Q1. Which of the following statements about epiphytes is correct?
- They are total parasites on host plants
- They kill the host plant to survive
- They use the host for support but not nutrition
- They grow underground
Correct Option: 3. They use the host for support but not nutrition
Explanation: Epiphytes are non-parasitic plants that grow on the surfaces of other plants, mainly trees. They use the host only for physical support to access sunlight, without taking any nutrients from it. Their roots are adapted to absorb moisture from the air and rainfall, not from the host plant. Examples include orchids and ferns. In contrast to parasites, epiphytes do not harm the host plant directly.
Q2. Which of these plants is used in local medicine for treating cholera and urinary disorders?
- Drosera
- Pinguicula
- Nepenthes
- Blumea
Correct Option: 3. Nepenthes
Explanation: The Nepenthes plant, besides being insectivorous, has important ethnomedicinal uses. In traditional medicine, the liquid inside the pitcher is used to treat cholera, urinary tract infections, and as eye drops. The plant is commonly found in the northeastern hill regions of India, particularly in Meghalaya. Its medicinal properties, however, have led to over-harvesting, which is a threat to its conservation.
Q3. What abiotic factor is responsible for the death of sal seedlings due to increased transpiration and frozen roots?
- Frost
- Snow
- High temperature
- Ultraviolet light
Correct Option: 1. Frost
Explanation: Frost occurs when the temperature drops below freezing, leading to the freezing of soil moisture. In this condition, plant roots cannot absorb water, even though the surrounding air may warm up in the morning. As transpiration increases with the sunlight, plants like Sal seedlings die due to water stress and cell dehydration. Frost also causes ice crystal formation, damaging cell walls and leading to tissue death.
Q4. Which of the following invasive alien flora is common in degraded lands and along railway tracks in India?
- Goat Weed
- Calotropis
- Blumea eriantha
- Needle Bush
Correct Option: 3. Blumea eriantha
Explanation: Blumea eriantha is a fast-growing, aggressive colonizer found commonly in degraded forest areas, along railway lines, and roadsides. Native to tropical America, it has spread throughout India. Like other invasive alien species, it competes with native vegetation, reducing biodiversity and altering ecosystem functions. Its seeds spread quickly, and it thrives in disturbed areas.
Q5. What is ‘Dieback’ in plant ecology?
- Growth of plants from the root only
- Sudden blooming and death of plants
- Backward death of branches due to pathogens
- Progressive death of shoot from the tip backward
Correct Option: 4. Progressive death of shoot from the tip backward
Explanation: Dieback is a phenomenon where the shoot or branches of a plant die progressively from the tip backward. This can occur due to drought, frost, fungal infections, or lack of light. It is also a survival mechanism in some species like Sal, Red Sanders, and Terminalia tomentosa, where the roots remain alive, and shoots regenerate when conditions improve. It reflects a plant’s adaptive strategy in response to environmental stress.