Thursday, November 04, 2010
Rare Grass Rediscovered
Hubbardia heptaneuron is a grass species originally described from the Jog Falls locality of Karnataka in 1919. Later efforts to relocate this plant from the type locality were not successful and therefore it was believed to be extinct. . However, it was located in the Thillari Ghat area of Maharashtra by Prof. Yadav and subsequently, species rehabilitation program was initiated. But surprisingly in 2010, this species was relocated in its original habitat of Jog Falls by Prof. Yadav's team. This is a good news for plant lovers, especially at the background of 'International Year of Biodiversity 2010'.
Monday, July 05, 2010
Mangroves of Kali Estuary, Karwar
Tsunami and Cyclone shock -absorbing Plants!
The Tsunami waves as high as 10-metre (33 feet) which struck the southern and eastern coastal areas of India on 26th December 2004 caused extensive damage in the Andaman and Nicobar Islands and the coastal districts of Tamil Nadu, Kerala, Andhra Pradesh and Pondicherry. According to Government reports, about 10,880 people lost their lives and 1,54,000 houses were either destroyed or damaged entailing losses of about Rs.994 crores. The tsunami destroyed or damaged nearly 75,300 fishing crafts leading to loss of livelihood for thousands and thousands of fishing families. In addition, standing crops of paddy, ground nut, coconut, cashew, mango, banana, minor millets and vegetables were totally destroyed in thousands of hectares and seawater intrusion rendered these productive lands unfit for cultivation.
However, post-tsunami observations indicated that the damage in terms of loss of lives
and properties, in the villages which are behind mangrove wetlands and other shelterbelt
plantations such as plantations of casuarina and of palm trees, was limited. This is because the intensity of the tsunami was reduced by these natural protective barriers. It has been reported that several villages of the Pichavaram mangrove region of Tamil Nadu which are under direct physical coverage of the mangrove wetlands were protected from the fury of the tsunami, though they are close to the sea. The mangrove trees along the first few rows bore the brunt of the tsunami waves and the friction created by these trees and the trees of subsequent rows reduced the speed of the water thereby saving the villages. This clearly indicates that both the mangrove forests and the associated wetlands together played a crucial role in mitigating the impact of the tsunami. Similar observations have also been made in Indonesia, Sri Lanka and Thailand.
Undisturbed mangrove stands in areas such as Rekawa, Kahanda and Kalametiya villages had contributed to reduce the damage caused by the tsunami. . In areas where the mangrove stands were totally or partially cleared in this district, the damage was high.
The protective qualities of mangroves were also observed in 1999 when a cyclone in the Bay of Bengal claimed more than 10,000 lives and washed away several coastal villages in the state of Orissa on India's eastern coast. This was one of the worst cyclones in history with winds of 160 miles per hour. However, amidst all the damages, it was noted that villages in and around neighboring Bhitarkanika were spared much of the cyclone's fury: Bhitarkanika is the second largest mangrove forest in India.
What are mangroves?
Mangroves are trees or shrubs that grow between low tide and high tide marks and beyond, where salt water reaches during spring tides. They form distinct communities commonly known as mangals or mangrove forests.
The mangrove communities occur in tropical subtropical areas where the water temperature does not fall below 200C, and rainfall is in excess of 1250 mm and mountain ranges close to the coast. As general rule dominant mangrove species run parallel to the shoreline or to the banks of the tidal creek systems.
The origin of the name 'mangrove' is not certain. It could be a combination of the Portuguese "Mangue" meaning as individual mangrove tree with the English 'grove'. Scientists theorize that the earliest mangrove species originated in the Indo-Malayan region, spreading westward by ocean currents carrying the floating propagules and seeds to India, East Africa and eastwards to America. That is the reason why Asia, India and East Africa contain more number of species.
In general, plants of the mangrove wetlands are divided into two groups namely, 1) Eumangroves or true mangrove species, and 2) associate mangrove species or mangrove associates.
