Plant Pathology : Plant pathology is the branch of botany which deals with the nature of plant diseases, their diagnosis, treatment, prevention and control.Another name of plant pathology is phytopathology.Classification of plant diseasesA disease is a harmful deviation from a normal functioning of physiological process. Following are the basis of the classification of plant diseases.Pathogen […]
Viruses : Viruses are very minute, acellular and ultramicroscopic particles consisting of one or more molecules of either DNA or RNA but not both, enclosed in a coat of protein.Viruses can live and multiply only in the host cells.Virology : The branch of science which deals with the study of viruses is called virology. Types
Bacteria : Bacteria are unicellular, minute, microscopic organisms. Bacteria were first observed by Anton van Leeuwanhoek in 1675.Occurence : Bacteria are found in soil, atmosphere or inside the living organisms. They are also found in deep sea water, water springs, and ice.Size : Majority of bacteria are in the range of 0.5 to 50 microns.
Microbiology : It is that branch of science which deals with the micro-organisms. These organisms can not be seen with the naked eyes.Microbiology includes the study of bacteria, viruses, yeasts moulds, microalgae, protozoa etc.Germ theory of diseases : This theory tells that all the contagious diseases are caused by micro-organisms. Branches of MicrobiologyMedical Microbiology :
Classification of plant kingdom can be dealt with as follows—Systematics : This deals with the study of diversity of organisms at all levels of organisation. It deals from cellular to population level.Taxon : Taxon is the unit of classification. The taxon includes species, genus family, order, series, class and division.Species : It is a group
Tissues called apical meristems are responsible for the growth of the plants. The primary structure to the plant body is given by apical meristems. These tissues increase the thickness of stems and roots. They also increase the height and weight of the plant. This growth in thickness is called secondary growth. This type of growth
Primary Dicot RootEpidermis : It is a protective layer. In it cuticle and stomata are absent.Exodermis : Its cells prevent the exit of water from the root.CortexGeneral Cortex : It is parenchymatous and keeps the food stored.Endodermis : It has casparian bands on radial walls and cells help in movement of water and salts from
Tissue : A tissue is defined as a group of similar cells which carry or help to carry a common function and has a common origin.Tissues are of two types—1. Meristematic tissue.2. Permanent tissue.Various types of tissues combine to form complex plant organs. These organs are roots, stem, fruits, flowers and leaves.1. Meristematic Tissue :
Taxonomy is an important branch of botany. It deals with the study of morphology, cytology, genetics, physiology etc. in botany. It also deals with the identification nomenclature and classification of plants.In taxonomy description of morphological characters are given.Aims of TaxonomyAims of taxonomy are—(a) It gives worlds flora through identification and description.(b) Taxonomy gives method of
Dispersal of seeds means how fruits and seeds disperse to distant places. Dispersal is very much essential for the new plants to grow. If they do not disperse, they will directly fall below the plant and germinate. New plants will grow below the mother plant. Due to this they will not get food and population
Fruit : After fertilization the ovary begins to develop into a fruit and the ovules inside the ovary develop into seeds. Such a fertilized, developed and ripened ovary is called a fruit.ParthenocarpyIn parthenocarpy unfertilized ovary develops into a fruit. Such type of fruits do not have seeds.Parthenocarpic fruits are of three types—(a) Genetic parthenocarpy :
The branch of science which deals with the development of embryo from zygote is called embryology.The sporophyte and gametophyte are two stages in the plant kingdom.Sporophyte : This is deploid stage. It is developed from zygote. Both the vegetative and reproductive organs (flowers) develop on this plant.Gametophyte : This is reduced haploid stage. The pollen
Pollination : Pollination is defined as the process of transfer of pollens from the stamens to the stigma. The flower may be same or different.Direct Pollination : It occurs in Gymnosperms where ovules are naked. The pollen grains fall directly on the ovule. This is called direct pollination.Indirect pollination : It occurs in angiosperms where
Flower : Flower is an important shoot meant for sexual reproduction. In a flower there are sepals, petals, stamens and carpels the four types of floral leaves. Sepals and petals are floral leaves. These are non-essential organs. Stemens and carpels are ‘essential’ organs.Parts of a FlowerA typical flower consists of four parts. These are (a)
Inflorescence : The mode of production of flowers on the peduncle is called inflorscence.Peduncle : The main axis that get flowers and helps in reproduction is called peduncle.Pedicels : In this the flowers are attached to the peduncle with their stalks are called pedicels.Sessile : The sessile are the flowers in which pedicels are absent.Terminal