Apricot

Basic Information
Tree ID: 
70
Family: 
Rosaceae
Genus and species: 
Prunus armeniaca
Variety: 
Moongold
Description: 
The apricot tree is a small tree with a dense, spreading canopy. Also known as the ansu apricot, Siberian apricot, or Tibetan apricot, its origin is not exact due to its extensive prehistoric history of cultivation, but it is almost certainly somewhere in Asia and commonly thought to be Armenia. In modern times, it is most heavily cultivated in the Middle East, Western Asia, Northeastern America, and Eastern China. Apricot trees are perennials, meaning that they can live for very long periods of time; apricots usually live between 40 and 150 years. The apricot is native to a continental climate with cold winters, but is somewhat versatile and can grow in more Medeterranian environments as long as they have a suffient dormant period. The apricot is quite cold-hardy, more so than most other drupes including the peach, and can withstand temperatures as cold as −30 °C.
Surveyors: 
Tori Hass-Mitchell, Harry Kane
Location
Area: 
Marsh and Farnam Gardens
Collected Data
Tree shape: 
Spreading
Date of tree entry: 
02/08/2017
Height: 
3.90 m
Diameter at breast height: 
0.32 m

There are too many multiple trunks to accurately measure the DBH, so this is just an estimate
Bark
The bark of the apricot tree is variable in color, ranging from brown to tan to grey with intersecting fissures. The bark of the thinner branches is very different from the bark of the trunk, with prominent lenticels in parallel arrangement. The bark of the apricot is highly susceptible to many fungal diseases, and those effects can be seen in the last picture above with dark black discoloration around crevices of the tree. The noticeable sap exuding from the bark is the tree's way of fighting off the disease.
Twigs & branches
Twigs and branches have prominent lenticels arranged in parallel. Maintenance and pruning is crucial to members of the rose family. The apricot tree is pruned of dead twigs and branches to encourage new growth, but if too much is cut back, very thin branches will be produced, which are inefficient and ineffective as they are not strong enough to produce fruit. The horizontal branch pattern shown is called the "open center" method, and this pruning technique achieves healthier foliage, stronger branches, greater light availability (and nutrient availability by photosynthesis), and greater air circulation- all of which contribute to a high-quality fruit crop.
Foilage
The leaves are ovate, usually around 5–9 cm long and 4–8 cm wide, with a rounded base, a pointed tip, and a finely serrated margin. The apricot is a deciduous fruit tree, meaning that it loses its leaves every fall to conserve energy and water. The first picture shows the new leaf buds of mid spring (4/24/2017) that emerge after flowers fall off. The second picture shows the full leaves present with the growing fruit.
Reproductive Structures
The flowers are around 2–4.5 cm in diameter, with five white/pink petals (since they are dicots). They are produced singly or in pairs in early spring before the leaves emerge. The first picture shows the very first flower present on the tree, photographed at the beginning of spring (4/5/2017). The second and third pictures show the dying flowers about to fall off the tree (4/24/2017). Apricot flowers are radially symmetric, slightly fragrant, and are pollinated by insects (typically the honeybee).
Fruit
The fruits of apricot trees are round, fleshy drupes, similar to small peaches. They range from about 1.5–2.5 cm in diameter and even larger in some modern varieties. Their color ranges from yellow to orange and is often tinged red on the side most exposed to the sun. The surface of an apricot can be smooth (glabrous) or velvety with very short hairs (pubescent). The flesh is usually firm, not very juicy, and its taste can range from sweet to tart. A typical stone fruit, the apricot's single seed is enclosed in a hard, stony shell, called the "stone", which mainly has a grainy, smooth texture except for some ridges running down one of its sides (pictured). Inside of the seed resides the apricot kernel (also pictured), which is thought to have cancer-killing properties (discussed in video below). This cancer-fighting ability is thought to be due to the presence of hydrogen cyanide; however, this is highly toxic and potentially lethal in large doses.
Seasons
  • Early Spring with Dying Flowers
  • Mid Spring with New Leaves
  • Early Spring with Budding Flowers
  • Summer with fruit (online image)
  • Fall with changing leaves (online image)
  • Winter
Research
Natural range of distribution: 
Habitat: 
The apricot tree is thought to naturally grow in China, Mongolia, India, and Armenia, but it is widely cultivated around the world and can withstand relatively harsh climates. It is fully hardy, and can withstand temperatures well below -15 ºC. It prefers moist soil, but can grow in a range of pH conditions (although has a preferred pH range of 6.5-7.5) and in partially shady environments. It grows well in loamy soil, but is sensitive to clay and chalky soils. This versatility means that the apricot tree is found throughout the world, as indicated by the map, and it can grow in many environments where there is moist, suitable soil. These trees frequently grow even in elevated areas of the Himalayas where foliage is typically sparse. They flower in May-April and subsequently produce fruit in July-September, and are accordingly reliant on regions with seasonal temperature cycles.
Origin, history, and uses: 

Botany research suggests that the apricot tree originated in China, but that claim is disputed.  Armenia is home to the largest variety of apricot species, and many people believe that to be its place of origin.  Human consumption of apricots in Armenia has been traced back 6000 years in archeological dig sites, and the tree was introduced to western society by Alexander the Great and the Roman general Lucullus.  English settlers and Spanish missionaries are largely responsible for its introduction throughout America.

