Question

Mention the functions of each of the following: (i) Tassels of Corn Cob, (ii) Scutellum

Hint:

- Corn tassels are elongated stigmas/styles specialized for trapping wind pollen. - The scutellum is simply a modified, shield-shaped monocot cotyledon whose specialized job is to act as a nutrient transfer bridge.

Answer 1

Concept: This question spans two critical dimensions of plant biology: anemophilous (wind) pollination adaptations and monocotyledonous seed anatomy. Maize (Zea mays) represents a monoecious plant containing distinct male and female inflorescences on a single plant body. Understanding the precise physiological structures of its reproductive units and its resulting seed anatomy helps clarify how these plants reproduce and germinate successfully.

Step 1: Detailed Functional Analysis of (i) Tassels of Corn Cob.
In a maize plant, the individual flowers are unisexual. The male inflorescence is situated terminally at the apex of the main stem and is referred to as the tassel, whereas the female inflorescence forms lower down on axillary branches and develops into the corn cob.
• Anatomy Context: What are popularly observed as the long, silky, hair-like projections hanging loosely outside the mature corn cob are technically the highly elongated styles and stigmas of the female florets.
• Primary Function: The core function of these long, feathery, dangling structures is to wave dynamically in the wind currents. By extending far beyond the protective cover of the leafy bracts (husks), they provide a vast surface area to successfully capture and trap wind-borne pollen grains floating in the surrounding air. This adaptation ensures high efficiency in wind pollination (anemophily).

Step 2: Detailed Functional Analysis of (ii) Scutellum.
The mature caryopsis (grain/seed) of maize is monocotyledonous and endospermic. Within this specialized monocot seed structure, the single, large, shield-shaped cotyledon is specifically designated as the scutellum.
• Anatomical Positioning: The scutellum is positioned laterally, sandwiched closely between the massive, starch-storing endosperm tissue and the delicate embryonic axis (comprising the plumule and radicle).
• Primary Function: The primary function of the scutellum is nutrient absorption, digestion, and translocation:
• During active seed germination, the embryonic axis secretes specific plant hormones (such as gibberellins) that trigger the aleurone layer of the endosperm to synthesize hydrolytic enzymes like $\alpha$-amylase.
• These enzymes digest the insoluble complex starch reserves within the endosperm into soluble forms, such as maltose and glucose.
• The scutellum directly absorbs these liberated soluble nutrients from the endosperm and translocates them efficiently to the growing zones of the embryonic axis (the developing root and shoot tips), fueling early vegetative growth before the plant can photosynthesize.