Leaf AnatomyLeaf Anatomy

Cross Section of a LeafCross Section of a Leaf

Leaf TissuesLeaf Tissues

A leaf is considered a plant organ and typically consists of the following tissues:

An epidermis that covers the upper and lower surfaces An interior parenchyma called the mesophyll An arrangement of veins (the vascular tissue).

EpidermisEpidermisThe epidermis is the outer one- or multi-layered group of cells covering the leaf. The epidermis has several functions: - protection against water loss (a vaxy cuticle)- regulation of gas and water vapor exchange( )stomata- secretion of metabolic compounds- absorption of water (in some species) .

A multi-layered epidermis

MesophyllMesophyll

means "middle of the leaf", i.e. the tissues of a leaf that are located in between the layers of epidermis and carry on photosynthesis.

The mesophyll of the leaf consists of parenchyma tissue. Since the mesophyll cells contain chloroplasts the tissue is also referred to as chlorenchyma .

Chlorenchyma cell

Functions of the MesophyllFunctions of the MesophyllIn most dicot leaves the mesophyll is differentiated into palisade parenchyma (A) and spongy parenchyma (B).

The palisade cells are responsible for photosynthesis because they contain chloroplasts.

The spongy mesophyll, together with the intercellular air spaces, allow for the interchange of gases

Vascular TissueVascular TissueVascular tissue is a complex tissue. The primary components of vascular tissue

are the xylem and phloem. These two tissues transport fluid and nutrients.

Vascular tissue is organized into discrete strands called vascular bundles.

Cross Section of Papyrus LeafCross Section of Papyrus Leafe epidermis

bb bulliform cells(they cause the leaf to roll up in response to low water availability )

skl sclerenchyma

cs vascular bundle

Clivia leaf cross section Clivia leaf cross section

silná kutikula, ztlustlá epidermis The epidermis has a thick cuticle.

European Yew (Taxus baccata)European Yew (Taxus baccata)Cross Section of a NeedleCross Section of a Needle

X – xylemf - phloemskl – sclerenchymae – epidermisku – cuticleka – cambium

pp – palisade parenchyma

hp – spongy parenchyma

Rubber fig (Ficus elastica)Rubber fig (Ficus elastica)Cross Section of a LeafCross Section of a Leaf

pp - palisade parenchyma hp - spongy parenchymae - epidermis ku - cuticlecs - vascular bundle st - stoma

ResourcesResourcesInternet:

http://www.ueb.cas.cz/laboratory_of_pollen_biology/pdf_subor/anatomie_list.pdf

http://cs.wikipedia.org/wiki/List#Anatomick.C3.A1_stavba_listu

http://botany.upol.cz/atlasy/anatomie/anatomieCR28.pdf

commons.wikimedia.org

http://www.uri.edu/cels/bio/plant_anatomy/

www. sci. muni. cz/ ~anatomy/ leaves/ html/ papyrus_1. htm

ThankThankss for for your your attentionattention

Lenka RydvalovaLenka Rydvalova