Dinoflagellate is a kind of unicellular assemblage plant with double flagella, and its shape is variable.Often distributed infreshwaterAnd in the sea water, some dinoflagellates are harmful, and their survival will have some special smell.Some can form "red tide" and "algal bloom", which can make local seawater appear red, yellow or brown.
Dinoflagellates, also known as "dinoflagellates", are a collection of unicellular dinoflagellates with double flagella.The shapes are spherical, filamentous, amorphous and amoeboid.
The cell wall of dinoflagellate is composed of cellulose, which contains chlorophyll a and c, lutein and β-Carotene。
The motor cells of dinoflagellate have two terminal or lateral flagella, one of which is the velvety whip type, the other is the tail whip type.
morphological character
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Single cell, minority or branched filamentous body;Most of them have two flagella of unequal length and arranged in an inappropriate way, and few of them have no flagella to move or cannot move like amoeba;The nucleus is large and obvious, with rosary chromoplasmic lines, nucleoli and nuclear endosomes. There is a large vacuole in the center of the protoplasm, and some have pulsation, some have a eyespot, and some have a single eye;One or more pigment bodies, yellow green or brown yellow, sometimes red;In addition to chlorophyll a, c and β - carotene, there are several special pigments in the pigment body, such as dimethoflavin, dinoflavin, neodinoflavin and cyclodinoflavin;The storage nutrient is starch, starch like substance or fat.
Mainly cell division and productionZoosporeSome can produce spores, and sexual reproduction is only seen in a few species.The cells are spherical, triangularNeedle shape, slightly flat at the front and rear or slightly flat at the left and right, with prominent horns at the front and rear ends. Except for a few naked types, they all have thick cell walls mainly composed of cellulose, called shells.The structure of the shell is complex, which is arranged by polygonal plates.It can be divided into two parts, the upper part is the upper shell, and the lower part is the lower shell. There is a horizontal groove between the two parts, and there is also a longitudinal groove perpendicular to the horizontal groove. Most of the longitudinal grooves are in the lower shell. The number and arrangement of plates are different, which can be used as the basis for classification;True hole with smooth surface or perforation, or pseudo hole with thick surrounding and thin center;Some of the shell surface is straight, and some has small spines or protuberances.There is one nucleus, round, oval, slender rod shaped or curved sausage shaped.There are 1 to several nucleoli.Chromosomes are arranged like beads, and the chromosomes of some species are lamellar (such as Polyonychia bipedata in Nanjing).The outer layer of cytoplasm is generally thick and granular, containingChromosome；The inner layer hasnucleusandvacuoleThe cytoplasm near the flagellar pores is mostly liquid and can protrudeProtoplasmThe line comes.ChromosomeIt is in the shape of disc, and most of them are arranged incytoplasmThe outer layer of, but there are also shuttle shaped or ribbon shaped radial arrangement.Many primitive species only have one or two large patchesChromosome。Yes NoChromosome, such asMarine productsSargassum acuminatum.The pulsatile vesicles are spherical or oblong in the center of the cell, and there are two pulsatile vesicles.There are tiny tubes fromFlagellumThe base extends out of the body, and there is ochre liquid in the bubble.Flagellum2, on the ventral side;Its structure and movement mode are different. One of them is banded around the horizontal ditch and swings horizontally in the ditch in waves;The other one goes through the longitudinal groove and extends out of the body, which is whip shaped, or linear or banded, and the movement is drag.2FlagellumWhen moving together, the algae will roll forward in a spiral shape, that is, the flagella in the horizontal ditch will roll the algae while those in the vertical ditch will advance the algae.
The most common reproductive mode of dinoflagellate is cell division.The winged dinoflagellates of the subclass Dipterodinoflagellate and Dipterodinoflagellate reproduce by longitudinal division, while other species of the class Dipterodinoflagellate reproduce by transverse division, such as the genus Polydinoflagellate, or by oblique division, such as hornwort.In addition, some species produce either zoospores or azospores.Noctiluca, etcHomogamy, triangular hornwort, etcHeterogamyPhenomenon.[1]
Distribution of origin
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The dinoflagellate is widely distributed in fresh water, brackish water and sea water. It is one of the main planktonic algae. There are many marine species, especially in tropical oceans. In frigid oceans, there are fewer species and more species.Many dinoflagellates have strong phototaxis and only grow in water layers with a certain luminosity. Some dinoflagellates prefer to grow in estuaries or coastal areas, and a few can grow on shallow sea beaches, which are green or brown.Most species living in fresh water prefer acidic waters, that is, dinoflagellates often exist when the water contains humic acid.Some species are parasitic, with fish, copepods or other hostsinvertebrateSome can coexist with coelenterates.
Ecological impact
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The requirements of dinoflagellates on water temperature are also more obvious than those of other algae. The water layer with constant water temperature is different from the water layer with variable water temperature. Most exposed species grow in the relatively constant ocean, while the sea areas vulnerable to coastal impact are mostly crustaceans.
When the light and water temperature are appropriate, dinoflagellates can multiply in a short period of time, which is the same as diatomsmarine animalIt is the main food of the sea, so it is called "marine forage".But it is also often poisoned by sudden death, often called“red tide”, causing death of fish and shrimp.
Because a large number of dinoflagellates die and deposit on the seabed every year, they are the main fossils in the ancient oil generating strata.In countries around the worldoil explorationThe dinoflagellate fossils are often regarded asStratigraphic correlationThe main basis of.In Liaohe, Hebei, Shandong and other places in China, Deflandrea and Bohaidinca can be used to compare the Tertiary geological strata. Because of the small ecological adaptability of dinoflagellates, the fossils of dinoflagellates can be used to speculate the ancient landform or paleogeography, such as the ancient water body shape, water salt content, water depth, water temperature, light intensity, etc.
