海藻学基础知识（英文版）

1、海藻学第一章i 海藻学study of the classification, morphology, structure, ecology, physiology,evolution, reproduction, and life histories of algae.藻类学： 研究藻类植物的分类、形态、构造、生态、生理、进化、繁殖和生活史ii 什么是海藻(i) algae show a broad range of complexity, they range in complexity from tiny, microscopic forms, to very complex forms

2、 such as the kelps. 藻类植物的形态多种多样。从微小的单细胞到长达上百米的大型褐藻。(ii)are simple construction，generally do not have vascular tissue，do not show high level of organ differentiation . more advanced brown algae have a certain degree of organ differentiation, and which even have a type of vascular tissue. 藻类植物结构简单，一般没

3、有维管组织，没有组织和器官的分化。大部分的高等褐藻有一定程度的器官分化和一套有特点的维管组织。(iii) they have naked reproductive structures.this means that there are no protective layers of cells surrounding reproductive structures. none of the algae have reached even the level of organization in reproductive structures shown by the archegoniate

4、 颈卵器plants, such as the mosses & liverworts. 藻类植物的升值结构裸露，周围没有专门的保护组织，藻类甚至没有颈卵器植物和苔藓和地钱那样的生殖结构(iv) most algaeare photoautotrophic, which means that they can make their own food materials through photosynthesis by using sunlight, water and carbon dioxide.藻类植物进行光合作用，光自养。in common with all plants, most

5、algae contain chlorophyll-a, as well as various other photosynthetic pigments. 与普通植物一样，大部分藻类植物还有叶绿素a和其他各种光和色素。(v) a few algae are not photoautotrophic, but they belong to groups which are usually autotrophs. strictly speaking, not all algae belong to the plant kingdom. (vi) 藻类是无胚的、具有叶绿素的自养叶状体的孢子植物叶状

6、体 （原植体）thyllus （ thylli pl ）:没有真正的根、茎、叶区别。全身都有吸收养料和进行光和作用的功能。虽然有些高等藻类在外形上出现类似高等植物的茎、叶、根的形态，但从基本构造来看，仅仅是有一些稍有分化的细胞组成的薄壁组织状的构造。thyllus meaning they lack true roots, stems, and leaves, fruits, connecting tissue etc. and photosynthesis occurs throughout the plant, not just the leaves.parts are called: h

7、oldfast, stipe, blade, air bladders (pneumatophores, 气囊). iii . what is algae in taxonomy? the algae-some major groupscyanophyta blue-green algaechlorophyta green algaephaeophyta brown algaerhodophyta red algaeeuglenophyta euglenoidschrysophyta golden-brown algae(incl. diatoms) pyrrophyta dinoflagel

8、lates(i) algae include both prokaryotic and eukaryotic organisms. the cyanophyta and prochlorophyta are both prokaryotic divisions, while all other algae are eukaryotes. 藻类植物既有原核生物又有真核生物。蓝藻门和原绿藻门属于原核生物，其它藻类属于真核生物.historically, algae were treated as belonging to the plant kingdom under a two kingdom

9、system in which all living things were considered either plants or animals. (ii) algae are polyphyleticthe algae are not a single cohered natural group, thety represent a kind of different organisms, there are many lines of evolution leading up to those organisms. the algae do, however, share a numb

10、er of features which allow them to be treated as a group, although as a group with a very mixed evolutionary history. (iii) algae constitute an artificial grouping of organisms. they are dealt with together because of historial beliefs and for the sake of convenience. as a group they are notoriously

11、 difficult to define.biologically, the name algae is given to a group of organisms of mixed affinity. the word itself has no taxonomic significance whatsoever. iv. habitat 生境algae occur in virtually any habitat on earth as long as water is found there at some time, even if it is just moisture which

12、might be present for a very short time.all major bodies of water have algae in abundance, including seas，lakes, small streams, large rivers, and even waterfalls. algae occur in fresh water, to the saline water of the sea, and even in salt pans. there are also algae that thrive in the heated water of

