Trianthema portulacastrum L. - AIZOACEAE - Dicotyledon

Common name : horse purslane.

Botany Biology Phenology Ecology Distribution Cultural control Biological control Chemical control

Botany :

Description :	Terrestrial, annual, prostrate herb, up to 40 cm long. Taproot white or brown. Stem procumbent, rounded, solid, hairy, succulent. Stipules present, glabrous. Leaves simple, entire, opposite and and very unequal in size (a great petiolate in front of a small sessile one), stalked, glabrous on both sides, margin entire, apex rounded or emarginated, base acute, obtuse or rounded, pinnately veined. Flowers bisexual, solitary or grouped in a few-flowered, axillary, sessile glomerule, sessile, white, pink, or purple, petals 5. Fruit a capsule opening circumsessile with a lid.
Seeds :	Kidney-shaped, in spiral ended by a beak, 2 mm in diameter. The tegument is tuberculate, reddish, brown to black.
Seedling :	Cotyledons elliptic lanceolated, petiole, of uneven size, a from 12 to 16 mm in length and 3 to 4 mm wide, the other one from 10 to 12 mm in length and 2 to 3 mm wide. Hairless and fleshy.

Trianthema portulacastrum is propagated by seeds and by fragments of stem which propagate from cuttings very easily. Two biotypes of T. portulacastrum occur in India. Typical description refers to red biotypes that from larger plants and reddish stems with long internodes and green bracts and pods, and white sepals. The red type is more abundant, but the green one appears earlier in the season.

Phenology :

Flowering June to October: fruiting July to December.

Ecology :

T. portulacastrum is cosmopolitan, with no known centre of origin and widespread in Southeast Asia, tropical America and Africa. Common from sea level, in the sandy and muddy coastal zones, up to near 800 m. In India, both red and green biotypes grow best under partial shade and thrive in neutral to alkaline soils that are low in organic matter. The plant grows in sunny and dry areas along roadside, in wastelands and in yards.

Distribution :

Pantropical.

Cultural control :

It may be difficult to control by tillage because of ready from cut stems.

Biological control :

Gibbago Trianthemae, the causal agent of leaf spot on T. portulacastrum, was isolated from diseased plants collected in Texas, USA. Plants sprayed with conidia were killed within 9 days. In host-range studies, the fungus was pathogenic only to T. portulacastrum. This fungus may be a useful agent for the biological control of this species.

Chemical control :

Propanil at 2 kg ha-1 applied two weeds after rice emergence or application 2-4-D at 500 g/ha or Almix at 4g/ha.

Uses :
Part used: Whole plant.
Constituents: Punarnative and trianthenol.
Medicine use:
The plant, dried out and reduced to powder, is reportedly used against throat troubles and anti-fungal agent. A decoction of the roots is reputedly used as an emmenagogue, and it larger doses it is abortive.
Recent studies have investigated potential hepatoprotective properties. The leaves are diuretic and applied in the treatment of oedema, jaundice, strangury and dropsy. A decoction of the herb is used as a vermifuge and is useful in rheumatism; it is considered an antidote to alcoholic poisoning. The fleshy nature of leaves makes them suitable for use as a wound-dressing or poultice.
In Nigeria the old leaves are used in a treatment against gonorrhoea, in Gabon the powdered herb is taken for venereal discharge.

Remarks :
The seeds are harmful contaminants in food grains and other crop seeds. The plant has a potential value as asource of organic matter because it contains considerable amounts of nitrogen, potassium and phosphorus.

References :
-Galinnato M., Moody K., Piggin C.M 1999. Upland rice weeds of south and Southeast Asia IRRI. Philippines.
-Radanachaless T., Maxwell J.F.1994. Weeds of soybean fields in Thailand. Multiple Cropping Center Publications. Thailand.

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