Australia: The Land Where Time Began

A biography of the Australian continent 

There are 70 species of carnivorous plant in the Kwongan flora, and a high proportion (93 %) of the them are endemic to the region of the Kwongan. The same applies to the similar region in southwest South Africa. In damp areas and deep dry sands, or laterite surfaces, Drosera species are common. Mucilage is secreted by stalked glands on their leaves that capture small invertebrates that are attracted to them. These glands produce organic acids and 6 different enzymes, the symbiotic bacteria in the glands adding more enzymes, one of which is chitinase. The result is that the prey is digested, releasing the nutrients into the mucilage. These glands have a high rate of metabolism, absorbing the nutrients. As well as amino acids and carbohydrates, the plants gain extra nitrates, sulphur, and calcium.

Among the endemic plants, Cephalotus, a picture plant, holds a pool of water in its specialised leaves, the drowned insects being digested by the enzymes released into the water, where they are absorbed by the plant. The digestion of the prey is assisted by bacteria, such as Pseudomonas that are present in the water.

Some species of bladderworts, Utricularia, have replaced their roots with nodule-like bladders. Insects touching sensitive hairs trigger the opening of the bladders to capture prey, enzymes being released to break down the insect body. Any nutrients in the water the plants grow in, as well as the nutrients in the water contained in the bladders, is absorbed into the vascular tissue of the plant.

Sources & Further reading

1. Mary E. White, Earth Alive, From Microbes to a Living Planet, Rosenberg Publishing Pty. Ltd., 2003