Avocado Plant (Persea Americana): Classification, History, Origin, Discovery, Distribution, Characteristics, Phytochemistry, and, Nutritional Attributes
Introduction
The Avocado, or Persea americana, is a wonderful fruit with numerous properties that are advantageous to both humans and several other creatures. Persea Schiedeana and Beilschmiedia are two closely related species to the avocado. The existence of the Persea species in rocky outcrops is confirmed by fossil records. As it travelled over the world from its southern Mexican birthplace, it gave rise to the Indian, Guatemalan, and Mexican races. Size, colour, and skin texture help identify the various varieties of avocados. Although Persea Americana normally has diploid chromosomes, one with triploid chromosomes has been discovered. The avocado counts three stages: germination, flowering, and fruiting, with one-year phenology. It is composed of two sexual varieties, flowers A and B, which open at various times of the day so that bees can pollinate both of them. The preservation of an avocado depends on whether it has been chopped or torn. Fresh fruit has a high nutritional content and is mostly consumed by both humans and animals as food. There are several medical applications for it, but the most typical ones are to treat coughs, diarrhoea, and bodily cleansing. Worldwide, Persea americana benefits from strong demand and high pricing.
Classification
Kingdom: Plantae
Order: Laurales
Family: Lauraceae
Genus: Persea
Species: P. americana
Scientific Name: Persea americana
Common Name(s): Alligator pear, Avocado, Avocado-pear, Butter fruit
History and Origin of the Avocado Plant
The Avocado is a fruit with a history of nearly 10,000 years that comes from tropical trees and has a pear-shaped, blackish-green colour, high nutritional content, a creamy texture, and a distinct flavour. Although it was grown from the Rio Grande to central Peru long before the arrival of Europeans, Julian F. Morton claimed that the avocado likely originated in southern Mexico. Because of this, it was transported to practically all tropical and subtropical regions with suitable environmental conditions, including the West Indies.
Discovery of the Avocado
The earliest Avocado remains were discovered in Coaxcatlan, Puebla, Mexico, about 10,000 years ago. The Aztecs, Olmecs, and Maya were three ancient civilizations in North, Central, and South America who revered avocados as a gift from God. The seed remains discovered in the Tehuacan Valley of Mexico may point to the prehistoric human presence there as early as 8000–7000 BC and may have been domesticated by the Mesoamericans at least 5000 BC.
Distribution
Avocado is currently grown worldwide and in great quantities, for instance in Indonesia, Brazil, South Africa, Israel, the USA (California and Florida), and Australia.
Characteristics
1. A subtropical fruit tree plant known as the avocado has gained popularity for its wholesome fruits.
2. P. americana is a 9–20 m tall medium to a big tree.
3. The avocado is categorised as an evergreen, even though certain cultivars briefly lose their leaves before flowering.
4. Tree canopies can be low, thick, and symmetrical, or they can be upright and uneven.
5. The form and length of the leaves vary from 7 to 41 cm (elliptic, oval, and lanceolate). They are frequently hairy and reddish while young, and when they are grown, they are smooth, leathery, and dark green.
6. Flowers measure 1-1.3 cm in diameter and are yellowish-green. In a pseudoterminal posture, the many-flowered inflorescences are carried. A shoot marks the end of the inflorescence’s central axis.
7. The fruit is a berry with a single big seed enclosed in a buttery pulp. It has 3–30% oil (Florida variants range from 3–15%). The thickness and texture of the skin might vary.
8. Depending on the cultivar, the fruit’s mature colour might be green, black, purple, or reddish. Fruits can be spherical or pyriform in shape and can weigh up to 2.3 kg.
