*~*‘The mission of the Royal Botanic Gardens, Kew is: "To enable better management of the Earth's environment by increasing knowledge and understanding of the plant and fungal kingdoms - the basis of life on earth. "’*~*
Our first stop on our tour of the gardens was one of the greenhouses behind the gardens, where they were growing and cultivating various plants, which liked humid conditions, such as the carnivorous plants, lillies and orchids.
Sarracenia
Sarracenia are herbaceous perennial plants, which are a member of the pitcher plant family. They are most commonly found on the southeast coast of the USA. They tend to inhabit areas that are acidic, with the soil being made up of sand and moss, which contain poor nutrients, as they extract their nutrients from their insect prey.
Each pitcher plant tube is split up into 5 separate zones, known as the Hooker zones, each playing a vital role in the survival of the plant, and how they gain they’re nutrients.
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Zone 1: The Operculum (Attraction)
This covers part of the pitcher opening, preventing rain and other substances from filling the tube, or diluting the digestible juices at the base of the tube. However its main function is to attract the prey into the pitcher tube by using bright colours, scent, and nectar glands, which the insects come to feed on, and downward pointing hairs.
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Zone 2: Peristome and the Trap entrance
The Peristome, or the lip of the mouth of the plant, there is a large amount of nectar secreted here, luring the insect to crawl onto the upper portion of the tube, where they may fall into the digestible juices at the base of the tube.
This is the leafy surface of the tube. In few species of the Sarracenia there are very fine downward pointing hairs, but this is not commonly known. If the insect has made it this far, it offers no chance of escape, as the tube has narrowed to such an extent, as the insect cannot use its wings.
This is the last zone in most species of the Sarracenia. It is situated in the base of the pitcher tube, containing digestive enzymes, which help to digest the prey to give the pitcher its nutrients, and downward pointing hairs making escape impossible.
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Zone 5: The base of the tube
This is only found in the Sarracenia purpurea. It’s smooth, has no hairs, very few glands so no absorption takes place here. No one has yet found out its function to the plant.
Flowers
The flowers of the pitcher plant are found on long stems above the pitcher trap, to avoid trapping the pollinators. They are produced in early spring with a diameter of 3-10cm depending on the species. It has a complicated design, which prevents self-pollination. The whole plant is held upside down, so it can catch the pollen, which may have fallen from the anthers. Their main pollinators are bees. To enter the chamber where the pollen is stored they must make their way past one of the stigmas. In here they will come into contact with a lot of pollen, which will be used to pollinate other Sarracenia. To avoid self-pollination they have to force their way out under one of the petals, keeping the bee away from the stigma.
Most of the flowers are scented, which has a very strong pungent which occasionally is very unpleasant. ‘The flowers generally last about two weeks, if pollinated the ovary begins to swell. Generally 300-600 seeds are produced in five lobes. The seed takes five months to mature, at this point the seed pod turns brown and splits open scattering the seeds.’ When the plants start growing, they produce the pitcher traps almost immediately; however they have a simpler structure than the adult traps.
Cultivation
Sarracenia are easy to grow and are cultivated among gardeners and carnivorous plant enthusiasts, however other species of carnivorous plant, such as the Venus flytrap, are given to the younger age groups, as they are easy to look after and don’t need much maintenance. Although they are naturally found in Canada and North America, you can cultivate Sarracenia within the UK.
Conservation
Sarracenia are threatened within the wild by development and their habitat being drained. There are estimates of around 97.5% of Sarracenia habitat has been destroyed in the southeast USA. If this keeps happening, they will eventually become extinct and, we won’t be able to learn enough about these plants that may help us, in the way they ain their nutrients, and nitrogen.
Several states have conservation laws that protect the Sarracenia however most of the areas in which they inhabit are on private land, which are not protected by these laws. The biggest threats are urban development, drainage of habitat, runoff of herbicides from agriculture, fire destruction and floristry and plant trade.
However there are certain groups and organisations, which work to conserve the pitcher plant, and the Sarracenia, such as The Nature Conservancy (TNC), the International Carnivorous Plant Society (ICPS), and Atlanta Botanical Gardens (ABG). These groups strive to help the Sarracenia and all carnivorous plants in restoring them to they’re native habitat, and helping other groups, by working together, to bring about new initiatives to tackle the problems facing all carnivorous plants.
Ethical
In many areas, of the USA in particular, they collect a variety of endangered carnivorous plants, and use tissue culture to copy them, so that specific species don’t die out. However there are many arguments about whether this should happen or not. Plant tissue culture involves growing plants in an artificial medium under sterile conditions in a jar, flask or test tube. This can produce many plants at once. The plants produced would be exact copies of the parents, in other words clones.
However if the seeds of the plant are tissue cultured, the plant will be genetically different from the parent, and this is how most of the carnivorous plants are produced.
This method is mainly used to find new ways of reproduce native plants. In ABG’s case they take their findings and sharing their results with other conservation groups. ‘When nurseries are able to get large numbers of native plants from commercial tissue culture labs, they are less likely to sell plants that have been taken out of the wild.’ Some of the rare plants that are grown in tissue culture will be planted in their native habitats. Others will be given to universities and conservational institutes for further study and research.
The ethical issues against tissue culture is that it is a form of cloning, so therefore the plant would loose the individual uniqueness, the possible effects on the whole plant family they would all be the same, no variety.
Economic
It has been found that the digestive enzymes in the carnivorous plants, Nepenthes alata, can be used for antibacterial products. The scientists found seven different proteins within the fluid, of which three were digestive and the other four, were believed to be preservatives against fungi and bacterial infections from other plants. If this is true and found to have no bad effects upon humans it will become a good source of income, as many people around the world want to be clear of infections and remain healthy.
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1This is taken from wikipedia, so is therefore a secondary source, however is fairly reliable.
