Plant kingdom - bryophytes
Eukaryotic domain
Plant kingdom
Bryophytes
Bryophytes, or bryophytes, are embryonic plants among non-vascular plants: they have tissues and organs and a closed reproductive system, but lack vascular bundles that transport water. They have no flowers or seeds, but are propagated by spores, and can also produce sperm and eggs, perform fertilization, but sperm still need to be water-mediated and have a stratum corneum. There are currently more than 20,000 species of bryophytes.
Bryophytes do not form a monophyletic group, but contain three taxa: Phylum dichophyllum, Phylum dichophyllus, and Phylum moss. Originally, these three taxa were three orders in the "Chinese old name" Bryophyta (Bryophyta as Bryophyta), but because they formed a cohologic group, they are now placed in three different phylums.
Marchantiophyta
Bryophyta
Anthocerotophyta
Such plants are usually haploid gametophytes, and only occasionally diploid spores appear. Therefore, the sex pattern of bryophytes is very different from other plants. There are two main sex patterns of bryophytes:
Hermaphroditic bryophytes will only have one of the sperm or neck-egg organs in a single plant.
Hermaphroditic bryophytes have both sperm and neck-egg organs on the same plant.
Some bryophytes can be hermaphroditic or hermaphroditic depending on the environment. The other species belong to only one of two models.
This is different from what is called "hermaphrodite" and "hermaphroditic" on seed plants, which means that a sporophyte plant will carry one or two gametes. Bryophytes are referred to as unisexual or bisexual gametophytes.
There is no consensus on the origin of bryophytes, and some believe that they originated from green algae on the grounds that they contain the same photosynthetic pigments; the same stored starch; that sperm each have 2 isometric apical flagella; that the protofilament formed when the spores germinate is also similar to that of filaments; and that the structure of the oocysts and spermatozoans of green algae is similar to that of the neck ovary and sperm organs of bryophytes.
Another view is that the naked ferns were degraded, with the naked fern appearing in the Silurian period and the bryophytes appearing in the middle Devonian period tens of millions of years later than the naked fern. In evolutionary order, it is likely that they originated from the same ancestor. However, there is insufficient evidence for both of these views until 2017, which will await further study in the future.
The gametophytes of bryophytes predominate, with sporophytes attached to the gametophytes. The gametophytes are simple in structure, have no real roots, have no transporting tissues, prefer to be wet and gloomy, and must resort to water when reproducing sexually. Therefore, it is difficult to further adapt and develop on land, which indicates that it belongs to the transitional type of plant from aquatic to terrestrial.
Bryophytes are a kind of small green plants with a gametophyte dominant in the history of life, with a simple structure, no vascular organization, no real differentiation of roots, stems, and leaves, and the stems, leaves and roots that we usually see should be called pseudo-stems, pseudo-leaf and quasi-roots.
Bryophytes usually prefer shady and wet environments, generally growing on stone walls, tree trunks and soil surfaces, or in wet forests and swamps, and some bryophytes can also survive in deserts and even deserts.
For more advanced species, the plant body has a differentiation of false roots and similar stems and leaves. The internal structure of the plant body is simple, the false root is composed of single cells or a column of cells, there is no column, only in the higher species, there is a cell population similar to the transport tissue. Although the morphology and structure of bryophyte bodies are so simple, because bryophytes have similar stem and leaf differentiation and release spores, they still have important biological significance for the study of terrestrial organisms. In the evolutionary process of the plant kingdom, bryophytes represent a type that gradually transitions from aquatic to terrestrial.
China is rich in bryophytes. There are 23,000 species of bryophytes in the world, and about 3,100 species in China, accounting for 12.2% of the world. Bryophytes include the Phylum Bryophytes, the Phylum Moss, and the Phylum Horned Bryophytes. Bryophytes contain 86 families, 386 genera, about 7500 species; mosses contain 120 families, 862 genera, about 13000 species of moss; horned bryophyte phylum has 6 families, 12 genera, about 200 species. There are about 152 families, 607 genera, and about 3100 species in China.
Chinese bryophytes are characterized by:
(1) Rich endemic taxa: According to the results of surveys in recent decades, there are only 35 endemic bryophytes in China and east Asian endemic bryosters that are mainly distributed in eastern Asia (only a few involve neighboring areas), accounting for 7.09% of the number of bryophyte genera in China. They contain a total of 48 species, subspecies or varieties, accounting for 2.2% of the total number of bryophyte species in China. These endemic genera and species have three distribution centers in the Hengduan Mountains of southwest China, the mountains in the middle reaches of the Yangtze River Basin, and the mountainous areas along the southeast coast;
(2) There are many taxa in the key position in phylogenesis: such as the primitive type of algae (Takakiales), the family Takakiaceae, and the two species of the genus Takakia; lepidozioides) and T. horned leaf moss ceratophylla) has been found in the alpine mountains of Chayu, Bomi and Mirin County in Tibet, China;
(3) Tropical and subtropical components are dominant.
Moss is not suitable for growing in complete shade, it needs a certain amount of scattered light or semi-shaded environment, the most important is to like humid environment, especially intolerant of drought and dryness. During the maintenance period, a certain brightness should be given, spraying water several times a day, (depending on the air humidity) should be kept above 80% of the relative humidity of the air. In addition, the temperature, the temperature should not be lower than 22 ° C, it is best to keep it above 25 ° C, it will grow well. Bryophytes are small, multicellular green plants that grow in wet and shady environments. The largest of the species is only tens of centimeters long. The shape is simple, similar to algae, and forms a flattened leaf-like body.
Bryophytes have a wide range and can survive in tropical, temperate and cold regions such as Antarctica and Greenland. Patches of bryophytes are called tundra, and the tundra is mainly distributed in northern Eurasia and northern North America, growing locally in alpine areas above the tree line.
Bryophytes that can prevent soil erosion generally grow densely and have strong water absorption, so they can grasp the soil and help to maintain water and soil. Can be used as food for birds and finches and mammals to help form soil bryophytes can accumulate moisture and dust in the surrounding environment, secrete acidic metabolites to corrode rocks, promote rock decomposition, and form soil.
The role of bryophytes in nature is mainly in the following aspects:
Many bryophytes are able to secrete a liquid that can slowly dissolve the surface of rocks, accelerate the weathering of rocks, and promote soil formation, so bryophytes are also pioneers in the growth of other plants.
Bryophytes can promote the landliness of swamps, so they are called "surface shapers". Peat moss, wet moss and other extremely water-resistant bryophytes, grow and multiply in lakes and swamps, their aging plant bodies or lower parts of the plant body, gradually die and decay, and settle to the bottom of the water, over time, plant remains will accumulate more and more, so that bryophytes continue to develop to the center of lakes and swamps, lakes and swamps The clean water area continues to shrink, the bottom of the lake gradually rises, and finally, the lakes and swamps become land.
Many species of bryophytes can be used as indicators of soil pH, such as the soil that grows white-haired moss, rocky black moss, and large blonde moss is acidic soil; the soil where wall moss grows is alkaline soil.
Bryophytes grow in clusters and mats, with plenty of gaps between plants. Therefore, they have a good effect on soil retention and water storage. Some bryophytes themselves also have the function of storing a lot of water, like the large water storage cells in the peat moss leaf, which can absorb up to 20 times the weight of the water itself.
Peat mosses can be used as fertilizer to increase the water absorption of sandy soil, and can also be dried as fuel for power generation.
Some types of peat moss can also be used as herbs, which can clear heat and reduce swelling, and peat phenol can treat skin diseases.
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