Method for mass production and harvesting of eelgrass seeds

Abstract

The present application belongs to the technical field of eelgrass bed ecological restoration and reconstruction, and particularly relates to a method for batch production and collection of eelgrass seeds. The method comprises propagation in autumn, separation in spring and collection in summer. In the separation in spring, the clonal growth eelgrass in a nursery 1 is divided into terminal branches and clonal lateral branches, all the terminal branches are transplanted into a nursery 2, and all the lateral branches are transplanted back into the nursery 1. In the collection in summer, eelgrass seeds are collected from the nursery 2 in summer. The mode of separation in spring and collection in summer is repeated every year, thereby realizing batch production and collection of eelgrass seeds. According to the method, the proportion of eelgrass reproductive branches is nearly 70%, thereby greatly improving the seed production and collection efficiency, and providing seed restoration materials for large-scale eelgrass bed restoration.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of eelgrass bed ecological restoration and reconstruction, and particularly relates to a batch production and harvesting method of eelgrass seeds. BACKGROUND

[0002] Eelgrass is a kind of monocotyledonous angiosperm that can completely live in seawater or brackish water in estuarine waters, belonging to Alismatales, and eelgrass distributed in China includes four families, namely Zosteraceae, Cymodoceaceae, Hydrocharitaceae and Ruppiaceae. A eelgrass community with a certain area is called eelgrass bed, which has important ecological service functions such as wave dissipation and shore protection and climate regulation, is an important spawning ground and nursery ground, and is also a key place for carbon storage.

[0003] Eelgrass (Zostera marina L.), also known as Zostera, belongs to Zosteraceae and Zostera, and is a kind of eelgrass that is distributed most widely and has the largest quantity in the northern temperate sea area of China, mainly distributed in the coastal waters of Liaoning Province, Hebei Province and Shandong Province. However, in recent years, under the direct and indirect influence of human activities, the eelgrass resources in China have been seriously degraded, the distribution area has been continuously reduced, and the eelgrass bed has been seriously patchy, so it is urgent to protect and restore the eelgrass.

[0004] Eelgrass has two kinds of reproduction modes, namely asexual reproduction and sexual reproduction. The asexual reproduction is to continuously branch out lateral branches through the apical meristem, and the sexual reproduction is to produce seeds through the reproductive branches. The technical means for eelgrass bed restoration and reconstruction mainly include transplanting repair method and seed repair method. The seed repair method can maintain the rich genetic diversity of eelgrass, and the eelgrass seed is small in size, convenient to transport, and especially suitable for carrying out large-scale repair work. At present, in order to repair the eelgrass bed by using the seed repair method, the eelgrass reproductive branches need to be collected from the natural eelgrass bed to obtain the seeds. However, the proportion of eelgrass reproductive branches in the natural eelgrass bed is only about 20%, and in the process of collection, not only the collection efficiency of the reproductive branches is low, but also the physical damage to the eelgrass plants is caused, the natural eelgrass bed is damaged, and the collection of the reproductive branches also reduces the seedling supplement of the natural eelgrass bed, affecting the natural recovery of the natural eelgrass bed. Therefore, it is urgent to construct an eelgrass seed production base to realize the batch collection and stable supply of the seeds, so as to provide repair materials for large-scale eelgrass bed restoration and reconstruction. At the same time, the eelgrass seed also has relatively high nutritional value and medicinal value, and has potential economic value. SUMMARY

[0005] In view of the above problems, the present application aims to provide a method for mass production and harvesting of Zostera marina seeds, so as to improve the harvesting efficiency of Zostera marina seeds and reduce the damage to natural seagrass beds.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A method for mass production and harvesting of Zostera marina seeds, comprising autumn propagation, spring separation and summer harvesting; wherein the spring separation is to divide the clonally grown Zostera marina in the nursery 1 into terminal branches and clonal lateral branches, transplant all the terminal branches into the nursery 2, and transplant all the lateral branches back into the nursery 1; the summer harvesting is to harvest Zostera marina seeds from the nursery 2 in summer; the mode of spring separation and summer harvesting is repeated every year, so as to realize mass production and harvesting of Zostera marina seeds.

[0008] Further, first, the nursery 1 is constructed in autumn, and the Zostera marina plants are clonally grown in the nursery 1; then in the spring of the second year, the clonally grown Zostera marina in the nursery 1 is divided into terminal branches and clonal lateral branches, all the terminal branches are transplanted into the nursery 2, and all the lateral branches are transplanted back into the nursery 1, and the Zostera marina seeds can be harvested from the nursery 2 in summer of the second year; from the third year, the terminal branches and the clonal lateral branches are separated from the nursery 1 every spring and transplanted into the nursery 2 and the nursery 1 respectively, and a large number of Zostera marina seeds are harvested from the nursery 2 in summer; the mode of spring separation and summer harvesting is repeated, so as to realize mass production and harvesting of Zostera marina seeds.

