It is a parasitic plant that derives nutrients from a host.
Explanation
Cuscuta, commonly known as Amarbel or Dodder, is a classic example of a parasitic plant. Unlike the majority of plants which are autotrophic, Cuscuta lacks the physiological machinery required to synthesize its own food.
Detailed Analysis:
- It is an autotroph capable of photosynthesis. is Incorrect: Cuscuta does not possess chlorophyll, the green pigment required for photosynthesis. Consequently, it cannot synthesize its own food and is not an autotroph.
- It serves as a host for nitrogen-fixing bacteria. is Incorrect: Cuscuta acts as a parasite, not a host. It attaches itself to other plants to derive nutrition. Leguminous plants are typical examples of hosts that harbor nitrogen-fixing bacteria in their root nodules.
- It is a parasitic plant that derives nutrients from a host. is Correct: Cuscuta is a total stem parasite. It develops specialized root-like structures called haustoria. These structures penetrate the stem of the host plant to reach the vascular tissues (xylem and phloem), allowing Cuscuta to absorb ready-made nutrients and water directly from the host.
- It exhibits a symbiotic relationship with fungi. is Incorrect: A symbiotic relationship implies mutual benefit between organisms (e.g., Lichens or Mycorrhiza). The relationship between Cuscuta and its host is parasitic because Cuscuta benefits at the expense of the host, often weakening or killing it.
Key Takeaway:
Cuscuta (Amarbel) is a non-photosynthetic, total stem parasite that relies entirely on a host plant for nutrition, extracting nutrients through specialized structures called haustoria.