True mangroves have a number of adaptations that help them thrive in this ecosystem between land and ocean including adaptations for mechanical fixing in loose soil, respiratory roots and aerating devices, specialized dispersal mechanisms and provision for coping with excess salt concentrations. Mangroves are the only true viviparous plants where the seed remains attached to the parent plant and germinates into protruding axis of the embryo (propagule) before falling from the tree.
On the other hand, mangrove associates are common plants which are found in mangrove as well as other terrestrial vegetation. They are not restricted only to mangrove habitats.
Mangrove forests are one of the most productive and bio-diverse wetlands on earth. Yet, these unique coastal tropical forests are among the most threatened habitats in the world. They are disappearing more quickly than inland tropical rainforest and so far with hardly any public notice.
Many factors contribute to mangrove forest loss, including the charcoal and timber industries, urban growth pressures and mounting pollution problems. However, one of the most recent and significant causes of mangrove forest loss in the past decade has been the consumer demand for luxury food item shrimps or 'prawns' and the corresponding expansion of mangrove destructive production methods of export oriented industrial shrimp aquaculture. Vast tracts of mangrove forest have been cleared to make way for the establishment of coastal shrimp farm facilities. The failure of union government to adequately regulate the shrimp industry, and the headlong rush of multilateral lending agencies to fund aquaculture development, without meeting their own stated ecological and social criteria, are other important reasons for this unfortunate degradation.
Mangroves have long functioned as a storehouse of materials providing food, medicines, shelter and tools. Fish, crabs, shellfish, prawns and eels, snakes and worms are found there. The fruit of certain species are eaten, the best honey is considered to be that produced from mangroves, particularly from river mangrove, Aegiceras corniculatum. Numerous medicines are derived from mangroves. Ashes or bark infusions of certain species can be applied to skin disorders and sores including leprosy, headaches, rheumatism, snakebites, boils, ulcers, diarrhoea, haemorrhages, and many more conditions are traditionally treated with mangrove plants. The latex from the leaf of Excoecaria agallocha can be used on sores and to treat marine stings, the leaves are also used to fishing when crushed and dropped in water, fish are stupefied and float to the surface. Certain mangrove trees are prized for their hard wood and used for boat building and cabinet timber, as well as for tools such as digging sticks, spears, thatching, basket weaving etc, various barks are used for tanning, pneumatophores make good fishing floats and so on.
Mangroves in most of the places are in a degraded state today, owing to indiscriminate felling for domestic purposes, recreational and developmental activities of human being.
Mangroves of the Kali Estuary of Uttara Kannada:
River Kali or Karihole is a major river of the northern coastal Karnataka at lat. 14048'N and Long. 74007'E. It has an estuary extending from Kodibag (S) and Devbag (N) at the river mouth up to Kunnipet (S) and Kadra (N), stretching to a distance of about 30kms. Another small river called Mavinahalla also joins this estuary, converting it into a estuarine complex.
The estuarine complex formed by rivers Kali and Mavinahalla, about three km north of Karwar (Uttara Kannada District of Karnataka) along the West Coast, supports mangrove vegetation along its shores and mud flats. Floristic studies have revealed that the isolated and remnant patches of mangrove forests of this area are rich in species diversity of both eumangrove and mangrove associate plants. L. V. Andrade and V. N. Nayak of the Karnataka University PG Centre, Karwar have identified a total of 130 species representing 106 genera and 50 families of plants in the Kali estuary which involves true mangrove species, associates and accidental mangroves.
Of the 15 species of eumangroves reported from Karnataka, as many as 13 species were found growing here. This includes the major mangrove genera such as Avicennia (3 species), Bruguiera (2 species), Rhizophora ( 2 species), Sonneratia (2 species), and one species each of Aegiceras, Excoecaria, Lumnitzera and Kandelia. Among these, Sonneratia alba, Rhizophora apiculata and Avicennia officinalis are the most dominant species.
A detailed description of all the true mangrove and the most common associated mangrove species of Kali estuary is provided in the following pages which would be useful particularly to students, teachers, foresters, NGO’s and generally to all other people interested in knowing and protecting these biologically unique and ecologically fragile category of plants.
