Stonewort grows on the seabed rocks below the dry tide line and at a water depth of about 10 m, preferring to be born in the clean water, smooth tides, high salinity sea area. from August to October, the water temperature of 25-27 ℃ for the breeding period. It grows on the seabed rocks near the big dry tide line to the water depth of 6-10 m. The production area is generally the outer sea area which is very little affected by fresh water. Algae born in clear water and rapid flow of the algae body is large and clean, born in turbid water and slow flow of the algae body is small, and there are often many epiphytic moss insects. The larvae of the stonewort are mostly found between September and December, and the tetrasporangia, spermathecae and cystocarps appear most frequently between July and October.
Stonewort reproduction
Stonewort reproduction is mainly sexual and asexual two forms, sexual reproduction is through the female and male gametophyte maturity, fruiting cells fertilized to form fruiting cysts, fruiting cysts mature to produce fruiting cysts;; asexual reproduction is through the tetrasporangium to produce tetrasporangia and carry out. These two forms of reproduction are ultimately spores, so it is called sporulation. In addition, stonewort has a special ability to propagate nutritionally, which can be divided into three main forms such as stolon propagation, pseudoroot propagation and algal regeneration. In addition to sporophyte generation and gametophyte generation, there is also fruit sporophyte generation in the life history of stonewort. However, the fruit sporophyte cannot exist alone and can only form, grow and develop on the female sporophyte. In the non-breeding season, it is not easy to distinguish between the three tetrasporangia of male and female gametophytes. We usually see all three types of algal bodies in Stonewort, only in the breeding season. After the reproductive organs are produced on the algal body, they can be distinguished from each other.
1. male and female gametophytes
(1) male gametophyte: after the male gametophyte matures, there are oval spermatophores grouped at the tip of the flattened spermatophore branchlets, which are formed by the transformation of the surface cells of the algal body into the spermatophore mother cells, and the spermatophore mother cells are formed after division: each spermatophore mother cell produces two spermatophores. The spermatozoa are colorless and round, without flagella, cannot swim, and depend on the flow of seawater to be carried to the fertilization filaments of the fruiting cells of the female gametophyte for fertilization.
(2) Female gametophyte: The female gametophyte approaches or matures to produce fruiting cell branchlets specialized in producing fruiting spores, which are produced by the apical branchlets of the main branch, and a few are formed directly at the tip of the main branch. At maturity, each side of the main axial cell of the fruiting branchlet divides into periaxial cells, and the third or fourth row of periaxial cells produces supporting cells and fruiting mother cells, which are transformed into fruiting cells by metamorphosis (the cells on the top). The fruiting cell has a rod-shaped fertilization filament extending from the surface of the algal body to a supporting cell below the fruiting cell, thus the fruiting cell branch consists of a single cell. During the development of the fruiting cell branch, the base of the second row of periaxial cells produces several rows of small cells, and the inside of each cell is rich in protoplasm, which is called nutrient cells or trophoblast cells, whose role is to provide nutrients for the development of the cystic fruit.
2. Fructosporangium: After the formation of the fruiting cell, it encounters the spermatozoon, which adheres to the fertilization filament and melts at its contact, while the sperm nucleus enters the base of the fruiting cell along the fertilization filament and combines with the egg nucleus to form the syncytium, which does not leave the mother. After fertilization, the fruiting cell then fuses with the supporting cells below to form a large fusion cell. The fusion cell produces many branched spore-producing filaments that penetrate. They enter the intercellular spaces of the nutritive tissues and absorb nutrients. In mature sporangia, the terminal cells elongate and divide into fruiting sporangia. At the same time as the fusion cell produces sporangia, the outer cortex of the sporangia further develops and bulges, forming an expanded portion of the alga called the fruiting sporangium or cystocarp. Observed in cross-section, the expanded part of the two incomplete separation of the chamber, the top of the chamber each has a hole with the outside world, this hole is called the cystic fruit hole, mature fruit spores that is from the cystic fruit hole out of the body. After the fruit spores are discharged, they will be dispersed with the water and drift, and when they meet the suitable substrate, they will be attached and germinate into tetrasporangia.
