Some insight for leaves

Leaves are in charge of respiration in plants. They consist of the main mechanism producing food for plants, using sunlight via photosynthesis through which food for many more organisms, animals, and humans are provided. Having been assigned to convert solar energy to food, which they’ve been doing for millions, perhaps billions, of years, plants have been a significant instrument for sustaining life on or planet. It is as if plants turn their leaves upward in prayer to ask for food on behalf of all living things.

Morphology of a leaf

Leaves are composed of three sections: the base, blade, and petiole. The blade is the most important part of the leaf; it is wide and flat. The exact shape of leaves vary according to climate, geographical conditions, life span and risk of consumption by other organisms. In tropical climates, the blade is often very wide. In drier climates, it is usually smaller, in order to reduce water loss.

Leaves of some plants undergo a transformation called “metamorphosis” to fulfill different tasks. For example, some leaves have a thorny shape and protect the plant form herbivorous animals. Some leaves are designed to store water, and some are converted into a trap in order to capture insects to nourish the plant.

On the cross section of a leaf, one can observe that four layers constitute the inner part. The first one is the epidermis, which covers the leaf from top to bottom. This layer protects the leaf against external elements and is lined with a waterproof, waxy substance.

The palisade parenchyma is located on the upper side of the inner tissue and it houses chloroplast rich cells, which are lined up densely and carry out photosynthesis. The spongy layer under the palisade tissue forms the intercellular air spaces and this layer is responsible for the respiration of the plant.

For photosynthesis to occur, the leaf needs to receive the maximum amount of sunlight. The sun must hit the leaf at a perpendicular angle; thus, the leaf must be amply wide and must sit level. Because the sun hits different latitudes at different angles, plants have branches of different lengths facing different directions, and leaves have different curvatures. Furthermore, leaves are also lined up in a way so as not to block the sun’s rays. For this to happen, it is required for the leaf base to be thin and the leaves to be lined up in a spiral fashion that enables both lower and higher ones to harvest sunlight in the most efficient way. This type of arrangement exemplifies the golden ratio, which is observed among many structures in nature.

Each leaf sprouts at an angle of either 222.5 or 137.5, derived from division of 360 degrees, from the previous leaf under. This spiral leaf growth provides them with the most suitable place to harvest sunlight maximally. This way the gaps around branches are minimized and a maximum number of leaves is positioned without reducing the light capture capacity of the plant.

Seasons and leaves

Plants work like factories during spring and summer, producing a great deal of food through photosynthesis. Some of these foods help the plant grow and some are stored as starch for winter. With the onset of autumn, a majority of plants outside tropical zones go through hibernation, like many organisms do, and enter a dormant period. In order for plants, like trees and bushes, to survive the cold, their leaves are shed to minimize their surface area and conserve energy. Perennial green plants lose their aerial parts, too, including stems and leaves, and hibernate underground as roots, bulbs, and tubers. They sprout back from their roots once spring brings warmer weather.

Many leaves begin to fade and fall once autumn arrives. The leaves of some hardy plants – like cypress, pine, and spruce trees – continue to function through winter. In some of these trees, like the bay tree and the Indian sandalwood, there are protective layers covering the leaves against the cold. Other leaves, like pine needles, are created in a spiny shape to resist the cold.

Colors of autumn

Leaves seem green during the spring and summer months because the chlorophyll found in them absorbs all wavelengths other than green. The other major pigments found in leaves are carotene (orange) and xanthophylls (yellow). These two pigments are the most common pigments in nature.

As autumn approaches, and photosynthesis begins to end, chlorophyll starts to degrade and the other pigments begin to show. Thus, leaves turn yellow and bright red.

As the weather gets colder, the chloroplasts that are near the leaf’s bottom are broken apart, and sugar levels begin to elevate. The sugars produced during this season accumulate in the leaves day by day due to lower photosynthetic speed and reduced transportation to other parts of the plant. These sugars are converted into anthocyanins. At first, leaves appear yellow. A couple weeks before they fall, most leaves shift from yellow to red. Under abundant sunlight, due to concentrated anthocyanins, leaves seem brighter and more colorful – and thus red. Once the live tissues die completely, all leaves turn brown. This is due to the high concentration of tannin.