Common true mangroves and associates found in Kali estuary:
The Tsunami waves as high as 10-metre (33 feet) which struck the southern and eastern coastal areas of India on 26th December 2004 caused extensive damage in the Andaman and Nicobar Islands and the coastal districts of Tamil Nadu, Kerala, Andhra Pradesh and Pondicherry. According to Government reports, about 10,880 people lost their lives and 1,54,000 houses were either destroyed or damaged entailing losses of about Rs.994 crores. The tsunami destroyed or damaged nearly 75,300 fishing crafts leading to loss of livelihood for thousands and thousands of fishing families. In addition, standing crops of paddy, ground nut, coconut, cashew, mango, banana, minor millets and vegetables were totally destroyed in thousands of hectares and seawater intrusion rendered these productive lands unfit for cultivation.
However, post-tsunami observations indicated that the damage in terms of loss of lives
and properties, in the villages which are behind mangrove wetlands and other shelterbelt
plantations such as plantations of casuarina and of palm trees, was limited. This is because the intensity of the tsunami was reduced by these natural protective barriers. It has been reported that several villages of the Pichavaram mangrove region of Tamil Nadu which are under direct physical coverage of the mangrove wetlands were protected from the fury of the tsunami, though they are close to the sea. The mangrove trees along the first few rows bore the brunt of the tsunami waves and the friction created by these trees and the trees of subsequent rows reduced the speed of the water thereby saving the villages. This clearly indicates that both the mangrove forests and the associated wetlands together played a crucial role in mitigating the impact of the tsunami. Similar observations have also been made in Indonesia, Sri Lanka and Thailand.
Undisturbed mangrove stands in areas such as Rekawa, Kahanda and Kalametiya villages had contributed to reduce the damage caused by the tsunami. . In areas where the mangrove stands were totally or partially cleared in this district, the damage was high.
The protective qualities of mangroves were also observed in 1999 when a cyclone in the Bay of Bengal claimed more than 10,000 lives and washed away several coastal villages in the state of Orissa on India's eastern coast. This was one of the worst cyclones in history with winds of 160 miles per hour. However, amidst all the damages, it was noted that villages in and around neighboring Bhitarkanika were spared much of the cyclone's fury: Bhitarkanika is the second largest mangrove forest in India.
What are mangroves?
Mangroves are trees or shrubs that grow between low tide and high tide marks and beyond, where salt water reaches during spring tides. They form distinct communities commonly known as mangals or mangrove forests.
The mangrove communities occur in tropical subtropical areas where the water temperature does not fall below 200C, and rainfall is in excess of 1250 mm and mountain ranges close to the coast. As general rule dominant mangrove species run parallel to the shoreline or to the banks of the tidal creek systems.
The origin of the name 'mangrove' is not certain. It could be a combination of the Portuguese "Mangue" meaning as individual mangrove tree with the English 'grove'. Scientists theorize that the earliest mangrove species originated in the Indo-Malayan region, spreading westward by ocean currents carrying the floating propagules and seeds to India, East Africa and eastwards to America. That is the reason why Asia, India and East Africa contain more number of species.
In general, plants of the mangrove wetlands are divided into two groups namely, 1) Eumangroves or true mangrove species, and 2) associate mangrove species or mangrove associates.
True mangroves have a number of adaptations that help them thrive in this ecosystem between land and ocean including adaptations for mechanical fixing in loose soil, respiratory roots and aerating devices, specialized dispersal mechanisms and provision for coping with excess salt concentrations. Mangroves are the only true viviparous plants where the seed remains attached to the parent plant and germinates into protruding axis of the embryo (propagule) before falling from the tree.
On the other hand, mangrove associates are common plants which are found in mangrove as well as other terrestrial vegetation. They are not restricted only to mangrove habitats.
Mangrove forests are one of the most productive and bio-diverse wetlands on earth. Yet, these unique coastal tropical forests are among the most threatened habitats in the world. They are disappearing more quickly than inland tropical rainforest and so far with hardly any public notice.