The apricot has enormous cultural significance in both Armenia and China, as can be seen in artwork from those countries.  In Chinese culture, the apricot is considered to be a symbol of medicine and education.  This symbolism appears to date back to the 4th century BC.  Apricot production is a large component of the Armenian economy, and apricots have much modern day significance there.  An Armenian postage stamp prominently features the apricot, and the wood of the tree is used to produce the duduk, a popular regional instrument.

Apricot trees are mainly used for their nutritious fruit, which is high in citric and tartaric acid, carotenoids and flavonoids.  It is often used for treatment of respiratory conditions, especially in Vietnam, and can be used to address a number of other health conditions as well (for example, the seeds contain a compound that hydrolyzes to hydrogen cyanide which can be useful in cancer treatment as mentioned before).  The bark of the tree actually produces a compound that can reportedly be used to neutralize hydrogen cyanide, which can be helpful in preventing overdoses. 

As commonly grown crops, apricot trees are subject to significant agricultural research.  This particular species of apricot tree was used in a 2002 study in which genes coding for viral coat proteins were injected into trees to defend against pathogens.  The study was successful, marking the first time the gene for a coat protein had been successfully expressed in a fruit tree, indicating a potential future area of focus for crop defense.

Phenology: 
The basic phenology of the apricot tree is as follows: in the winter, the tree is bare (no leaves, fruit, or flowers). In the spring, buds swell, flowers emerge and fall off, then leaf buds swell and leaves emerge. In the summer, usually around July, fruit ripens and is ready for harvest. In late fall, around October, leaves fall, and the tree is dormant for the entirety of the winter.
References: 

“Apricot.” Wikipedia. Wikimedia Foundation, 18 Apr. 2017. Web. 22 Apr. 2017.  (This source was used for information on apricot foliage, flowers, fruit, and for the map of the natural range of distribution.)

Schalau, Jeff. “Pruning Deciduous Fruit Trees.” Backyard Gardener . UArizona: College of Agriculture and Life Sciences, 22 Mar. 2005. Web. 25 Apr. 2017.  (This source was used for information on pruning techniques.)

Waterworth, Kristi. “Apricot Tree Bug Control – Learn About Common Pests On Apricot Trees.” Gardening Know How. Gardening, 27 Dec. 2015. Web. 25 Apr. 2017.  (This source was used for the picture of the apricot leaves and fruit.)

Nichols, Hannah. “Apricot Seeds: Cancer Treatment or Danger to Health?” Medical News Today. MediLexicon International, 27 Nov. 2016. Web. 22 Apr. 2017.  (This source was used for the picture of the apricot seed.)

“Organic Wild Apricot Kernels (Sweet).” Nuts.com. Nuts.com, 07 Apr. 2017. Web. 22 Apr. 2017.  (This source was used for the picture of the apricot kernel.)

IHealthTube. “Apricot Kernels Kill Cancer Cells.” YouTube. YouTube, 24 Oct. 2013. Web. 22 Apr. 2017.  (This source was used for the video explaining the cancer-killing properties of apricot kernels.)

“Prunus Armeniaca - L.” Pfaf Plant Search. Plants for a Future, n.d. Web. 25 Apr. 2017. <http://www.pfaf.org/User/Plant.aspx?LatinName=Prunus%2Barmeniaca>.

Huizhong. Five-colored Parakeet on Blossoming Apricot Tree. Ca. 1100-1119. Museum of Fine Arts, Boston. Digital Scrolling Paintings Project. University of Chicago. Web. 25 Apr. 2017. <https://scrolls.uchicago.edu/scroll/five-colored-parakeet-blossoming-apr….

da Câmara Machado, M.L., da Câmara Machado, A., Hanzer, V. et al. Regeneration of transgenic plants of Prunus armeniaca containing the coat protein gene of Plum Pox Virus.  Plant Cell Reports (1992) 11: 25. 

“Autumn at Sunstone.” Sunstone Farm and Learning Center. N.p., 23 Nov. 2009. Web. 26 Apr. 2017. <https://sunstonefarmandlearn.com/2009/11/23/autumn-at-sunstone/>.

“How to Grow Apricots.” Regenerative. Regenerative Leadership Institute, Inc., 16 Dec. 2016. Web. 26 Apr. 2017. <https://www.regenerative.com/magazine/grow-apricots>.

Media and Arts
This video describes the cancer-killing properties of apricot kernels.
 
 
Ode to an Apricot Tree
an epic limerick by Harry Kane and Tori Hass-Mitchell
 
Many years ago here in Marsh gardens,
the life of a young tree was started,
with many ovate leaves,
and pollen spread by bees,
this deciduous plant became heartened.
 
But sometimes the tree felt quite glum,
since it wasn’t quite sure where it’s from,
it was oft told Armenia,
but with fervor and mania,
some argued China, or India, and then some.
 
Regardless, the tree is quite hardy,
even in the cold it can party,
if the soil is moist,
spreading branches it hoists,
it can grow in the shade, at least partly.
 
The tree is best known for its fruit,
It’s a fleshy and medium-sized drupe,
and if it cures cancer,
we don’t know the answer,
but they’re healthy and taste good to boot.