What are the propagation methods for Dianthus plumarius?
Dianthus plumarius is a perennial herbaceous plant with rhizomes, swollen nodes, and opposite simple leaves. The plant height is 10-15 cm. It stays green all year round and blooms in three seasons. It has wide adaptability, resists severe cold (it can withstand low temperatures of minus 35°C), tolerates drought and poor soil (it only needs watering once a month and rarely needs fertilizer), and its flowers are very beautiful (during full bloom the flowers can cover the ground). It is not very strict about soil pH either (it can be planted in soil with a pH between 5 and 8), has strong tillering and differentiation ability, propagates easily, and grows quickly.
Dianthus plumarius has an extensive root system, which can prevent soil erosion and water loss, and it can also resist harmful gases, pests, and diseases. It has important sanitary and environmental protection functions. It can serve as an important part of gardens, and can also be cultivated inside and outside courtyards, along roadsides, in scenic tourist areas, and in open-air activity and rest areas. It not only has a good beautification and greening effect, but also has strong ornamental value.
At present, common lawns are mostly Carex stenophylla, bermudagrass, carpet grass, and so on. They are fresh and green in spring, summer, and autumn, turn yellow and withered in winter, do not bloom, and lack cold resistance, stress resistance, aesthetic appeal, and persistence. If, in combination with local resource characteristics and market advantages, Dianthus plumarius is introduced to form large-scale production and gradually replace existing poor-quality lawns, it can produce relatively large social benefits. At the same time, calculated at the current market price of 1.10 yuan per plant and 10-11 seedlings per sq m, each mu will yield an economic income of 6000-7000 yuan, so its economic benefits are considerable.
At present, the propagation methods for Dianthus plumarius are mainly division and tillering, but it is difficult to rapidly propagate seedlings on a large scale, which is also one of the important reasons why Dianthus plumarius seedlings are currently rather expensive. This article introduces a method for rapid propagation of test-tube plantlets through tissue culture of the terminal buds and axillary buds of Dianthus plumarius. Using this technique, millions of seedlings can be propagated in a short period, with the characteristics of low cost and high benefit.
I. Preparation of culture media
According to different needs, accurately weigh various chemical reagents to prepare different types of culture media. The callus induction medium is MS+2 mg/L 6-BA; the differentiation medium is MS+1 mg/L 6-BA+0.1 mg/L NAA; the rooting medium is MS+0.1 mg/L IAA+0.1 mg/L IBA. The high-pressure sterilization conditions are 120°C, 1.1-1.2 atmospheres, for 20 minutes.
II. Culture methods
1. Callus culture. Wash young branches of Dianthus plumarius clean in clear water, cut off the leaves and most of the stem segments, take the stem tips and axillary bud parts, rinse 1-2 more times, and drain. On an ultra-clean workbench, first soak the stem tips in 75% ethanol for 30-60 seconds, then soak them in 0.1% HgCl2 for 10 minutes, and finally rinse them several times with sterile water. Use tweezers and a scalpel to remove tissue blocks including the growing point, and inoculate them onto the callus induction medium. The culture conditions are: 10-12 hours of light per day, light intensity of 1000-2000 Lx, and a temperature of about 25°C. After about 15-25 d, the inoculated explants can swell and form callus. After 1 week, the callus can be subcultured or differentiated.
2. Subculture. Under sterile conditions, take the callus out of the test tube or culture bottle, use tweezers and a scalpel to remove the medium attached to the callus blocks, and repeatedly wash them several times with sterile water until no residual medium remains on the callus blocks. Use a scalpel to cut the callus blocks into several small pieces, then inoculate them into culture bottles containing callus induction medium, and continue culturing under the same culture conditions as for callus induction. After a few days, the small callus pieces in the culture bottles can gradually grow larger, and this process can be repeated. Through subculture of callus, a large number of new shoots can be propagated from one originally inoculated stem tip tissue for use in differentiation culture.
3. Differentiation culture. Under sterile conditions, take the callus out of the test tube or culture bottle, wash it clean with sterile water, cut it into small inoculation pieces, and inoculate them into culture bottles containing differentiation medium. The conditions for differentiation culture are the same as for callus culture. After about 1 month, the callus can differentiate into buds and continue to grow new shoots. When the differentiated new shoots grow to 1-2 cm or a certain number have differentiated, take these small seedlings out under sterile conditions for rooting culture or re-induction of differentiation.
4. Rooting culture. When the seedlings in the culture bottles grow to about 2 cm, take the seedlings out under sterile conditions and place them into culture bottles containing rooting medium for culture. The culture conditions are the same as for differentiation culture. After about half a month, the seedlings can take root.
5. Hardening off. When the roots of the seedlings have grown to a certain extent and the seedlings appear robust, take the seedlings out and wash off the medium attached to the roots in clear water (note: be sure to wash them strictly clean, otherwise the roots will rot). Arrange the washed seedlings neatly, spray them moist with clear water, and harden them off for 12-24 hours under conditions of 15°C-25°C and 60%-80% humidity.
6. Transplanting. After hardening off, transplant the seedlings into an acclimatization nursery composed of vermiculite for acclimatization. Regularly spray the seedlings with acclimatization culture solution and clear water every day. After about 15-20 d, depending on the growth of the seedlings, they can be transplanted into the nursery.