Effect of grass seed storage on germination rate

1. Species and Storability of grass seeds: 1

We all know that the Storability of legume seeds such as white clover and alfalfa is obviously better than that of Gramineae seeds. Some studies have proved that some legume seeds stored for 10 years can still maintain more than 80% germination rate. The Storability of Gramineae seeds is much weaker. The typical seeds that we often contact are Festuca arundinacea and Festuca glomerata, which can be reduced to almost no germination rate within one or two months under the adverse conditions of high temperature and humidity. The experience is that the seeds of two or three years ago have no obvious drop in bud rate. In the most commonly used seeds of ryegrass, tall fescue and Poa pratensis, the Storability of Poa pratensis seeds may be slightly better than that of ryegrass and tall fescue. In a high temperature and humidity aging experiment, the germination rate of a tall fescue seed with high germination rate dropped to less than 30% at 48 hours.

2. In seed production, the factors that may affect seed storage capacity are as follows

Different seed production fields have different water and fertilizer management conditions, combined with the impact of seed growth and harvest season climate conditions, as well as the differences in harvest time, seed plumpness and color of different batches of seeds are different. Generally speaking, the seeds with poor plumpness have less nutrients stored in them. When the seeds are stored for a long time or under poor storage conditions, they are more likely to exhaust the nutrients and die first.

Seed moisture content is also an important factor affecting its storability. There are standards for seed moisture content in various countries. For example, the water content of gramineous grass species should be lower than 11 or 12% (different from different species) in China. Foreign grass seeds also have water content standards when cleaning and packing. If the moisture content exceeds the standard, the seeds with unqualified moisture content can not pass the certification. High moisture seeds have stronger respiration and consume more nutrients. At the same time, they also have fever, which leads to early death of seeds.

3. The effects of seed storage conditions on germination rate were as follows

Humidity and temperature are the most important factors affecting the Storability of grass seeds. Low temperature and drying can effectively prolong the seed life, whereas high temperature and humidity can shorten the seed life.

Low temperature and low water content of seeds can reduce the respiration of seeds, reduce the consumption of nutrients and prolong the life of seeds. Some studies have found that the seed life is doubled when the temperature is between 50-0 ℃. In many cases, humidity has a more obvious impact on seed longevity, because humidity will directly affect the moisture content of seeds. When the moisture content of seeds is in the range of 5% - 14%, the life span of seeds will be reduced by half for every 1% increase of water content, which is called "Harrington general rule".

It should be pointed out that the moisture content of seeds will be changed due to the change of humidity in the storage place, because the cellulose and starch and other substances contained in the seeds are hygroscopic. When they are in different air humidity environment, water exchange will be carried out in the air. Generally, the relative humidity is more than 70%. If the grass seeds are stored for 10 days, the moisture content can be increased to more than 14% through water exchange.

A typical example is that a customer imported several containers of grass seeds. The arrival time was high temperature and humidity in summer. Due to the problem of documents, the terminator stayed in Shanghai port for more than two weeks, and then it was transferred to inland. During customs clearance, it was found that the weight of each container was several hundred kilograms higher than that of foreign shipment. The customs considered that it was inconsistent with the documents, so it opened the box for counting, The results showed that the number of packages was correct, but the weight of each package of seeds was slightly higher than the nominal value, which was actually caused by the absorption of moisture in the air, and the actual weight gain was 3% - 4%.

4. Some suggestions on seed storage

At present, most grass seeds are stored in the normal temperature warehouse, which can only prevent the seeds from being exposed to the sun and rain, and the temperature and humidity can only be determined by God. Not all seeds can survive the summer safely under the high temperature and humidity conditions. If it is necessary to store the seeds over the summer, we suggest to improve the storage conditions of the seeds as far as possible. In terms of the seed stacking method, it is recommended to use wooden pallets under the seed stacks, and control the width and height of each stack. Sufficient ventilation space should be reserved between stacks, walls and roofs. It is better to install electric row The fan strengthens the air circulation to reduce the temperature and humidity.