3. Phytohormones and Their Physiological Effects

3.1. Development, growth and differentiation 3.1.1. Development Development is an umbrella term, referring to the sum of all of the changes that an organism goes through in its life cycle – from germination of the seed through growth, maturation, flowering, and senescence. Development is most readily manifest in changes in from of the organism or organ, such as the transition from the vegetative to flowering condition or from leaf primordium to fully expanded leaf. Development may also be manifest at the subcellular and biochemical levels, such as when chloroplasts appear in leaf cell brought into to the light and the enzymes of photosynthesis become active. Development is the sum of growth and differentiation.