STEM STRUCTURE

The internal structure of the stem is more complex. Stem is differentiated into nodes and internodes. The leaves are inserted on the nodes. The arrangement of leaves on the ‘nodes has made the stem more complicated. Stem has three fundamental systems. These tissues systems are epidermis or dermal tissues, ground tissues and vascular tissues. In conifers and dicotyledonous plants the ...

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Puccinia

Occurrence Puccinia is large genus. It has several obligatory parasitic species.tritici is a parasite of wheat. It completes its life cycle in two different hosts: wheat and barely. Thus it is hetcrocious rust. It infects the stem of wheat and causes black or stem rust.   Life cycle The life cycle of Puccina is divided into five stages on the ...

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Phytochrome

Discovery of Phytochrome Phytochrome is a blue-green pigment involved in the perception of photoperiodic stimuli controlling flowering and other growth phenomenon such as seed germination, etc. The discovery of phytochrome was made during studies by Borthwick, Hendricks and their colleagues. They revealed that a pigment system is involved in the germination of lettuce (Lactuca sativa) seeds. They found that germination ...

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Agaricus Campestris

The members of this genus are commonly called mushrooms. Mushrooms grow on soil. They are abundantly found on soil with decry plant material and moisture. The specie ,4garietts campsites is very common. This species is edible. It is cult hated for commercial purposes. General structure The mature plant body is composed of two parts: vegetative mycelium and sporophores Vegetative mycelium: ...

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ECONOMIC IMPORTANCE OF FUNGI

(a) Role of fungi in Agriculture or crop production Decomposition and humus formation: Fungi decompose the dead animals and plants. Fungi change them into humus. rums is decomposed organic matter. It plays an important role in germination of plant. It provides important nutrient to plants. Humus also holds the soil particles. Thus it reduces the chance of soil erosion. Humus ...

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Fungal diseases in plants

RUSTS Causative agent: Puccinia graminh (Basidiomycota) Affected plants: Wheat, barberry Symptoms: Reddish streaks (pustules) appear on the stems and other parts of wheat. These streaks may affect most of the plant. They give rusted appearance to whole of the plant. As the season advance-, the streaks change from red to bl wk. The crop gives burnt dried look. The barberry ...

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LICHENS

General characters:The intimate symbiotic association of fungi and algae is called lichens.Algae get protection and get moisture from fungus.Fungi get nutrition from the algae.The food substances diffuse from algae to fungi.The algae of lichens mostly belong to Chlorophyta and cyanobacteria. Distribution: Lichens have worldwide distribution. The form major part of vegetation in Polar Regions. They can withstand extreme temperatures. Classification: ...

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Physcia

General structure Physcia is foliose lichen. Physcia is divided into four regions internally. These regions are: 1. Upper cortex: It is present at the upper regions. It is composed of closely packed hyphae. Spaces are absent between them. if spaces are present, they are filled by gelatinous material. The upper surface may be smooth or it has hair like structures. ...

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BRYOPHYTES

Occurrence of bryophytes Bryophytes are terrestrial plants. They mostly grow in moist and cold habitats. Some species can grow in dry places. But they depend on moisture for the reproductive stage. Bryophytes have world wide in distribution. They are found in tropical, temperate, subarctic and arctic regions. General structure Bryophytes show alternation of generation. Gametophyte The dominant generation in bryophyte ...

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Riccia

Scientific classification Division Bryophyta Class Hepaticae Order Marchantiales Family Ricciaceae Genus Riccia OCCURRENCE The genus Riccia has aboutI30 species. Some botanists have reported its 200 species. Many of its species are found in Punjab. Kashmir and Western Himalayas. The species are found scattered from hilly and plains areas. All the species are terrestrial. They grim on damp soil or moist ...

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