How do the various leaf modifications help plants?
The benefits of the different modification of the leaves in plants are:
(a) Tendrils: Tendrils are found in pea plant and help the plant in climbing.
(b) Spines: The leaves in cactus are modified into sharp spines that protect the plant and act as a defence organ.
(c) Storage: The leaves of onion become fleshy and help in the storage of food in plants. 
(d) Phyllode - The leaves of some Australian acacia are short-lived and soon replaced by flattened, green structures called phyllodes that arise from the petiole of the leaves. The petioles in these plants synthesize food.
(e) Pitcher - The leaves of the insectivorous plants like pitcher plant are modified into pitcher-like structures, which contain digestive juices and help in trapping and digesting insects.
