What part if a green plant shows the greatest increase in chloroplasts by the end of spring?

The part of a green plant that shows the greatest increase in chloroplasts by the end of spring is typically the young, actively growing leaves. During this time, as the plant undergoes rapid growth and photosynthesis increases due to longer daylight hours and warmer temperatures, chloroplast numbers in these leaves expand to maximize light absorption for energy production. This adaptation supports the plant's growth and overall health as it prepares for the growing season.