Elaeagnus umbellata is a species of flowering plant known as Japanese silverberry, autumn olive, autumn elaeagnus,

Description

Elaeagnus umbellata grows as a deciduous shrub or small tree, typically up to tall, with a dense crown. It commonly bears sharp thorns in the form of spur branches.

Fruit

thumb|150px|The fruit of a Japanese silverberry plant

The fruit is a small round drupe in diameter. The unripe fruit is silvery-scaled and yellow. It ripens to red, dotted with silver or brown. The ripe fruits are pulpy, juicy and sweet, 3–9 mm in length, 5 mm in diameter, and average 137 milligrams in weight, with a thin skin covering the whole fruit. When mature, the red berries contain carotenoids, including considerable amounts of lycopene. They are smooth and leathery, with their front side being a dull green color, with the backside silvery white, which makes the pant noticeable in the wind and in direct sunlight. The veins of the leaf have a prominent central vein with branching veins stemming from the center, giving the leaf an oval shape with pointed tips at the ends.

Leaf cross-section

thumb|150px|Cross-section of the stem, showing the outermost layer of cells

The epidermis is made of a single layer of cells as the protective layer of the leaf. The epidermis functions to reduce water loss via transpiration and provide protection from pathogens and damage. It protects photosynthetic tissues. The trichomes (leaf hairs), hair-like structures made of epidermal cells, are usually located on both upper and lower surfaces of the leaf. They function to reduce water loss by creating a slightly humid layer over the leaf surface. They reflect excess sunlight to protect the leaves. They also deter herbivores to reduce leaf deterioration. In Elaeagnus umbellata, trichomes help the plant survive in dry, sunny, or exposed habitats, making it an extremely resilient plant and contributing to its invasiveness.

Stem

The stem is composed of many shoots extending outwards from the perpendicular stem. The stems of a typical autumn olive plant are woody and slender, slivery and brownish gray. The stems have this color due to scales located on the stem that give rise to the speckled appearance. The stems are smoother on younger plants and rougher and bushier on older plants. Especially the young stems bear short thorns that extend from the stem.

The outermost single layer of cells that covers the stem has a waxy cuticle with little porosity that serves to protect against water and mineral loss and pathogen invasion. In the autumn olive plant, it helps the plant withstand dry and variable autumn climates.

The cortex is the region immediately beneath the epidermis and is composed of parenchyma and collenchyma cells, which provide support. The cortex stores nutrients for the plant's growth, such as carbohydrates, for the plant to survive colder seasons.

Naturalization

In its origin regions of tropical and temperate Asia, E. umbellata is not considered to be an invasive species, but in many world regions, it has become invasive across wild and cultivated areas, particularly in the eastern United States. it has been planted for wildlife management in parts of the U.S. In Canada, it is a "prohibited noxious weed" under the Alberta Weed Control Act 2010.

Because it fixes atmospheric nitrogen in its roots, E. umbellata may grow vigorously and sometimes competitively in infertile soils. It can increase available nitrogen in soils and benefit some nearby plants, and when grown in orchards, it can increase yields of adjacent fruit trees up to 10%. However, its ability to change soil chemistry can severely alter or destroy native plant communities.

Cultivated varieties

  • Charlies Golden - yellow fruits variety
  • Ruby
  • Elsberry
  • Brilliant Rose
  • Cardinal - american variety ,selected 1963.
  • Jewel
  • Delightful
  • Sweet and Tart
  • Redwing
  • Amber – yellow fruits, old Japanese variety
  • Turdus – german variety,on market since 1992.
  • Serinus – german variety ,on market since 1992.

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File:Autumnolive2.JPG|Leaves

File:Honey bee foraging on Autumn Olive.jpg|Blossoms

File:Elaeagnus umbellata Frucht.jpg|Ripe fruit

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References

  • Elaeagnus umbellata images; Bioimages from Vanderbilt University, Nashville, TN, USA
  • Species Profile - Autumn Olive (Elaeagnus umbellata), National Invasive Species Information Center, United States National Agricultural Library.