Flowering
During the flowering season, an avocado tree typically produces over a million blooms, however, the majority of them die without bearing fruit. The avocado flower possesses both female and male organs because the flower is bisexual. It has protogynous dichogamy, which is defined by the fact that each bisexual bloom opens twice and then immediately closes. The flower opens the first time (stigmas are receptive), functioning as a female; the second time, it closes and reopens the following day, functioning as a male (dehiscence of anthers). The stigma is whitish and becomes pollen-receptive before the anthers dehisce (release of the pollen grains from the pollen sacs). Only 1% of the flowers created during anthesis can yield fruit. Environmental factors are quite important in this phenomenon. In a study conducted in southern Spain under the direction of Alvarez and Hormuz, it was determined why certain flowers prematurely wither while others stay attached to the tree. The evergreen avocado tree is indigenous to Mexico and Central America. Three horticultural races of avocados can be distinguished: Mexican (also known as subtropical), Guatemalan (also known as semitropical), and West-Indian (called tropical). Based on the various physical, physiological, and horticultural characteristics, the races are distinguished. The female stage flower opens first and remains open for the first two to three hours before closing. The flower blooms the following day, but the stigma is no longer open to pollen spores. The blossom in this male-stage flower releases pollen before shutting once more. The cultivars of avocado are divided into two complementing flowering types based on the order in which they bloom: A-type cultivars and B-type cultivars. The bloom becomes functionally feminine when it opens in the morning. It closes at noon and resumes operations as a male establishment in the afternoon of the next day. On the other hand, type B cultivars have blooms that open in the afternoon as females, close overnight, and then reopen the following morning as males. Environmental factors have a significant influence on how avocado blooms behave. Pollination is an essential phase in sexual plant reproduction as well as an essential step in ensuring fertilisation and seed generation. When flowers close in the female stage, the majority of them do not receive pollen. Burd, Larson and Barrett and Ashman et al. claim that the number of pollen grains needed to fertilise the ovules is smaller than the quantity that lands on the stigma, yet insufficient pollination may be the cause of the low yield. Alvarez and Hermaza’s investigations on avocado production revealed that insufficient pollen expulsion on the stigma of female flowers is the primary factor restricting fruit set.
Phytochemistry
Alkanols (also known as “aliphatic acetogenins”), terpenoid glycosides, different furan ring-containing derivatives, flavonoids, and coumarin are the main chemical components of numerous plants. Avocado’s highly functionalized alkanols have so far demonstrated a wide range of biological characteristics. Oberlies et al., for instance, isolated 1,2,4-trihydroxyheptadec-16-ene, 1,2,4-trihydroxyheptadec-16-yne, and 1,2,4-trihydroxynonadecane from the unripe fruits of P. americana, and they discovered that these compounds were moderately cytotoxic when tested against a small panel of cancer cell lines. Kawagishi et al. identified five alkanols from avocado fruits that had “liver suppressing activity” (as seen by changes in plasma levels of alanine and aspartate aminotransferase).
Nutritional Attributes
The Nutritional Worth of Avocado
The fruit known as the avocado is unique. It is rich in good fats, as opposed to other fruits, which are mostly made of carbohydrates. Numerous studies have demonstrated the tremendous health advantages of avocados.
The nutritional worth of Avocado is highlighted below
Avocados are Nutrient-Rich Fruits
A single serving of 3.5 ounces (100 grammes) of avocado fruit contains 10% of the dietary value (DV) of vitamin E, 20% of the DV of folate, 17% of the DV of vitamin C, 26% of the DV of vitamin K, and 26% of the DV of vitamin B5. Additionally, it has trace levels of phosphorus (P), niacin, copper (Cu), iron (Fe), zinc (Zn), magnesium (Mg), manganese (Mn), and manganese oxide (MnO) (vitamin B3).
Avocados Have a Higher Potassium Content Than Bananas
The potassium content in avocados is high. 3.5 ounces (100 grammes) of bananas, a typical high-potassium food, only provide 14% of the daily required amount (RDA).
Avocado Is High in Monounsaturated Fatty Acids
Monounsaturated fatty acids are beneficial for heart health. Avocados are very fattening. It is one of the fattiest plant foods on the globe due to its 77% fat-calorie content. But they don’t contain just any fat. Avocados contain significant amounts of oleic acid, a monounsaturated fatty acid with several beneficial health properties.
Avocados Are a Great Source of Fibre
When compared to other foods, avocados contain a lot of fiber—roughly 7% of their weight. The benefits of fibre on metabolism and weight loss may be significant.
Avocado Eaters Are Often Healthier
People who ate avocados were shown to be much healthier than people who did not. Avocado eaters ingested significantly more nutrients and had a significantly lower risk of developing metabolic syndrome, a constellation of symptoms that is a major risk factor for diabetes and heart disease. Additionally, avocado eaters were leaner, had a lower BMI, and had significantly less belly fat. Additionally, they had higher amounts of “good” HDL cholesterol.
Avocados May Assist with Weight Loss
There are some signs that avocados are food that promotes weight loss. According to one study, participants who ate avocado with their meal felt 23% fuller and had a 28% lower appetite for food during the following five hours than those who did not. Including avocados in your diet may immediately reduce the number of calories you consume and make it easier for you to keep up with healthy eating habits if this remains true over time.
