what is the meaning of azolla

What is Azolla?

Azolla may also be referred to as red azolla, feathered mosquito fern, water velvet or African azolla and has a native range extending from Africa to India, Southeast Asia and Australia. Basic requirements Azolla must be grown in fresh water or wet mud in order for the plant to thrive as the plants will die within a few hours if allowed to dry out.

Is Azolla asexual or asexual?

The plants are typically red, and have small, water repellent leaves. Azolla reproduces sexually, and asexually (by splitting). Like all ferns, sexual reproduction leads to spore formation, but unilke other members of this group Azolla is heterosporous, producing spores of two kinds.

When was Azolla first used in agriculture?

Rice farmers used Azolla as a rice biofertilizer 1500 years ago. The earliest known written record of this practice is in a book written by Jia Ssu Hsieh (Jia Si Xue) in 540 A.D on The Art of Feeding the People (Chih Min Tao Shu).

What is the yield of Azolla plant?

Azolla is a highly productive plant. It doubles its biomass in 3–10 days, depending on conditions, and yield can reach 8–10 tonnes fresh matter/ha in Asian rice fields.

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Where is Azolla located?

Ecology. Azolla cover ing the Canning River, Western Australia. Azolla on the Canning River, Western Australia. Azolla is a highly productive plant. It doubles its biomass in 1.9 days or more, depending on conditions, and yield can reach 8–10 tonnes fresh matter/ha in Asian rice fields. 37.8 t fresh weight/ha (2.78 t DM/ha dry weight) ...

When was Azolla used?

Rice farmers used Azolla as a rice biofertilizer 1500 years ago. The earliest known written record of this practice is in a book written by Jia Ssu Hsieh (Jia Si Xue) in 540 A.D on The Art of Feeding the People (Chih Min Tao Shu).

What is the relationship between Azolla and Anabaena azollae?

They form a symbiotic relationship with the cyanobacterium Anabaena azollae, which fixes atmospheric nitrogen.

What animals can you feed Azolla to?

Studies describe feeding Azolla to dairy cattle, pigs, ducks, and chickens, with reported increases in milk production, weight of broiler chickens and egg production of layers, as compared to conventional feed. One FAO study describes how Azolla integrates into a tropical biomass agricultural system, reducing the need for inputs.

How did Azolla affect the climate?

It indicates that massive patches of Azolla growing on the (then) freshwater surface of the Arctic Ocean consumed enough carbon dioxide from the atmosphere for the global greenhouse effect to decline, eventually causing the formation of Ice sheets in Antarctica and the current "icehouse period". This theory has been termed the Azolla event .

How does Azolla work?

Azolla have been used to control mosquito larvae in rice fields. The plant grows in a thick mat on the surface of the water , making it more difficult for the larvae to reach the surface to breathe, effectively choking the larvae.

How does Azolla reproduce?

Azolla reproduces sexually, and asexually (by splitting). Like all ferns, sexual reproduction leads to spore formation, but unilke other members of this group Azolla produces two kinds. During the summer months, numerous spherical structures called sporocarps form on the undersides of the branches.

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What is an azolla?

Azolla, Azolla pinnata, is an aquatic fern belonging to the plant family Azollacea which is grown primarily as a fodder for livestock. Azolla is a small branching plant with a main stem and pinnate side branches.

How to grow Azolla?

Basic requirements Azolla must be grown in fresh water or wet mud in order for the plant to thrive as the plants will die within a few hours if allowed to dry out. Azolla plants can be cultivated in ponds or purpose-built pits and will spread rapidly. If grown in water, there should be little to no current as strong water currents can damage the fronds of the plants. Azolla will grow best in standing water which is between 5 and 12 cm (2.0-4.7 in) deep with a pH between 4 and 7. The roots of the plant should not be able to come into contact with soil at the bottom of the pond or pool as this can cause nutrient deficiencies. Plants will grow optimally at temperatures between 20 and 28°C (68-82.4°F) in partial shade or full sunlight. Heavily shaded areas should be avoided. Propagation Azolla is initially grown by inoculating a prebuilt pit or pond with seed. The azolla will quickly colonize the water and become self propagating. Some of the harvest should be held back to allow the plant to recolonize. Plant matter should be harvested every day to every other day to prevent the pond becoming overcrowded.

How to propagate azolla?

Propagation Azolla is initially grown by inoculating a prebuilt pit or pond with seed. The azolla will quickly colonize the water and become self propagating. Some of the harvest should be held back to allow the plant to recolonize.

Where does Azolla live?

