Which of the following exhibits the highest rate of respiration?

1.  Growing shoot apex

2.  Germinating seed

3.  Roottip

4.  Leaf bud

 

 
(b) Germinating seeds have the highest rate of respiration. As soon as the water is imbibed by seeds, hydrolytic enzymes comeinto action and mobilise the reserve food materials so the seeds show high metabolic activity and germinate into a tiny plant.
All these activities require energy, which is derived from increased rate of respiration.