A few days ago we went on a three hour hike to a traditional fijian village. On the way we saw many different plants that are used by the fijian people. One of them was kava, a plant used to make a traditional fijian drink, also called kava. It had interesting properties so I decided to examine it.
Common names: Kava, Kava Kava, Yangona, Awa
Scientific name: Piper Methysticum. Piper is latin for pepper and methysticum is greek for intoxicating.
|Species||Piper Methysticum G. Forst||-Kava|
The plant is native to Vanuatu, a small country in the south pacific ocean, but has been introduced to other countries such as Germany, Papa New Guinea, Samoa, The Solomon Islands, Tonga, and Fiji. The plants are generally two to four meters, with several stems sprouting from a main rootstock at or below ground level.
The plant is a dicot, hence the class magnoliophyta. Though it rarely produces fruit, when it does, the seed has two cotyledons. You can also tell from the leaf structure, as it has a midrib (main vein) with other veins branching off of this, a sign of a dicot.
Though the plant produces seeds, this is not its main method of reproduction. The plant reproduces asexually using vegetative propagation. Once the plant matures, after around 15-30 years, the stolons (above ground stems) form new rootstocks which then sprout more stems.
The plant does not require pollination so therefore does not require any animals to spread its pollen. It also is not eaten by any animal other than humans, so it has a relatively small role in its ecosystem. Deforestation is a threat to this plant in some places, but many of the places it grows are protected, such as in native villages in Fiji. It does not have any natural threats to its existence and is grown by humans so it is unlikely to go extinct.
This plant does bear fruit, but only rarely. The fruit is a small berry, with one seed in it.
Kava uses transpiration and root pressure to transport water and thee dissolved minerals within the water up the stem to the leaves. Transpiration occurs when the guard cells on the stomata of the leaf are turgid. A stomata is a small opening on the bottom of the leaf, and guard cells are the cells that make up the edge of the stomata. When a lot of water enters these cells through osmosis, they become inflated with turgid pressure and this allows the stomata to open, letting water evaporate through it. This is where root pressure becomes involved. The absence of this water in the leaves creates a pressure that pushes water and the dissolved minerals in it up the xylem. This creates more root pressure and causes water and minerals from the soil to enter through the root hairs and into the root.
Kava grows best on rich well-drained soil (of a pH level of about 5.5-6.5, near neutral, slightly acidic) in mountainous areas of about 0-800 meters, in temperatures of roughly 20–35°C. It also prefers shady regions when young but is attracted to the sun when matured, and prefers a level of rainfall at about 1000-3000mm. It grows well in gardens. It is susceptible to damage by moderate to strong winds.
Kava is used to treat many ailments, including anxiety, stress, restlessness, and insomnia. This happens because lactones in the roots of kava have an effect on the brain an the central nervous system and are responsible for these effects. Drinking it can lead to a short period of numbness in the mouth and through area and can cause drowsiness, hence its use for these various ailments