Mangrove Palm a Versatile Unique Palm

BIJU DHARMAPALAN, M.S. JYOTHISH , AJITH ASHOKAN & P.V. HARINANDANAN

Feature Mangrove Palm A Versatile Unique Palm

Short Perhaps very few of us have come Nypa fruticans has a horizontal trunk across mangrove palms. Nipa (Nypa that grows beneath the ground and only fruticans) is one such palm. It occurs the leaves and flower stalk grow upwards ALMS are valued because of their between the latitudes of 25oN and 20oS, above the surface. The leaves can extend beauty and economic value. On on the tidal shores and estuaries of Sri up to nine meters (30 feet) in height. Erect, Phearing the word “Palm”, we usually Lanka, the Ganges Delta, the Malay the spirally inserted leaves are borne near think of the coconut palm (Cocos Peninsula and archipelago, and Pacific the apex of a horizontal stem which divides nucifera), oil palm (Elaeis guineensis) and islands (from northern Australia to the at intervals. The younger leaves appear date palm (Phoenix dactylifera). The Solomons), Philippines and the Ryukyus. It from the middle of the crown and push Palmaceace family has many members, is known by different names in different the older leaves aside before they dry including the Royal palm (used for countries: attap palm (Singapore), buah and fade away, leaving bulbous leaf bases landscaping) and the red palm. atap (Indonesia), buah nipah (Malaysia), or scars behind. Any leaf may subtend an All Palmaceace members have ging pol (Sri Lanka), gol pata (Bangladesh), inflorescence. The flowers are a globular some common features like an upright and dani (Burma). stem, trunkless and monopodial growth (in Nipa is the only palm found in the an upward direction from one point). mangrove habitat. This species is found on Generally, Plants with monopodial growth (in contrast the landward side of a mangrove forest seedlings are to sympodial growth) have one stem or that is subject to frequent tidal inundation raised on trunk, and they add leaves to the apex as and is exposed to saline water at high tide nursery beds they grow. There are genera that show but freshwater at low tide. regularly sympodial growth patterns like Rattans. Even though the plant is not common Almost all genera of palms with large in India except in the Sunderbans and inundated by evergreen palmately (‘fan-leaved’) or Andaman and Nicobar Islands, fossil pollen tidal water. pinnately (‘feather-leaved’) compound grains of the palm genus Nipa described leaves. All leaves have a tubular sheath at under Spinizonocolpites have been the base. The inflorescence (arrangement reported from the west coast of India in of flowers on the plant, in relation to its the tertiary sediments of the Warkalli and Fossil of a Nipa drupe shoot system) is a panicle (irregularly (Source: http:// Quilon formations in Kerala, and in the www.sheppeyfossils.com/pages/ branched and where each branch has a sediments of the Ratnagiri Beds in plant_material.htm) terminal flower) or spike surrounded by Maharashtra. The only extant species of one or more bracts or spathes that this monotypic genus is Nypa fruticans become woody at maturity. (Thunberg) Wrumb. The fossil evidence proves that it is one of the most ancient inflorescence of female flowers at the tip angiosperms and probably the oldest with catkin-like red or yellow male flowers species of palm. on the lower branches. Nipa is a monoecious palm with Pollination is carried out by a variety special characteristics. Like other of insects and wind, although drosophilid vegetation that live in mangroves, Nipa flies are particularly important. Fertilised thrives in river estuaries and brackish water flowers develop into fibrous, chestnut- environment. It also lacks an upright stem, brown fruit and form a large spherical which is a characteristic feature of the infructescence (ensemble of fruits derived palms. The palm also exhibits a colonial from ovaries of an inflorescence) upon growth habit, forming thick stands or a maturation. mono-specific fringe along the coastline. The fruit is a woody nut (drupe) The trunk or stem of the Nipa palm is under arranged in a cluster compressed into a the mud; only the leaves project upwards. ball up to 25 cm (10 inch) across on a Nipa palms in Sunderbans For the observer, the large fronds appear single stalk. The infructescence is usually (Source: http://www.banglapedia.org/httpdocs/HT/F_0107.HTM) to rise up from the surface of the mud. composed of fertile fruits as well as partially 53 SCIENCE REPORTER, JULY 2012 Short Feature