13、 hot springs. in the sea they may occur below the range of tidal exposure - in the subtidal zone as well as in the harsh intertidal environment of the seashore, where they may be beaten by waves. growing in the intertidal zone, algae are subjected to a number of stresses胁迫 and disturbances干扰. at low

14、 tide, they may be baked in the sweltering sun, rained on by fresh water and beaten by waves. those algae which live attached to the bottom of a water body are called benthic底栖 algae.small, microscopic algae which drift about in bodies of water are called phytoplankton 浮游植物. some algae can even grow

15、 on the seabed, beneath a thick blanket of arctic or antarctic sea ice, even though they are in total darkness for a considerable part of the year. algae are found in snow too. in some parts of the world, blooms of snow algae may paint the snow beds red in spring. algae even occur in the driest dese

16、rts. in some areas of the namib desert in south africa, one often finds many quartz stones石英石 scattered about on the ground. since quartz is quite translucent, the stones permit a considerable amount of light to pass through, so there is sufficient light for photosynthesis to take place underneath t

17、he stones.a small amount of moisture may be retained in the soil under the quartz stones, so unicellular algae are able to grow underneath them. algae are also found in the air, for there are many algae that colonize new bodies of water by simply drifting about through the air. there is even a unice

18、llular green alga called prototheca which causes disease in humans. it produces skin lesions损害. some algae enter into symbiosis with other organisms, for example, the symbiotic organisms that we call lichens地衣.coral reefs form a symbiotic partnership with tiny single-celled algae called zooxanthella

19、e虫黄藻. the zooxanthellae which live in the tissues of the coral, share with it the organic products of their photosynthesis, as well as helping the coral with the construction of its limestone skeleton. v. life strategiesseaweeds must cope with a disturbed environment. seashore and rock pool species

20、in particular experience daily and seasonal extremes of salinityor moisture and temperature, and the attentions of animal grazers. because of regular exposure to air when the tide is out, the most dessication-resistant seaweeds usually live at the top of the shore. although they may dry out at low t

21、ide, they can rapidly absorb seawater and resume photosynthesis as soon as the tide returns. many seashore seaweeds produce mucus, both to keep from drying out and to deter grazers and colonizing animals. some seaweeds are annuals, so they grow, reproduce,and die within a year. others are perennial,

22、 or have parts from which new fronds grow each year. many red seaweeds that colonize disturbed habitats have a two-phase life history, with conspicuous, erect filaments or fronds, present only during the calm season, and a perennial crust or creeping filament that helps it withstand abrasion during

23、storms. these phases look so different that they were first described as separate species. the distinctive red seaweeds called coralline algae have a heavily calcified, pink frond,too hard for most grazers to eat. in some species, the frond is jointed, while others form crusts on rock. an unattached

24、 version, maerl, forms hard, free-living nodules on the sea bed. some seaweeds are parasites of other seaweeds, obtaining at least part of their nutrition.from the host.vi. marine plantsmarine plants include seaweeds, microscopic algae, mangroves, marsh grass, and sea grasses. the last 3 groups are

25、marine angiosperms (flowering plants).mangroves are 80 unrelated species of flowering plants adapted to various ways to survive in the salty environment. seagrasses are not grasses, and their closest relatives are probably lilies. pollen is carried by water currents and seeds are dispersed by water

26、currents and feces of fish and other animals that browse of the plants. dried seagrass material was commonly used as housing insulation and roofing thatch. chapter two thallus organization in algaei unicellularthe simplest form of organization in photosynthetic organisms is of course the single cell

27、. many groups of algae have single celled forms, and these may be coccoid (lack flagella), or they may be flagellated. a third type of unicell shows amoeboid movement, this type being called rhizopodial organization.ii colonialthe next level of complexity in organization is the colony. colonial form

28、s occur in many groups of algae, including cyanobacteria, the chlorophyta, and the heterokontophyta. at the simplest level, colonial forms may just be a few cells embeded in a common gelatinous matrix, the colony then being known as a palmella (adj. palmelloid). if the number of cells in the colony

