• Cold injuries lead to a diminished stand and subsequently to a reduction in yield.
  • Cold that presents early in the season, has a sizable influence on the development of maize.
  • Changes in soil temperature are a factor that subjects maize to stress after planting.

How does the life of a maize plant begin?

What controls germination?

What happens with the seed after planting to emergence?

Seed planting steps.

Why is maize so sensitive to early season cold stress?

  • Maize is a warm-season crop – optimal temperatures for germination are from 25°C; in other words, italways experiences a certain degree of cold stress.
  • Prolonged exposure to temperatures below 10°C promotes seed degeneration and seedling diseases.
  • Fluctuations in soil temperature of only 3°C can affect mesocotyl growth.
  • The cold spell can cause seeds to rot underground; seeds die before or shortly after germination.

Imbibitional chilling injury

  • Imbibitional chilling injury causes physical damage to the seed.
  • The germination process requires heat units.
  • Cold, wet soil requires more heat units to heat soil to 20°C/25°C.
  • Seed rot occurs in cold soil if the temperature is below 13°C.
  • During imbibition, and with temperatures lower than 13°C, the metabolic activities in the seed begin to decrease.
  • The seed in the soil absorbs water without any active metabolic processes.
  • This causes the cell membranes to break and the proteins to leak into the soil as in figure 2.
  • As soon as the temperature of soil increases after a cold spell, the cell membranes can recover, and normal germination can take place.
  • If the temperature of soil remains low, it prevents cell membrane repair and degeneration takes place.

Figure 2. Broken cell membrane showing protein leaking into the soil.

Cold stress.

Cold imbibition leads to: