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.