Female inflorescence of Nypa fruticans Infructescence of Nypa fruticans Nypa fruticans growing in the palmetum of Kerala (Source: http://wiki.trin.org.au/pub/Mangroves/Nypa_fruticans) (Source:http://www.flickr.com/photos/joyloh/2630141155/) Forest Research Institute, Peechi

developed but sterile carpels. Each fruit occasionally germinating while still water- coastal ecosystems of India to generate consists of a unilocular endocarp covered borne. The mangrove palm exhibits a revenue for the rural folk. In 2002, the India with a fibrous mesocarp and a smooth, unique phenomenon known as Posts released a Commemorative stamp outer epicarp. The distal end of the fruit cryptovivipary, in which the embryo grows on Nypa fruticans to signify the importance bears an umbo (knob-like protrusion that to break through the seed coat but not of this plant. the fruit wall before it splits open. Today, the Nypa vegetation in the Sundarbans is under great stress due to Uses changes in geomorphic and ecological In Bangladesh and India, Nypa fruticans is conditions. The western and used mainly for roof thatching, food, fuel, southwestern regions of this delta have fence making, medicine, cigarette been raised, shifting the main delta wrapping, molasses, wine, fishing etc. The towards Bangladesh. This geomorphic kernels of immature fruits are used as food. evolution has an adverse effect on the The juice is used for making jaggery and Nypa vegetation due to lack of alcohol. Newly developed shoots are freshwater supply from the Ganges reported to be used as a vermicide. Ash distributaries that are essential to leach Schematic diagram of a Drupe from the palm is used as an analgesic for out excessive salt contents from the soil. (Source: http://en.wikipedia.org/wiki/Drupe) tooth pain and headache, and for treating A distinctive decrease in natural Herpes. Dry leaves, petiole, stem wood, regeneration is probably due to overall arises from the hinge of a bivalve shell or fruit residues etc. are used as fuel. increase in salinity in the Indian part of near the scale tip of a seed-bearing The rhizomes of the palm are Sundarbans. cone). Commonly, the fruit is ridged extensively used in fishing, and they Urgent measures are needed to longitudinally and may show some facilitate the fishing net to float over the protect the remaining population of the angularity. These angled edges are caused water surface. Farmers also report that species in the Indian subcontinent. Both in by the growth of adjacent fruits tightly Nipa floating in the river or sea attracts vitro and ex vitro techniques can be used abutted against one another in the dense deep-water fish. Sap from Nipa is used for for the purpose. Nipa regenerates infructescence. fattening livestock. In Nigeria, dye from the naturally in the mangrove. It can also be The individual fruits are dispersed by fruits is used to dye fishing nets to make propagated artificially by planting the tides and currents. As an adaptation them less conspicuous to the fish and seedlings along the muddy banks of for the submerged environment, the fruit is improve fish catch. In some villages in mangrove forests and also in exposed designed to float, and this buoyancy is Nigeria, the seeds are used for making shorelines. attributed to its thick fibrous mesocarp and jewellery and hair clips. Leaves are also Generally, seedlings are raised on endocarp. The ripe nuts separate from the used as roofing mats and to make hats. nursery beds regularly inundated by tidal ball and float away on the tide, The Food and Agricultural water. Usually two months old seedlings Organization (FAO) describes Nipa palm attaining height of about 25 cm are as a non-threatened and underutilized suitable for planting. The Kerala Forest palm in South Asia. In the Sundarban Institute, Peechi has successfully raised Nipa Reserve Forest, it is believed that traditional in its palmetum by providing the forest-users collect an average of 60000 appropriate soil pH and continuous metric tons of fronds each year. Large inundation. amounts of biomass are produced in this particular environment and its characterization will create new The authors belong to the Department of Plant unexploited raw materials for fuels and Biotechnology, Mar Athanasios College for chemicals. The plant can be judiciously Advanced Studies (MACFAST), Tiruvalla-689101, Kerala; Email: [email protected] Commemorative stamp on Nypa fruticans introduced into the other degraded SCIENCE REPORTER, JULY 2012 54