Differentiate between apocarpous and syncarpous ovary.

1. Morphology:

(Greek, morphe-form; logos-study) is the branch of biological science that deals with the study of form, size, colour, structure, and relative position of various parts of organisms.

2. Need to study morphology:

(i) Essential for recognition and identification of plants (anatomy).

(ii) Provides information on variations found amongst species (genetics).

(iii) Required for classification of plants (taxonomy).

(iv) Used by horticulturists to make gardens, lawns, and parks (peculiar plants).

(v) Ecological adaptations can be studied.

(vi) Morphological changes due to deficiency and toxicity symptoms can be studied.

Angiosperms are the only flowering plants of the plant kingdom showing large differences in their morphological segments-roots, stem and leaves.

4. The Root:

(i) The root is the underground descending non-green portion of the plant axis which develops from the radicle.

(ii) Roots do not have nodes and internodes. They do not bear leaves, buds, or reproductive organs.

(iii) Root apex is protected by a root cap.

(iv) Roots are negatively phototropic, positively geotropic, and positively hydrotropic.

(v) Roots are the anchorage organs that help in the fixation of plants into the soil.

(vi) Morphological variations in roots help them to carry out diverse functions.

(vii) The roots arising from the radicle are called tap roots, and those arising from any part other than the radicle are adventitious roots.

5. The Stem:

(i) The shoot system or the stem is the main ascending axis of the plant. It develops from the plumule of the embryo. In flowering plants, it bears leaves, branches, flowers, and fruits. It has nodes and internodes, even if it happens to be an underground stem.

(ii) The stem is negatively geotropic and positively phototropic.

(iii) The stem apex bears a terminal bud. The stem apex is always apical in position.

(iv) The stem is differentiated into nodes and internodes.

(v) Leaves and branches arise at the nodes on the stem.

(vi) The underground stems of potatoes, ginger, turmeric, etc., are modified to store food in them.

(vii) Stem tendrils help the plants in climbing as in cucurbits.

(viii) Thorns are modified forms of axillary buds and act as protective organs, e.g., Citrus, Bougainvillea.

(ix) Phylloclade is a stem modified to perform the function of a leaf in some xerophytic plants.

6. The Leaf:

(i) The leaf is a lateral, generally flattened structure borne on the stem. It is the main photosynthetic organ.

(ii) Leaf develops at the node and bears an axillary bud in its axil. It later develops into an axillary branch.

(iii) The arrangement of leaves on a stem is called phyllotaxy.

(iv) The arrangement of veins and the veinlets in the lamina of the leaf is termed venation.

(v) In dicots, the venation is reticulate, and in monocots, it is parallel.

(vi) Leaves are simple or compound. In a simple leaf, the lamina is entire, or when incised, the incisions do not touch the midrib.

(vii) Compound leaves are of two subtypes- Pinnate and Palmate compound leaves.

(viii) In pinnately compound leaves, a number of leaflets are present on a common axis called rachis. The rachis represents the midrib of the leaf as in neem.

(ix) In palmately compound leaves, the leaflets are attached at a common point, i.e., at the tip of the petiole as in silk cotton. In these leaves, the rachis is too condensed.

(x) Leaves are often modified to perform functions other than photosynthesis. They are converted into tendrils for climbing, as in peas or into spines for defence as in cacti.

7. The Flower:

(i) Flowers possess two accessory whorls, calyx and corolla, and two essential whorls, androecium and gynoecium.

(ii) Flowers exhibit enormous variations in the structure, symmetry, the position of the ovary in relation to other floral parts, arrangement of sepals, petals, ovules, etc.

(iii) Androecium is composed of stamens. The number of stamens varies greatly in different plants of the same family or of different families. These stamens are free or variously united.

(iv) Gynoecium can be composed of one or more than one carpel. The carpels may be fused (syncarpous) or free (apocarpous).

(v) The ovary is swollen basal part of the carpel and contains ovules.

(vi) Based on the position of the ovary on the thalamus, it can be superior, inferior, or semi-inferior.

(vii) The floral features are represented in a summarised form as a floral diagram and floral formula.

8. The Inflorescence:

(i) The arrangement of flowers on the floral axis is called inflorescence, which is of racemose and cymose types.

(ii) The arrangement of sepals and petals in a floral bud with respect to the members of the same whorl is called aestivation.

9. The Fruit:

(i) The occurrence of fruit is a characteristic feature of angiosperms.

(ii) The fruit is defined as a ripened ovary.

(iii) If any other part, such as the thalamus or receptacle matures into a fruit, it is called false fruit.

(iv) The fruits are of three kinds- simple, aggregate and composite (or multiple).

(v) Mango fruit is drupe in which mesocarp is fleshy and endocarp is stony hard.

(vi) Coconut fruit is also drupe where mesocarp is fibrous. The fibres are used as coir of commerce.

10. The Seed:

(i) The nutritive layer around the endosperm in cereals (maize) is called aleurone layer.

(ii) The dispersal of seeds and fruits has three agencies such as air (anemochory), water (hydrochory) and animals (zoochory).