Plant Growth And Development

The formation of root nodules in leguminous plants is a multi-step process involving chemical signaling and physical changes in root tissues:
1. (d) The legume root releases flavonoids, sugars, and amino acids into the rhizosphere. These act as chemical signals to attract Rhizobium bacteria.
2. (b) In response, Rhizobium induces curling of root hairs, creating a trap for bacterial entry.
3. (a) Infection threads are formed — tubular structures through which bacteria enter into the plant root.
4. (e) The bacteria are then released into cortical cells from the infection thread.
5. (c) Finally, the plant stimulates cell division in the cortex and pericycle, leading to nodule formation.
This sequence ensures successful colonization and symbiotic nitrogen fixation.

Step 1: Understand the Purpose of a Herbarium Sheet

A herbarium sheet is a preserved plant specimen that is dried, pressed, and mounted on a sheet of paper. It is primarily used for:

• Scientific study
• Documentation
• Future reference and species verification

Each herbarium sheet includes a label that provides essential data about the specimen.

Step 2: What a Herbarium Label Typically Includes

The following information is usually recorded:

• Date of collection: When the specimen was gathered.
• Place of collection: Specific locality details (e.g., forest, latitude/longitude, altitude).
• Common name: The plant’s locally known name, if applicable.
• Family of the plant: Its taxonomic grouping (e.g., Rosaceae, Poaceae).
• Collector’s name: The botanist or individual who collected the specimen.

Step 3: Conclusion

Option (3) — Date, place of collection, common name and family of the plant, and collector’s name — includes all the essential data points typically found on a herbarium sheet label.

✅ Correct Answer: (3)