Many factors contribute to mangrove forest loss, including the charcoal and timber industries, urban growth pressures and mounting pollution problems. However, one of the most recent and significant causes of mangrove forest loss in the past decade has been the consumer demand for luxury food item shrimps or 'prawns' and the corresponding expansion of mangrove destructive production methods of export oriented industrial shrimp aquaculture. Vast tracts of mangrove forest have been cleared to make way for the establishment of coastal shrimp farm facilities. The failure of union government to adequately regulate the shrimp industry, and the headlong rush of multilateral lending agencies to fund aquaculture development, without meeting their own stated ecological and social criteria, are other important reasons for this unfortunate degradation.
Mangroves have long functioned as a storehouse of materials providing food, medicines, shelter and tools. Fish, crabs, shellfish, prawns and eels, snakes and worms are found there. The fruit of certain species are eaten, the best honey is considered to be that produced from mangroves, particularly from river mangrove, Aegiceras corniculatum. Numerous medicines are derived from mangroves. Ashes or bark infusions of certain species can be applied to skin disorders and sores including leprosy, headaches, rheumatism, snakebites, boils, ulcers, diarrhoea, haemorrhages, and many more conditions are traditionally treated with mangrove plants. The latex from the leaf of Excoecaria agallocha can be used on sores and to treat marine stings, the leaves are also used to fishing when crushed and dropped in water, fish are stupefied and float to the surface. Certain mangrove trees are prized for their hard wood and used for boat building and cabinet timber, as well as for tools such as digging sticks, spears, thatching, basket weaving etc, various barks are used for tanning, pneumatophores make good fishing floats and so on.
Mangroves in most of the places are in a degraded state today, owing to indiscriminate felling for domestic purposes, recreational and developmental activities of human being.
River Kali or Karihole is a major river of the northern coastal Karnataka at lat. 14048'N and Long. 74007'E. It has an estuary extending from Kodibag (S) and Devbag (N) at the river mouth up to Kunnipet (S) and Kadra (N), stretching to a distance of about 30kms. Another small river called Mavinahalla also joins this estuary, converting it into a estuarine complex.
The estuarine complex formed by rivers Kali and Mavinahalla, about three km north of Karwar (Uttara Kannada District of Karnataka) along the West Coast, supports mangrove vegetation along its shores and mud flats. Floristic studies have revealed that the isolated and remnant patches of mangrove forests of this area are rich in species diversity of both eumangrove and mangrove associate plants. L. V. Andrade and V. N. Nayak of the Karnataka University PG Centre, Karwar have identified a total of 130 species representing 106 genera and 50 families of plants in the Kali estuary which involves true mangrove species, associates and accidental mangroves.
Of the 15 species of eumangroves reported from Karnataka, as many as 13 species were found growing here. This includes the major mangrove genera such as Avicennia (3 species), Bruguiera (2 species), Rhizophora ( 2 species), Sonneratia (2 species), and one species each of Aegiceras, Excoecaria, Lumnitzera and Kandelia. Among these, Sonneratia alba, Rhizophora apiculata and Avicennia officinalis are the most dominant species.
A detailed description of all the true mangrove and the most common associated mangrove species of Kali estuary is provided in the following pages which would be useful particularly to students, teachers, foresters, NGO’s and generally to all other people interested in knowing and protecting these biologically unique and ecologically fragile category of plants.
Common true mangroves and associates found in Kali estuary:
| Family | Genus | Species |
| Rizophoraceae Avicenniaceae Sonneratiaceae Combretaceae Euphorbiaceae Myrsinaceae Acanthaceae Pteridaceae Fabaceae | Rizophora Bruguiera Kandelia Avaicennia Soneratia Lumnitzera Excoecaria Aegiceras Acanthus Acrostichum Caesalpinea Dalbergia Derris | R. apiculata R. mucronata B. gymnorrhiza B. cylindrica K.. candel A. officinalis A alba A marina S. Caseolaris S. alba L. racemosa E. agallocha A. corniculatum A. ilicifolius (AM) A. aureum (AM) C. crista (AM) C. bonduc (AM) D. spinosa (AM) D. trifoliate (AM) D. scandens (AM) |
Tuesday, May 04, 2010
Biodiversity and its values.
