Germination rate refers to the percentage of the number of germinated test seeds in the total number of test seeds.Germination rate is one of the important indicators for testing seed quality,agricultural productionIt is often used to calculate the seed consumption.
Germination rate refers to the percentage of the number of germinated test seeds in the total number of test seeds.If 95 out of 100 test seeds germinate, the germination rate is 95%.Germination rate is one of the important indicators for testing seed quality, and it is often used to calculate seed consumption in agricultural production.The days specified for calculating crop seed germination rate are:Corn, wheatmillet、soybean、Sunflower7 days for crops,sorghum8 days,rice、Mung bean、peanut10 days for other crops.[1]
significance
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While measuring the germination rate of seeds, the germination potential of seeds should also be measured, so as to reasonably and accurately determine the sowing amount and sowing depth per unit area, so as to ensure that seedlings can be preserved in one sowing.Germination potentialIt refers to the germination speed and uniformity of test seeds. Its expression is to calculate the percentage of the total number of test seeds in the number of germinated seeds from the beginning of germination to the peak of germination.The larger the value, the stronger the germination potential.It is also one of the important indicators for detecting seed quality.
Crop seeds with high germination rateGermination potentialStrong, indicating that the seedlings emerge quickly and orderly, and the seedlings are strong;If the germination rate is high and the germination potential is weak, it indicates that the seedlings are uneven and weak.Generally speaking, the germination rate of old seeds is not necessarily low, but the germination potential is not high, while the germination rate and germination potential of new seeds are high, so the production should try to "discard the old and take the new".
influence factor
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Production link
External factors
Seed germination requires water, temperature, oxygen, light and other conditions. Different crops require different conditions for germination due to different ecological environments of origin and evolution.
Water: water is the key factor for seed germination, and seeds must absorb enough water togerminationHowever, too much water will increase the probability of seed mildew and pathogen infection.Generally, the germination bed is selected according to the crop type and seed size, and then appropriate water is added according to the water requirements of different germination beds.
Temperature: under suitable temperature conditions, the temperature control of seed germination isconstant temperatureAnd variable temperature.No matter what kind of temperature control mode is adopted, too low temperature during germination will delay the physiological function of seeds, and too high temperature will cause abnormal seedlings due to the inhibition of their physiological activities.
Oxygen: oxygen is also an important factor affecting seed germination. Generally speaking, more water and less oxygen on the germination bed will result in sprouting;On the contrary, less water and more oxygen are suitable for growing roots.
Light: Different crop seeds have different responses to light when germinating. Generally, they are divided into light demanding seeds, dark demanding seeds and light insensitive seeds.mostField cropAnd vegetable seeds are not sensitive to light, and can germinate well under light or dark conditions, but it is better to use light.
Physiological factors
The physiological state of seed is one of the main factors that affect seed vigor and longevity (germination).Physiological status mainly includes the maturity and water content of seeds.In general, the better the maturity of the seed, the higher the vitality and the longer the duration, and the higher the germination rate;It is difficult to obtain higher vitality if the seeds do not reach physiological maturity or are poor, and the germination rate of seeds will also be affected and show lower performance.Under the same conditions, the higher the water content is, the stronger the seed hydrolase activity is, the faster the metabolism is, the more nutrients are consumed, and the faster the seeds age and deteriorate. With the passage of time, the vitality of the seeds is depleted, and the germination rate is reduced.
Seed maturity: Generally, seeds with high maturity have high germination rate.This is because normally mature seeds can provide sufficient nutrients for their germination, but not normally mature seeds.
seed dormancy The seeds of most plants, such as rice and wheat, can germinate when they are mature. However, the seeds of some plants cannot germinate even if the external conditions are very favorable after they leave the mother body. They must go through a period of dormancy, such as alfalfa and ginkgo.
Seed moisture content: In a certain range and under the same test conditions, the higher the water content of the seed itself, the more conducive to germination.However, when seeds are stored, if the water content of seeds is too high, the respiration of seeds will be enhanced, which will lead to the increase of seed temperature, sweating, dewing, and even mildew of seeds, seriously affecting the germination rate of seeds.In the process of harvesting and drying, if the seeds are exposed to the sun for a long time on the cement ground, the water content of the seeds will drop sharply, forming the so-called "iron seeds", and the germination rate of the seeds will also be greatly reduced.
Drug injury: onSeed coating(or reagent seed mixing)Seed coating agentIf the quality of (or medicament) is not up to standard or the ratio of traditional Chinese medicine to seed is too large during the operation, the seeds will be damaged to some extent and the germination rate of seeds will be reduced.Some data showed that the germination test was carried out immediately after the wheat was coated. Compared with the blank control within the specified time, the germination was slow and the germination rate was low.
human factor
Incomplete cleaning and sterilization: the germination box and germination box should be cleaned and sterilized before each use, and the germination paper (or sand) should also be sterilized before use.If the above items are not cleaned and disinfected or sterilized incompletely, they will increase the chance of seeds infected with bacteria, thus reducing the germination rate.
Improper water addition: during the management process, the germination bed is too dry or wet, and the repeated water addition is inconsistent, which will affect the normal germination and seedling growth, leading to inaccurate results.
