We are familiar with the parasitic phenomena in the animal kingdom, but in the plant world, parasitic is also ubiquitous, and parasitic plants are generally considered to be harmful to the host. So why are they parasitic? How is it parasitic?
In fact, the reason why parasitic plants are parasitic on other plants is also forced to survive. Due to the lack of sufficient chloroplasts, the roots or leaf organs of parasitic plants degenerate, lose their autotrophic capacity, and cannot survive independently. They have to adhere to other plants. All parasitic plants have a special organ, which is the sucker. The parasitic plant forms a connection with the host’s vascular bundle tissue through the suction device, and obtains the nutrient, moisture and other substances required for growth from the host, resulting in a large loss of the host nutrient, which seriously affects the growth and reproduction of the host.
There are many kinds of parasitic plants. According to their relationship with the host, the parasitic characteristics and the presence or absence of chlorophyll determine the dependence of the parasitic plants on the host, the parasitic plants can be simply divided into parasitic plants and semi-parasitic plants. No chlorophyll, can not independently assimilate carbon and nitrogen, no leaf or leaf degradation, no photosynthesis, its conduit and screen are respectively connected with the host plant xylem duct and phloem screen, completely relying on the host to provide nutrition is called full parasitic Plants, such as the genus Cymbidium, the genus Corydalis, and the plants of the genus Lepidoptera; and those that contain chlorophyll, which are capable of photosynthesis, are called semi-parasitic plants, such as the genus Mulberry, the genus Aspergillus, and the genus Sandalwood.
Under the same “house”, the “lazy and lazy” parasitic plants will cause no small harm to the host plants. The harmfulness of parasitic plants is mainly manifested by pathogenic effects. It has a strong parasitic pathogenic ability and is mainly parasitic on annual plants, which can cause the host plants to wilting, decline in viability, and cause large-scale death in severe cases, which has a great impact on yield. The semi-parasitic mainly parasitizes on perennial woody plants, and the initial stage of parasitization has no obvious effect on the host. When the late population is large, the host grows poorly and prematurely decays.
Studies have shown that under certain conditions, Dodder can help establish a “alliance” against insects between different hosts. A dodder can often be parasitic on multiple adjacent hosts at the same time, thereby connecting different hosts. The study found that Dodder and the host have extensive material exchanges. The same as the “telephone line” can allow different hosts to exchange information and play a “communication channel” when insects feed on a host. This host can generate a signal that not only triggers the insect resistance of the plant being fed, but also transmits it to other host plants through the dodder, which also enhances the insect resistance of these plants and establishes resistance between different hosts. The “alliance” of pest defense.