morphology

• The description of the diverse forms of life on earth was made only by observation through naked eyes or later through magnifying lenses and microscopes.
• The description is mainly of gross structural features, both external and internal.
• Observable and perceivable living phenomena were also recorded as part of this description.
• Before experimental biology or more specifically, physiology, was established as a part of biology, naturalists described only biology.
• Biology remained as a natural history for a long time.
• Various types of placentations found in flowering plants have been described.
• The arrangement of floral members in relation to their insertion on thalamus has been described.
• A flower of the family Solanaceae has been chosen and its semi-technical description and floral diagram have been written.
• The parts of a typical angiosperm flower have been defined.
• The term inflorescence has been defined and its different types in flowering plants have been explained.
• The description, by itself, was amazing in terms of detail.
• The detailed description was utilised in the later day reductionist biology where living processes drew more attention from scientists than the description of life forms and their structure.
• The description of morphological and anatomical features is presented separately for plants and animals.
• Katherine Esau was born in Ukraine in 1898 and studied agriculture in Russia and Germany.
• Katherine Esau received her doctorate in 1931 in United States.
• Katherine Esau reported in her early publications that the curly top virus spreads through a plant via the food-conducting or phloem tissue.
• Dr Esau’s Plant Anatomy, published in 1954, took a dynamic, developmental approach designed to enhance one’s understanding of plant structure and had an enormous impact worldwide, literally bringing about a revival of the discipline.
• The Anatomy of Seed Plants by Katherine Esau was published in 1960 and was referred to as Webster’s of plant biology – it is encyclopediac.
• Katherine Esau was elected to the National Academy of Sciences in 1957 and received the National Medal of Science from President George Bush in 1989.
• Katherine Esau died in the year 1997 and Peter Raven, director of Anatomy and Morphology, Missouri Botanical Garden, remembered that she ‘absolutely dominated’ the field of plant biology even at the age of 99.
• The wide range in the structure of higher plants will never fail to fascinate us.
• Even though the angiosperms show such a large diversity in external structure or morphology, they are all characterised by presence of roots, stems, leaves, flowers and fruits.
• The main functions of the root system are absorption of water and minerals from the soil, providing a proper anchorage to the plant parts, storing reserve food material and synthesis of plant growth regulators.
• The stem bears nodes and internodes.
• In monocotyledonous plants, the primary root is short lived and is replaced by a large number of roots.
• The region of the stem where leaves are born are called nodes while internodes are the portions between two nodes.
• The stem is the ascending part of the axis bearing branches, leaves, flowers and fruits.
• The underground part of the flowering plant is the root system while the portion above the ground forms the shoot system.
• The primary roots and its branches constitute the morphology of flowering plants.
• Some stems perform the function of storage of food, support, protection and of vegetative propagation.
• These roots originate from the base of the stem and constitute the fibrous root system.
• In some plants, like grass, Monstera and the banyan tree, roots arise from parts of the plant other than the radicle and are called adventitious roots.
• In majority of the dicotyledonous plants, the direct elongation of the radicle leads to the formation of primary root which grows inside the soil.
• The stem conducts water, minerals and photosynthates.
• The root is covered at the apex by a thimble-like structure called the root cap which protects the tender apex of the root as it makes its way through the soil.
• The cells of the elongation zone gradually differentiate and mature, hence, this zone, proximal to region of meristematic activity, is called the region of maturation.
• From this region some of the epidermal cells form very fine and delicate, thread-like structures called root hairs which absorb water and minerals from the soil.
• The main function of the stem is spreading out branches bearing leaves, flowers and fruits.
• A few millimetres above the root cap is the region of meristematic activity where the cells are very small, thin-walled and with dense protoplasm.
• Stem is generally green when young and later often become woody and dark brown.