BOT2601
ASSIGNMENT 2 SEMESTER 2 2025
UNIQUE NO. 158633
DUE DATE: 12 SEPTEMBER 2025
, Plant Anatomy, Structure and Function
QUESTION 1
1.1 Structure and function of the cuticle
The cuticle is a thin, waxy, and non-cellular layer secreted by the epidermal cells of
aerial plant parts. Structurally, it is made up of cutin, cuticular waxes, and occasionally
cutan, forming a hydrophobic barrier. The cuticle covers the epidermis of leaves, young
stems, fruits, and other exposed organs. Its primary function is to reduce excessive
water loss through transpiration. It also provides mechanical protection against physical
damage, prevents pathogen entry, reflects harmful ultraviolet radiation, and protects
internal tissues from air pollutants and chemical injury.
1.2 Non-glandular trichomes
Non-glandular trichomes are simple, hair-like outgrowths of the epidermal cells. They
can be unicellular or multicellular, unbranched or branched, and often appear as thin
projections. Unlike glandular trichomes, they do not secrete substances. Their functions
include reflecting excess light, reducing leaf temperature, creating a still-air boundary
layer to minimize transpiration, and providing a mechanical barrier against herbivores
and insects. In some species, non-glandular trichomes also aid in water absorption from
dew or mist.
1.3 The “typical” Kranz anatomy
Kranz anatomy refers to the specialized leaf structure in C4 plants. In this arrangement,
vascular bundles are surrounded by large, chloroplast-rich bundle sheath cells, which in
turn are encircled by mesophyll cells. The two types of cells are connected by
plasmodesmata, ensuring efficient metabolite transfer. This structure separates the
initial carbon fixation in mesophyll cells (into oxaloacetate via PEP carboxylase) from
the Calvin cycle in the bundle sheath cells, thereby minimizing photorespiration. The
ASSIGNMENT 2 SEMESTER 2 2025
UNIQUE NO. 158633
DUE DATE: 12 SEPTEMBER 2025
, Plant Anatomy, Structure and Function
QUESTION 1
1.1 Structure and function of the cuticle
The cuticle is a thin, waxy, and non-cellular layer secreted by the epidermal cells of
aerial plant parts. Structurally, it is made up of cutin, cuticular waxes, and occasionally
cutan, forming a hydrophobic barrier. The cuticle covers the epidermis of leaves, young
stems, fruits, and other exposed organs. Its primary function is to reduce excessive
water loss through transpiration. It also provides mechanical protection against physical
damage, prevents pathogen entry, reflects harmful ultraviolet radiation, and protects
internal tissues from air pollutants and chemical injury.
1.2 Non-glandular trichomes
Non-glandular trichomes are simple, hair-like outgrowths of the epidermal cells. They
can be unicellular or multicellular, unbranched or branched, and often appear as thin
projections. Unlike glandular trichomes, they do not secrete substances. Their functions
include reflecting excess light, reducing leaf temperature, creating a still-air boundary
layer to minimize transpiration, and providing a mechanical barrier against herbivores
and insects. In some species, non-glandular trichomes also aid in water absorption from
dew or mist.
1.3 The “typical” Kranz anatomy
Kranz anatomy refers to the specialized leaf structure in C4 plants. In this arrangement,
vascular bundles are surrounded by large, chloroplast-rich bundle sheath cells, which in
turn are encircled by mesophyll cells. The two types of cells are connected by
plasmodesmata, ensuring efficient metabolite transfer. This structure separates the
initial carbon fixation in mesophyll cells (into oxaloacetate via PEP carboxylase) from
the Calvin cycle in the bundle sheath cells, thereby minimizing photorespiration. The
