Primary fruit ripening

Differentiation can be defined as the process of specialisation in terms of shape and function. An example is cell differentiation in plants, animals and humans a young cell, which is initially multifunctional, gradually acquires one specific function and shape. Specialisation is a refinement that is expressed in terms of shape, scent and colour. For example, fruits ripen, leaves change colour in the autumn, the growth of a shoot ends in a terminal bud and seeds become dormant. The primary components are converted into secondary components such as phenols, vitamins, aromas, wax, and so on. Thus differentiation in this context has a broader meaning than only the formation of a new plant organ . 

Figure 6. The potential sites for modification of Type I primary cell walls by enzymes and/or expansins. The activities of the enzymes/expansins are associated with numerous aspects of plant growth and development including cell expansion, fruit ripening, and organ abscission.

The balance of the evidence available suggests that the activity of endogenous cellulase in degrading, primary-wall microfibrils does not contribute significantly to fruit tissue-softening accompanying ripening. 

Plants and microorganisms synthesize their own carotenoids, while animals appear to obtain theirs from primary producers. In the development of many fruits (e.g., citrus fruits, apricots, tomatoes) ripening is associated with the accumulation of carotenoids and the... 

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