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Monday, August 3, 2009

An Introduction to Cynodon dactylon Pers.(doob)

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Cynodon dactylon Pers. (Doob/Durva)

The Taxonomic status of the plant

The Plant Cynodon dactylon Pers. is commonly known as Bermuda Grass, Cocksfoot-grass, Couch grass, Dog’s tooth, European Bermuda Grass, Grama, Handjes grass and Stalian Ayrigi. It belongs to the family Gramineae (Poaceae). In Hindi language it is known as Doob and Durwa in Sanskrit.


General description of the plant

Cynodon dactylon Pers. is an evergreen perennial grass growing from 0.3m to 0.5m at a medium rate. It bears leaves all through the year and passes through flowering session usually ranging from August to October months.

The plant is strongly rhizomatus or stoloniferous, perennial, often mat like with stems usually prostrate or decumbent. It is found rooting at nodes when it remains in the contact of moist soil. Leaves are alternate with ligules less than 0.5mm long, membranous, densely ciliated with glabrous sheaths. Sheaths are ciliated near summits. Blades are linear, flat, 1.5 to 1.55mm wide, glaborous to soft-puberulent with minutely scabrus margins.

Plants vary greatly in soil and climate. They occur in many natural strains which differ widely in size. The colour of the plant is usually bright yellow green to dull blue green. Many varieties of this plant are poor in seed production. They are propagated by their creeping stems called runners.

The inflorescence is typically composed of 3 to 7 spreading spikes each 2 to 8 cm in length. Spikelets are 2 to 3mm long; sessile, appressed, alternating in two rows, compressed & composed of one floret. Glumes are lanecolate and 1- nerved. The lower ligule is usually 1 to 1.5mm long and slightly curved. The upper ligule is 1 to 2mm long and straight. Lemmas are 2 to 2.25mm long, with apex blunt to obtuse [Arnow (1987), de Wet and Harlon (1970), Munz (1969), Smith (1993)].

The flowers of Cynodon dactylon Pers. are hermaphrodite and like most grasses they are pollinated by the agency of wind (Proctor et.al. 1996). Strains of the grass show considerable variations with respect to seed-set. In general the production of seeds is very low. But the longevity and viability of seeds are very high. Once, when the plant is well established in soil, it primarily reproduces by vegetative means by rhizomes and stolons that develop extensively (Dona and De Kroon 1994).

The natural population of Cynodon dactylon Pers. has considerable genetic variation for growth traits as reported by Rochecouste (1962a, 1962b) & Speranza (1995). Growth traits include erect versus prostrate stems, penetration potential of roots and the tolerance of soil temperature (Speranza, 1995).

Distribution : Geographic

The plant Cynodon dactylon Pers. prefers light sandy, medium loam and heavy clay soils. It also prefers acidic, neutral and alkaline soils and it can grow in very acidic, very alkaline and saline soils. However, it cannot grow in shady places. It requires moistures in soil. The plant is a native of South Africa. It has been introduced throughout warm-temperate and the sub-tropical world primarily for use as a lawn grass or as a forage grass, especially in saline habitats as reported by various workers (de Wet and Harlan, 1970; Gibbs Russell et al. 1955; Omacini et.al. 1990; Santosh and Boechat, 1994; Stromberg 1995; Thomasson and Theodore 1997; and Toth et.al. 1997). Geographically, this grass is cosmopolitan in distribution.

Distribution : Ecological

The grass Cynodon dactylon Pers. is generally distributed on sandy and saline soils of open places like road sides, agricultural fields, along irrigation canals, orchards an waste places (Arnow 1987).

This plant preferably grows in a warm and sunny position in a well drained soil (Huxley, 1992). It can grow in very diverse conditions of soil, moisture and temperature. It can withstand drought conditions and has a tendency to eliminate other plants that grow besides it (Duke 1983). This grass propagates very rapidly. It roots at nodes when it comes in contact of soil. Thus it grows in such a way that it is difficult to eradicate it. This is one reason of its becoming a serious weed in a cultivated land (Duke 1983).

