Pollen–pistil interaction: path of the pollen tubeपराग-स्त्रीकेसर संकर्षण: पराग नलिका का मार्ग

NCERT Fig 1.12 · Class 12 Biology · Chapter 1 · interactive diagram

Parts and their functions

• Pollen grains on stigma (वर्तिकाग्र पर पराग कण) — Pollination lands pollen on the stigma. The pistil recognises it: compatible pollen is accepted; incompatible pollen (other species or self-pollen of a self-incompatible plant) is rejected.
• Stigma (वर्तिकाग्र) — Receives pollen; compatible pollen germinates here.
• Style (वर्तिका) — The pollen tube grows through the tissues of the stigma and style.
• Ovary (अंडाशय) — The pollen tube reaches the ovary, then enters an ovule.
• Ovule (बीजांड) — The pollen tube enters the ovule through the MICROPYLE.
• Embryo sac (भ्रूणकोश) — The tube enters one of the synergids through the filiform apparatus (which guides it).
• Pollen tube (पराग नलिका) — Grows out through a germ pore; the contents of the pollen grain move into it. If pollen was shed 2-celled, the generative cell divides into 2 male gametes while the tube grows in the stigma; 3-celled pollen carries both gametes from the start.
• Two male gametes (दो नर युग्मक) — Released into the synergid → double fertilisation follows.

Steps

1. Pollination: pollen grains land on the stigma; the pistil recognises compatible pollen.
2. Pollen germinates: a pollen tube comes out through a germ pore.
3. The tube grows down through the stigma and style.
4. It reaches the ovary and enters the ovule through the micropyle.
5. Guided by the filiform apparatus it enters a synergid and releases 2 male gametes. (Pollen deposition → tube entering the ovule = pollen–pistil interaction.)

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 1.12. Report a mistake