2010 - International Year of Biodiversity:
2010 has been declared as the 'International Year of Biodiversity' by UNO. 'Biodiversity is life, celebrate it' is the slogan. In this context, its better to know what is biodiversity and why so much of importance is given to it?
Monday, May 03, 2010
IDA - Our missing Grand mother?
'Missing Links' are a mystery in tracing our evolution. They provide vital clues to understand the leaps and jumps we have taken during our evolutionary walk. The story of one such recently discovered missing link called IDA...
Brain Circuits
Brain is nothing but a circuit of neurons..?
'Connectomics' is a branch of neurobiology trying to study and write the circuit of neural networks in the human brain. If it succeeds, shortly we may have a complete circuit diagram of our own brain which will be followed by 'artificial brain circuits' or brain chips!
'Connectomics' is a branch of neurobiology trying to study and write the circuit of neural networks in the human brain. If it succeeds, shortly we may have a complete circuit diagram of our own brain which will be followed by 'artificial brain circuits' or brain chips!
What is the Value of Indian Forests?
The Value of India’s Forest Cover:
Over the course of a series of hearings in the Supreme Court on forest conservation, it decreed that those who cut forests must now pay for the loss of the intangible benefits of forests, in addition to the usual payment for the loss of trees. The SC has assigned a range of Net Present Values (NPV) to forests that will be sacrificed to developmental projects. The NPV assigned to different types of forests is as follows:
Forest Type | NPV in Rs./Hectare |
Scrub Forest Land | 5.8 lakh |
Open Forest Land | 7.0 lakh |
Dense Forest Land | 9.2 lakh |
If this NPV is applied to the standing forests of the different states of India, what would be the total value of the forest cover of India? It sums up to an amazing amount of Rs 59,20,190.2 crore! The state-wise NPV of forests is given below:
State | NPV of Forest | State | NPV of Forest |
Andhra Pradesh | 4,26,739.0 | Mizoram | 1,44,825.8 |
Arunachal Pradesh | 5,95,783.2 | Nagaland | 1,05,552.2 |
Assam | 2,30,123.2 | Orissa | 4,36,940.0 |
Bihar | 48,166.0 | Punjab | 20,605.8 |
Chhattisgarh | 4,79,632.0 | Rajasthan | 1,57,042.4 |
Goa | 18,592.0 | Sikkim | 29,589.0 |
Gujarat | 1,39,111.0 | Tamil Nadu | 1,96,315.8 |
Haryana | 15,294.2 | Tripura | 57,328.8 |
Himachal Pradesh | 1,26,746.6 | Uttar Pradesh | 1,19,877.4 |
Jammu & Kashmir | 1,92,629.2 | Uttaranchal | 2,12,885.0 |
Jarkhand | 1,90,051.2 | West Bengal | 89,676.4 |
Karnataka | 3,35,301.2 | A & N Islands | 63,014.6 |
Kerala | 1,35,230.2 | Chandigarh | 74.0 |
Madhya Pradesh | 6,58,521.4 | D & N Haveli | 1,865.2 |
Maharashtra | 4,35,935.4 | Daman & Diu | 46.4 |
Manipur | 1,32,146.0 | Delhi | 883.8 |
Meghalaya | 1,23,088.4 | Lakshadweep | 248.4 |
TOTAL: 59,20,190.2 crore
Source: Down to Earth, July 31,2005.
Sunday, May 02, 2010
Transgenic Plants
Transgenic plants
Genetic engineering technique is being used to create genetically modified plants by transferring useful genes into them from outside. Genetically modified plants which contain one or more artificially transferred genes in their cells are called transgenic plants.The artificially transferred gene is called transgene. Genetic modification of eukaryotic cells (plant or animal) by transfer of foreign gene is called transfection. The process of producing transgenic organisms like plants and animals by transfection is called transgenesis.