29、is always the same, the colony is called a coenobium. iii multicellularmulticellular algae may be either filamentous, being composed of chains of inter-connected cells, or they may be parenchymatous. parenchymatous forms usually have true tissues.(i) filamentous filamentous algae may consist of simp

30、le, unbranched filaments as in the case of most filamentous cyanobacteria, and some green algae such as spyrogyra, zygnema, and chaetomorpha.a. filamentous unbranchedb. filamentous branchedfilamentous algae may also consist of branched filaments, which may be fairly simple to quite elaborately branc

31、hed.c. pseudoparenchymatousthe ultimate elaboration of the filamentous thallus occurs when the filaments are united into a solid structure, which is differentiated into regions that resemble tissue. algae with this type of organization are referred to as pseudoparenchymatous algae. the pseudo portio

32、n of the word means false and parenchymatous refers to tissues; hence pseudoparenchymatous algae are based on the elaboration of the filamentous condition to produce complex thalli that appear to be made up of tissues. many of the larger algae are pseudoparenchymatous, including the brown algal oder

33、 chordariales, and most red algae.the concept of a pseudoparenchymatous thallus construction is difficult to convey in words, but easy to understand once observed. the red alga dumontia incraassata is a north atlantic species of red alga that illustrates this concept very well. in d. incrassata, the

34、 internal construction is based on the aggregation of filaments. it gives the appearence of tissue in that the plants are substantial, and sections reveal a degree of specialization in the cells of the filaments. the outer ones contain most of the pigment, and are specialised for photosynthesis, whi

35、le the inner ones are primarily structural.(ii) parenchymatousin the parenchymatous type of thallus organization, thalli are organized into true tissues composed of several different types of cells. parenchymatous organization is common among algae, particularly among the larger brown algae found in

36、 the orders laminariales, fucales, and durvillaeales. all of the green plant groups (e.g. mosses, ferns, gymnosperms, angiosperms) have a parenchymatous construction.iv siphonocladousin some algae, nuclear division proceeds independently of the formation of cross walls between cells. as a result, ce

37、lls may contain several nuclei. thus thalli are composed of multinucleate cells, such algae being referred to as siphonocladous (or semicoenocytic) in their construction. algae showing a siphonous (coenocytic) organisation usually consist of hollow bags or filaments (siphons), in which cells are lac

38、king. instead of cells, there are no cross walls separating nuclei, thus the whole thallus consists of a continuous mass of cytoplasm contained only by the outer walls of the filament or sac.the genus codium is well rep pseudoparenchymatous.microalgae generally refer to unicells, colonies and filame

39、nt types of algae. in contrast, macroalgae refer to coenocytic (siphonous), pseudoparenchymatous and parenchymatous bodies of algae.chapter three growth in algaea number of different patterns of growth are possible in multicellular algae, ranging from the simplest diffuse growth to the more complex

40、localized meristematic cells or meristems. as the complexity of algal thalli increases, there is a tendency for increasing cell specialization and the localization of cell division in specialized meristematic cells or meristems. use the navigation folders at the left to study this topic further or f

41、ollow a linear path through the material below。i diffuse growth 弥散生长in algae which show diffuse growth, virtually any cell is capable of cell division. this type of growth occurs in the simpler, filamentous forms, such as the blue-green algae (cyanobacterium) oscillatoria, the green algae ulothrix a

42、nd zygnema, and the brown alga ectocarpus.ii localized growthin algae with localized growth, cell division is restricted to one or more meristematic cells or regions. localized growth may be apical or intercalary. sometimes meristems can be recognized in filaments or sections by the presence of nume

43、rous small, unspecialized cells which suggests that they are a site of cell division. in the case of apical growth, there is often a prominent apical cell, from which the origins of other nearby cells can be traced.(i)apical growth顶端生长algae with apical growth have a meristem located at the apex (tip

