etiolated seedlings have an apical hook in the dark

1. What is apical hook?
2. What is etiolated seedling?
3. What is apical hook formation in dicot seedlings?
4. Which type of phytochrome predominates in etiolated seedlings?
5. Which plant hormone leads to exaggerated apical hook formation?
6. What is horizontal growth of seedlings?
7. What does etiolated mean?
8. What are the symptoms of Etiolation?
9. What are the benefits of Etiolation?

What is apical hook?

The apical hook is a developmentally regulated structure that appears in dicotyledonous seedlings when seeds germinate buried in the soil.

What is etiolated seedling?

Skotomorpho- genesis in dark-grown (''etiolated'') seedlings is characterized by an elongated hypocotyl and the maintenance of an apical hook that protects unopened cotyledons shielding the shoot apical meristem, while pro-plastid differentiation and root elongation are attenuated [1, 2].

What is apical hook formation in dicot seedlings?

In darkness, the dicot seedlings produce an apical hook as result of differential cell division and extension at opposite sides of the hypocotyl. This hook protects the apical meristem from mechanical damage during seedling emergence from the soil.

Which type of phytochrome predominates in etiolated seedlings?

From comparisons of deduced amino acid sequences and peptide sequences it is known that the PHYA gene encodes the apoprotein moiety of the well-characterized, light- labile phytochrome species that predominates in etiolated plant tissues, and which is now referred to as phytochrome A (phyA).

Which plant hormone leads to exaggerated apical hook formation?

Ethylene causes exaggeration of the apical hook, a response together with shortening and thickening of the hypocotyl and inhibition of root elongation, known as the triple response (Knight ., 1910).

What is horizontal growth of seedlings?

Horizontal growth of seedling. Climacteric is increase in the rate of respiration in ripening fruits due to the production of ethylene. Loosening fruits. To prevent fruits from ripening oxygen must be eliminated from the environment in which the fruits are stored.

What does etiolated mean?

transitive verb. 1 : to bleach and alter the natural development of (a green plant) by excluding sunlight. 2a : to make pale.

What are the symptoms of Etiolation?

Lack of sufficient light retards chlorophyll formation and promotes slender growth with long internodes, thus leading to pale green leaves, spindly growth, and premature drop of leaves and flowers. This condition is known as etiolation.

What are the benefits of Etiolation?

Etiolation increases the likelihood that a plant will reach a light source, often from under the soil, leaf litter, or shade from competing plants. The growing tips are strongly attracted to light and will elongate towards it.