Mimosa pudica L. - MIMOSACEAE - Dicotyledon

Common name : sensitive plant, touch me not.

Botany Biology Phenology Ecology Distribution Agricultural importance Cultural control Biological control Chemical control

Botany :

Description :	Terrestrial, annual or perennial, erect to prostrate, thorny herb, up to 200 cm long. Roots fibrous, white or brown. Stems rounded, solid, glabrous. Stipules present, spiny. Leaves compound, bipinnate, paripinnate, alternate spiral, stalked, leaflets linear, glabrous on both sides, margin entire, apex acute, base rounded, one-veined. Flowers bisexual, grouped in an axillary, stalked head, sessile, petals 4, pink. Fruits an articulated pod.
Seeds :	Seeds sub orbicular to broadly ellipsoidal, flattened, 2.5-3 mm long, pale brown, surface finely granular.
Seedling :	With epigeal germination, smelling like garlic, cotyledons ovate, sagitate at base, truncate to emarginated at apex, glabrous, hypocotyls up to15 mm long, hairy, epicotyl absent, first leaf solitary, with 3 pairs of leaflets.

The persistence and spread of sensitive plant is aided by its prolific seed set. There are approximately 110 seeds/g. It can complete its life cycle in 3 month. At nightfall the leaflets fold together and the rachises bend down.

Phenology :

Flowering and fruiting throughout the year.

Ecology :

A weed of pastures , roadsides, coconut plantations, scrub; in fences on rivers banks; in sunny to rather heavily shaded, usually moist places; from 0-1000 m altitude. Flowers throughout the year. Seed germinate within 2 weeks (scarification helps); after 19 years storage, 2-percent still developed.

Distribution :

Pantropical, probably originating from South America.

Agricultural importance :

A serious weed in maize, tea and upland rice in Indonesia. Can become a pest in pastures.

Cultural control :

Although the thorns make hand pulling unpleasant, the plant can be controlled by hoeing. Cultivation can also held keep the plant under control.

Biological control :

Are often found attacked by a fungus Ramularia mimosae, which grows on the upper surface of the leaflets, forming irregular white spots.

Chemical control :

Foliar treatment ( wetting must be through): 2,4,5-T (1 kg/500 l, spot-spraying, 500 g/ha, Jamaica, grassland, 3 kg/ha, Malaysia, rubber) amitrole (4.5 kg/ha, Ceylon, Tea), picloram ( pasture), ametryne ( cane), fenoprop, ioxynil plus 2,4–D.

Uses :
The infusion of the twigs with leaves possess antipyretic, soothing and sudorifie properties. Apart from the toxicity from mimosine, the plant has shown a significant hypotensive, sedative and anti-inflammatory effect. An alcoholic extract has shown to lower blood glucose concentrations in diabetic rats. The alkaloidal extracts of the roots is antagonistic to both acetylcholine and histamine and histamine. A crude ethanol extract of the leaves was found to have insecticidal activity against one Trilobium species.

References :
-Henty E.E. and G.S. Pritchard. 1973. Weeds of New Guinea and their control. Botany bulletin No 7.
-Marita I.G., Keith Moody, Colin M. Piggin. 1999. Upland Rice Weeds of Southeast Asia, IRRI.
-Soerjani M., Kostermans A. J. G. H., Tjitrosoepomo G. 1987. Weeds of rice in Indonesia. Balai Pustaka. Jakarta.
-Waterhouse, D.F. & K.R. Norris. 1987. Biological Control. Pacific Prospects. Inkata Press, Melbourne. 454 pp.

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