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pharynx
defoliant or desiccant. Pesticides can be divided into a number of groups of
chemicals: organic pest control, organometallic pest control, inorganic agricultural, environmental pest control, degradation products and metabolites,
drugs used in agriculture and food production and other materials used in
agriculture and food processing, such as antioxidants, surfactants, dispersants, spreaders, thickeners, solvents, propellants, etc. More than 2000 different chemicals are in use as pesticides. Depending on the purpose of use, pesticides may have a great variety of functional groups.
pH a measure of the concentration of hydrogen-ions. pH is defined by pH=
-log[H+ J. A pH value of 7 is neutral. The pH range 0 to 7 is called acidic and
the range 7 to 14 alkaline. The pH of seawater is relatively constant and seldom outside the range of 7.8 to 8.3 in the euphotic zone of the open sea. This
small range is due to the buffering action of the carbonic acid system. High
pH values are observed at the end of vigorous phytoplankton blooms, when
considerable amounts of free carbon dioxide have been converted to organic matter by photosynthesis. The opposite occurs in winter in temperate seas.
In deeper layers, where photosynthesis is absent and organic matter oxidation is a continuous process, the pH is always low . .-talkalinity and .-tionic product of water.
Phaeocystis .-tPrymnesiophyta and .-tsea foam.
Phaeophyta (brown algae) phylum of the kingdom Protoctista, ranging from microscopic algae to kelps of more than 50 m long. They contain chlorophyll-c and
fucoxanthin, and store dissolved laminarin as the chief carbohydrate reserve.
Reproductive cells are formed in special parts of the plant-body, each cell liberating one zoid or many zoids. The genus Fucus and relatives produce eggs.
Most brown algae prefer cold water. They all start their lives attached to rocks
or other substrates but some survive detachment. The drifting Sargassum of
the Sargasso Sea harbors a special life community. Kelps are harvested for
their cell wall material, alginate. Fucus is used as soil fertilizer in some coastal
regions. Few fossils can be assigned unequivocally to Phaeophyta.
phagocytosis is the ingestion of particulate material such as bacteria by Protozoa and
phagocytic cells of higher organisms. The cell simply engulfs the food particle.
phagotroph organism which feeds by the process of phagocytosis. In the process
the phagotroph engulfs a food particle from its surrounding into its cytoplasm, e.g., in a membrane-covered vacuole, where digestion takes place.
pharynx part of the alimentary canal between the oral (mouth) cavity and the
esophagus.
pharynx
defoliant or desiccant. Pesticides can be divided into a number of groups of
chemicals: organic pest control, organometallic pest control, inorganic agricultural, environmental pest control, degradation products and metabolites,
drugs used in agriculture and food production and other materials used in
agriculture and food processing, such as antioxidants, surfactants, dispersants, spreaders, thickeners, solvents, propellants, etc. More than 2000 different chemicals are in use as pesticides. Depending on the purpose of use, pesticides may have a great variety of functional groups.
pH a measure of the concentration of hydrogen-ions. pH is defined by pH=
-log[H+ J. A pH value of 7 is neutral. The pH range 0 to 7 is called acidic and
the range 7 to 14 alkaline. The pH of seawater is relatively constant and seldom outside the range of 7.8 to 8.3 in the euphotic zone of the open sea. This
small range is due to the buffering action of the carbonic acid system. High
pH values are observed at the end of vigorous phytoplankton blooms, when
considerable amounts of free carbon dioxide have been converted to organic matter by photosynthesis. The opposite occurs in winter in temperate seas.
In deeper layers, where photosynthesis is absent and organic matter oxidation is a continuous process, the pH is always low . .-talkalinity and .-tionic product of water.
Phaeocystis .-tPrymnesiophyta and .-tsea foam.
Phaeophyta (brown algae) phylum of the kingdom Protoctista, ranging from microscopic algae to kelps of more than 50 m long. They contain chlorophyll-c and
fucoxanthin, and store dissolved laminarin as the chief carbohydrate reserve.
Reproductive cells are formed in special parts of the plant-body, each cell liberating one zoid or many zoids. The genus Fucus and relatives produce eggs.
Most brown algae prefer cold water. They all start their lives attached to rocks
or other substrates but some survive detachment. The drifting Sargassum of
the Sargasso Sea harbors a special life community. Kelps are harvested for
their cell wall material, alginate. Fucus is used as soil fertilizer in some coastal
regions. Few fossils can be assigned unequivocally to Phaeophyta.
phagocytosis is the ingestion of particulate material such as bacteria by Protozoa and
phagocytic cells of higher organisms. The cell simply engulfs the food particle.
phagotroph organism which feeds by the process of phagocytosis. In the process
the phagotroph engulfs a food particle from its surrounding into its cytoplasm, e.g., in a membrane-covered vacuole, where digestion takes place.
pharynx part of the alimentary canal between the oral (mouth) cavity and the
esophagus.