Avocado Varieties
There are many different sizes and forms of avocados. Despite having a pear form, for the most part, some varieties are almost round. Depending on the type, they are available in a range of sizes. The most common types of avocado are Bacon, Fuerte, Gwen, Hass, Pinkerton, Reed, and Zutano, with many chefs favouring the Hass variety. One of the most common varieties, the Hass Avocado, is sometimes referred to as the Avocado Pear or Alligator Pear in some regions due to its pebbly, rough surface. Even without a label, you can still tell them apart based on how they look and feel. Although their ideal season is in the late winter or early spring, avocados are always accessible in the market. Avocados, which were formerly a special delicacy, are now commonly available and even found on fast food sandwiches.
Medicinal Properties
The avocado fruit has several medicinal qualities despite being primarily used as food. The benefits of avocado for health are as follows:
A Cure for High Cholesterol
A small-scale scientific experiment involved 16 males, ages 27 to 72, who received varying doses of avocado (12 to 112 fruits per day). While none of the others experienced an increase, only half of them experienced a sizable decrease in cholesterol. Avocados might not be a bad choice for people with high triglyceride or cholesterol levels.
Atherosclerosis, Angina Pectoris, And Alzheimer’s Disease
Alpha-carotenes, which are found in the fruit and have antioxidant properties, may guard against the oxidation of “bad” LDL-cholesterol and reduce the risk of atherosclerosis. Avocado eating may also be beneficial for people with angina pectoris brought on by atherosclerosis. The number of antioxidants in the blood may affect how quickly Alzheimer’s disease develops. Studies show that people with this disease have considerably lower blood levels of alpha-carotene than healthy individuals.
Aid In Digestion and Blood Sugar Balance
The Avocado fruit is thought to be helpful for people with ulcers or gastritis due to its alkaline properties and the softening and protective effects of the fat on the mucous membranes. Studies have shown that eating avocados helps diabetics keep their ideal blood sugar levels, indicating that the fruit may be beneficial for diabetes.
Skincare Using the Pulp of Avocado
Avocado fruit pulp, when mashed, can be applied directly to the skin to soothe irritation and prevent sunburns. Additionally, it is employed to shield skin from irritants and suppurating sores. Additionally, it can be massaged onto the scalp to reduce itchiness and encourage hair growth. You can produce a calming and cooling face mask for dry or ageing skin by combining mashed avocados with egg white, egg yolk, or honey.
Avocado Oil in Aromatherapy, Cosmetics and Skincare
As a natural carrier oil, Avocado oil is becoming more and more well-liked. It may be found in a wide range of cosmetic products and aromatherapy blends. It can be found in various kinds of natural skincare products, including lotions, liniments, shampoos, conditioners, massage oils, and creams for sore muscles. Avocado oil is a gentle, vitamin-rich oil that hydrates and safeguards the skin. The skin readily absorbs and evenly distributes avocado oil. Dermatitis, dry, ageing skin, and skin damaged by the sun are all greatly helped by the oil. When coupled with vitamin B12, avocado oil is beneficial for treating psoriasis. It may benefit those with eczema, according to some specialists.
Antioxidant Property
Avocados are rich in antioxidants and also facilitate the absorption of antioxidants from other foods. Lutein and zeaxanthin, two carotenoids, are advantageous for eye health. Studies show a strong correlation between them and much lower rates of macular degeneration and cataracts, two conditions that are common in older people. Consuming avocados will therefore have long-term benefits for your eye health.
The Anti-Inflammatory and Anti-Microbial Properties
An Avocado seed extract reportedly showed anti-inflammatory properties in a lab test, according to researchers at Penn State. Thus, it might be a source of new anti-inflammatory compounds that could be used in medicine or as functional food ingredients. To look into the anti-inflammatory properties of avocado seed extract, the researchers used cell culture models and enzymes related to immune response and inflammatory diseases. It proves that avocado seeds contain bioactive compounds with anti-inflammatory effects. Combating infectious disorders in general and microorganisms that are resistant to antibiotics can be accomplished with the help of antimicrobial therapy. The antimicrobial metabolites in avocados are diverse. The 1,2,4-trihydroxy-n-heptadeca-16-en substance that was isolated from avocado fruit and seeds has proven to have antibacterial properties.
Anti-Ulcer Property
The prolonged use of anti-inflammatory drugs is the most frequent cause of stomach ulcer disease, one of the gastrointestinal issues that affect people worldwide. Avocado seeds are frequently wasted and thrown away. But seeds can also be used to treat digestive problems. Caffeoylquinic acid, flavonoids, phenylpropanoids, and tannins are significant phenolic chemicals found in avocado seeds that block the processes implicated in the development of stomach ulcers. In light of this, avocado seed extract may be a great all-natural source for preventing and treating stomach ulcers.
