Plant Morphology Chapter 2

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Questions and Answers

What does plant morphology focus on?

The evolution of plant species

The chemical composition of plant tissues

The physical forms and external structure of plants (correct)

The internal structure of plants

Which family do grasses belong to?

Rosaceae

Gramineae (Poaceae) (correct)

Asteraceae

Fabaceae

Which type of root system is first formed during grass seed germination?

Fibrous root system

Primary root system (correct)

Tap root system

Secondary root system

What best characterizes the root system of mature grasses?

A fibrous and extensively branched structure Signup and view all the answers

Which of the following is NOT a member of the grass family?

Tomato Signup and view all the answers

What is a feature of the leaves of monocotyledonous plants like grasses?

Parallel venation Signup and view all the answers

How are cultural management practices related to morphological features of crops?

Cultural practices are influenced by the morphological features of crops. Signup and view all the answers

What characteristic of grasses makes them important as food sources?

Their numerous species and high nutritional value Signup and view all the answers

What is the correct term for the young primary root of grasses?

Radicle Signup and view all the answers

Which part connects the primary root system to the secondary root system in grasses?

Mesocotyl Signup and view all the answers

Which of the following is a characteristic of the leaf sheath in grasses?

It encircles the culm and protects growing points. Signup and view all the answers

What type of inflorescence consists of spikelets that are sessile on a rachis?

Spike Signup and view all the answers

Which structure serves as the junction between the leaf blade and the leaf sheath?

Ligule Signup and view all the answers

What is a function of the brace roots in grasses?

Provide structural support Signup and view all the answers

Which part of the grass leaf is usually more prominent than other veins?

Midrib vein Signup and view all the answers

What is the name for the specialized roots that arise from the nodes above ground?

Aerial roots Signup and view all the answers

Which term describes the parts of a grass inflorescence that are loosely branched and bear spikelets on pedicels?

Panicle Signup and view all the answers

What is the importance of the collar in grass leaves?

It distinguishes textures and colors at sheath junction. Signup and view all the answers

Study Notes

Plant Morphology/Phytomorphology

Focuses on the physical forms and external structures of plants, distinct from anatomy.
Aids in visual identification and classification of plant species.
Similar morphological forms indicate closer taxonomic relationships.
Morphological features reflect plant responses to environmental stimuli and management practices.

Morphology of Grasses

Grasses belong to the Gramineae (Poaceae) family, with over 5000 species crucial for human and animal consumption.
Characterized by monocotyledonous traits: one seed-leaf, parallel leaf venation, and scattered vascular bundles.
Exhibit annual or perennial life cycles, primarily herbaceous with jointed stems and sheathed leaves.
Key examples include rice, corn, sorghum, and wheat.

Grass Plant Structure

Comprised of two primary systems: shoot system and root system.

Root System of Grasses

Fibrous Root System: Extensively branched roots of uniform size.
Primary Roots: Develop during germination to absorb nutrients but typically die as the plant matures.
Secondary Roots: Grow above the primary roots, functioning as the main absorption system as the plant matures.
Related terms:
- Radicle: The young primary root.
- Seminal Roots: Branches from the radicle.
- Mesocotyl: Connects primary and secondary roots.
- Brace/Prop/Aerial Roots: Arise from nodes above the ground for support.
- Crown: Transition point from root system to shoot system.
- Crown Roots: Emerge from the coleoptilar node.

Shoot System of Grasses

Comprises all above-ground plant parts: stems, leaves, and inflorescences (flowers and fruit clusters).

Stems

Consist of nodes (solid joints) and internodes (hollow cylindrical sections).
Nodes give rise to true leaves and can be identified by their solid structure.

Leaves

Two types: modified (coleoptile) and true leaves.
Coleoptile: Protective covering for true leaves before emergence.
True Leaves: Feature a leaf sheath and leaf blade; may include appendages.
- Leaf Sheath: Protects growing points and provides support.
- Leaf Blade: Flattened section, notable for a prominent midrib vein.
- Ligule: Membranous structure at the sheath-blade junction, prevents moisture entry.
- Collar: Distinct texture zone at the junction of blade and sheath.
- Auricles: Lobes extending from the leaf blade, may partially encircle the culm.
- Axillary Buds: Located in leaf axils; can develop into new culms.

Inflorescence Types in Grasses

Spike Type: Spikelets are directly attached to the main stem (rachis), as in wheat.
Panicle Type: Loosely branched; individual spikelets attached via pedicels, seen in rice, corn, and sorghum.
Raceme Type: A modified spike-like panicle with shorter peduncle rays, as in foxtail millet.

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Description

Explore the fundamentals of plant morphology in Chapter 2, where we delve into the physical forms and external structures of field crops. This quiz will help reinforce your understanding of how plant forms relate to their environmental responses and classification. Tackle key concepts to enhance your visual identification skills.