Home Garden
# Home & Garden >> Plants, Flowers & Herbs >> Growing Beans

The Effect of Water on Bean Seed Germination

Water is one of four major environmental factors that influences the germination of seeds, including beans. In some instances, water is the only factor limiting whether or not a seed will germinate. In the case of beans, a certain temperature must break dormancy for the beans to begin the first phase of water uptake. Bean seeds uptake water in three phases, each characterized by how much water is being taken in and what effect it is having on the bean seed itself.

  1. Water Potential

    • To understand the three phases of germination, you must first learn about water potential. Water potential is a measurement of the potential for a cell to take up water from its surrounding environment. Changes in this water potential are the driving forces behind the start of germination. If you were to plant a dry, dormant bean seed in dry soil, the water potential would be very low. By watering the seed, the potential changes. The effect of watering your beans can be described in three phases.

    Phase 1: Imbibition

    • Bean seed pods

      Imbibition is the initial stage of water uptake and is often a rapid process. Imbibition of bean seeds will occur in both alive and dead seeds. Imbibition is a physical process related to matric forces. Matric forces occur when water saturates dry components. You can think of matric forces as a sponge, or wick. Water is quickly uptaken by the bean seed in the first 10 to 30 minutes, slowing for five to 10 hours. The volume of the seed increases, and the seeds become "leaky." Leakiness occurs due to the fact that the cellular membranes are not fully functional, and solutes such as amino acids, organic acids, inorganic acids, sugars, phenolic and proteins can be detected in a leaky seed that is in phase 1.

    Phase 2: Lag Phase

    • The lag phase of seed germination is characterized by a reduced or no water uptake after the initial imbibition. The water that was imbibed in phase 1 is key to the physiological processes that take place during phase 2. Cellular activities such as mitochondrial "maturation," protein synthesis, metabolism of storage reserves and the activation of enzymes in loosening cell walls occur during this phase. These processes make way for the third phase.

    Phase 3: Radicle Protrusion

    • The radicle is the root of the embryo and is the first part of the plant to emerge. The enlargement of the cell by water uptake is the primary reason behind this emergence, and not necessarily because of cell division. This enlargement of the small root helps to weaken the cell walls and breaks through the seed coat. As you can see, water plays a major factor in all three phases of germination.

Previous:

Next:

Growing Beans
  1. The Effect of Abiotic Factor on Seed Germination
  2. Germination of Bean Seeds Without Soil
  3. The Effect of Carbonated Water on Bean Plants
  4. The pH of Water & the Growth of Bean Plants
  5. The Effect of pH on the Germination of Bean Seeds
  6. The Effect of Water Temperature on Bean Seeds
  7. Germination of a Green Bean Seed
  8. Magnetism and Bean Seed Germination
  9. Stages of Bean Seed Germination
  10. Description of the Germination of a Bean Seed
  11. Acid Water Effect on Bean Plants
  12. The Effect of Gibberellic Acid on Seed Germination

Home Garden © https://www.98905.com