Vascular Systems in plants – an introduction to plant anatomy

Cells & Tissues. Organization intostructural entities.

Lycopodium

gnidiodes

PericycleEndodermis

primitive vascular plants

Lycopodium claviatum

primitive vascular plants

PROTOXYLEM

Psilotum has no leaves or roots!

PROTOXYLEM

PHLOEM

Detail of a cross section of the stem of Psilotum

primitive vascular plants

TRABECULA

XYLEMPHLOEM

Trabeculae are modified endodermal cells – pericycle surround vascular bundle.

primitive vascular plants

Rumohra

ENDODERMIS

PERICYCLE

PHLOEM

primitive vascular plants

FIBERS

PROTOPHLOEM

PHLOEM FIBERS

Encephalartos.Gymnosperm

PHLOEM

TRACHEIDS

RAY

CAMBIUM

PHLOEM

Araucaria (Gymnosperm)

INTERNAL PHLOEM

EXTERNAL PHLOEM

Cucurbita

Zea mays Monocotyledon.

(Atactostele) highly advanced

Nymphoides stem

Hydrophytes have a reduced Hydrophytes have a reduced xylem component in the xylem component in the vascular system. Here, only a vascular system. Here, only a few XYLEM VESSELS are few XYLEM VESSELS are visible. The phloem on the visible. The phloem on the other hand appears to be well-other hand appears to be well-developed, and consists of developed, and consists of sieve tubessieve tubes companion companion cellscells and and phloem phloem parenchymaparenchyma. I. I

Several ASTROSCLERIEDS can be seen interspersed with the ground parenchyma

Ligustrum (Privet) Leaf

Advanced foliage leaf, dicotyledon.Note mesophyll divided into upper palisade and lower spongy layer.Smaller veins (like these) are embedded within the mesophyll, between palisade and spongy layers.

These are MINOR veins

Zea mays leaf

The pine leaf

In Gymnosperm leaves such as the In Gymnosperm leaves such as the pine leaf, the vascular system is pine leaf, the vascular system is reduced to the central region. You reduced to the central region. You should be able to see two vascular should be able to see two vascular bundles in this example.bundles in this example.The xylem is composed of The xylem is composed of TRACHEIDSTRACHEIDS and the phloem of and the phloem of SIEVE CELLSSIEVE CELLS and and ALBUMINOUS ALBUMINOUS CELLS.CELLS.

vascular bundlecambium

endodermis

endodermis

sunken stomate