UPPSC 2023 Prelims GS Paper-I · Question 7 of 150

Correct — A, Nepenthes. Nepenthes, the tropical pitcher plant, is a carnivorous (insectivorous) plant whose leaf tip is modified into a jug-shaped 'pitcher' holding digestive fluid; insects that slip in are trapped and dissolved. Such plants grow in nitrogen-poor, boggy soils and digest insects to obtain the nitrogen the soil cannot supply — they still photosynthesise for energy.

• (b)Nelumbo — This is the lotus genus (e.g. Nelumbo nucifera, the sacred lotus) — an aquatic flowering plant, not carnivorous.
• (c)Nyctanthes — Nyctanthes arbor-tristis is the night-flowering jasmine (harsingar / parijat) — an ornamental shrub, not insectivorous.
• (d)Nicotiana — This is the tobacco genus (source of nicotine) — an ordinary crop plant that feeds from the soil, not insectivorous.

Insectivorous (carnivorous) plants supplement their nutrition by trapping and digesting insects. They typically grow on nitrogen-deficient soils (bogs, marshes) and use the insects as a nitrogen source, while still making their own food by photosynthesis. In Nepenthes the trapping organ is a modified leaf that forms the pitcher, with a lid and slippery, enzyme-filled interior.

The trap here is that all four options begin with 'N', so recognition rests on knowing the genera: Nelumbo (lotus), Nyctanthes (harsingar), Nicotiana (tobacco) are ordinary plants, while Nepenthes is the classic pitcher plant.

• Nepenthes traps insects using pitcher-shaped modified leaves that secrete digestive enzymes.
• Insectivorous plants trap insects for nitrogen (poor soils), not for energy — they still photosynthesise.
• Other carnivorous plants: Drosera (sundew), Utricularia (bladderwort), Dionaea (Venus flytrap).
• Nepenthes khasiana is India's only native pitcher plant, endemic to the Khasi hills of Meghalaya (endangered).

• Confusing Nelumbo (lotus) or Nicotiana (tobacco) with a carnivorous plant.
• Assuming insectivorous plants do not photosynthesise — they do; they trap insects only for nitrogen.

Straight 'which is an insectivorous/carnivorous plant', or 'which part of the pitcher plant is modified into the pitcher (the leaf)', or 'why are some plants insectivorous (nitrogen-poor soils)'.

• practice — not a real PYQ

  Insectivorous plants typically grow in soils deficient in:

  • (a)Nitrogen
  • (b)Carbon
  • (c)Oxygen
  • (d)Potassium

  Answer(a) Nitrogen — they trap insects to obtain nitrogen the soil lacks.

• practice — not a real PYQ

  In the pitcher plant (Nepenthes), the pitcher is a modification of the:

  • (a)Stem
  • (b)Root
  • (c)Leaf
  • (d)Flower

  Answer(c) Leaf — the lamina is modified into the pitcher.