Root Structure of Rice Parasitized by Striga hermonthica

Root Structure

• Striga hermonthica is a parasite that attacks rice roots
• The haustorium of S. hermonthica penetrates the rice root, with the parasite xylem (Px) and host xylem (Hx) visible in a cross-section
• The hyaline body (HB) and cortical parenchyma (COR) are also present in the interface between the haustorium and the host root
• Tomato roots exhibit secondary growth

Stem Structure

• Aerial stems are above-ground stems that grow upwards
• Underground stems are below-ground stems that grow horizontally
• Stems can be modified to perform specialized functions, such as:
  • Stem tendrils: slender, thread-like structures that help in climbing and support
  • Twining stems: stems that wrap around a support in a helical manner to climb
  • Rhizomes: underground stems that grow horizontally and have nodes, buds, or scale-like leaves
  • Corms: short, swollen underground stems
  • Bulbs: underground stems with a bud enclosed by fleshy scale leaves and/or leaf bases
  • Tubers: thickened branches of underground stems with leaves/leaf scars and axillary buds

Modified Stems

• Cladodes: green, flattened or cylindrical, thick, succulent modified main stems that serve as photosynthetic and storage organs
• Hooks: plant stems modified to form hooks
• Prickles: sharp outgrowths from the epidermis of a stem
• Thorny stems: short, pointy woody structures derived from reduced branches
• Stolons/Runners: vegetative shoots that spread along the surface of the ground and root at the nodes, giving rise to new plantlets

This quiz covers the root structure of rice plants affected by the parasitic plant Striga hermonthica, including the anatomy of the haustorium and its interaction with the host root.