提示:以上内容由人工智能生成合成。举报反馈
显示排序
After the construction, the field will be lichened.
施工完后,将使地面长满地衣。
The stone stairway was covered with lichen.
那石级长满了地衣。
However, Bacillus licheniformis was aerotolerant anaerobe, in a shape of ellipse and swelled in the middle with production of Arginine hydrolase.
地衣芽孢杆菌是兼性厌氧菌,芽孢呈椭圆形中间膨大,能产生精氨酸双水解酶。
Fragments of the thallus containing both phycobiont and mycobiont cells may also grow into new lichens, a from of asexual reproduction.
地衣的碎裂片中,如含有藻类和真菌共生时,也可长成独立植株,这是一种无性的生殖形式。
The lichen is a typical example of the intergrowth among the microorganism, it is fungi, blue bacterium or homobium of the alga.
地衣就是微生物间共生的典型例子,它是真菌和蓝细菌或藻类的共生体。
Reproduction in lichens may be asexual by soredia (algal cells enclosed by fungal hyphae) or by sexual fungal spores, which can survive only if some algal cells are also present.
地衣可以利用粉芽(真菌菌丝包裹藻类细胞)进行无性生殖或利用真菌孢子进行有性生殖。
These species hailed from three different evolutionary lineages.
这10种地衣来自三支不同的进化谱系。
They also feed on moss and lichen growing on the outside.
它们也吃树外面长的苔藓和地衣。
Litmus itself comes from lichen, a small plant that grows on rocks and trees.
石蕊本身来自地衣,一种生长在岩石和树上的小植物。
So these monkeys have developed a very unusual diet — toxic moss and lichens.
因此滇金丝猴开发出一种非比寻常的食谱——有毒的苔藓和地衣。
Ammonia contains nitrogen-a valuable fertilizer-so the winds carry nourishment to nearby mosses and lichens.
氨中含有氮,而氮是一种非常有价值的肥料,因此风会将营养物质吹到附近的苔藓和地衣那里。
It takes these map lichens, from frigid Greenland, a century to grow a single centimeter.
这些来自寒冷格陵兰的地图地衣需要一个世纪才能长出一厘米。
In 2007, those map lichens survived atmospheric re-entry on a simulated meteorite.
2007 年的那些地图地衣在模拟陨石和大气再入中幸存下来。
As for whether some lichens might have four, five species?
至于是否有地衣含有第四或第五种成分?
Because this study indicates lichens are truly more than the sum of their parts.
因为这项研究表明,地衣不仅仅是各部分的单纯相加。
Closer inspection showed that lichens were more interesting than magical.
要是更仔细地观察一下,你便会发现,地衣与其说是具有魔力,不如说是很有意思。
... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ... no changes ...
形态上地衣有三种:
而地衣结构一般可分为上皮层、藻胞层、髓层和下皮层。
Usnea australis, a fruticose form, growing on a tree branch
The cyanobacterium Hyella caespitosa with fungal hyphae in the lichen Pyrenocollema halodytes
Physcia millegrana (a foliose lichen), with an unlichenized polypore fungus (bottom right), on a fallen log.
Hypogymnia cf. tubulosa with Bryoria sp. and Tuckermannopsis sp. in the Canadian Rockies
Lecanora cf. muralis lichen on the banks of the Bega canal in Timisoara
In American English, "lichen" is pronounced the same as the verb "liken" (/ˈlaɪkən/). In British English, both this pronunciation and one rhyming with "kitchen" /ˈlɪtʃən/) are used.
Common groupings of lichen thallus growth forms are:
There are variations in growth types in a single lichen species, grey areas between the growth type descriptions, and overlapping between growth types, so some authors might describe lichens using different growth type descriptions.
These growth form groups are not precisely defined. Foliose lichens may sometimes branch and appear to be fruticose. Fruticose lichens may have flattened branching parts and appear leafy. Squamulous lichens may appear where the edges lift up. Gelatinous lichens may appear leafy when dry. Means of telling them apart in these cases are in the sections below.
Different colored lichens may inhabit different adjacent sections of a rock face, depending on the angle of exposure to light.
Color is used in identification. Color changes depending on when a lichen is wet or dry. Color descriptions when used for identification are based on when the lichen is dry. Dry lichens with a cyanobacterium as the photosynthetic partner tend to be dark grey, brown, or black.
In crustose areolate lichens, the edges of the areolas peel up from the substrate and appear leafy. In squamulose lichens the part of the lichen thallus that is not attached to the substrate may also appear leafy. But these leafy parts lack a lower cortex, which distinguishes crustose and squamulose lichens from foliose lichens. Conversely, foliose lichens may appear flattened against the substrate like a crustose lichen, but most of the leaf-like lobes can be lifted up from the substrate because it is separated from it by a tightly packed lower cortex.
