Biological Spectrum -A table which shows the percentage frequency of occurrence of the various plants and animals in a defined area.

Bioluminescence - The enzymatic emission of light by living organisms, without their being previously illuminated. It is. exhibited DY some bacteria and fungi. It is wrongly called phosphorescence. The light is produced by the action of the enzyme luctiferase in oxidizing the ligh-producing molecule lutiferin.

Biomass - A mass of living material at a place at a time with in the frame of reference of study. For example, in the study of plant as an individual, biomass implies total mass of living material in that plant while in the study of as community, it implies total mass of all the living organisms included in that community.

Biome. A large community of plants and animals which has been characterized by its particular type of dominant vegetation and its associated animals, e.g., tundra.

Biometer - A method used of assessing the amount of life by meassuring the respiration, e.g., in a soil sample.

Biometry - The use of mathematics, especially statistics in the study of living organisms.

Bios Factor - A substance which is essential for the growth of plant, especially yeasts, obtained from the environment. It is a mixture of aneurin, biotin, and, other substances. Biotin means Vitamin H, and is probably identical to the co-enzyme R.

Bioseries. In evolution, a historical sequene which is formed by the changes in anyone inheritable character.

Biosphere - Used for a zone which includes earth's surface (and surface water) its atmosphere, underlying crust where life can exist and the biome of this zone. Biosphere can be considered to be a single ecosystem and is often termed as ecosphere.

Biosynthesis - Synthesis of a substance which is taking place by some biochemical reaction or a series of biochemical reactions (biosythetic pathway.)

Biosystematics - Involves the study of variations and relationships in populations rather than individuals. It is possible to assess genetic and evolutionary nature of groups by examining cytology, comparative morphology and ecology. It is often considered as the taxonomic application of genecology or occasionally as experimental taxonomy.

Biota - Used for flora and fauna either of a particular region or of a given geological period.

Biotic Adaptation - Changes in form or physiology, which are believed to have arisen as a result of competition with other plants.

Biotic Climax - A climax community which is being maintained by living organisms, e.g., grassland prevented from becoming forest by the grazing of animals.

Biotic Factor. The influence of one living organism on another.

Bipinnate. Used for a pinnate leaf in which leaflets themselves have been further subdivided pinnately e.g., in Mimosa pudica.

Bird's-Nest Fungi. An order of Nidulariales of Gasteromycetes having some 9 genera and 60 species. They have nest-like wa11 of basidiocarp having a number of separate spore masses (eggs) which get exposed after drying back of covering membrane.

Biurer Test - A test for protein which in the presence of strong alkaline solution, and copper ions (as copper sulphate) yields a pinkish-mauve colour.

Blackman Reaction - A term including all the reactions in the photosynthetic process which do not requre light (dark reactions). Named after the discoverer.

Bladder - A modified leaf present on the bladderwort. It is used for catching small aquatic animals.

Blanket Bog - It consists of acid peat which is formed from remains of bog plants. It varies in thickness and its high acidity (pH 3.0.4.5) is caused by continuous flow of water through peat which washes away bases and prevents minerals from underlying rocks reaching plant roots. Such bog can be formed over limestone.

Blastospore - The spores which are produced by budding as in Taphrinales where these have been formed by budding of ascospores.

Bleeding - The exuding of sap from a wound. BLEEDING PRESSURE=ROOT PRESSURE.

Blemmatogen - A layer of hyphae having thickened walls, which covers the button of an agaric, and sometimes forms the veil

Blending Inheritance - The inheritance of characters so that the off-spring, and successive generations are intermediate in form between the original parents. This is because the character has been controlled by several genes.

Blepharoplast - A granule present at the base of a flagellum. It is probably a centrosome.

Blight The plant diseases in which leaves are suddenly and seriously damaged. Diseases are caused by many types of pathogens. Examples of diseases are late and early blight of potato and fire blight of pears caused by fungi Phytophthora infestans, Alternaria solani and bacterium Erwinia amylovora respectively.

Bloom - Grains, short rods, or crusts of wax deposited on the surface of some leaves and fruits.

Blue-Green Algae - The members of Cyanophyta. Plants have body which is surrounded by mucilage sheath. Their cell structure is always prokaryotic and sexual reproduction is not known. No flagellate structures are formed at any stage in life.

Body Cell - A fertile cell which is formed along with infertile stalk cell after mitotic division of generative cell in the pollen tube of gymnosperms. It gets divided at a later stage to form 2 antherozoids (sperm cells).

Bog. A region of permanently wet land which is subjected to high rainfall and poor drainage resulting in persistent moist atmosphere in the area. These conditions result in a climax community without trees. The most common plants in this region are bog mosses, ling, crossed leaved heath, bog myrtle, rushes and sedges as common plants. Bog is commonly found in upland and western areas of temperate regions. There are three main types of bog; blanket bog, raised bog and valley bog.

Bolting - Used for the permature production of flowers and seeds in plants. It is common in biennial crops e.g., sugar beet. If they run to seed in the first growing season then their yield is generally considerably reduced.

Bordeaux Mixture. A fungicide made of copper sulphate and quick lime. A common formula is 4 lb. copper sulphate and quick lime, dissolved in 50 gal. water.

Border Parenchyma - A sheath of one or more layers of parenchyma which are surrounding a vascular bundle. .
Bordered Pit - A thin area in the wall between two vessels surrounded by overchanging rims of thickened wall.
Boreal Forest (taiga northern coniferous forest). Used for a cold forest having relatively few types of trees, mainly fir, pine and spruce with some deciduous birches and larches. Such forests are found in North America and northern Eurasia.

Bostryx - Used for a coiled helicoid cyme (See monohcasium) in which overall structure is resembling a spring e.g., inflorescence Hypericum species.

Bottom Yeast - A yeast collecting at the bottom of the vessel during alcoholic fermentation.

Boundary Layer A layer of liquid or gas next to a solid surface. It flows more slowly than that away from the surface. in plants there exists a boundary layer of air at a leaf surface, whose width in inversely proportional to wind speed. This layer also offers resistance to transpiration.
Brachyscleried (stone cell). A relatively short, more or less issodiametric schlerenchyma cell, present singly or in small groups although they are found in large numbers in some tissues e.g., fleshy part of pear fruit.