Question

Parkinsonia and Australian Acacia are examples of
A. Phylloclade
B. Winged fruit
C. Parachute mechanism
D. Phyllode

Answer 1

Hint: A green exogenous laterally flattened outgrowth present on the node of a stem or its branch is known as a leaf. It has the specialty to undergo photosynthesis. Leaves can be modified into leaf tendrils, leaf spines, phyllodes, leaflet hooks, leaf bladders, leaf pitchers, succulent leaves, scale leaves, coloured leaves, and floral organs.

Complete answer: Phylloclade is a modified branch and functions as a photosynthetic shoot.
A flattened wing of fibrous papery tissue develops from the ovary wall of some fruits. Such a fruit is known as a winged fruit.
-A structure called the pappus causes fruit and seed dispersal by the parachute mechanism.
-The bipinnate lamina is absent in many species of Acacia. Acacia is found in the deserts of Australia. In this case, the petiole and part of the rachis become flattened and develop into sickle-shaped structures. These structures play an important role in food synthesis. Thus, a phyllode is a flattened petiole that carries out the functions of the lamina. Transpiration is reduced by this type of modification because of its vertical position and due to the presence of fewer stomata. A few species of Acacia are A. longifolia, A. glaucescens, A. recurve, A. auriculiformis.
-In Parkinsonia, a spine is present at the end of the rachis. Rachis branches function as phyllodes by becoming elongated, flattened, and green. Though they have small leaflets, they fall off very early.
Thus, Parkinsonia and Australian Acacia are examples of D, i.e., Phyllode.

Note: Some important points are listed below:
1. Phyllodes function to serve the purpose of a leaf.
2. As these become flattened, the leaves vanish off altogether.
3. And they used to develop into sickle-shaped structures.