Grass Plant Structure and Functions Quiz

Objectives

• Students should be able to identify the vegetative and reproductive parts of grass.
• Students should be able to explain the functions of the different parts of the grass.

Structure of the Grass Plant

• The grass plant has various parts including: inflorescence, internode, stolon, roots, rhizome, spikelet, peduncle, leaf blade, leaf sheath, and node.

Vegetative Parts

• Root system: Anchors the plant, absorbs water and nutrients, stores reserve nutrients. Roots can grow up to 2 meters deep and wide in sandy soil. Hard soils restrict nutrient and water access to plants.
• Stolons: Runners growing above ground that root at each node. Stolons produce green leaves at their nodes.
• Rhizomes: Runners growing below ground that root at each node. Rhizomes produce small, brown, scale-like leaves at their nodes.
• Culms: Upright stems in the middle of a shoot. They are solid at the nodes and often hollow in the internode area. In some grasses, internodes are short until flowering. Culms range from unbranched to many-branched.
• Leaves: Elongated structure at the node consisting of leaf blade (lamina), leaf sheath, and ligule.
  • Leaf blade: Used for photosynthesis, longitudinal with parallel veins. Can be different lengths and breadths depending on the species and can be open, rolled, or folded.
  • Leaf sheath: Modified leaf base originating at the node encloses the internode, strengthening the culm and protecting the internode’s growth zone.
  • Ligule: Found between the leaf blade and leaf sheath, against the culm. Its function is uncertain but thought to prevent water, insects and other organisms from entering the sheath. Ligule types are useful for identification within a genus. Some grasses lack ligules. Ligules can be a membrane, a ring of hairs, or a membrane with a hairy margin.

Reproductive Parts

• Inflorescence (Flower head): Flowering portion of the plant, including all structures above the last leaf of the culm or base. Consists of numerous spikelets arranged on branches or the main axis.
• Spikelets: Flower-bearing parts of the plant, that produce seeds and disperse them. They have a uniform structure within a genus, therefore are useful in identifying grasses at the genus level. Vary in form but two main groups can be distinguished: 1) single floret, 2) numerous florets.
• Types of Inflorescence:
  • Spike: A group of flowers arising from the main stem without individual stalks (sessile)
  • Raceme: A flower spike where flowers have stalks of equal length, and the tip of the stem continues growing and producing more flowers.
  • Panicle: A branched inflorescence with a primary (central) axis that gives rise to branched secondary axes.
  • Types of Panicles: True panicles (branched inflorescences with racemes or groups of racemes and various spathes), False panicles(branching inflorescences), Digitate panicles (two or more branches arising from almost the same point).
  • Kikuyu Grass: The only grass with no visible inflorescence.

Test your knowledge on the vegetative and reproductive parts of grass plants. This quiz will help you identify key structures such as roots, stolons, and rhizomes, as well as their functions. Perfect for students studying botany or plant biology.