PLANTS UNDER CULTIVATION

Tree yields commercial gum arabic, used extensively in pharmaceutical preparations, inks, pottery pigments, water-colors, wax polishes, and liquid gum; for dressing fabrics, giving lustre to silk and crepe; for thickening colors and mordants in calico-printing; in confections and sweetmeats. Causing partial destruction of many alkaloids including atropine, hyoscyamine, scopolamine, homatropine, morphine, apomorphine, cocaine, and physostigmine, gum arabic might be viewed as a possible antidote. Pharmaceutically used mainly in the manufacture of emulsions and in making pills and troches (as an excipient); as demulcent for inflammations of the throat or stomach and as masking agent for acrid tasting substances such as capsicum; also as a film-forming agent in peel-off masks. Its major use is in foods, for example, as suspending or emulsifying agent, stabilizer, adhesive, flavor fixative, and to prevent crystallization of sugar, etc. Used in practically all categories of processed foods (candy, snack foods, alcoholic and nonalcoholic beverages, baked goods, frozen dairy desserts, gelatins, and puddings, imitation dairy products, breakfast cereals, and fats and oils). Use levels range from less than 0.004% (40 ppm) in soups and milk products, 0.7 to 2.9% in nonalcoholic beverages, imitation dairy, and snack foods, to as high as 45% in candy products (Leung, 1980). Strong rope made from bark fibers. White wood used for tool handles, black heartwood for weaver's shuttles. The long flexible strands of surface roots provide one of the strongest of local fibers, used for cordage, well-ropes, fishing nets, horsegirdles, footropes, etc. Seeds are dried and preserved for human consumption (NAS, 1980). Young foliage makes good forage. Plants useful for afforestation of arid tracts, soil reclamation, and windbreaks (Duke, 1981a). In modern pharmacy, it is commonly employed as a demulcent in preparations designed to treat diarrhea, dysentery, coughs, throat irritation, and fevers. It serves as an emulsifying agent and gives viscosity to powdered drug materials; is used as a binding agent in making pills and tablets and particularly cough drops and lozenges. Because of its enzyme, the gum is not suitable for use in products having readily oxidizable ingredients. For example, it reduces the vitamin A content of cod liver oil by 54% within three weeks. It is incompatible with aminopyrine, morphine, vanillin, phenol, thymol, a- and b-naphthol, guiacol, cresols, creosol, eugenol, apomorphine, eserine, epinephrine, isobarbaloin, gallic acid, and tannin; also with strongly alcoholic liquids, solutions of ferric chloride and lead subacetate and strong solutions of sodium borate. It was formerly given intravenously to counteract low blood pressure after hemorrhages and surgery and to treat edema associated with nephrosis, but such practices caused kidney and liver damage and allergic reactions and have been abandoned (Morton, 1977).

The medicinal properties of Aloe vera have been known, and recorded since biblical times. It has been used for a variety of ailments, and as an ointment for burns, cuts, and rashes, as well as an ingredient in various beauty preparations.

The sap of the Aloe is a thick, mucilaginous gel. It is this gel which is used medicinally. The outer skin has essentially no value, but because it is commercially easier and less expensive to utilize the entire leaf, 'whole leaf' Aloe juice has been hyped as the 'best'. This is not the case.

Because Aloe plants consist of 95% water, they are extremely frost tender. If they are grown outdoors in warm climates, they should be planted in full sun, or light shade. The soil should be moderately fertile, and fast draining. Established plants will survive a drought quite well, but for the benefit of the plant, water should be provided. Because of their popularity, Aloe vera plants are available at almost every garden shop or nursery. Unless you live in area with a very mild climate, it's best to leave your Aloe plant in the pot and place it near a window that gets a lot of sun. You can move the pot outdoors during the summer months. Aloe vera is a succulent, and as such, stores a large quantity of water within its leaves and root system. During the winter months, the plant will become somewhat dormant, and utilize very little moisture. During this period watering should be minimal. Allow the soil to become completely dry before giving the plant a cup or two of water. During the summer months, the soil should be completely soaked, but then be allowed to dry again before re-watering.

Aloes have a shallow, spreading root system, so when it is time to repot choose a wide planter, rather than a deep one. Use a planter with a drainage hole, or provide a 1-2 inch layer of gravel in the bottom of the pot to ensure adequate drainage. Use a good commercial potting mix with extra perlite, granite grit, or coarse sand added. You may also use a packaged 'cacti mix' soil. Fertilize yearly, in the spring with a dilute (half strength), bloom type fertilizer (10-40-10).

Aloes are propagated by removing the offsets which are produced around the base of mature plants, when they are a couple inches tall (or larger). They may also be grown from seed.

As to the claims of the medicinal properties of the Aloe plant, I can only speak from my personal experience. I have kept an Aloe plant around for years, primarily for burns. In case of burns, an immediate application of fresh gel has relieved much of the pain, and prevented blistering, many times. I also found it to be quite effective to relieve itching from stings, bites and various 'stinging' plants, such as poison ivy. It is also good for the same problems, when they are encountered by your pets.