3. Tetrasporangium: After the maturity of the tetrasporangium, an expanded ovate tetrasporangium branch is formed at the tip of the branch, and the tetrasporangium is formed by the surface cells of the branch. At maturity, the tetrasporangium is gradually buried in the algal cells as a result of the upward growth of neighboring trophoblasts. Each tetrasporangium mother cell undergoes meiosis to form four tetraspores, which are arranged in a zigzag pattern in the tetrasporangium. When the tetraspores are mature, they are small purple-red spots on the surface of the alga, which are slightly raised and arranged along the flat side of the branchlets. After the maturation of the tetrasporangium, the wall of the sporangium ruptured, and the spores were dispersed in the seawater, and when they met the suitable substrate, they adhered to it and formed the male and female gametophyte.
4, spore dispersal and attachment: when the mature tetrasporangium discharge, in the sporangium branches can be seen at the mouth of the sporangium overflow tetrasporangium, when the overflow of nearly half, the rest of the rapid roll out. The time of tetrasporangial discharge was generally half a minute to one minute. After the discharge of tetrasporangia, they are still spherical, they stay at the discharge port for a while, and then begin to float up and away from the mother. It can be seen that the discharge of tetraspores of C. stonecropylus is firstly discharging the tetrasporangia. After a period of time, the tetraspores suddenly split at the cracks of the tetrasporangium, probably due to the gelatinization of the wall of the sporangium, and the tetraspores were released and dispersed in all directions, with the distance between them getting larger and larger, and then slowly sinking. The just separated tetraspores are long conical, long ovate, or irregularly long conical, etc. The tetraspores are not only long conical, but also long ovate, long ovate, or irregularly long conical.
After the fruit spores mature, their discharge process is, sometimes first from a cystic fruit holes to release 2--3 fruit spores, and then from another cystic fruit holes to release 1, so that the fruit spores have been released from the first release of the fruit holes in a regular pattern of dispersal; and sometimes from the two fruit holes in turn to release, or from a fruit holes to release two, and then from another fruit holes to release the fruit spores. Fruiting spores are also released in the form of fruiting spores. The form of fruit spores released is also different, some are ejected, the big head of fruit spores outward and the small head inward from the fruit of the capsule out rapidly; some are released in the form of spillage, the action is more slow. The newly dispersed fruit spores are oblong-ovate, conical or irregularly conical, etc. When the fruit spores are dispersed, their heads are outwardly and inwardly ejected rapidly from the capsules. Fruit spores scattered, the interval is also different, sometimes 1 minute to release 1 or 2 or 3, sometimes 2 or 3 minutes or even longer time to release 1.
The tetrasporangium branches and fruiting branches of stonewort will naturally discharge tetraspores and fruiting clasps after maturity, but the amount of dispersal varies greatly. It was observed that during the time when the spores were centrally discharged, the tetraspores could disperse 10,000 spores per hour per gram of cysticercus branch; the fruit spores could disperse 10 per hour per gram of cysticercus branch. This indicates that tetraspores disperse significantly more than fruit spores.
As to the attachment of spores, Sudo of Japan believed that spores could be attached within 5-10 minutes after leaving the parent body. Minoru Katada also pointed out that most of the spores were attached within a few minutes after they were released. If the spores do not meet the growth substrate for a long period of time (more than 3 hours), they will lose their adhesion, and if they meet the growth substrate again in the future, the spores will not be able to attach. In natural sea areas, most spores attach near the parent body, while spores that are carried elsewhere due to seawater activity may lose their ability to attach because they are released for too long.
5. Spore germination and seedling growth: tetraspores or fruiting spores have to germinate after attachment. Their germination and growth process is the same, and its size, form is also the same. It is globular amoeboid, 27.836.7 μm in diameter, 32 μm on average, with a nucleus in the center, thick protoplasm around the nucleus, and red coarse pigmented bodies diffused in the spores. The released tetraspores were reported to be naked", but when germinating, the tetraspores were wrapped in a wall. Usually the spores are released for several hours before they begin to germinate. When germination occurs, the pigment granules first become dispersed, and at the same time, on the outer side of the cell, a hyaline expanded protuberance is produced, which is called the germination tube. Then, the spore content moved into the germination tube, and the original spore vacuole remained at one end. About 2 hours after spore germination, a septum is created between the germinal tube and the spore. The cell produced after spore germination is called the basic cell, which is oblong or oblong-ovate, with a central nucleus and pigment bodies slightly reticulate and unevenly distributed within the cell. The specific morphology of the basic cell is of great significance to the subsequent division. According to Huang Lijuan's observation, when the spore divides, it first splits into two cells, a small spindle-shaped cell with pointed ends and a large cell with rounded ends and a slightly narrower center. In general, the small cell is on the upper side and the large cell is close to the original spore shell.