[0009] Specifically, the method comprises the following steps:

[0010] (1) Autumn propagation, the nursery 1 is constructed in autumn of the first year, Zostera marina plants are collected from a natural seagrass bed, and then the Zostera marina plants are transplanted into the nursery 1 for clonal growth;

[0011] (2) Spring separation, in the spring of the second year, the clonally grown Zostera marina in the nursery 1 is divided into terminal branches and clonal lateral branches, all the terminal branches are transplanted into the nursery 2, and all the clonal lateral branches are transplanted back into the nursery 1;

[0012] (3) Summer harvesting, in summer of the second year, the terminal branches of Zostera marina in the nursery 2 are transformed into reproductive branches and matured, and then the Zostera marina seeds can be harvested;

[0013] (4) From the third year, the mode of spring separation and summer harvesting is repeated every year, the terminal branches and the clonal lateral branches are separated from the nursery 1 every spring and transplanted into the nursery 2 and the nursery 1 respectively, and a large number of Zostera marina seeds are harvested from the nursery 2 in summer, so as to realize mass production and harvesting of Zostera marina seeds.

[0014] In step (1) autumn propagation, when the Zostera marina plants are collected from the natural seagrass bed, the aboveground leaf sheath and leaf part of the Zostera marina plants are retained for 20 cm, and the underground stem and root are retained for 5-10 cm.

[0015] Step (1) the time of autumn propagation is from September to October.

[0016] Step (2) the time of spring separation is March.

[0017] Step (3) the time of summer harvest is from late June to early July.

[0018] In step (1) of autumn propagation, one eelgrass plant is one transplant unit, and the interval between each transplant unit is 20-30 cm.

[0019] In step (2) of spring separation, one clonal lateral branch is one transplant unit, and the interval between each transplant unit is 20-30 cm.

[0020] The nursery 1 and the nursery 2 are the same or different and are arranged in a sea area or a coastal seawater pond with gentle current, water depth of 1-3 m, good water quality, and muddy sand bottom.

[0021] The transplanting method of eelgrass plants in the nursery 1 and the nursery 2 is determined according to the hydrodynamic conditions.

[0022] The transplanting density of eelgrass plants in the nursery 2 is determined according to the specific conditions. If it is in a natural sea area, the density can be referred to the density of seaweed in a natural seaweed bed. If it is in a coastal artificial seawater pond, the plant density can be significantly increased according to the water quality, preferably 2 times the density of the natural seaweed bed.

[0023] The number and relative position of the nursery 1 and the nursery 2 are determined according to the specific conditions.

[0024] The beneficial effects of the present application are:

[0025] 1. The present application realizes batch production and harvest of eelgrass seeds through the mode of spring separation and summer harvest. In the spring separation, the eelgrass plants in the nursery 1 are divided into terminal branches and clonal lateral branches, all the terminal branches are transplanted into the nursery 2, and all the lateral branches are transplanted back into the nursery 1. The nursery 1 provides a large number of terminal branches for easy separation, and the nursery 2 produces seeds in batches. With the passage of time, the area of the nursery 1 will become larger and larger year after year due to the large-scale propagation of eelgrass plants in autumn, which can support the seed production of a larger scale of nursery 2. Compared with the existing method of collecting eelgrass reproductive branches from natural seaweed beds to obtain seeds, the proportion of reproductive plants is greatly improved, and the production and harvest efficiency of seeds is improved. At the same time, the present application also avoids the damage to natural seaweed beds caused by seed collection.

[0026] 2. In the method of the present application, more than 60% of the eelgrass terminal branches transplanted from the nursery 1 are converted into reproductive branches, which significantly improves the conversion rate of eelgrass terminal branches to reproductive branches compared with the proportion of 20% of eelgrass reproductive branches in natural seaweed beds. Therefore, the method of the present application improves the harvest efficiency of eelgrass seeds.

[0027] 3. The method of the present application only needs to collect eelgrass plants from natural eelgrass beds in autumn of the first year, and then can provide eelgrass plant materials by itself, which can effectively reduce the damage to natural eelgrass beds caused by the collection of reproductive branches.

[0028] 4. The method of the present application utilizes natural sea areas or culture ponds to build seed production bases, and the cost is low. DETAILED DESCRIPTION

[0029] The present application will be further described in detail below with reference to examples.

[0030] Example 1

[0031] A eelgrass seed production base was constructed in a certain sea area in Hebei.

[0032] In October 2020, eelgrass plants were collected from a natural eelgrass bed, and the aboveground sheath and leaf part was retained about 20 cm, and the underground stem and root was retained about 5-10 cm, and then 22 eelgrass plants were transplanted into nursery 1 by direct insertion method, one eelgrass plant was one transplant unit, and each transplant unit was spaced 25 cm apart; nursery 1 was located in the sea area around the natural eelgrass bed, the sea area had gentle current, water depth of 1-2 m, and sandy bottom.

[0033] In December 2020, it was observed that the eelgrass transplanted in nursery 1 increased the number of branches by 8 times through clonal growth, and in March 2021, the eelgrass in nursery 1 after clonal growth was divided into terminal branches and clonal lateral branches, all terminal branches were transplanted into nursery 2 by direct insertion method, and all clonal lateral branches were transplanted back into nursery 1 by direct insertion method, one clonal lateral branch was one transplant unit, and each transplant unit was spaced 25 cm apart. In nursery 2, the density of transplanted terminal branches was 1000 plants / m 2 . Nursery 2 was located in a seawater pond along the coast around the natural eelgrass bed, with water depth of 1.5 m, good water quality, and sandy bottom, and was 1000 m away from nursery 1.

[0034] In early June 2021, it was observed that 67% of the eelgrass terminal branches transplanted in nursery 2 had turned into reproductive branches.

[0035] In late June 2021, after the reproductive branches in nursery 2 matured, eelgrass seeds were collected, and the seed yield was 143 kg / acre (wet weight), or 90 kg / acre (dry weight).

[0036] In the following years, the spring separation and summer collection mode was repeated.

[0037] Comparative Example

[0038] In the natural eelgrass bed near nursery 1, in early June 2021, the plant density was 1004 plants / m 2The proportion of the reproductive branch is 20%, and the seed is collected in late June 2021 after the reproductive branch matures, and the seed collection yield is 42 kg (wet weight) per mu, or 26 kg (dry weight) per mu.

[0039] As can be seen from the examples and comparative examples, the method of the present application can continuously provide seedlings in nursery 1 by separating the terminal branches and the clonal lateral branches of eel grass in spring, and can harvest a large amount of seeds in nursery 2; in the example of nursery 2, although the plant density is not different from that of the natural grass bed, the proportion of the reproductive branch of the eel grass in nursery 2 is 67%, which is significantly higher than the proportion of the reproductive branch of 20% in the comparative example, so the seed yield of the example of nursery 2 is significantly higher than that of the natural grass bed. At the same time, the present application can avoid the damage to the natural seagrass bed caused by people collecting seeds.

[0040] In summary, the seed mass production and collection method provided by the present application can convert a high proportion of eel grass plants into reproductive branches, improve the collection efficiency of eel grass reproductive branches, and can be self-sustaining, only needs to collect plants from natural seagrass beds once, and can effectively reduce the damage to natural seagrass beds. In fact, with the extension of years, the area of nursery 1 will become larger and larger due to the large expansion of eel grass plants in autumn, in addition to supporting larger scale seed mass production of nursery 2, nursery 1 can also provide a large number of seedlings for the ecological restoration of degraded seagrass beds in the surrounding sea area.

Claims

1. A method for mass production and harvesting of eelgrass seeds, characterized in that: (1) Propagation in autumn: In the first autumn, nursery 1 was constructed, and eel grass plants were collected from natural seagrass beds. Then, the eel grass plants were transplanted to nursery 1 for clonal growth. (2) Separate in spring. In the spring of the second year, the eel grass in nursery 1 after cloning growth is divided into terminal branches and cloning lateral branches. All terminal branches are transplanted to nursery 2, and all cloning lateral branches are transplanted back to nursery 1. (3) Harvest in summer. In the summer of the following year, after the terminal branches of Eriocaulon ferns in nursery 2 have transformed into reproductive branches and matured, the seeds of Eriocaulon ferns are harvested in a concentrated manner. (4) Starting from the third year, repeat the spring separation and summer harvesting pattern. Every spring, separate the terminal branches and cloned lateral branches from nursery 1 and transplant them to nursery 2 and nursery 1 respectively. In summer, harvest a large number of eel grass seeds from nursery 2, thereby realizing the mass production and harvesting of eel grass seeds.

2. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Step (1) Propagation in autumn: When collecting eel grass plants from natural seagrass beds, retain 20cm of the above-ground leaf sheaths and leaves, and 5-10cm of the underground stems and roots.

3. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Step (1) The autumn propagation period is from September to October.

4. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Step (2) The spring separation time is March.

5. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Step (3) The summer harvesting time is from late June to early July.

6. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Step (1) When propagating in autumn, one plant of Eriocaulon buergerianum is a transplanting unit, and the interval between each transplanting unit is 20-30cm.

7. The method for mass production and harvesting of eelgrass seeds according to claim 1, characterized in that: Nursery 1 and Nursery 2 are located in the same or different locations in sea areas or coastal artificial seawater ponds with gentle currents, water depths of 1-3m, good water quality, and muddy or sandy bottoms.