44、) of the upright part of the thallus. the primary meristem usually consists of a single cell, but may also involve a number of apical cells. in the case of a single apical cell, one cell is usually cut off from it, and then divides further to give rise to the other cells of the thallus. apical growt

45、h is typical of the brown algal orders dictyotales and sphacelariales, and most red algae.the genus dictyota is dichotomously branched thalli that are sometimes iridescent blue or bluish purple. plants are quite thin, consisting of only a single layer of cells, and growth occurs via single apical ce

46、ll. at the tip of each branch of the thallus (diagram right), there is a single apical cell, below which other cells making up the branch of the thallus are cut off (top illustration). since the fronds are divided dichotomously, this cell splits vertically to give rise to two new apical cells (middl

47、e illustration), that carry on growing. each of the resulting apical cells produces one arm of the dichotomy (lower illustration). (ii)intercalary growth居间生长in algae with intercalary growth, the meristematic region is located neither apically nor basally, but somewhere within the thallus. two types

48、of intercalary growth may be recognized, considered here under the headings; trichothallic and regional growth.a. trichothallic growth毛基生长in algae with trichothallic growth, cell division occurs at the base of a filament, a colorless hair, or a group of filaments or colorless hairs. trichothallic gr

49、owth is restricted to the phaeophyceae. a young thallus of desmarestia sp. 酸藻showing the meristematic cells (blue) and their immediate derrivatives (red) located at the base of a filament within the main axis of the thallus.b.regional growth 居间生长the meristematic zone is located within the thallus, b

50、ut is not at the base of a filament or hair. in forms with only a single blade, such as the south african kelp laminaria pallida, the meristem is located in the transition zone between the blade and the stipe (right). new blade cells are cut off above, and new stipe cells below this meristem. in mul

51、ti-bladed forms, each bladelet has its own meristem at its point of attachment (below). the kelp macrocystis angustifoliais a common member of south african kelp beds. there are a number of bladelets that arise from a common stipe. at the base of each bladelet is a float (pneumatocyst). there is a t

52、ransition zone meristem for each of these bladelets.in ecklonia maxima(below), the primary blade that is evident in juvenile plants soon develops secondary blades from the margin. ultimately the secondary blades prevail, and the primary blade is reduced to a kite-shaped portion at the top of the sti

53、pe. there is a primary transition zone meristem at the base of the primary blade, but each secondary blade arising from the primary blade has its own transition zone meristem. secondary blades are deciduous, and it is not uncommon to see e. maxima plants that lack secondary blades entirely. in such

54、plants, the blades will eventually grow back.in sporophytes of the laminariales, all of which are complex parenchymatous forms, there is a secondary superficial meristematic region which is responsible for increasing thallus girth (thickness). this secondary meristem, called meristoderm, is located

55、near the periphery of the plant.since the meristematic region in the laminariales is located in the transition zone, as the plant grows new blade tissue is produced at the base of the blade. old tissue erodes off the tip, and is an important source of particulate and dissolved carbon in kelp bed eco

56、systems. this mode of growth also means that it is fairly easy to measure growth in kelps. holes can be punched in the blades just above the transition zone, and growth can be recorded as the distance from the transition zone to the holes, as the holes move along the growing blade.chapter four algal

57、 reproductive types1. asexual reproductionasexual reproduction does not involve the fusion of gametes or meiosis. some algal species reproduce only asexually. under conditions favorable to growth, asexual reproduction allows organisms to replicate themselves without the need to produce gametes and f

58、ind mates. thus, asexual reproduction allows rapid population growth.2. sexual reproductionsexual reproduction involves gametes production, gametes fusion, zygote production and zygote development into an algal body.many algae reproduce by both sexual and asexual processes. sexual reproduction allows populations to increse genetic variability, fostering the ability to respond to environmental change by means of evolution.many algae use tough, resistant structures generated by sexual processed to survive periods unfavorable to growth. chapter five adaption of algae in wateri the l