The members of chilling-sensitive plants are characterized by

• higher proportion of saturated fatty acids

• lower transition temperature

• lower proportion of saturated fatty acids

• lower transition temperature and higher proportion of unsaturated fatty acids

Chinese Brake fern (Pteris vittata) is a hyperaccumulator of:

• Cadmium

• Arsenic

• Lead

• Chromium

73.

Asada-Halliwell pathway protects plants against oxidative stress during unfavourable environmental growth regimes. The following are some statements related to the stress tolerance mechanisms through this pathway inplants.

A. Oxygen accepts electrons asan alternative electron acceptor.

B. Hydrogen peroxide is reduced by catalase to form water.

C. Ascorbate is oxidized and regenerated.

D. Glutathione is oxidized and reduced.

Which one of the following combinations of the above statements is true?

• B, C, and D

• A, B, and C

• A, B, and D

• A, C, and D

The following are certain facts regarding biological nitrogen fixation in plants:

A. Oxygen irreversibly inactivates nitrogenase enzyme involved in nitrogen fixation.

B. The nod genes that code for nodulation proteins are activated by NodD.

C. The two components of nitrogenase enzyme complex, the Fe protein and MoFe protein can show catalytic activity independently.

D. During the reaction catalyzed by nitrogenase enzyme, the Fe protein reduces the MoFe protein while the MoFe protein reduces N₂.

Which one of the following combination of the above statements is correct?

• A, B, and C

• B, C, and D

• A, C, and D

• A, B, and D

Secondary metabolites are diverse array of organic compounds in plants. The following are certain statements about secondary metabolites:

A. They protect plants against being eaten by herbivores and against being infected by microbial pathogens.

B. Terpenes, the largest class of secondary metabolites are synthesized by methylerythritol phosphate (MEP) pathway and shikimic acid pathway.

C. The most abundant classes of phenolic compounds in plants are derived from phenylalanine.

D. Alkaloids are nitrogen-containing secondary metabolites in plants.

Which one of the following combinations of the above statements is correct?

• A, B, and C

• B, C, and D

• A, C, and D

• A, B, and D

The following are some statements about long distance translocation of photoassimilates in higher plants:

A. Sugars are translocated in the phloem by mass transfer along a hydrostatic pressure.

B. Gibberellic acid stimulates the unloading of sugars from phloem tissue into apoplasts.

C. Munch pressure-flow hypothesis is crucial to drive translocation in the phloem.

D. Allocation and partition of carbon within a source leaf determine the phloem loading phenomenon.

Which one of the following combinations of the above statements is true?

• A, B, and D

• A, B, and C

• A, C, and D

• B, C, and D

Directional growth of plants induced by light is called phototropism. Some statements on phototropism are given below:

A. Phototropism is a photomorphogenic response.

B. PHOT1 and PHOT2 genes mediate phototropism.

C. CRY1 and CRY2 genes although help to perceive blue light are not involved in phototropism.

D. Perception of blue light by phyA photoreceptor initiates phototropism.

Which one of the following combination of the above statements is correct?

• A, B, and C

• B, C, and D

• A, C, and D

• A, B, and D

Plants make several hormones that are important for growth and development. Some statements on plant hormones are given below:

A. Auxin is produced primarily in the root apices.

B. Cytokinins are a smaller group of related compiunds.

C. Gibberellins are a large group of related compounds defined not by their structures.

D. Brassinosteroids are an important class of plants hormones, which control a broad spectrum of developmental reposes including pollen tube growth.

Which one of the following combination of the above statements is correct?

• A, B, and C

• B, C, and D

• A, C, and D

• A, B, and D

The ethylene signaling pathway is important for fruit ripening. Which one of the following responses is routinely used to identify ethylene signaling pathway components?

• Cotyledon expansion response

• LAteral root formation response

• Triple response

• Flowering time response

During the operation of C₂ oxidative photosynthetic cycle, which of the following metabolites is transported from chloroplast to peroxisome?

• Glycerate

• Serine

• Glycine

• Glycolate