Total and Partial Root & Stem Parasites

Parasites can be classified into two categories :
(i) Total parasites. (ii) Semiparasites or partial parasites.
(i) Total parasites : These plants never possess chlorophyll, hence they always obtain their food
from the host. They may be attached to branches, stem (stem parasites) or roots (root parasites) of
the host plants. Total stem parasite: Cuscuta is a rootless, yellow coloured, slender stem with small
scale leaves, which twines around the host. The parasite develops haustoria (Small adventitious
sucking roots) which enter the host plant forming contact with xylem and phloem of the host. It
absorbs prepared food, water and minerals from the host plant. Total root parasite: Total root
parasites are common in the families like Orobanchaceae, Rafflesiaceae, Balanophoraceae,
etc. Orobanche, Rafflesia and Balanophora are some of the common root parasites. Orobanche is
commonly known as broom rape. It has scale leaves and pinkish or bluish flowers. The tip of the
root of parasite makes haustorial contact with the root of host and absorbs food from the
host. Orobanche is usually parasitic upon brinjal, tobacco. In Rafflesia (stinking corpse lily) another
root parasite, vegetative parts of the plant are highly reduced and represented by cellular filaments
resembling fungal mycelium. These filaments get embedded in the soft tissue of the host while the
flowers emerge out in the forms of buds. Balanophora occurs as a total stem parasite in the roots of
forest trees.
(ii) Semiparasite or partial parasite: Such parasitic plants have chlorophyll and, therefore,
synthesize their organic food themselves. But they fulfill their mineral and water requirements
from their host plants. These are two types : Partial stem parasites : The well known example of
partial stem parasite is Viscum album (mistletoe) which parasitizes a number of shrubs and trees.
The mature plant of Viscum is dichotomously branched with green leaves born in pairs attached on
each node of stem. The shoots are attached to the host by means of haustoria. The primary
haustoria reaches upto cortex of the host which runs logitudinally. It sends secondary haustoria
which make connection with the xylem of the host and absorb water and minerals Loranthus is
another partial stem parasite. Partial root parasites: The common example of partial (semi-
parasite) root parasite is Santalum album (Sandal wood tree) which is an evergreen partial root
parasite which grows in South India. It grows on the roots of Dalbergia sisso, Eucalyptus. Like other
partial parasites, it also has green leaves and absorbs only minerals and water from the host plants.
Similarly, Striga on roots of sugarcane and Thesium on the roots of grasses are other partial root
parasites.




ALL the Videos Lectures on Angiosperm Plant families for M.Sc. Botany Entrance Exam:
1. M.Sc. Botany Entrance | Angiosperm Families (Ranunculaceae, Nymphaeaceae,
Nelumbonaceae, Magnoliaceae, Annonaceae) | Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
2. M.Sc. Botany Entrance | Angiosperm Families (Papaveraceae, Brassicaceae also known as
Cruciferae, Caryophyllaceae and Malvaceae) | Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
3. M.Sc. Botany Entrance | Angiosperm Families (Dipterocarpaceae, Rutaceae, Meliaceae) |
Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
4. M.Sc. Botany Entrance | Angiosperm Families (Fabaceae and Rosaceae) | Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
5. M.Sc. Botany Entrance | Angiosperm Families (Myrtaceae and Lythraceae) | Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
6. M.Sc. Botany Entrance | Angiosperm Families (Cucurbitaceae, Cactaceae & Apiaceae=
Umbelliferae) | Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
7. M.Sc. Botany Entrance | Angiosperm Families (Rubiaceae and Asteraceae= Compositae) |
Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
8. M.Sc. Botany Entrance | Angiosperm Families (Apocynaceae and Asclepiadaceae) |
Important Notes:    • M.Sc. Botany Entrance | Angiosperm Fa...  
9. M.Sc. Botany Entrance | Angiosperm Families (Solanaceae and Convolvulaceae) | Important
Notes:    • M.Sc. Botany Entrance | Angiosperm Fa...  
10. M.Sc. Botany Entrance | Angiosperm Families (Scrophulariaceae and Acanthaceae) |
Important Notes:
   • M.Sc. Botany Entrance | Angiosperm Fa...  
11. M.Sc. Botany Entrance | Angiosperm Families (Lamiaceae and Verbenaceae) | Important
Notes:    • Lamiaceae & Verbenaceae | M.Sc. Botan...  
12. M.Sc. Botany Entrance | Angiosperm Families (Amaranthaceae, Chenopodiaceae and
Polygonaceae) | Important Notes:    • M.Sc. Botany Entrance | Angiosperm Fa...  
13. M.Sc. Botany Entrance | Angiosperm Families (Euphorbiaceae and Moraceae) | Important
Notes:    • Euphorbiaceae & Moraceae | M.Sc. Bota...  
14. M.Sc. Botany Entrance | Angiosperm Families (Orchidaceae and Liliaceae) | Important
Notes:
   • Orchidaceae and Liliaceae | M.Sc. Bot...  
15. M.Sc. Botany Entrance | Angiosperm Families (Iridaceae, Musaceae and Zingiberaeae) |
Important Notes:    • M.Sc. Botany Entrance | Angiosperm Fa...