Plant Pathology Introduction
Importance of the Plant Diseases Globally, enormous losses of the crops are caused by the plant diseases. The loss can occur from the time of seed sowing in the field to harvesting and storage. Important historical evidences of plant disease epidemics are Irish Famine due to late blight of potato (Ireland, 1845), Bengal famine due […]
Citrus Canker
Citrus canker is one of the most feared of citrus diseases, affecting all types of important citrus crops. The disease causes extensive damage to citrus and severity of this infection varies with different species and varieties and the prevailing climatic conditions. Citrus canker presently occurs in over thirty countries in Asia, the Pacific and Indian […]
Dolipore septum
The transverse septa which divide both monokaryotic and dikaryotic hyphae into segments are incomplete; they contain a central pore which permits cytoplasmic continuity between adjacent segments. The septal pore is surrounded by a barrel-shaped flange of thickened wall material. Such septa, which are characteristic of basidiomycete mycelia, are known as dolipore septa (Lat. dolium= large […]
Puccinia
Occurence: Puccinia includes about 700 species which are important as they cause rust dieseases of economically important crop plants such as wheat,barley, eats etc. The most important of all is P. graminis. It is an internal obligate parsite and is found in associated with wheat growing areas. It is an heteroecious (requiring two hosts; wheat and barbery for […]
Chara
Occurrence: Chara is a fresh water, green alga found submerged in shallow water ponds, tanks, lakes and slow running water. C. baltica is found growing is brackish water and C. fragilis is found in hot springs. Chara is found mostly in hard fresh water, rich in organic matter, calcium and deficient in oxygen. Chara plants […]
Algae: Life cycles
Following types of life histories are found in algae: (a) Haplontic Monophasic: It is a primitive life cycle. In this case, vegetative plant body remains haploid. Gametes are produced by mitosis and fuse to form diploid zygote. First division in zygote is meiosis. It forms haploid vegetative body. Thus zygote is the only diploid stage […]
Cyanophyceae
The Cyanophyceae or blue-green algae are, today, usually referred to as the cyanobacteria (bluegreen bacteria). The term cyanobacteria acknowledges that these prokaryotic algae are more closely related to the prokaryotic bacteria than to eukaryotic algae. Cyanobacteria have chlorophyll a (some also have chlorophyll b or d), phycobiliproteins, glycogen as a storage product, and cell walls […]
Algae Plastids
The basic type of plastid in the algae is a chloroplast, a plastid capable of photosynthesis. Chromoplast is synonymous with chloroplast; in the older literature a chloro plast that has a color other than green is often called a chromoplast. A proplastid is a reduced plastid with few if any thylakoids. A proplastid will usually develop into […]
Algal Cell walls
In general, algal cell walls are made up of two components: (1) the fibrillar component, which forms the skeleton of the wall, and (2) the amorphous component, which forms a matrix within which the fibrillar component is embedded. The most common type of fibrillar component is cellulose, a polymer of 1,4 linked -D-glucose. Cellulose is […]
Algae: Flagellation
The flagella of the green alga Chlamydomonas have been used as a model of flagellar structure. Flagella structure has been highly conserved throughout evolution, images from Chlamydomonas are virtually indistinguishable from flagella (or cilia – a term for a short flagellum) of mammalian cells including human sperm and certain epithelia. Chlamydomonas has been chosen because […]