What conditions are necessary for germination?
Answers
Suitable Temperature - Most flowering plants germinates best in cool-weather, as they germinate best at temperatures that range from 45 to 65 degrees Fahrenheit. Colder temperatures delay germination and may cause seed decay due to the soil's initial spring dampness. Planted too late into the warm months, the seeds germinate poorly, if at all, when daytime temperatures exceed 75 F.
Water - In addition to heat, flowering plants need moisture to germinate. While dormant, flowering plant (pea seeds) store food in their endosperms, or inner tissues, and in their cotyledons, or first leaves. As they absorb water, this food is released and converted into energy needed by the developing embryo. Pea seeds deprived of water shrivel and die, while those that receive too much water become water-logged and start to decay. Proper watering ensures that the soil around the bases of the pea vines is damp but not saturated, with additional watering scheduled during dry spells.
Air - In the dormant condition the seeds respiratory rate is very low and so oxygen is required in very small quantities. But for germination, oxygen is needed in large quantities. The seeds obtain oxygen that is dissolved in water and from the air contained in the soil. If soil conditions are too wet, an anaerobic condition persists, and seeds may not be able to germinate.
Sunlight- Some seeds need light for germination, while in some seeds germination is hindered by light. Germinating pea seeds do not need light to complete the first stage of their growth, all of which takes place below the soil. A small root is the first thing to emerge on one end of the seed, followed by a small sprout bearing two small leaves called a cotyledon. Once the cotyledon rises above the soil, light becomes a crucial factor in the pea plant's proper development. At least 6 hours of direct sunlight are needed at this stage to encourage the plant to produce its own food through the process known as photosynthesis.
Seed germination depends on both internal and external conditions. The most important external factors include right temperature, water, oxygen or air and sometimes light or darkness. Various plants require different variables for successful seed germination.