Leaf Venation
Definition:
Arrangement pattern of the veins of the leaf.
More about Leaf venation:
The fine lines present on the leaf are called ‘leaf veins’.
The single middle prominent vein is known as ‘mid rib’ or the primary vein.
The veins other than the primary vein are called ‘secondary veins’.
The leaf veins consists of vascular bundles that help in the transport of mineral nutrients and
water from the roots to the leaf and the materials produced in the leaf to the rest of the plant.
The pattern of leaf venation is important characteristic for the identification of plants.
The veins are present on either side of the mid rib in different fashion.
The secondary vein can create other pattern where they may or may not be parallel to each other.
The primary vein can be considered like a ‘tree trunk’ and the secondary vein as the branches of
the tree.
Leaf venation is basically of two types.
a) Reticulate venation:
In this type, the veins branch and unite forming a complicated network .
All the veins are interconnected, like the strands of the net.
Leaves of ‘Dicot plants’ generally have reticulate venation.
e.g., Hibiscus, Redgram,
b) Parallel venation:
In this type, the veins run parallel or nearly parallel to each other and are connected by
smaller veins.
Leaves of ‘Monocot plants’ generally have parallel venation.
e.g., Banana, Wheat
Diagram :
http://waynesword.palomar.edu/termlf1.htm
http://www.cactus-art.biz/note-book/Dictionary/Dictionary_V/dictionary_vein.htm
Video links:
http://www.youtube.com/watch?v=iBgzYmTPJYc
http://www.youtube.com/watch?v=JaCFdmKKFh0
http://www.youtube.com/watch?v=OxQka2Bai7M at 2:40 to 3:00
http://www.youtube.com/watch?v=swLVNljDS64
http://www.youtube.com/watch?v=WFAFtkDZO-4
Question based on Leaf Venation
1) What are the functions of the veins in the leaf?
Solution:
The veins of the leaf consist of the vascular bundles such as xylem and phloem.
These vascular bundles help in the transport of the nutrient and water to the leaf and the
materials produced in the leaf to various parts of the plant.
Moreover, the pattern in which these veins are arranged is of botanical importance, as it
an important characteristic for the identification of plant.
2) Most of the Dicotyledonous plants have Reticulate venation.
a) True
b) False
Solution: (a) Generally, most of the Dicotyledonous plants have Reticulate venation and
monocots have parallel venation.