Which of the following is/are the adaptive mechanism(s) of plants to avoid adverse conditions? 1. Dieback 2. Viviparity mode of reproduction 3. Pneumatophores 4. Dormant Select the correct answer using the code given below:

Which of the following is/are the adaptive mechanism(s) of plants to avoid adverse conditions? 1. Dieback 2. Viviparity mode of reproduction 3. Pneumatophores 4. Dormant Select the correct answer using the code given below: Correct Answer 1, 2, 3 and 4

The correct answer is 1, 2,3 and 4 

Key Points

• Adaptive Mechanism:
  • Dieback
    • A condition in trees or woody plants in which peripheral parts are killed, either by pathogens, parasites or due to conditions like acid rain and drought.
    • Example – Sal Tree
• Viviparity mode of reproduction
  • Plants on whose super terranean parts small green plantlets form, fall to the ground, and then develop into adult individuals (vivipary). In many mangrove forests, large shoots develop in fruit still hanging on the trees. The germination of standing crops in cereal grains is superficially similar to this phenomenon; however, the ripe grains that begin to grow have already lost their physiological connection with the mother plant.
  • Other viviparous plants form leafy shoots (saxifrage, stonecrop), bulblets (some meadow grasses), or tubercles (buckwheat) instead of flowers. These viviparous plants inhabit predominantly polar, highland, dry steppe, and desert regions where the vegetative period may be too short for seeds to mature. In their mode of reproduction, they are closely related to plants that propagate vegetatively by means of air nodules. A number of viviparous plants (Bryophyllum and some tropical ferns) have aggregates of meristem cells on the leaves, out of which green plantlets grow.
• Pneumatophores
  • Pneumatophores are specialized root structures that grow out from the water surface and facilitate the aeration necessary for root respiration in hydrophytic trees such as many mangrove species (e.g., Avicennia germinans and Laguncularia raecemosa), bald cypresses, and cotton (tupelo) gum ( Nyssa aquatica).
• Dormant
  • Nearly all plants go dormant in winter—whether they‘re growing indoors or out in the garden. This period of rest is crucial to their survival in order to regrow each year. While plant dormancy during cold conditions is important, it may be equally important during times of stress. For instance, during periods of extreme heat or drought, many plants (especially trees) will go into a dormancy-like state, shedding their leaves early in order to conserve what little moisture may be available to ensure their survival.