What is Aerenchyma Tissue?

What is Aerenchyma Tissue?

What is Aerenchyma Tissue?

Aerenchyma is defined as a special type of parenchyma. It is a plant tissue which have large gas spaces than those present in intracellular spaces. It develops in the roots and shoots of wetland species and also in the roots and shoots of some dryland species, under unfavorable conditions, either naturally or as a result of abiotic stress.

The cells in aerenchyma have normal airspaces or air chambers which lets gases to spread and provide buoyancy to aquatic plants like lotus and water hyacinth. Wheat, rice and corn have lysigenous aerenchyma. As it grows, intercellular gas spaces develop inside a tissue without cell death, which results in schizogenous aerenchyma.

The primary tissues which are there in plants are divided into- parenchyma, collenchyma and sclerenchyma.

  • The function of parenchyma cells are photosynthesis, storage, and secretion. Parenchyma is a word which is used to name the functional tissues in plants and animals. They are living and thin walled.
  • Aerenchyma is a special type of parenchyma.
  • The function of collenchyma cells is to help and transport nutrients.
  • Sclerenchyma cells are the dead cells which help in providing support, protection, and to transport water.
  • Phloem is the vascular bundle in plants which transport food (sucrose) in the plant.
  • Xylem is the vascular tissue of the plant which transports water and dissolved minerals from the roots to the rest of the plant and to provide physical support.

What is Aerenchyma? Give example.

Aerenchyma can be described as a spongy tissue which forms spaces or air channels in the leaves, stems and roots of some plants. It lets exchange of gases between the shoot and the root. Aerenchyma is present in aquatic and wetland plants which grows in hypoxic soils.

In which type of plants Aerenchyma is found?

Aerenchyma are a special type of parenchyma which form a connection with air spaces for gaseous exchange. This feature makes the plant bodies light and adds buoyancy, which is why they can float on water. Aerenchyma are thus present in aquatic plants.

Does hydrilla have aerenchyma tissue?

Eichhornia is a water hyacinth and is a floating type aquatic flowering plant with light purple-colored flowers. There is exchange of gas between the root and the shoot. Therefore, aerenchyma is a tissue found in aquatic plants like hydrilla and Eichhornia.

How is Aerenchyma formed?

Aerenchyma is the name given to plant tissues which have enlarged gas spaces exceeding those which are found as intracellular spaces. It develops in the roots and shoots of wetland species and in some dryland species in unfavorable conditions, either naturally or because of abiotic stress.

Is Aerenchyma alive or dead?

Names of living cells are apical Meristem, aerenchyma, collenchyma xylem parenchyma, phloem parenchyma, sieve tubes.

Is Sclerenchyma a dead tissue?

Mature sclerenchyma cells are dead cells which have heavily thickened secondary walls consisting of lignin. They have very thick, hard secondary walls which are lined with lignin. As a result, sclerenchyma serves as an additional support and strength to the plant body.

Is Collenchyma a dead tissue?

Collenchyma which are found in plants support tissue of living lengthy cells with irregular cell walls. Collenchyma cells consists of thick deposits of cellulose in their cell walls and they look polygonal in cross section. Unlike collenchyma, mature cells of this tissue are dead and it has got thick walls consisting of lignin.

What is a dead tissue?

The death or decay of body tissue which results in the loss of blood supply or trauma is a dead tissue.

Is phloem a dead tissue?

Xylem is composed mainly of dead cells. But the phloem is made up of still-living cells which transfers sap. The sap is a water-based solution which are rich in sugars made by photosynthesis.

What does dead tissue look like?

Symptoms of necrotic wounds: There are two types of necrotic tissue which are present in wounds: eschar and slough. Eschar are thick, dry, leathery tissue which are either tan, brown or black in color. Slough are moist, loose and has   a stringy appearance. They are yellow, tan, green, or brown in color.

Aerenchyma formation and hypoxia

When soil gets flooded, then hypoxia starts, because soil microorganisms consume oxygen faster. Wetlands are characterized by the presence of hypoxic soils. Many wetland plants have aerenchyma, and is some cases such as water-lilies, there is heavy flow of atmospheric air through leaves and rhizomes.

There are other chemical results of hypoxia. For example, nitrification is stopped as low oxygen occurs and then toxic compounds are developed, as anaerobic bacteria use nitrate, manganese, and sulfate as alternative electron acceptors.

Low oxygen lets trees and plants to produce ethylene.

Learn more concepts from theAnatomy of Flowering Plants from Class 11 Biology

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