Imbibition refers to the seed's uptake of

• A. Water
• B. Soil nutrients
• C. Air
• D. Heat

Answer: (A)

Imbibition is the seed’s uptake of water, the first crucial step in germination. A dry seed sits in an environment with higher water potential, so water moves into the seed by osmosis, causing it to swell and rehydrate stored nutrients and enzymes. This rehydration unlocks metabolic activities, activates enzymes, and allows membranes and cellular processes to resume, setting the stage for growth. Nutrients from the soil aren’t taken up during this step; they’re absorbed later as the seedling develops roots. Air isn’t the focus of imbibition either—the key event is water entering the seed, with temperature mainly influencing how fast this uptake occurs. So the correct concept is water uptake.