The coloring of the leaves of plants and their seasonal changes depend on the presence and the chemical composition of plant pigments and special molecular structure of the surface of the leaves, which reflects or absorbs light to a greater or lesser extent.The pigments, colored molecules contain electrons that determine the reflection or absorption of light and belong to groups influenced by complex interactions of chemical substances that form the cell sap.These substances (sugars, proteins and acids) ensure plant growth and health.
The gardener learns to observe how the colors indicate how health and abnormal discoloration indicate problems.It's probably not necessary to study the complexity of the behavior of pigments for gardening but no doubt about the understanding of scientific processes that govern nature and add interest to work ing to plan the use of color.
Chlorophyll is a pigment found in the cell plastids (chloroplasts), only soluble in fat.It is the green plants and is ordered to efficiently meet its role in photosynthesis.During the day, carbon dioxide is taken in through tiny holes exist in the leaves (stomata).The chloroplast, which contains chlorophyll and uses all wavelengths except the green (which is reflected) is located inside the cells of the leaves.
The water and minerals needed for plant growth spread in the sap through the veins running through the leaf surface, where solar energy captured separates water into hydrogen and oxygen.The hydrogen combines with carbon dioxide to form sugars, which are distributed throughout the plant, while the oxygen is dispersed into the atmosphere.Although chlorophyll is the pigment important for photosynthesis, plastid pigments are soluble in the cell sap are present on the surface of the leaves.As the chlorophyll is destroyed in the fall, there are droplets of carotenoid pigments, the leaves turning pale yellow.Then, as the nights grow cooler, sugar-usually scattered throughout the plant tissues, triggers a process in the leaf tissue that gives rise to anthocyanin and anthoxanthins, become active pigments in the leaves of red and gold .
Intensity of the colors of the leaves
The intensity of fall colors, like that of the flowers depends on soil conditions.The areas of high acidity and red produce vivid scarlet dyes while calcareous soils, high alkalinity, resulting in less vivid colors, purple and different shades less.
During the spring, these pigments also occur in the shoots and young leaves.The anthocyanins, which give them a pink or red color characteristic protected green growing points of the strong ultraviolet rays.
In the leaves of some plants, these soluble pigments are present all the time, masking all or part of the green and giving the leaves a tanning effect or purple.In deciduous species, the colors last a full season but as summer approaches become less noticeable, becoming more green and darker.In perennial species, only the young foliage often have reddish hues, while the leaves mature they turn green or purple.
Disciplined leaves, variegated or marbled do not always have these designs as soluble anthocyanin pigments and anthoxanthins but often result from the presence of imperfect chloroplasts within leaf cells.When a leaf is edged with yellow or white, the inner layer of green pigment is normal, but in the outer layer, or they lack chloroplasts contain only the precursor of chlorophyll, protochlorophyllide (which makes the color look yellow).In the leaves with white or yellow center and green edge, the inner layer is defective.In the latter case, chlorophyll often reprises his role and becomes all green leaf.Some species of Ilex and Eleagnus responding to this model: core designs have leaves with white or yellow and whole branches that revert to green benefit to the vigor of the plants but not for the gardener who looks for special effect color.
In the case of grasses, reeds and lily variegated (including the host, and some hemerocallis Phormium), chloroplasts produce imperfect yellow and cream stripes that contrast with the normal green.
There are also houses that are variegated species because they are sick of viruses (which do not eliminate them, but on the contrary, make them more attractive).This is the case of the bond of love (Clorophytum comosum) and marbled Chinese lantern (Abutilon japonicum).
Typically, plants with variegated leaves, where chlorophyll areas are masked normal, are at a disadvantage.All need more care and protection both in culture and in use in the garden.Varieties with yellow or variegated leaves are smaller in growth compared to the normal kind of green and may never reach the same height and the same development.