In a case where one fungal partner simultaneously had two green algae partners that outperform each other in different climates, this might indicate having more than one photosynthetic partner at the same time might enable the lichen to exist in a wider range of habitats and geographic locations.
Phycobionts can have a net output of sugars with only water vapor. The thallus must be saturated with liquid water for cyanobionts to photosynthesize.
Moisture makes the cortex become more transparent. This way, the algae can conduct photosynthesis when moisture is available, and is protected at other times. When the cortex is more transparent, the algae shows more clearly and the lichen looks greener.
Secondary metabolites are thought to play a role in preference for some substrates over others.
Lichens often have a regular but very slow growth rate of less than a millimeter per year. Different lichen species have been measured to grow as slowly as 0.5 mm, and as fast as 0.5 meter per year.
In crustose lichens, the area along the margin is where the most active growth is taking place. Most crustose lichens grow only 1–2 mm in diameter per year.
"Lichenized fungus" may refer to the entire lichen, or to just the fungus. This may cause confusion without context. A particular fungus species may form lichens with different algae species, giving rise to what appear to be different lichen species, but which are still classified (as of 2014) as the same lichen species.
Lichens independently emerged from fungi associating with algae and cyanobacteria at least twice in history.
Thalli produced by a given fungal symbiont with its differing partners may be similar, and the secondary metabolites identical, indicating that the fungus has the dominant role in determining the morphology of the lichen. But the same mycobiont with different photobionts may also produce very different growth forms. Lichens are known in which there is one fungus associated with two or even three algal species.
Although each lichen thallus generally appears homogeneous, some evidence seems to suggest that the fungal component may consist of more than one genetic individual of that species.
Two or more fungal species can interact to form the same lichen.
The same cyanobiont species can occur in association with different fungal species as lichen partners. The same phycobiont species can occur in association with different fungal species as lichen partners. More than one phycobiont may be present in a single thallus.
Depending on context, "lichenized fungus" may refer to the entire lichen, or to the fungus when it is in the lichen, which can be grown in culture in isolation from the algae or cyanobacteria. Some algae and cyanobacteria are found naturally living outside of the lichen. The fungal, algal, or cyanobacterial component of a lichen can be grown by itself in culture. When growing by themselves, the fungus, algae, or cyanobacteria have very different properties than those of the lichen. Lichen properties such as growth form, physiology, and biochemistry, are very different from the combination of the properties of the fungus and the algae and/or cyanobacteria.
The same fungus growing in combination with different algae and/or cyanobacteria, can produce lichens that are very different in most properties, meeting non-DNA criteria for being different "species". Historically, these different combinations were classified as different species. When the fungus is identified as being the same using modern DNA methods, these apparently different species get reclassified as the same species under the current (2014) convention for classification by fungal component. This has led to debate about this classification convention. These apparently different "species" have their own independent evolutionary history.
Lichen identification uses growth form and reactions to chemical tests.
In addition to distinct physical mechanisms by which lichens break down raw stone, recent studies indicate lichens attack stone chemically, entering newly chelated minerals into the ecology.
Over time, this activity creates new fertile soil from lifeless stone.
Lichens have been shown to degrade polyester resins, as can be seen in archaeological sites in the Roman city of Baelo Claudia Spain. Lichens can accumulate several environmental pollutants such as lead, copper, and radionuclides.
Lichens produce metabolites proven useful in the medical community. Most metabolites produced by lichens are structurally and functionally similar to broad-spectrum antibiotics while few are associated respectively to antiseptic similarities. These organic acids are the metabolic byproducts of Crassulacean acid metabolism, the means of photosynthesis by lichens.
Usnea australis, a fruticose form, growing on a tree branch
The cyanobacterium Hyella caespitosa with fungal hyphae in the lichen Pyrenocollema halodytes
Physcia millegrana (a foliose lichen), with an unlichenized polypore fungus (bottom right), on a fallen log.
Hypogymnia cf. tubulosa with Bryoria sp. and Tuckermannopsis sp. in the Canadian Rockies
Crustose lichens on limestone in Alta Murgia-Southern Italy
Cladonia cf. cristatella, a lichen commonly referred to as 'British Soldiers'. Notice the red tips.
Foliose lichens on rock growing outward and dying in the center. These lichens are at least several decades old.
Letharia sp. with Bryoria sp. on pine branches near Blackpine Lake, Washington
Xanthoria sp. lichen on volcanic rock in Craters of the Moon National Monument (Idaho, USA)
Microscopic view of lichen growing on a piece of concrete dust.