Polysaccharides are polymeric carbohydrate molecules composed of long chains of monosaccharide units bound together by glycosidic linkages, and on hydrolysis give the constituent monosaccharides or oligosaccharides. They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose and chitin. Polysaccharide Series,Cordyceps Polysaccharide,Hericium Erinaceus Polysaccharide,Goji Polysaccharide Excellent Health Products Co.,Ltd. , http://www.sino-excellent.com
Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks. They may be amorphous or even insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more than one type of monosaccharide is present they are called heteropolysaccharides or heteroglycans.
Natural saccharides are generally of simple carbohydrates called monosaccharides with general formula (CH2O)n where n is three or more. Examples of monosaccharides are glucose, fructose, and glyceraldehyde. Polysaccharides, meanwhile, have a general formula of Cx(H2O)y where x is usually a large number between 200 and 2500. When the repeating units in the polymer backbone are six-carbon monosaccharides, as is often the case, the general formula simplifies to (C6H10O5)n, where typically 40≤n≤3000.
As a rule of thumb, polysaccharides contain more than ten monosaccharide units, whereas oligosaccharides contain three to ten monosaccharide units; but the precise cutoff varies somewhat according to convention. Polysaccharides are an important class of biological polymers. Their function in living organisms is usually either structure- or storage-related. Starch (a polymer of glucose) is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, sometimes called "animal starch". Glycogen's properties allow it to be metabolized more quickly, which suits the active lives of moving animals.
Cellulose and chitin are examples of structural polysaccharides. Cellulose is used in the cell walls of plants and other organisms, and is said to be the most abundant organic molecule on Earth.It has many uses such as a significant role in the paper and textile industries, and is used as a feedstock for the production of rayon (via the viscose process), cellulose acetate, celluloid, and nitrocellulose. Chitin has a similar structure, but has nitrogen-containing side branches, increasing its strength. It is found in arthropod exoskeletons and in the cell walls of some fungi. It also has multiple uses, including surgical threads. Polysaccharides also include callose or laminarin, chrysolaminarin, xylan, arabinoxylan, mannan, fucoidan and galactomannan.
Non-pollution Control Technology of Tomato Root-knot Nematode Disease
I. Symptoms: Tomato root-knot nematode disease mainly damages the roots of plants, and occurs mostly on fibrous roots or lateral roots. It causes swollen and deformed roots and is chicken-shaped. The roots of the nematode nematodes can be found buried in it. The upper part of the plant showed poor development, yellow leaves and short plants. The results were small and small, yield was low, and the quality was poor. When drought occurs, diseased plants tend to wilt until the pruning plants die. Second, the incidence of the law: the pathogen is a southern root-knot nematode, with 2 - 3 instar larvae or eggs with the disease in the soil in the winter, through the soil, sick, diseased seedlings spread with fertilization, irrigation and agricultural operations. Root-knot nematodes generally endanger more than 30 centimeters of soil, and are most distributed in 5-20 centimeters of soil. In the terrain with high dryness, loose soil, suitable humidity and low salinity, the damage is serious. Many years of continuous cropping has been seriously affected. According to the survey, the origin of root-knot nematode infection in tomato roots in Angezhuang Town of this county may be the nursery soil of peanut field. Third, control methods: To control the occurrence of pathogens in protected areas, to reduce the first time the source of field dip, take agricultural measures to prevent and control, combined with the necessary chemical control. (a), agricultural control: 1, with disease-free soil seedlings, the application of pathogen-free organic fertilizer as a base fertilizer, and the selection of disease-free seedling colonization; 2, completely remove the diseased body: the sick body after harvest clean, especially Tomato root, bring out the rural concentrated burned; 3, deep turning the soil: the topsoil deep to less than 20 cm, can reduce the source of initial infusion; 4, rotation: serious disease fields and gramineous crops or with onions, garlic, leeks and other crop rotation 2-3 years, it is best to plant 1 rice; 5, the use of high temperature to kill nematodes: greenhouses in the summer season can be used in summer heat, digging furrows in summer, ridge irrigation, ridge cover mulch, and closed shed Room more than 15 days, so that 30 cm soil temperature reached 54 °C above, keep more than 50 minutes, can kill most of the nematodes; (b), chemical control: 1, soil treatment: before sowing or 15 days before planting, selection 10% Limanku, 50% Yishuning, 3% Milur and other granules 3-5 kg ​​mixed soil after deep turning; Before planting with 1.8% Insect grams or 6.73% Awei insect clear, 1 liter amount of acres , Duishui 5000-6000 times liquid, ditch or hole application, and then seal ridge, 1 month later In the irrigation time, valid for up to 20 days, the control efficiency of 90%. 2. Pharmaceutical Irrigation: After planting, when the plants in the shed are partially damaged, 50% phoxim EC can be used to irrigate the roots, 0.25-0.5 kg per plant, and the soil kills the root-knot nematodes in the soil. .