Parasitic Plants & Animal Relation: Parasites are the organisms which rely on another organism for food, shelter, safety and in return they harm that organism which is also known as host.
This type of relationship is called as parasitic relationship. Parasites infect both animals and plants. The parasitic plants have roots which are modified, known as haustoria. These roots penetrate the host plants and they are connected to the conducting system of plants.
The system for food and water transmission in plants, which is based on xylem and phloem cell system.Through this mechanism they extract food and water from plants to fulfill their basic needs for their nutritional development.
Classification
- Obligate parasites: Those which cannot complete their life cycle with the host
- Facultative Parasites: Those which can complete their life cycle without any host
- Stem Parasites: Feed through stem of plants
- Root Parasites: Feed through roots of plants
- Hemi-parasites: Which are photosynthetic in nature up to some extent, under natural conditions
- Holo-Parasites: which derives the fixed carbon from their hosts
Some of the parasites parasitize the members of their own family.
There are more than 4000 species of parasitic plants in the world. I will discuss only few of them here.
Dodder
Cuscuta species is a well-known group of parasitic plants, commonly seen everywhere. We also call them the leafless vines. These parasitic plants use their haustoria (roots) to get food from their host. They penetrate their roots in stems of plants and siphon out food and water for their development.
Ultimately the host dies. The don’t have the chlorophyll so they cannot synthesize their own food. It’s difficult for dodder seedlings to find a host, because they run out of nutrients from the seeds in 5-10 days.
Various studies have discussed that these you dodder seedlings use air borne volatile organic compounds for their survival. Once they find a host, they penetrate the haustoria in host stem, then they completely reply on host for their growth and development.
Mistletoe
Arceuthobium (dwarf mistletoe) species are found throughout the world, commonly they parasitize the conifer trees. They also have same function as in dodder, they employ nutrients from their hosts through their haustoria. They also have little or no photosynthesis. They start spreading through the tree top by using high velocity projectile seeds.
These plants seeds appear like bullets. Each seed is covered with sticky material. As the seed grows there is pressure on the fruit wall and it ruptures. And shoots the bullet like seed at the speed of 56 mph. the sticky substance around the seed helps it to attach, where it lands.
Thurber’s Stemsucker
Pilostyles thurberi, this plant is native to deserts of south and north America. Stemsucker is an obligate parasite. Mostly parasitize the stems of shrubs of family Fabaceae. They are about 0.3 inches long. These are the tiny plants which lives in the stem tissues of their hosts.
They lack roots, leaves even chlorophyll. Each individual plant produces male or female and scientists are not sure that either these plants pollinates or not. If pollinates then How?
Giant Flowering Plant (Corpse Flower)
Rafflesia arnoldii, this is the world’s nasty individual largest flowering plant. Commonly found in forests of Malaysia and Indonesia. It’s giant red-brown blossom is nearly 3.3 feet in diameter and weighs up to 24 pounds.
It smells like rotting flesh to attract the feeding flies as pollinators and its sticky fruit is spread by mice. This plant lacks leaves and obligate in nature. It steals nutrients from its neighboring vines Tetrastigma. This plant smells nasty.
Australian Christmas Tree (Nuytsia floribunda)
This is a tall, attractive flowering free. This is and elegant parasitic plant. Commonly found in southeast Australia. Nuytsia is equipped with green leaves. This plant can photosynthesize his own food. But steals water from its neighboring plants.
Facultative in nature. Australian Christmas tree has maintained a diverse network of roots to obtain water from neighboring plants. Haustoria are penetrated in the conductive system of other plants. Haustoria are equipped with guillotine like structure. So, these can even break underground fiber optic cables.
So, all these parasitic plants are nasty in nature and they feed on other plants. There are lots of forests which are covered entirely with such plants. Parasitic plants are also found in aquatic setup. These plants have developed themselves in a complex way. It will take time to understand their complexity.
Authors: Hammad Ur Rehman Bajwa, Muhammad Kasib Khan, Zaheer Abbas, Arsalan Zafar, Muhammad Uzair Asghar
Department of Parasitology, University of Agriculture, Faisalabad Pakistan