Page 12 - Lesson Notes-Morphologyof flowering plant

Modification of Leaves
Leaves of plants are modified to perform different additional functions in addition to
their main function, i.e., photosynthesis.
i. Leaf Tendrils
These are thread-like sensitive structures, which can coil around a support to help
the plant in climbing, e.g, Wild pea (Lathyrus aphaca), Pisum sativum (sweet pea)
and Gloriosa superba (glory lily). ”
ii. Phyllode
It is a green, short lived and flattened petiole or rachis of a leaf, which performs the
function of photosynthesis, e.g, Australian Acacia. Phyilodes develop usually
vertically and possess fewer stomata hence, reduce transpiration.
iii. Bladder
The segments of the leaf modify into bladder-like structures, which trap small
insects present in the water. e.g., Bladderwort (Utricularia).
iv. Pitcher
It is a petiole modified into a tendril to hold the pitcher upright. The leaf base is
expanded to carry out photosynthesis. The leaf apex is modified into a lid, e.g,
Nepenthes, Dischidia and Sarracenia.
v. Leaf Spines
The entire leaf or a part of a leaf may be modified into a pointed structure called a
spine, as in Opuntia.
vi. Scale Leaves
These are thin, membranous leaves found at the nodal region. Each scale leaf
contains an axillary bud in its axil, e.g, Zingiber officinale (ginger).