When you need to use it medicinally, just remove a lower leaf from the plant, slice it open, and apply the gel on the affected area.

http://www.thegardenhelper.com/aloe~vera.html

As a result of the ubiquitous nature of the tree, an immense amount of botanical literature has been produced relating to its description and ecology. Only a brief summary will be presented here (for more detailed information the reader is directed to the selected references). The tree ranges in height from 5 - 12m with an open, umbrella shaped crown, straight trunk (10-30cm thick) with corky, whitish bark. The tree produces a tuberous tap root which helps explain its observed tolerance to drought conditions. The evergreen or deciduous foliage (depending on climate) has leaflets 1-2 cm in diameter, the flowers are pleasantly fragranced, white or cream coloured and are borne profusely in axilliary drooping panicles 10-25 cm long. The fruits (pods) are initially light green, slim and tender eventually becoming dark green and firm up to 120cm long depending on the variety. Fully mature, dried seeds are round or triangular shaped, the kernel surrounded by a lightly wooded shell with three papery wings.

Originally considered a tree of hot, semi-arid regions (annual rainfall 250 - 1500mm) it has also been found to be well adapted to hot, humid, wet conditions with annual rainfall in excess of 3000mm. The tree was originally considered to be suitable only for lowland cultivation at altitudes less than 600m. However, the adaptability of the tree has been demonstrated by the discovery of natural stands at altitudes of 1200m in Mexico and in excess of 2000m in Zimbabwe. M.oleifera can also grow in a variety of soil conditions. Although preferring well drained sandy or loamy soils, heavier clay soils will be tolerated although water logging should be avoided. The tree is reported to be tolerant to light frosts and can be established in slightly alkaline soils up to pH 9.

The use of natural materials of plant origin to clarify turbid surface waters is not a new idea. Sanskrit writings in India dating from several centuries BC make reference to seeds of the tree Strychnos potatorum as a clarifier, Peruvian texts from the 16th and 17th centuries detail the use by sailors of powdered, roasted grains of Zea mays as a means of settling impurities. More recently, Chilean folklore texts from the 19th century refer to water clarification using the sap from the 'tuna' cactus (Opuntia fiscus indica). However, of all the plant materials that have been investigated over the years, the seeds from M.oleifera have been shown to be one of the most effective as a primary coagulant for water treatment.

The traditional use of the M.oleifera seeds for domestic household water treatment has been limited to certain rural areas in the Sudan. Village women collecting their water from the River Nile would place powdered seeds in a small cloth bag to which a thread is attached. This would then be swirled around in the turbid water. Water soluble proteins released from the powdered seeds, attach themselves to, and bind between, the suspended particles forming larger, agglomerated solids. These flocculated solids would then be allowed to settle prior to boiling and subsequent consumption of the water.

Since the early 1970's a number of studies have been carried out to determine the effectiveness of the seeds for the treatment of surface water at individual household level. Utilising artificially prepared turbid water and naturally turbid raw waters, laboratory investigations have confirmed the seeds to highly effective in the removal of suspended solids from waters containing medium to high initial turbidities. At low turbidities, as may be experienced during the dry season, the seeds are less effective although their performance is very much dependant on the raw water to be treated. Work is currently underway at the University of Leicester examining the potential of utilising the seeds within a contact flocculation filtration process for the treatment of low turbidity water. Preliminary results have demonstrated some considerable success.

The majority of the early work has been carried out with a view to establishing the viability of using the seeds within household water treatment practices. Following success in the laboratory, the Environmental Engineering Group extended its activities to an evaluation of the seeds effectiveness on continuous flow systems. Pilot plant trials and full scale trials carried out in Malawi in collaboration with the Polytechnic of Malawi (contacts) demonstrated that the seeds could be used effectively on continuous flow systems producing treated water quality similar to that of aluminium sulphate.

The active fraction of the seeds has received much interest. Investigations by Professor Tauscher at the University of Karlsruhe, Germany, have revealed that the coagulant properties of the seeds are due to a series of low molecular weight cationic proteins. Under current CEC funding, attempts to isolate and characterise these active proteins are continuing.

The potential toxicity of the seeds has been considered in two major studies. The conclusions of both were that the doses typically used for water treatment posed no serious threat to human health. Further details of these studies may be found in the articles by Berger et al.,1984 and Grabow et al.,1985, detailed in the selected reading list below.

Waste minimisation is a major concern of the whole Moringa concept. A single stage steam pyrolysis process has been shown to yield an activated carbon with treatment performance as efficient as commercially available carbons. Funded by the ODA, this work is a collaborative venture with the Polytechnic of Malawi and is continuing.

