Budding treatment of Pinus koraiensis Seeds with variable temperature

Korean pine is an excellent timber forest and food forest in Northeast China. Korean pine seed coat is thick and hard, with a layer of wax, impervious to water and air, tannin in the seed coat and abscisic acid in other parts. These affect the rapid germination of Korean pine seeds and make Korean pine seeds dormant for a long time. Under natural conditions, Korean pine seeds should be released from long-term dormancy. After maturing, the seeds are buried in winter-summer-winter and taken out in the spring of the third year before they can be sown. In recent years, due to the shortage of Korean pine seeds and high market price, there is no stock of Korean pine seeds in the seed bank, so the traditional overwintering burial method can not be used to deal with Korean pine seeds. In order to cultivate Korean pine seedlings better, Hebei Forestry Bureau of Heilongjiang Province has used the newly collected Korean pine seeds to accelerate germination since 2003. The Korean pine seeds treated by this method were unearthed 3-5 days after sowing, and all emerged in about 7 days, and the annual emergence rate was more than 90%.

I. preparatory work

First, lay the floor in the seed treatment room, the floor is 30 centimeters high from the ground, do a good job of heat preservation; second, prepare sufficient river sand, the volume of which is twice the volume of the treated seeds; third, prepare heating facilities; fourth, disinfect the seed treatment room with formaldehyde and disinfect the river sand with 0.5% potassium permanganate.

II. Specific measures

1. Control the moisture (humidity) conditions: after selecting the newly collected natural mature Korean pine seeds, use clean water, preferably soak them in flowing river water for 3 to 5 days, then fish out the seeds for further water selection. After water separation, disinfect the seeds (0.5 kg potassium permanganate per 500 kg of seeds). After disinfection, the seeds are mixed with sand, and the sand volume ratio is 1:2, and the humidity of sand planting is generally maintained at 40% to 50%.

2. Control the temperature conditions: after sand mixing, the seed treatment room begins to heat up gradually. The sand planting temperature is controlled at 10% 12% in the first 10 days and 15% in the last 20 days. After 30 days of treatment, when the seed embryos of 40% color 50% seeds turn light yellow, they can be transferred to low temperature treatment. The temperature in the seed treatment room is gradually reduced, and the sand planting temperature is controlled at 0 ℃-5 ℃, about 15 days later. Freezing is carried out when the sand planting temperature is below 0 ℃. The best height of sand planting is 40 cm, never more than 60 cm. In the stage of high temperature treatment, it is tipped up and down every 6-8 hours, three times a day, and when each time it is overturned, warm water is sprayed on the sand to keep the temperature and humidity of the sand suitable. Turn over once a day when treated at low temperature. This is a measure that must be taken to make the sand planting temperature uniform in the process of seed treatment.

3. Do a good job of ventilation: according to data, when carbon dioxide increases to 17%, it will inhibit seed germination, or even poison seeds and cause death. Therefore, in the process of variable temperature germination of Pinus koraiensis seeds, the air window or door should be opened and ventilated at the right time when the sand is turned over.

To sum up, in the process of using Korean pine seeds to accelerate germination by changing temperature, in addition to ensuring the use of naturally mature seeds, the temperature and humidity of sand planting should be strictly controlled. At the same time, good observation should be done every day, recording the temperature of sand planting, indoor temperature and humidity of sand planting, timely cooling and timely ventilation, so as to ensure that the treatment time of seeds is short, and the treated seeds have the advantages of fast emergence, evenness and uniformity.