In actual work, it is often necessary to grasp the viability of the seed lot within a short time. If the seed is in a dormant state at this time, it is difficult to obtain the result through germination measurement. The determination of seed viability can satisfy this requirement and the tetrazolium assay can determine the viability of dormant seed samples. The tetrazolium assay was invented by Prof. Laikang of Germany in 1942. With the development of tetrazolium measurement technology, ISl and A (International Seed Testing Association) established the tetrazolium measurement technical committee in 1950. 1 Viability concept Seed vigor is the potential ability of the seed to germinate or the vitality of the embryo. 2 Significance of determination of seed viability 2.1 can determine the viability of dormant seeds Newly harvested or seed-stored seeds that are dormant at low temperature, before seeding, seeds with low germination rate and high viability, and for those seeds with low germination rate and low viability, only determine the germination rate by germination test, it is impossible. To determine the highest germination rate of a seed, it is necessary to further determine its viability in order to understand the potential germination ability of the seed. In actual work, if fresh germinating seeds or hard seeds are found at the end of the germination test, the viability test can be performed according to the actual situation, and then the germination test can be performed. . 2.2 Rapidly predict seed germination ability Dormant seeds can be used for germination tests after breaking down dormancy with various pretreatments, but the time is longer. In the seed trade, often due to time constraints, it takes longer to use regular germination tests to determine the germination rate. Biochemical rapid test can be used to determine seed viability and provide reference for the quality of the seed 3 Tetrazole determination applicable range The tetrazolium assay is generally applied to the following conditions: seeds that need to be sown immediately after harvest; seeds that have deep dormancy; seeds that are germinating slowly; seeds that require germination potential. In addition, it is also suitable for the determination of the viability of individual seeds at the end of germination, particularly when dormancy is suspected; for the determination of germinated seeds, or for the presence of different types and processed damage (heat damage, mechanical damage, or worms, etc.) during harvest; Solve the problems existing in the germination test, such as unclear causes of abnormal seedlings or the treatment effect of bactericides. 4 The principle of tetrazolium staining assay The viability was determined by using a colorless solution of 2,3,3-triphenyltetrazole (tetrazolium, rITllC) as an indicator. This indicator is a kind of red, stable, non-diffusing and water-insoluble triphenyl formate which is absorbed by the living tissue of the seed and then receives hydrogen from the living cell dehydrogenase. Accordingly, viable and non-viable seeds can be distinguished based on staining reaction of embryo and endosperm tissue. 5 Tetrazole determination procedure 5.1 The number of sources for the test sample Samples for viability determination should be randomly selected from 100 seeds with 2.4 repeats or with fewer than 100 replicates from a net sample after thorough analysis of the purity of the seeds. If it is to determine the viability of dormant seeds at the end of germination , You can use the dormant seeds at the end of the test alone, or you can take random numbers directly from the test sample. 5.2 Seed Pretreatment Before the determination, the measured seed sample must be pretreated (pre-measured pre-wet). The main purpose is to make the seed accelerate and fully absorb moisture, soften the seed coat, facilitate sample preparation and promote the activation of the living tissue enzyme system to increase the staining. The uniformity, reliability and correctness of the identification. Pre-measurement refers to removing the external appendages of the seeds before the seeds are pre-wetted and breaking the seed coats at the non-critical parts of the seeds. For example, the rice seeds need to be removed from the inner and outer clam shells, and the hard legumes of the legumes are pierced with seed coats. It must be noted, however, that the preconditioning cannot damage the main structures of the seed's internal embryos. Most of the seeds do not need to be pre-treated, but some seeds are pre-treated before pre-wetting. 5.3 Sample preparation before dyeing In order for the tetrazolium solution to infiltrate the whole living tissue of the seed quickly and fully, to speed up the dyeing reaction and to correctly identify the main structure of the embryo, most seeds must use proper methods to make the main structure of the embryo and/or live trophic tissue before staining. Completely exposed. 5.4 Tetrazole staining The tetrazolium solution must completely submerge the seeds. The solution cannot be exposed directly. Because the light may reduce the concentration of tetrazolium salts and reduce their concentration, affect the dyeing effect. 5.5 Pre-assessment In order to ensure the correctness of the identification results, the dyed seed samples should also be properly treated, and then the main structure of the embryos and live vegetative tissue should be clearly exposed for observation and identification. 5.6 Observation and identification The reliability of the measurement results depends on the comprehensive ability of the inspectors to correctly identify the staining tissue and site, work experience, and judgment ability. Inspection personnel should carefully observe the assessment criteria to ensure the correctness of the identification results. ', 6 The advantages and disadvantages of tetrazole determination 6.1 Benefits (1) The principle is reliable and the result is accurate. Tetrazole determination is based on the main anatomy of the embryo's staining pattern to determine the seed's death and activity. And the measurement technology has developed into a mature period. Comparison tests of standard germination and tetrazolium assays show that the tetrazolium assay can be used correctly. Tetrazole measurement results and germination errors generally do not exceed 3% to 5% (2) Not subject to sleep restrictions. The tetrazolium assay is not based on the germination test, but is evaluated based on whether the growth of the seedlings is normal or not. Instead, the seeds are considered to be life and death independent of dormancy by using the reduction reactions present inside the seed to develop color. (3) The method is simple, save time and quickly. The required equipment, equipment, and articles are less, and the measurement method is also relatively simple, generally only 6 ~ 24 h. Can get results. (4) Low cost 6.2 There are practical flaws (1) The seed examiner's experience and skills are relatively high. (2) The result cannot provide the degree of hibernation. (3) The treatment of seeds will not reflect the harm of medicines like the germination test condition. Ffp2 Face Mask,Disposable Masks,Ffp2 Medical Mask,Disposable Face Mask Shaoxing Aladdin Enterprise Co.,Ltd , https://www.xhemostat.com