Selection of production area and base
The production area shall be reasonably selected and arranged according to the accumulated temperature, climate, light, air humidity, cultivated land conditions and production conditions of the crop varieties produced, so as to ensure that the plants are free from adverse factors during the growth and development process and complete the normal maturation process of the seeds.
Effects of production technical regulations on seed growth and development
The production technical regulations have a decisive impact on the production quality of seeds. Scientific and reasonable production technical regulations should be formulated.Whether each link of the production process is carried out correctly will have an impact on the health and vitality of the seeds.The details are as follows:
Production and processing
florescencePollinating insectThe bee source is insufficient, the pollination quality is poor, and there are more blighted seeds and no embryos;When nitrogen fertilizer was applied, the plants were overgrown and lodging, and the seeds were mildewed on the plants;Wrong drug use causes drug damage, which hinders the growth and development of plants;The control of diseases, pests and grass pests is unfavorable, affecting the quality of fruit setting;Damp heat mildew and corrosion occur in the stages of harvesting, ripening, fermentation and drying, damaging the germ;The measurement and method used in the seed medicament treatment process are unreasonable, the seed embryo is damaged, and the germination ability of the seed is affected;Mechanical damage, corrosion and high temperature caused by seed processing;The changes inside the seeds after coating directly or indirectly affect the germination ability of the seeds.
Adverse climate
Drought and high temperature resulted in poor development of seeds, accelerated maturity, decreased plumpness and light blight of seeds;Continuous rainy weather at maturity and after harvest makes seeds germinate or mildew on plants;Late maturing varieties suffer frost and seed embryos are damaged, which is the decline of germination rate.In addition, the unsuitable variety factors to the growth environment and climate will also affect the germination rate.
Storage process
The seeds should be stored under dry and low temperature conditions.The storage place has the functions of ventilation and moisture removal, temperature control and heat dissipation, light control and sealing, which are conducive to seed storage;It has the ability to regularly detect the changes of warehouse insects and microorganisms and their storage environment, and has the management ability and system of regulation.The physical and chemical indexes of stored seeds should meet the requirements of storage methods;The seeds with different morphological and physiological characteristics and different water content shall be stored separately to facilitate the application of temperature, humidity, ventilation, chemical treatment and other control measures.
Storage method: normal temperature storage, vacuum storage, sealed low temperature, ultra low temperature (- 196 ℃) storage and ultra dry (moisture below 5%) storage operation technology should meet the requirements of safe storage, and pass a certain period of crop variety test and meet the storage requirements.Otherwise, incorrect methods will lead to the decline of seed germination rate.
Storage period: during the storage of seeds, with the extension of storage time, the germination rate gradually decreased.Different storage methods, different seed heredity, different seed characteristics and chemical composition, and different seed lifespan;Long life seeds still have good germination rate after being stored for more than 15 years, while short-lived seeds rapidly decline after being stored for 2-3 years.
test method
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Put the seeds under the most suitable germination conditions to calculate the number of seeds germinated within the specified days, and calculate the percentage of the tested seeds.
The germination rate was determined to be 7 days,Germination potentialDetermined for 3 days.
Preparation of germination bed
According to the technical regulations, select an appropriate germination bed, lay 1cm thick washed fine sand or two layers of filter paper in the petri dish or dish, and inject clean water until it is saturated.
All appliances and germination beds used for the germination test must be sterilized by boiling with steam or water.
test method
Test germination rate
1. Preparation of samples Take 4 groups of samples randomly from the good seeds that have been tested for cleanliness, and take 100 samples as a group (4 × 100).
2. Place seeds
The seeds shall be placed on the germination bed in groups, and the distance between the seeds shall be 1~2 times of the seed length.After placing (the seeds can be pressed into the sand gently when using the sand bed, and the fine sand of the seeds can be flattened), cover it, but do not hinder the air circulation.
3. Send it into the germination chamber after marking
Label the germination dish, indicating the sample number, variety name, test start date, or only the germination bed number, and establish a separate germination test record.Finally, send the germination bed into the germination chamber or thermostat, and conduct the germination test according to the temperature and days specified in the technology.
4. Inspection
After the start of the germination test, in addition to maintaining the moisture and temperature required for germination, the germination condition shall be checked once a day, and the normal and abnormal germinated seeds shall be timely checked and recorded according to the specified deadline for germination potential and germination rate.
(1) Normal germinated seeds
The young roots of long grain seeds of cereals reach the length of seeds, and the young buds reach at least 1/2 of the length of grains.Although there is no main root in cereal seeds, lateral roots develop normally.
(2) Abnormal germinating seeds
The young roots or buds of cereal seeds are incomplete, deformed or decayed.
The young roots were significantly atrophied, with fibrous young roots in the middle and swollen buds without root hairs.
(3) When determining the aging degree of grain quality to identify germination, the normal germinated grain is that the fresh bud breaks through the seed coat (commonly known as dew).
Result calculation
The seed germination test is expressed in terms of germination potential and germination percentage.seedGermination potentialAnd seed germination rate are calculated according to Formula (1) and Formula (2) respectively.