Azolla may also be referred to as red azolla, feathered mosquito fern, water velvet or African azolla and has a native range extending from Africa to India, Southeast Asia and Australia. Azolla pinnata. Azolla fronds. Feathered mosquito-fern (Azolla pinnata) Azolla (macro) Azolla. Azolla filiculoides.

How deep does Azolla grow?

Azolla will grow best in standing water which is between 5 and 12 cm (2.0-4.7 in) deep with a pH between 4 and 7. The roots of the plant should not be able to come into contact with soil at the bottom of the pond or pool as this can cause nutrient deficiencies.

Why is Azolla important?

In fact, the Anabaena – Azolla association has been shown to be of major agronomic importance for its potentiality as a biofertilizer to substitute chemical nitrogen compounds. Azolla has been used as “green manure” in several countries to fertilize rice paddies and to increase rice yields ( van Hove and Lejeune, 2002 ).

What is Azolla Lamarck?

1 Introduction. Azolla Lamarck is a genus of aquatic ferns characterized by its small floating sporophyte, which consists of a profusely branched stem bearing alternately arranged imbricate leaves and pendulous roots ( Saunders and Fowler, 1993 ).

What is the difference between Salvinia megaspores and Azolla megaspores?

Salvinia megaspores are globose and characterized by a thick perispore, three distal chambers, and a three-lobed cavity, whereas those of Azolla have large floats at the distal end that provide a diagnostic feature for their identification as fossils ( FIG. 11.204) (Hall and Swanson, 1968).

How many lobes does Azolla have?

The leaves are two-lobed : one floating dorsal lobe and one submerged ventral lobe. Azolla is heterosporous and carries indusiate sori on short stalks surrounded by a parenchymatous layer known as the sorophore envelope ( Nagalingum et al., 2006 ).

What are the constraints of Azolla?

Other notable constraints to Azolla growth are temperature (both high and low temperatures inhibit growth), high water requirement, and pests and diseases ( Giller, 2001 ). More work is required and an analysis of the economics of such work relevant for climate-affected regions. View chapter Purchase book.

What are the two types of cell division in Azolla?

Gunning and his co-workers, who studied cell differentiation in the roots of Azolla, observed two types of cell division which they termed formative and proliferative . The cells that make up the different tissues of the root are produced as a result of cell divisions in the root apical meristem. The cells of any given tissue can be traced back to a particular cell within the root apical meristem (see Fig. 9.12 ). A formative division is one in which the daughter cells differ morphologically or biochemically from their parents; a proliferative division results in daughters that resemble their parents. A proliferative division increases the number of cells of a particular lineage, whereas a formative division might establish a new lineage or precede the terminal differentiation of one of the daughters. The concept of “formative” divisions implies that important decisions about cell determination or differentiation are initiated during cell division.

Is Azolla a nuisance?

However, in many areas of the world where Azolla has been introduced, for example South Africa, it can also be a nuisance by blocking water channels. Recently attention has been given to control of Azolla by insects and other agents, and in its use for feeding fish, poultry, and pigs.

What is the genus Azolla?

Definition of the genus Azolla. The genus Azolla is defined as a heterosporous leptosporangiate fern from aquatic and semi-aquatic habitats. It is assigned to the monogeneric Family Azollaceae.

What is the classification of azolla?

Classification of Azolla. “It is a small aquatic plant which appears to float on the water surface in the manner of Lenticules (Lemna) with whom it seems to have a great relation and which nevertheless looks like a small fern.” (translation from the French) Lamarck’s observation of azolla’s habitat must have been based on Commerson’s own ...

Why are azolla hybrids used?

Azolla hybrids have been developed to improve the plant’s temperature tolerance and biomass production. For example, hybridization between A. microphylla and A. filiculoides improves annual biomass production, as illustrated by a study by Van Cat et al. (1989).

What is the meaning of the word "azo"?

Traditionally, the name is referred to a conjugation of two Greek words, azo (to dry) and allyo (to kill), because the fern is killed by drought, but Carrapiço (2010) has suggested that the name was adopted from a word used by the local population in Argentina or Chile where Commerson collected his specimens of azolla.

How many species are there in Azolla?

According to Francisco Carrapiço (personal communication to J. Bujak), the genus Azolla has six species and three subspecies: “The problem related to the modern Azolla species is still an open question, but based on the classification proposed by Saunders & Fowler (1993) we can consider the following species and subspecies:

Which country has the largest germplasm collection of azolla?

The Philippines ’ International Rice Research Institute (IRRI) has the world’s largest germplasm collection of azolla with more than 500 hybrids. The IRRI is a Foundation Associate and has kindly agreed to make it available to the Azolla Foundation for research projects.

Overview

Species

Ecology

Reproduction

Applications

Invasive species

Importance in paleoclimatology

Bioremediation