Write a project work on Insectivorous plants ?
Answers
Darwin’s work on insectivorous plants began by accident. While on holiday in the summer of 1860, staying with his wife’s relatives in Hartfield, Sussex, he went for long walks on the heathland and became curious about the large number of insects caught by the common sundew (Drosera rotundifolia). He reported to his friend Joseph Dalton Hooker: ‘I amused myself with a few observations on the insect-catching power of Drosera; & I must consult you some time whether my “twaddle” is worth communicating to Linnean Soc.’ He initially collected a dozen plants and found that over half of the leaves had the remnants of dead insects adhering to them. The project was a welcome distraction from his daughter Henrietta’s long-term illness, probably typhoid fever. While caring for Etty, Darwin’s wife Emma wrote to a friend:
‘Charles is too much given to anxiety, as you know, and his various experiments this summer have been a great blessing to him , as he can always interest himself about them. At present he is treating Drosera just like a living creature, and I suppose he hopes to end in proving it to be an animal.’ (Emma Darwin 2: 177)
By the end of August he had ascertained that the sticky tentacles on the upper surface of the Drosera leaf bend over to trap insects. He had been busy performing experiments on the rate of inflection of the leaves and their sensitivity to various household substances. He concluded: ‘The leaves are first rate chemists & can distinguish even an incredibly small quantity of any nitrogenised substance from non=nitrogenised substances’.
In this song the lyrics are based on Darwin's statements about insectivorous plants in his letters.
In September, Darwin roped in Hooker’s assistant at Kew Gardens, Daniel Oliver, to help him with his observations, initiating a sustained correspondence on insectivorous plants, the two men exchanging over twenty letters in the autumn of 1860 alone. Darwin started by asking Oliver to compare Drosera with Dionaea muscipula (the venus flytrap) and stated that 1/1920th part of a single grain of ammonia was all that was needed to cause decided movement of a Drosera leaf, adding that his facts were ‘not stated without numerous & carefully repeated experiments’. Oliver observed related plants in the collection at Kew, such as the Australian Drosera, and tried to reproduce Darwin’s results on the reaction of Drosera leaves to various substances. When Oliver got a reaction from gum which Darwin had not, Darwin exclaimed: ‘I am infinitely obliged for your note … For Heaven sake try some pure gum.— You have given me a panic. I tried milk on 9 leaves thin Gelatine on 4 White of egg on 6 Saliva on 8 Urine on 11 Mucus on 4 infusion of meat 1 — 43 leaves.— and all strongly contracted on different plants’. He continued his experiments on an extended trip to Eastborne where his daughter was recuperating and wrote to the American botanist Asa Gray
Answer:
“Insectivorous plants are the plants that derive their nutrition by feeding on insects and other organisms.”
Characteristics of Insectivorous Plants
The important characteristics of insectivorous plants are mentioned below:
Nitrogen Deficiency
They are found in the places, where there is a lack of some nutrients, especially nitrogen. They entrap insects and digest them to suffice their nitrogen requirement.
Attractants
The insectivorous plants are colourful and shiny in appearance to attract insects. They often have nectars and a pleasant odour to attract insects.
Inescapable Traps
Many insectivorous plants have special or modified plant parts to trap insects. The mouth of the insectivorous plants has hair-lined lined edges that snap or shut as soon as the insect touches the hair, thereby, trapping the insects. Some of the plants’ stalks are covered with sticky mucus-like substances where the insect sticks and cannot move.
Digestive Enzymes and Organisms
Some insectivorous plants secrete digestive enzymes that dissolve the insect for absorption. Others have bacteria or mites in their digestive tract that mimic the functions of the human digestive tract. They digest the prey for absorption by the plants.
Types of Traps In Insectivorous Plants
The leaves of the plants are modified in the form of traps. The trapping mechanisms are designated as active or passive depending upon whether they move to capture the prey or not. The different types of traps found in insectivorous plants are mentioned below:
Pitfall Traps: These are found in a pitcher plant. They comprise of a hollow leaf with a lid, filled with liquid to digest the prey.
Snap Traps: These type of traps are found in Venus flytrap. They shut their leaves rapidly as the prey touches the trigger hair.
Bladderwort Traps: These are commonly found in Utricularia. They use a partial vacuum to suck the small organisms.
Flypaper Traps: These traps are sticky and adhesive. The leaves are covered in stalked glands that secrete sticky mucilage.
Lobster-pot Traps: These are found in corkscrew plants. They possess downward-pointing hair that pushes the prey deep inside the trap.