Cynodon dactylon Pers. grass is reported to tolerate an annual rain fall of 9 to 29 cm and an annual temperature range of 5.9 to 27.8oC. Also, it can tolerate a pH in the range of 4.3 to 8.4. It can also tolerate alkaly soil conditions, disease (to some extent), drought, frost, grazing, herbicide, heavy metal, heavy soil, insects, nematodes, peat, poor soil, salt, sand, atmospheric pollution, ultraviolet rays, viruses, waterlogging and competition of weeds (Duke 1983). This grass is best adapted to relatively fertile, well-drained soils with a pH of 6.0 to 7.0 in humid areas. Plants produce a little growth in dry weather conditions (Duke 1983). This species is hardy to about -10oC temperature as reported by Huxley (1992).

Artificial propagation
Cynodon dactylon Pers. can be artificially propagated in green houses by means of seeds. Germination of seeds may take more than two weeks under suitable conditions. Though the viability percentage of seeds of Cynodon dactylon Pers. is very low, it can be propagated by seeds and replanted in suitable conditions. Duke (1983) has reported on the propagation of this plant through seeds and has estimated that 1 kilogram of seed contains, 4,000,000 seeds (Duke - 1983).

Plants of Cynodon dactylon Pers. can be propagated very easily from rooted side-shoots.

Ecological status of the plant

Cynodon dactylon Pers. or the Bermuda grass is a preferred food plant of sub-urban populations of Black-gloved Wallaby and Western grey Kangaroos in Australia (Wann and Bell, 1997). It is used as Biomass, ground cover against soil erosion through rain water and wind storms and also as soil-stabilizer. Plants of Cynodon dactylon Pers. are grown as a cover for warm sunny banks. They are also used for lawns (Huxley, 1992). Grass communities have been reported to play singnificant roles in land management besides causing seasonal variations in the biomass of standing crops as reported by Barik and Misra (1997). On the other hand, ecological studies of grassland communities have been done by various workers like Misra and Puri (1954), Misra and Misra (1981), Misra and Misra (1983), Misra (1992), Smith (1993), Speranja (1995), Wann and Bell (1997) - in respects of plants ecology, seasonal changes in leaf area index and chlorophyll in an Indian grassland, biostatistics, grassland community of South Orissa, Cynodon, morphology and phenology of Cynodon dactylon Pers. and, dietary preferences of the black goved Wallaby.
These plants stay green even during hot and dry weather conditions. They give complete ground cover in 4 to 8 weeks if they are planted 30 to 45 cm apart (Duke, 1983). They succeed on most soil types and they require very little mowing on poor soils.
This grass is very important for soil conservation due to its long runners which remain rooting at nodes. The annual biomass productivity range of this grass ranges from 4 to 52 tonnes per hectare (Duke, 1983).

Medicinal uses of Cynodon dactylon Pers.

Plants of this grass are well known for their Astringent. Diuretic and Ophthalmic properties. It has been reported that this grass is alterative, anabolic, antiseptic, aperient, astringent, cyanogenetic, demulcent, depurative, emollient, sudorific and vulnerary (Duke, 1983). A decoction of roots of Cynodon dactylon Pers. is often used as diuretic in the treatment of dropsy disease and also in the treatment of secondary syphilis (Chopra, Nayar, and Chopra, 1986). It has also been reported that an infusion of roots of this plant stops bleeding from Piles (Chopra, Nayar, and Chopra, 1986).

Ethno-herbological importance of Cynodon dactylon Pers.
According to an estimation of the World Health Organisation, 80% of the worlds population relies on herbs for its primary health care needs. Ayurveda and Siddha in India, Chinese medicines in China, Unani Medicines in Islamic Countries are traditional knowledge systems that use herbs or plant products for therapeutics on a large scale. More than 35,000 plant species are being used around the world for medicinal purposes in traditional and ethnomedicinal practices (Kumar and Singh, 2001). Cynodon dactylon Pers. occupies a key position in ethnomedicinal practices and traditional medical (Ayurvedic, Unani, Nepalese and Chinese) knowledge systems. In India and other countries herbal preparations of Cynodon dactylon Pers. are being used based on folklore and traditional wisdom.

