Auxins and phytochromes are plant chemicals which can work on the metabolic processes of the plants.
Auxins are class of plant hormones that works on the growth and behavioural processes of plants. It is also essential for cell growth as it affect the cell division and cell expansion and cell differentiation. Auxins are produced in the apical bud. Since not all cells can produce auxins, it should be distributed where it is needed. If not properly distributed, the growth of the plant will suffer and will have uneven growth in the areas of the plant.
Phytochromes are pigments which are photoreceptors. It is sensitive to light from red to far-red region of the visible spectrum. Phytochromes are found in most of the plants and are situated in leaves. If not properly distributed abnormal functions may happen such as: seed germination, elongation of seedlings, leaf structure and synthesis of chlorophyll.