Sunday, December 20, 2009

study of LEAF modifications-pharma-D-lab manual


AIM: tos tudy different types of modifications in leaf

Leaves can be modified to serve other functions:
The scales of many bulbs (e.g. daffodil) are leaves that serve as storage tissue.Scale leaves provide protection for buds and can be further modified for food storage to form a bulb
Tendrils (on pea, morning glory, etc.) are modified leaves that allow plants to vineTENDRILS support the stems of climbing plants.
Spines or thorns on some plants are modified forms of leaves that protect the plant from predation. SPINES function to protect the plant (eg. barberry).
BRACTS are leaves associated with flowers; they may be green or brightly colored and mistaken for petals.
Bud scales are modified leaves that protect dormant buds in perennial plants.

In some plants leaves are modified to form spines, which are had, dry, and nonphotosynthetic. The term “spine” and “thorn” are frequently used interchangeably, but technically thorns are modified branches that arise in the axil of leaves. Another term used incorrectly is prickle. A prickle is neither a stem nor a leave but a small, slender, sharp outgrowth from the cortex and epidermis of a stem. The so-called thorns on rose stems are prickles.

Tendrils are modified leaves that grow indefinitely, unlike normal leaves, and coil around objects they touch. This coiling is a growth response: when the tendril touches an object, the side facing the object stops growing while the other side continues to grow.

different types of leaf modifications were observed

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