How to Grow and Take Care of an Avocado Tree
How to Plant an Avocado Tree
Avocado trees should ideally be planted outside in the spring. This gives the tree plenty of time to establish itself before the chilly winter weather arrives. This is particularly crucial in the hardiness zones for avocado trees in the north. Select a planting place where there will be enough space for these tall trees to flourish. If you’re planting more than one avocado tree, space them at least 30 feet apart and at least 10 feet away from any buildings.
Remember that avocado trees’ roots are highly delicate, and make an effort to avoid disturbing them needlessly while planting. Wider than the root system, dig a hole. Since planting the tree too deep or too shallowly can result in issues, the depth of the hole should typically match the height of the root ball.
As a result of the tree’s susceptibility to strong winds, very young, delicate, and immature trees might benefit from support. Your tree will stay upright and healthy if you put it in an area that gives wind shelter. Make sure your tree has good soil drainage and receives lots of sunlight. Sand or another well-draining substrate can be added to the soil to improve it if the soil is not in optimal condition before planting. Although doing so would eventually slow their growth, avocado trees can also be planted in containers.
Avocado Tree Care
Light
The Avocado tree needs a lot of sunlight to thrive, like most tropical plants. Give this tree at least 8 hours of direct sunlight per day when you plant it. Although these trees may tolerate some shade, full sun is optimum for their growth and fruit production.
Soil
Avocado trees prefer loamy, fertile soil that drains well. To prevent root rot, it’s crucial that the soil is aerated and doesn’t retain too much water. Ideal soil pH ranges from 5 to 7, which ranges from acidic to neutral. Alkaline soil can harm these trees.
By adding a layer of mulch all around the tree, you can preserve its shallow root system and help the soil retain the correct amount of moisture. To prevent suffocating the roots or creating collar rot, make sure to keep the mulch about 6 inches away from the base of the tree.
Water
Trees that bear avocados benefit from sporadic, heavy watering. This promotes the development of stronger, deeper roots. When the soil starts to dry out, water deeply. The avocado tree will need to be watered more frequently throughout the hot, sometimes dry summer months. Additionally, as the tree becomes older, it has to be watered more frequently. A week’s worth of watering for mature trees should be about 2 inches.
Temperature and Humidity
Unless you want to grow an avocado tree indoors, these well-known fruit trees can only be cultivated outside in USDA hardiness zones 9–11, restricting them to tropical and subtropical regions. They like growing at temperatures between 50 and 85 degrees Fahrenheit and are frost-sensitive.
Fertilizer
An Avocado tree will produce more fruit and develop healthier if fertilised during the growing season. Depending on the exact directions contained with your chosen fertiliser, begin in the late winter or early spring and continue feeding until the fall. Make sure the fertiliser you select has high levels of nitrogen because this tree needs it. It works well to use fertilisers made specifically for citrus or avocado trees.
Pollination
An Avocado tree can be challenging to pollinate. These trees have blooms that have both female and male components, or what are known as “perfect” flowers. The female and male sections of avocado tree flowers open at different times, making self-pollination possible but not always successful. It is essential to have two avocado plants for the best pollination.
There are two types of avocado trees: type A and type B. The male portions of Type A trees open in the afternoon of the second day and the female parts open in the morning of the first day. The male portions of Type B trees open in the morning of the second day, whereas the female parts open in the afternoon of the first day. Cross-pollination between the two varieties is made feasible by these various timeframes. For the greatest outcomes, plant both type A and type B trees when selecting which ones to plant.
How to Grow Avocado Trees From Seed
An easy and enjoyable endeavour is growing avocado trees from seed. It’s crucial to remember that seeds do not always result in trees that are exact replicas of their parent plants. A tiny pot, well-draining potting soil, toothpicks, a sharp knife, an avocado seed, and a jar of water are all needed for this project. then adhere to these guidelines:
1. Make three or four holes around the avocado seed with a sharp knife.
2. Put the toothpicks through the openings. By doing this, you’ll build the supports the seed needs to float in the water.
3. Put the seed’s thick, or bottom, end, into the water. The water should contain around one-third of the seed.
4. Place the seed in direct sunlight, and replace the water every day.
5. After a few weeks, the top of the seed should develop leaves and roots.
6. When that happens, gently put the seed in soil that drains well.
Frequently Asked Questions
Question: How long does it take for the Avocado plant to fruit?
Ans: Three to four years
Question: How long do Avocado plants live?
Ans: Hundreds of years.
Question: What fertilizer is best for Avocado trees?
Ans: Nitrogen, and a little zinc
Question: Can I grow Avocados indoors?
Ans: Yes
Question: How big do Avocado trees get?
Ans: At full maturity, it will grow to a height of 15 to 20 feet and a width of 5 to 8 feet.
Question: Are Avocados difficult to grow?
Ans: Yes