In ethnomedicinal practices the juice of the plant Cynodon dactylon Pers. is used as astringent and is applied to fresh cuts and wounds (Chopra, Nayar and Chopra 1986). It is used internally in the treatment of chronic diarrhoea and dysentery (Nepal Dept. of Medicinal Plants, Nepal, 1993). It is also useful in the treatment of Catarrhal ophthalmia (Chopra, 1986). The leaves of Cynodon dactylon Pers. are also used in the treatment of hysteria, epilepsy and insanity.The plant Cynodon dactylon Pers. is also a folk remedy for anasarca, calculus, cancer, carbuncles, convulsions, cough, cramps, cystitis, diarrhoea, dysentery, headache, haemorrhage, hypertension, kidneys, laxative, measle, rubella, sores, stones, tumours, uro-genital disorders, warts and wounds (Duke, 1983). This traditional knowledge is in full practice among Santals and other tribe-races in Jharkhand (India) also. Arunachalam (2001) has reported that there is sufficient scope to fine tune the tribal indigenous knowledge for optimizing benefits. To facilitate this process we need to understand science behind traditions.

Place of Cynodon dactylon Pers. in Religion and Culture

In Hindu religion Puranas reveal that Durva (doob=Cynodon dactylon) was extracted out of Kshir-sagar at the time of "Samudra Manthan" by Gods and Devils. Thus, it is regarded as younger sister of Godess Lakshami. Durva is used at the time of worship of Gouri and Ganesh for `Achaman' purpose. God Ganesh loves Durva very much. Hence terminal leaf-buds of Durva are offered to God Ganesh while his worship. In Balmiki Ramayan the body colour of God Rama has been compared to the colour of Durva. Goswami Tulsi Das in his Ram Charit Manas has accepted Durva alongwith other worship - materials. In Hindu religion this grass is regarded as sacred since it is beloved of Gods, human being and also of animals. Grass Cynodon dactylon Pers. has been taken as a symbol of birth and reproduction. Hence Durva leaves are offered to newly-wed daughters at the time of their departure for their husbands' homes. Its green colour is taken as a symbol of welfare. Thus, Hindus regard this plant, a sacred plant and use it during various ceremonies they perform the whole life from birth till death.

In Sarna religion of tribes of Jharkhand, plant Cynodon dactylon Pers. has been accepted as most sacred. Since Sarna Tribes are worshipers of nature, they worship trees and plants. But Cynodon dactylon Pers. or `Doob Ghas' is given greater importance by them. In tribal culture of Sarna, infants are subjected to `Sacred-bath' with pure water mixed with leaves of Cynodon dactylon Pers. At the time of nomenclature of young children, buds of Doob-ghas are used along with turmeric, Akshat (rice-grains), water and cups of leaves. These tribal people use Doob in every ceremony at the time of wedding. Also, no worship is completed without the use of doob-ghas in Sarna religion. Even when these tribal people return after the cremation / burning of a dead body they make themselves `Pavitra' (free from all impuritries and germs) by spraying a mixture of doob leaves, turmeric paste and water on their bodies. Pahans (Priest-heads of tribal people) use doob during post-cremation ceremonies. Tribal houses are made `Pavitra' or sacred by spraying or sprinkling water with the help of doob-branches in all the corners.

The traditional, religious and cultural practices detailed above may or may not have science and technology behind them, they are very essential for the conservation and maintenance of ecosystems and environment. These were just two examples. Grass Cynodon dactylon Pers. is regarded as a sacred plant also in other religions and sects. Since this plant is included in Dharma, there should not be a question against the scientific validity of those practices with it. Khoshoo (1999), reports that Dharma embodies all that is universally and eternally true. Without Dharma, nothing can make sense. Since we cannot raise the carrying capacity of the Earth System we should conserve all resources & biodiversity with all means, traditions and religious practices. "To save our planet with all its living and non-living manifestations and to ensure the diversity that has been its strength, there is an urgent need to adopt a code, which may be called the Dharma of Ecology" (Khosoo, 1999).


Weed Status :
Noxious, Invasive and Injurious Aspects

The grass Cynodon dactylon Pers. or the Bermuda grass has been reported to be Photosensitizing in animals to cause contact - dermatitis and Hayfever (Duke, 1983). This grass has been listed as noxious for California and Utah.
This grass is considered a noxious weed in agricultural practice at a global level by the U.S., but its State Department of Food and Agriculture has not considered it to be a noxious weed. However, it has been considered the most difficult grass weed in the Southern United States.

Reference:

Mishra, M P (2005). Succession of fungi and their ecomicrobial involvement inthe decay of Cynodon dactylon Pers. 14-21.