Later, the two cells produced by each division divide again in a transverse direction, while at the same time a hyaline cell with almost no pigmentation is produced at the tip of the large cell. This cell elongates anteriorly to form the initial pseudoroot, and then the young sprouting cells divide again in successive irregular longitudinal and transverse divisions. After the sprouting tube protrudes for 20 to 25 hours, the number of cells increases to 20 to 30, and its length is about 50 micrometers or so by removing the empty shell of the initial pseudoroot and protospores. After the sprouting tube protruded for 70- 80 hours, a hyaline growth point cell appeared at the opposite end from the pseudoroot.
After the first pseudoroot grows from the larger cell, a second pseudoroot usually emerges from the smaller cell, but sometimes the growth order is reversed and the first pseudoroot grows from the smaller cell first.
After 5 or 6 days of incubation, the growth point began to divide, growth accelerated, and the original boundary between the two cell division areas gradually became less obvious. The original spore residue shell gradually blurred or disappeared. At this time, the length of the larvae is about 60 microns, and the length of the primary pseudopodia is about 120 microns.
After 10 days of incubation, the larvae grew to an average length of about 100 micrometers, and the primary pseudoroot reached its maximum length of about 180 micrometers. From then on, the initial pseudoroots began to shrink. After 15 days, the average length of the seedlings was about 140 microns. 21 days, the seedlings could reach a length of about 80 microns, the lateral pseudoroot bundles began to appear, the basal part of the branchlets appeared, and the primary pseudoroots continued to shrink. After 31 days of cultivation, the seedlings were up to 1 mm long, individually up to 2 mm, and the primary pseudoroots were all atrophied, but some of them regenerated secondary pseudoroot bundles, and the lateral pseudoroot bundles increased. 35 days later, the seedlings were 1-2 mm long; most of them regenerated secondary pseudoroot bundles, and became the primary roots. 41 days later, the seedlings were up to 2 mm long, and all of them regenerated secondary pseudoroot bundles; the lateral pseudoroot bundles increased to 5-6 bundles per seedling or more, and they became creeping seedlings. They became creeping seedlings. And then under the sea to raise a month, creeping seedlings can grow into stone cauliflower seedlings. 1. Stolon propagation: stone cauliflower larvae grow to a certain size, it will be from the base in the horizontal direction to grow out of stolons, stolons continue to spread growth. Stolon branches down to give birth to pseudo-roots, and attached to the substrate, upward growth of straight three-dimensional. This continuous growth increases the number of uprights, resulting in the formation of many upright seedlings. Stolon propagation is a unique form of nutrient propagation of stonewort, and this form of propagation has great significance in the breeding process of stonewort.
2. Pseudoroot reproduction: the pseudobranch tip of stonewort, from its morphology and structure, is similar to the young shoots that grow after the germination of spores. If we remove the root tip, after a period of cultivation, this root tip is still able to regenerate prostrate and erect branches, and grow into independent new individuals. Stonewort that grows in natural sea areas is often knocked off the rocky seabed by wind and waves, or harvested by people. However, the pseudoroots of the rockweed can easily break off and remain on the rocks where they were growing, and these remaining pseudoroots on the rocks are often able to form new individuals. Pseudoroot propagation of rockweed is a propagation method of great importance to rockweed culture, and by utilizing this propagation habit of rockweed, we can harvest the adult rockweed on the rearing ropes directly after the rockweed spore harvesting culture is finished, and leave the pseudoroots on them, so that these pseudoroots can re-grow to form new seedlings, and continue to be reared.
3. Propagation of nutritive branches: If the branch or main branch of the stonewort is removed, the incision of the part left on the rock can still send out new shoots and continue to grow to form a complete individual. The excised branch, if clamped to a seedling rope; it then continues the growth of the nutrient body. The branching raft culture technology of rockcress is to utilize the characteristics of the branch body to grow away from the body, harvest rockcress from the natural sea area as seed, and then split the branch body and clip it on the seedling rope to raise.