytophthora palmivora is identified by observing Oozing of gum. An early symptom of Phytophthora gummosis is sap oozing from small cracks in the infected bark, giving the tree a bleeding appearance. The gumming may be washed off during heavy rain. The bark stays firm, dries, and eventually cracks and sloughs off. This disease is commonly seen in mandarin, sweet orange, lemons and other citrus fruits.

[#95] Which ones produce androgenic haploids in anther cultures?
Correct Answer

(D) Young pollen grains

Explanation

Solution: Young pollen grains produce androgenic haploids in anther cultures. The term androgenesis refers to plant regeneration directly from microspore culture under in vitro conditions. The underlying principle of androgenesis is to stop the development of pollen cells, which normally become sexual cells, and to force their development directly into a complete plant. The androgenic method of haploid production is from the male gametophyte of an angiosperm plant i.e., microspore (immature pollen). Young pollen grains produced androgenic haploids in anther cultures while the anther wall, a tapetal layer of the anther wall and connective tissue are the parts of the anther.