真菌(fungus)
真菌界腐生或寄生性生物，约五万种，包括酵母菌、锈菌、黑粉病、霉、蘑菇等，特徵为无叶绿素，无根、茎、叶等有组织的植物器官。研究真菌的学科称为真菌学。真菌有助於有机物的崩解，使碳、氧、氮及磷等从死亡的动、植物体释出，进入土壤或大气中。真菌又可与活的生物构成共生或寄生的关系。真菌可见於世界所有地区的水、土壤、空气、植物、动物中，只要该处有足够的水分可供其生长。真菌为许多家庭和工业生产过程所必需，又用於生产、有机酸、维生素（维他命）和抗生素。青霉菌是一种绿色的霉菌，能抑制细菌的生长（1928年佛来明首次发明），它只是许多对人类环境有利影响的真菌种类之一。真菌又能毁坏庄稼，引起足癣、癣等疾病，又会使衣服、食物等发霉、腐败。典型真菌的原植体由菌丝体构成，菌丝体是一团称作菌丝的有分枝、管状的丝状体，细胞质在其中流动。菌丝体通常通过形成孢子进行繁殖，孢子或直接从菌丝生出或在特化的子实体内形成。土壤为大量真菌种类提供理想的生境。因为真菌不含叶绿素，故不能进行光合作用，必须将分泌到它们生长环境的表面，从而获得所需的碳水化合物。将食物消化，然後养分由菌丝的细胞壁直接吸收。腐生的真菌生活於死亡的生物体上，对有机物质的分解具一定的作用。寄生的真菌侵入活的生物体内吸取营养，常引起疾病和死亡（参阅parasitism）。真菌能与其他生物建立共生关系，如真菌与藻类共生形成地衣，与植物共生形成菌根，又可与昆虫共生。
English version：
fungus
Any of about 50,000 species of organisms of the kingdom Fungi, or Mycota, including yeasts, rusts, smuts, molds, mushrooms, and mildews. Though formerly classified as plants and still considered plants in some systems, they lack chlorophyll and the organized plant structures of stems, roots, and leaves. Fungi contribute to the disintegration of organic matter that results in the release of carbon, oxygen, nitrogen, and phosphorus from dead plants and animals into the soil or the atmosphere. They can be found in the water, soil, air, plants, and animals of all regions of the world that have sufficient moisture to enable them to grow. Essential to many household and industrial processes, fungi are also used in the production of enzymes, organic acids, vitamins, and antibiotics. They also can destroy crops, cause such diseases as athlete's foot and ringworm, and ruin clothing and food with mildew and rot. The thallus, or body, of a typical fungus consists of a mycelium through which cytoplasm flows. The mycelium generally reproduces by forming spores, either directly or in special fruiting bodies that are generally the visible part of the fungus. The soil provides an ideal habitat for many species. Lacking chlorophyll, fungi are unable to carry out photosynthesis and must obtain their carbohydrates by secreting enzymes onto the surface on which they are growing to digest the food, which they absorb through the mycelium. Saprophytic fungi live off dead organisms and are partly responsible for the decomposition of organic matter. Parasitic fungi invade living organisms, often causing disease and death (see parasitism). Fungi establish symbiotic relationships with algae (forming lichens), plants (forming mycorrhizae; see mycorrhiza), and certain insects.
