12.22 菌类营养 -- -- 高级
Section outline
-
So what do "eat"?
::那么"吃"是做什么的呢?Just about anything. From dead plants to rotting fruit . Shown here are fungi sprouting from dead material in the woods. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange.
::从死植物到腐烂的水果。在这里展示的是真菌从树林中的死物质中发芽。真菌在有机物质的分解中起着不可或缺的作用,在养分循环和交换方面起着根本作用。Nutrition
::营养营养营养Fungi get their nutrition by absorbing from the environment. Fungi are heterotrophic; they rely solely on carbon fixed by other organisms for their metabolism and nutrition. Fungi have evolved in a way that allows many of them to use a large variety of organic substrates for growth, including simple compounds such as nitrate, ammonia, acetate, and ethanol. Their mode of obtaining nutrition defines their role the environment.
::菌类通过吸收环境来获得营养。 菌类是血化营养;它们仅仅依靠其他生物的碳固定进行新陈代谢和营养。 菌类的进化使得它们中的许多人能够使用多种有机基元素来生长,包括简单的化合物,如硝酸盐、氨、乙酸盐和乙醇。 它们获得营养的方式决定了它们对环境的作用。Fungi obtain nutrients in three different ways:
::菌类以三种不同的方式获得营养:-
They decompose dead organic matter. A
saprotroph
is an organism that obtains its nutrients from non-living organic matter (usually decaying plant or
matter) by absorbing soluble organic compounds. Saprotropic fungi play very important roles as recyclers in an ecosystem's
energy
flow and in
biogeochemical cycles
. Saprophytic fungi, such as shiitake (
Lentinula edodes
) and oyster
mushrooms
(
Pleurotus ostreatus
), decompose dead plant and animal
tissue
by releasing
from hyphal tips. In this way, they recycle organic materials back into the surrounding environment.
::它们分解了死亡有机物。 衰变是一种通过吸收可溶性有机化合物而从非生物有机物(通常是腐烂的植物或物质)获得养分的有机体。 热带真菌在生态系统的能源流动和生物地球化学循环中起着非常重要的回收者作用。 预防性真菌,例如尖虫和牡蛎蘑菇(Pleuratus ostreatus),通过释放催眠药分解死亡植物和动物组织。 这样,它们就把有机物质循环回到周围环境。 -
They feed on living hosts. As
parasites
, fungi live in or on other organisms and get their nutrients from their
host
. Parasitic fungi use enzymes to break down living tissue, which may causes illness in the host. Disease-causing fungi are parasitic. Recall that
parasitism
is a type of symbiotic relationship between organisms of different
in which one, the parasite, benefits from a close association, while the other, the host, is harmed.
::寄生虫以活体宿主为食,作为寄生虫,真菌以其他生物为生,从宿主处获取养分。寄生虫真菌使用酶来分解活体组织,这可能造成宿主的疾病。引起病菌的寄生虫是寄生虫。请注意,寄生虫是不同生物体之间的一种共生关系,其中寄生虫从密切关联中受益,而寄生虫则受到伤害。 -
They live mutualistically with other organisms. Mutualistic fungi live harmlessly with other living organisms. Recall that
mutualism
is an interaction between individuals of two different species, in which both individuals benefit.
::它们与其他生物体相互生活,相互性真菌与其他生物体无害地生活,回顾相互性是两种不同物种个人之间的一种互动,对两者都有利。
Both parasitism and mutualism are classified as symbiotic relationships, but they are discussed separately here because of their different effect on the host.
::寄生炎和相互性都被归类为共生关系,但由于对宿主的不同影响,此处分别讨论。Forest Decomposers. These forest mushrooms may look fragile, but they do a powerful job. They decompose dead wood and other tough plant material. Fungal hyphae are adapted to efficient absorption of nutrients from their environments, because hyphae have high surface-area-to-volume ratios, as shown in Figure . These adaptations are also complemented by the release of hydrolytic enzymes that break down large organic molecules , such as polysaccharides , , and , into smaller molecules. These molecules are then absorbed as nutrients into the fungal . One enzyme that is secreted by fungi is cellulase , which breaks down the polysaccharide cellulose . Cellulose is a major component of plant cell walls . In some cases, fungi have developed specialized structures for nutrient uptake from living hosts, which penetrate into the host cells for nutrient uptake by the fungus.
::如图所示,这些调整还辅之以释放液解酶,将大型有机分子(如聚沙焦)分解成小分子。这些分子随后作为养分被吸收到真菌中。真菌中隐秘的一种酶是细胞酶,它打破了聚沙焦化纤维素。细胞素是植物细胞壁的主要组成部分。在某些情况下,真菌开发了从活体宿主吸收养分的专门结构,这些结构渗透到宿主细胞中,由真菌吸收养分。Fungal mycelia. Fungi absorb nutrients from the environment through mycelia. The branching mycelia have a high surface-area-to-volume ratio which allows for efficient absorption of nutrients. Some fungi digest nutrients by releasing enzymes into the environment. Mycorrhiza
::脑膜炎A mycorrhiza (Greek for fungus roots) is a symbiotic association between a fungus and the of a plant. In a mycorrhizal association, the fungus may colonize the roots of a host plant by either growing directly into the root cells or by growing around the root cells. This association provides the fungus with relatively constant and direct access to glucose , which the plant produces by . The mycelia of the fungi increase the surface area of the plant’s root system . The larger surface area improves and mineral nutrient absorption from the soil .
::菌株(Greek for truggus root)是真菌和植物之间的共生联系。在菌株协会中,真菌可能直接生长在根细胞中,或生长在根细胞周围,从而将宿主植物的根根殖民化。这个协会为真菌提供了相对固定和直接的获取葡萄糖的途径。真菌的神话增加了植物根系统的表面面积。更大的地表面积改善了土壤中的矿物养分和吸收。Summary
::摘要-
Fungi are heterotrophic. They get their nutrition by absorbing organic compounds from the environment. Fungi, along with bacteria that are found in soil, are the primary decomposers of organic matter in terrestrial ecosystems.
::菌类具有血氧营养学,它们通过吸收环境的有机化合物获得营养。 菌类以及土壤中的细菌是陆地生态系统有机物的主要分解物。 -
Some fungi are parasitic and break down living tissue, while others form mutualistic relationships with other organisms.
::有些真菌是寄生虫,分解活组织,另一些则与其他生物形成相互关系。 -
Fungal hyphae are adapted to efficient absorption of nutrients from their environments.
::富豪海绵可适应有效吸收其环境中的养分。
Review
::回顾-
Describe how fungi obtain nutrients.
::描述真菌如何获得养分。 -
Define the role of mycorrhiza.
::界定了乳房腐蚀的作用。 -
How do fungi decompose decaying plants?
::真菌如何分解腐烂植物?
-
They decompose dead organic matter. A
saprotroph
is an organism that obtains its nutrients from non-living organic matter (usually decaying plant or
matter) by absorbing soluble organic compounds. Saprotropic fungi play very important roles as recyclers in an ecosystem's
energy
flow and in
biogeochemical cycles
. Saprophytic fungi, such as shiitake (
Lentinula edodes
) and oyster
mushrooms
(
Pleurotus ostreatus
), decompose dead plant and animal
tissue
by releasing
from hyphal tips. In this way, they recycle organic materials back into the surrounding environment.