The following general steps are involved in the formation of transgenic plants:
1. Transferring useful gene to the isolated and cultured plant cells by appropriate gene transfer methods.
2. Obtaining transgenic plants from the genetically modified cells, using the tissue culture technique.
Methods of gene transfer to plant cells:
1. Vector mediated Transfer: Many different vector DNA molecules are used to carry genes to plant cells. The most commonly used vector is the Ti plasmid (Tumour inducing plasmid) of a bacterium Agrobacterium tumefaciens and Ri plasmid of Agrobacterium rhizogenes.
2. Direct gene transfer: Many techniques are available to introduce the gene directly to the nucleus of the plant cells. Important techniques are
a) Microinjection: A microscopic syringe is used to penetrate the nucleus of the cell and place the gene inside.
b) Electroporation: Electric current is used to force metal beads carrying the gene into the plant cells.
c) Gene guns: Gun like structures are used to forcefully push the gene into cells.
General steps involved in the production of transgenic plants by Agrobacterium mediated
gene transfer:
· The gene to be transferred (target gene) is first linked to a Ti plamid vector by recombinant DNA method.· The recombinant Ti plasmid is inserted into Agrobactrium cell by usual bacterial transformation technique (incubating Agrobacterium cells and recombinant Ti plasmid in the presence of Calcium Chloride).
· Cells of the plant to be modified are inoculated and incubated with transformed Agrobacterium cells having the target gene. Now the Agrobacterium cells infect the plant cells and transfer the Ti DNA along with the target gene to plant cells. Thus, plant cells get genetically modified.`
· The genetically modified Plant cells are selected and cultured on a suitable nutrient medium and plants are regenerated from them. These plants carry the transferred foreign gene in their cells and therefore become transgenic plants.
Examples and Application of transgenic plants:
1. Engineering plants with improved nutritional quality: eg: Golden Rice.
Golden rice is a transgenic rice variety created in 1999 by Ingo Potrykus and Peter Beyer. It was made by inserting three important genes needed for producing beta-carotene - a vitamin A precursor substance, to the genome of rice. These genes actually code for three different enzymes involved in the synthetic pathway of beta carotene from the stating compound geranylgeranyl diphosphate. These genes express only in the endosperm of rice because they are added along with endosperm-specific promotor sequences.
Of these three genes, two were from the daffodil plant (Narcissus psuedonarcissus). They are psy gene coding for the enzyme phytoene synthase and lyc gene for lycopene cyclase. The third one called ctrl gene for an enzyme phytoene desaturase was from the soil bacterium Erwinia uredovora.The transgenic rice plants containing these genes produce significant amounts of beta-carotene in their endosperm, which give the rice grains a characteristic yellow color. Therefore the name golden rice.
Eating golden rice helps to prevent diseases like xerophthalmia and blindness that are caused by vitamin A deficiency.
2. Engineering plants with resistance to pests and diseases: eg. Bt Cotton, Bt Corn etc. which contain a gene called Bt gene transferred from the bacterium Bacillus thuringeinsis. This gene produces a toxin called protoxin in plant cells. This toxin acts as a pesticide, protecting the plant against insect pests.3. Engineering plants with resistance to herbicides or weedicides: The development of herbicide - resistant crop varieties facilitate easier contol of weed plants. When the herbicide is sprayed, the herbicide sensitive weeds are killed while the herbicide resistant crop plants are not affected. eg. Soyabean plants resistance to the herbicide glyphosate.
4. Engineering plants with other novel charecteristics: Plants can be genetically modified to produce commercially important proteins like vaccines, biodegradable plastic, etc. eg. Water melon plants have been genetically designed to produce rabies vaccine in their fruits. Such vaccines which are produced inside edible parts of plants are called edible vaccines.
Transgenic vaccine against acute gastroenteritis causing virus (Norwalk virus) was produced in transgenic potato tubers. The plant Arabidiopsis thaliana has been genetically modified to produce a polyester known as polyhydroxy butyrate (PHB) which can be used as a biodegradable plastic.
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