, native to eastern and tropical Asia, Australia, and Pacific islands. It is often known by the synonym '' Pongamia pinnata''. Its common names include Indian beech and Pongame oiltree.
Description
''Millettia pinnata'' is a
legume
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock for ...
tree that grows to about in height with a large canopy that spreads equally wide. It may be
deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...
for short periods. It has a straight or crooked trunk, in diameter, with grey-brown bark, which is smooth or vertically fissured. Branches are glabrous with pale stipulate scars. The
imparipinnate
Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, an ...
leaves of the tree alternate and are short-stalked, rounded, or cuneate at the base, ovate or oblong along the length, obtuse-acuminate at the apex, and not toothed on the edges. They are a soft, shiny burgundy when young, and mature to a glossy, deep green as the season progresses, with prominent veins underneath.
Flowering generally starts after 3–4 years with small clusters of white, purple, and pink
flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanis ...
s blossoming throughout the year. The
raceme
A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...
-like
inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are forme ...
s bear two to four flowers that are strongly fragrant and grow to be long. The
calyx
Calyx or calyce (plural "calyces"), from the Latin ''calix'' which itself comes from the Ancient Greek ''κάλυξ'' (''kálux'') meaning "husk" or "pod", may refer to:
Biology
* Calyx (anatomy), collective name for several cup-like structures ...
of the flowers is bell-shaped and truncated, while the
corolla
Corolla may refer to:
*Corolla (botany), the petals of a flower, considered as a unit
*Toyota Corolla, an automobile model name
*Corolla (headgear)
A ''corolla'' is an ancient headdress in the form of a small circlet or crown.
Croppings of indehiscent pods can occur by 4–6 years. The brown seed pods appear immediately after flowering, and mature in 10 to 11 months. The pods are thick-walled, smooth, somewhat flattened, and elliptical, but slightly curved with a short, curved point. The pods contain within them one or two bean-like brownish-red seeds, but because they do not split open naturally, the pods need to decompose before the seeds can germinate. The seeds are about long with a brittle, oily coat, and are unpalatable in natural form to herbivores.
The species is naturally distributed in tropical and temperate Asia, from India to Japan to Thailand to Malesia to north and north-eastern Australia to some Pacific islands; It has been propagated and distributed further around the world in humid and
subtropical
The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...
environments from sea level to 1200 m, although in the Himalayan foothills, it is not found above 600 m.Pongamia pinnata - a nitrogen fixing tree for oilseed Withstanding temperatures slightly below and up to about and annual rainfall of , the tree grows wild on sandy and rocky soils, including oolitic limestone, and will grow in most soil types, even with its roots in salt water.
The tree is well suited to intense heat and sunlight, and its dense network of lateral roots and its thick, long
taproot
A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...
make it drought tolerant. The dense shade it provides slows the evaporation of surface water and its
root nodules
Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria kno ...
promote
nitrogen fixation
Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...
, a symbiotic process by which gaseous
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
(N2) from the air is converted into
ammonium
The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaterna ...
(NH4+, a form of nitrogen available to the plant). ''M. pinnata ''is also a freshwater flooded forest species, as it can survive total submergence in water for few months continuously. ''M. pinnata'' trees are common in Tonlesap lake swamp forests in
Cambodia
Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand ...
diploid
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectiv ...
legume tree, with a diploid
chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
number of 22. Root nodules are of the determinate type (as those on soybean and common bean) formed by the causative bacterium ''
Bradyrhizobium
''Bradyrhizobium'' is a genus of Gram-negative soil bacteria, many of which fix nitrogen. Nitrogen fixation is an important part of the nitrogen cycle. Plants cannot use atmospheric nitrogen (N2); they must use nitrogen compounds such as nitrate ...
''.
trad
Uses
''Millettia pinnata'' is well-adapted to
arid
A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...
zones, and has many traditional uses. It is often used for landscaping as a
windbreak
A windbreak (shelterbelt) is a planting usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted in hedgerows around the edges ...
or for shade due to the large canopy and showy, fragrant flowers. The flowers are used by gardeners as
compost
Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting ...
for plants requiring rich nutrients. The bark can be used to make twine or rope, and it also yields a black gum that has historically been used to treat wounds caused by poisonous fish. The wood is said to be beautifully grained, but splits easily when sawn, thus relegating it to
firewood
Firewood is any wooden material that is gathered and used for fuel. Generally, firewood is not highly processed and is in some sort of recognizable log or branch form, compared to other forms of wood fuel like pellets or chips. Firewood ca ...
, posts, and tool handles.
''Millettia pinnata'' seeds generally contain oil (27-39%), protein (17-37%), starch (6-7%), crude fiber (5-7%), moisture (15-20%) and ash content (2-3%). While the oil and residue of the plant are
toxic
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a sub ...
and induce nausea and vomiting if ingested in its natural form, the fruits, sprouts and seeds are used in
traditional medicine
Traditional medicine (also known as indigenous medicine or folk medicine) comprises medical aspects of traditional knowledge that developed over generations within the folk beliefs of various societies, including indigenous peoples, before the ...
. Nearly half of the oil content of ''M. pinnata'' seeds is
oleic acid
Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated o ...
soap
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...
making, and as a
lubricant
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ...
. The oil has a high content of triglycerides, and its disagreeable taste and odor are due to bitter
flavonoid
Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans.
Chemically, flavonoids ...
tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The term ''tannin'' (from Anglo-Norman ''tanner'' ...
rainwater harvesting
Rainwater harvesting (RWH) is the collection and storage of rain, rather than allowing it to run off. Rainwater is collected from a roof-like surface and redirected to a tank, cistern, deep pit (well, shaft, or borehole), aquifer, or a reservoir w ...
ponds up to in water depth without losing its greenery and remaining useful for biodiesel production.
Long used as shade tree, ''M. pinnata'' is self-seeding and can spread lateral roots up to long in 18 years. If not managed carefully, it can quickly become a weed. ''M. pinnata'' is broadly distributed across India, Asia, Africa, northern Australia and the Pacific and Caribbean Islands and has been cultivated and transported since the 19th century or earlier. As a result, some literature declares ''M. pinnata'' naturalized in Africa and certain parts of the United States, while its status as naturalized or native is uncertain in other regions.
This dense network of lateral roots, though, makes this tree ideal for controlling
soil erosion
Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, a ...
and binding
sand dunes
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...
.
Research
The seed oil has been found to be useful in diesel generators, and along with '' Jatropha'' and castor, it is being explored in hundreds of projects throughout India and the third world as feedstock for
biodiesel
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat ( tallow), soybean oil, or some other vegetable oi ...
. ''M. pinnata'' as a biofuel is commercially valuable to the rural populations of places such as India and Bangladesh, where the plant grows abundantly, because it can support the socioeconomic development of these areas.
Several unelectrified villages have used pongamia oil, simple processing techniques, and diesel generators to create their own grid systems to run water pumps and electric lighting.
Research indicates potential use of ''M. pinnata'' as a food source for cattle, sheep and poultry, as its byproduct contains up to 30% protein.Heuzé V., Tran G., Delagarde R., Hassoun P., Bastianelli D., Lebas F., 2017. Karanja (Millettia pinnata). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/636 A report commissioned and financed by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH found that the protein-rich byproduct can be free from
alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of simila ...
s and therefore a dietary source of protein for humans.
See also
*
Solar power in India
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The country's solar installed capacity was 61.966 GWAC as of 30 November 2022.
Solar power generation in India ranks fourth globally in 2021.
The Indian Government had an initial tar ...