One of the most common vernacular names for Moringa oleifera is the horse-radish tree. This arose from the use of the root by Europeans in India as a substitute for horse- radish. Such a practice would not now be recommended as the root has been shown to contain 0.105% alkaloids, especially moriginine, and a bacteriocide, spirochin, both of which can prove fatal following ingestion. The leaves are widely used, particularly in India, the Philippines, Hawaii and parts of Africa, as a highly nutritious vegetable supplement. Analyses of the leaf composition have revealed them to have significant quantities of vitamins A, B and C, calcium, iron and protein. The leaves are considered to offer great potential for those who are nutritionally at risk and may be regarded as a protein and calcium supplement. The flowers, which must be cooked, are consumed either mixed with other foods or fried in batter and have been shown to be rich in potassium and calcium. The seeds are utilised in some regions of India either as a green 'pea', in their immature state, or fried, in their mature state, possessing a peanut like flavour.

The immature green pods are probably the most valued and widely used of all the tree parts. The pods are generally prepared in a similar fashion to green beans and have a slight asparagus taste. The pods are highly nutritious containing all the essential amino acids. Although primarily utilised world-wide by the Asian population as a vegetable, usage by other peoples is increasing. An international market already exists for both fresh and tinned pods. The photographs below show fresh pods imported to the UK from a variety of sources. The tinned pods were imported from India.

Almost all parts of the tree have been utilised within traditional medicine practices. For detailed listings those interested are directed towards the selected reading list. As interest in the medicinal properties of various parts of the tree has grown there has been an increase in the number of scientific studies that have been carried out to isolate active ingredients and determine mechanisms of action.

The wood provides a pulp that is considered suitable for newsprint, wrapping, printing and writing papers and for viscose rayon grade pulp for textiles and cellophane.

The information available on optimum cultivation procedures for M.oleifera is limited. Outside certain regions of India, where large scale cultivation is practiced, the tree receives little or no horticultural attention. In general terms it is known that the tree will grow rapidly from seeds or cuttings. Seeds require little or no pretreatment prior to germination with viability rates for fresh seeds having been reported to be up to 80% reducing to approximately 50% after 12 months storage. Seeds may be sown directly or in seed beds with transplanting after 2/3 months. The best time of year for sowing is reported to be at the beginning of the wet season. If planted out during the dry season half-shade should be provided and watering should be carried out regularly until the tree is established. Watering every other day has been reported to increase the drought tolerance of the tree.

Cuttings are primarily utilised for the establishment of live fences. Branches 1 - 1.5 m in length will take root readily in just a few months. From both seed and cuttings the tree grows at a remarkable rate, 3-4 m growth in a year is not unusual. In addition, first fruits may be expected within 6-12 months of planting out. Depending on the variety, the extent of fertilisation and other factors, a single tree may produce between 400 and 1000 pods annually. Pollarding or pruning following harvesting is recommended to promote branching, increase pod production and facilitate harvesting. The use of fertiliser and regular irrigation is not essential and is seldom practiced outside of India, however, manuring prior to the rainy season is said to increase yields three-fold.

The tree is not affected by any serious diseases in India. A root-rot caused by Diplodia sp. has been observed. The hairy caterpillar, Eupterote molifera Wlk., can cause defoliation and requires spraying to control it. Other pests noted in the literature originating from Indian studies include an aphid Aphis caraccivera, caterpillars Tetragonia siva, Metanastia hyrtaca and Heliothis armigera, a scale insect Ceroplastodes cajani, a borer Diaxenopsis apomecynoides and a fruit fly Glitonia (Ramachandran et al, 1980).

The optimisation of production through the selection of suitable clones depends on the purpose for which the tree is to be grown. In India a short stem variety of M.oleifera (designated PKM1) has been developed in an attempt to optimise pod production. Originally developed as a perennial tree, many of the farmers grow this variety as an annual. Following harvesting (two harvests per year have been reported) the tree is dug up and a new set of seedlings is planted out. One of the advantages of such a practice is that a tree kept only for a year is less likely to fall prey to disease . There is also the potential for the hybridisation of M.oleifera with other members of the same family. Moringa stenopetala Cufod. (M.stenopetala) has been shown to contain flocculating agents that show a high homology to those in M.oleifera. With M.stenopetala producing bigger seeds than M.oleifera it may be possible to increase the seed yield from such a hybrid. It may be possible to increase the oil yield of M.oleifera by producing a hybrid with the higher yielding (approximately 50% oil) Moringa peregrina (Forsk) Fiori. The selection of clones and the development of hybrids is considered essential to maximise the full potential of M.oleifera.

Alley cropping is the practice of growing food crops in alleys between hedgerows of trees or shrubs which are regularly 'coppiced' or severely pruned. This agroforestry technique is used with the PKM1 M.oleifera in southern India. The prunings are placed on the soil as a mulch around the food crops, providing valuable nutrients on decomposition. Alternatively, the leaves may be used for human food or animal feed. M.oleifera possesses the general characteristics of useful species for alley cropping:

can be easily established;

is fast growing and therefore produces much biomass;

is deep rooted without many shallow, lateral roots;

sends out new growth rapidly after repeated severe pruning;

provides useful by-products;

has high protein (nitrogen) content in the foliage;

has a loose canopy preventing excessive crop shading.

Department of Engineering, University of Leicester, United Kingdom - http://www.le.ac.uk/engineering/staff/Sutherland/moringa/cultivat/cult.htm