Plant Pathology - Study Mode

[#381] The site for light reaction is
Correct Answer

(A) Grana

Explanation

Solution: The site for the light reaction is Grana. The light reaction takes place in Grana i.e. in the discs of the thylakoid. There, water (H 2 O) is oxidized and oxygen (O 2 ) is released. The electrons freed up from water are transferred to ATP and NADPH. The dark reaction occurs outside of the thylakoids.

[#382] Yellowvein mosaic of Abelmoschus esculanta (okra) is spreads by
Correct Answer

(A) Bemisia tabaci

Explanation

Solution: The yellow vein mosaic of Abelmoschus esculanta (okra) is spread by Bemisia tabaci. Yellow vein mosaic disease (YVMD) is a major biotic constraint on okra (Abelmoschus esculentus) cultivation in Sri Lanka. Diseased plants show characteristic symptoms of mosaic and vein yellowing on leaves and small and yellowish-green fruits. The virus is transmitted by whitefly (Bemisia tabaci Genn.), which is the most severe pest of many crops in the world. The virus is responsible for 80–90% of yield losses and it affects all the developmental stages of okra plants.

[#383] Which of the following pathogens has lemon shaped conidia?
Correct Answer

(C) Pythium

Explanation

Solution: Pythium is the pathogen among the following options that have lemon-shaped conidia. Pythium is a genus of parasitic oomycetes. They were formerly classified as fungi. The conidia are thick-walled, round to lemon-shaped, and rough to spiny with hyaline or brown cell walls.

[#384] The innermost wall layer of pollen sac is tapetum. Its function is in
Correct Answer

(B) Nutrition

Explanation

Solution: The innermost wall layer of the pollen sac is the tapetum. Its function is in Nutrition. The tapetum is a specialized layer of nutritive cells found within the anther, of flowering plants, where it is located between the sporogenous tissue and the anther wall. Tapetum is important for the nutrition and development of pollen grains, as well as a source of precursors for the pollen coat.

[#385] Teliospore of rust have germpores in number
Correct Answer

(B) 2

Explanation

Solution: Teliospores of rust have germ pores in two numbers. Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi (rusts and smuts), from which the basidium arises. Teliospores consist of dikaryotic cells. As the teliospore cells germinate, the nuclei undergo karyogamy and thereafter meiosis, giving rise to a four-celled basidium with haploid basidiospores.