NEET BIOLOGY

Detailed explanation-1: -Light is not necessary for a seed to germinate, no. The majority of seeds grow most effectively in the dark. Light, which is essential for seedling growth, may actually hinder the germination process. The three primary and necessary conditions for a seed to germinate are water, oxygen, and temperature.

Detailed explanation-2: -Light is also an important signal for seed germination and seedling development. Many plants, such as lettuce, show photoblastic seed germination, requiring light exposure for germination (e.g. Borthwick et al., 1954).

Detailed explanation-3: -Only some seeds need light to germinate. They include some vegetable seeds, which are usually among the smallest seeds, and lettuce, which also does not need to be covered with soil, though the seeds can tolerate a thin layer. Other seeds also require little soil cover and therefore may germinate in light.

Detailed explanation-4: -Most of the seeds germinate best in dark environments. The presence of light tends to inhibit their growth. The light decomposes carbonic acid gas and expels oxygen which leads the seed to harden. These gases are key factors that promote germination.

Detailed explanation-5: -All seeds need water, oxygen and the right temperature to germinate. Dormancy is a state of suspended animation in which seeds delay germination until conditions are right for survival and growth. Some Australian plants need fire or smoke to germinate, while others rely on insects and animals.