Question

For seed samples kept in an incubator for germination test, light is– *​

Answer 1

Answer:

The purpose of laboratory testing of seed germination is to assess seed quality or viability and to predict performance of the seed and seedling in the field. A NOTIFIED laboratory under SEEDS ACT or qualified laboratory of 1STA for testing seeds must test seed processed for sale. The ultimate aim of testing the germination in seed testing laboratory is to obtain information about the planting value of the seed sample and by inference the quality of the seed lot. In addition, the laboratory germination results are also required for comparing the performance potential or superiority of the different seed lots. In general, the farmers, seeds men and public agencies use the germination results for the following purposes:

1. Sowing purposes, with a view to decide the seed rate to achieve desired field establishment.

2. Labeling purposes.

3. Seed certification purposes.

4. Seed Act and Law Enforcement purposes.

In seed testing germination has been defined as "the emergence and development from the seed embryo of those essential structures which, for the kind of seed tested indicate its ability to develop into a normal plant under favorable, conditions in soil". The seedlings devoid of an essential structure; showing weak or unbalanced development; decay or damage affecting the normal development of seedling are not considered in calculating the germination percentage. Factors that can affect the performance of seed in germination tests include; diseased seed, old seed, mechanically damaged seed, seed stored under high moisture, and excessive heating of seed during storage or drying.

In most cases a seed treatment will improve germination of seed only if the poor quality is due to seed-borne disease. Several different kinds of testing are available depending on the type of seed to be tested, the conditions of the test, and the potential uses of the seed. The most common tests are the cold germination test, accelerated aging test, the tetrazolium test and warm germination test. Each test is designed to evaluate various qualities of the seed.

1. Germination Testing

The most common test is a warm germination test because it is required by seed laws to appear on the label. The percentage of germinating seed in a Warm germination test must be printed on the label of the seed if it is to be sold as seed. The Warm germination test reflects the field emergence potential of a seed lot under ideal planting conditions. Usually 400 seed from each seed lot are placed under moist conditions on blotters, rolled towels, or sand and maintained about 75to 85 degrees F for about seven days in most of the cases. At the end of this period the seedlings are categorized normal, abnormal, or diseased, and dead or hard seeds. The percentage germination is calculated from the number of normal seedlings from the total number of seeds evaluated. The method of testing germination is discussed below.

The first and foremost step is to draw a true representative sample from the seed lot. To obtain a random sample for testing it is always best to take samples from different parts of the bag or container. If the seed to be tested is from a seed lot that contains more than one bag, samples must be taken from several bags. A good rule of thumb for determining how many bags to sample is to take samples from a number of bags that represents the square root of the lot size. For example if the lot contains 100 bags, the sample at least three bags. If the lot contains 100 bags, the sample at least 10bags. The sample thus drawn is further divided and the required numbers of seeds are the taken to perform the actual test.

Answer 2

Answer:

Not essential. Light is not essential for seed germination.

Explanation:

• Seed germination requires air, water, and a suitable temperature.
• Rapid cell division occurs during germination which requires energy. Energy is obtained by oxidation. Hence, the air is essential for seed germination.
• Food is stored in dry form in the seed. The developing embryo utilizes only food in liquid form and dissolved oxygen. Hence, water is essential for seed germination.
• High temperature destroys delicate tissues of the embryo and low temperature retards the embryo growth. Hence, a suitable temperature is required for seed germination.
• Light is not essential for seed samples that are kept in an incubator for the germination test.

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