Leaf color varies not only because of plant genetics and external factors, but also because of climate. Temperature, humidity, soil composition, and levels of sun exposure all affect color. There is a higher degree of color change in the leaves of trees that grow in lower temperatures.

The composition of soil plays a major role in the color of leaves. Leaves that turn yellow early indicate a nitrogen shortage; on the other hand, the presence of a strong red color indicates very acidic soil. A high alkaline ratio is present in places where leaves are purple.

Walking among fallen leaves and the colorful scenery in a forest in autumn can trigger unique emotions. Depending on the psychological state of a person, the colors of autumn sometimes remind us about the briefness of this world, but they can also hint at the infinite life to come.

The motifs and patterns of leaves

Receiving sufficient sunlight is a significant matter for leaves. Therefore, they are created differently. No two plant leaves are the same.

Some of the leaves are simple and some are compounds. According to their arrangements, opposite, alternate, whorled, and rowed forms exist. Leaf blades can be ovals, kidneys, triangles, or even hearts. Edges can be smooth, serrated, toothed, or lobed. Leaf veins can also have many different motifs.

Each plant species has its own leaf motif. The alfalfa leaf has a triple pattern of specific angles; walnut leaves have an opposite arrangement of eight to ten. A hand-like motif, like the fingers of a praying hand, formed of seven leaves, can be observed on chestnut trees.

Among the most visible characteristics of this age, we see that right is consistently sacrificed for the sake of might, selfish interests replace all other considerations, racial discrimination has a pre-eminent role in determining social attitudes and relations, and force (in one form or another) is resorted to as the single means to resolve national and international differences. Power must have its due place in the scheme of things, but if we see it as the single or most effective means of solving problems, we will have to explain why we, as human beings, are endowed with such faculties as reason and compassion. All the social revolutions and military movements of the past which were not based on belief, knowledge, moral values and sound reasoning failed to endure much beyond the lifetimes of their leaders.

When used to serve the cause of right and sound reasoning, power may do some good on the way to resolving problems. However, power has always been a means of destruction when subject to the rule of ambition and greed, of coarse feelings and coarse ideas. It is the madness of disposing and increasing power that drove Alexander to military ventures in Asia, which brought the genius of Napoleon to ruin, and most recently made Hitler the most accursed of the human race. Despite these lessons, right and intelligence remain under the dominion of power in the world.

Behind the chaotic whirl of damnable ideas and events in the world, there lies the abuse of power, the over-rating of its usefulness, so that human values, reasonableness and respect for right have been replaced by the resort to force. And it would seem that the chaos is set to continue until the few who dispose great power are submitted to the cause of right. Only then will the many, freed from the chaos and confusion, see the world and events taking place in it clearly without any bartier before them.

For oppressed peoples to survive in a world where only the mighty have the right to live, it is essential that they free themselves from the clutches of the minority who wield power, and bring that power under the dominion of right.

While learning lessons from the past, we should know how to prepare a desirable future for ourselves. In order to have hope for the future and not to sink deeper into a darker whirl of new, greater confusions, we need altruistic souls who live not for themselves but for others, who prefer others’ happiness to their own. Only those willing and able to sacrifice themselves for the well-being of humanity as a whole can save mankind from today’s chaos and confusions.

When the light-diffusing ideas, united with love and altruism, are shared by the majority of mankind, the ‘storms’ blowing world-wide will stop and the pains and sufferings come to an end. When the ideas of the heroes of love and altruism, combined with just discipline and balanced freedom, are a determining factor in the power balance of the world, world-wide social crises and massive problems arising from international relations will be solved one by one and the balance between joy and sorrow and happiness and misfortune reestablished.

Humanity expect from us – from the believers – great efforts to move mankind towards the realization of world peace and harmony. Every attempt, every effort, made to attain this goal, every movement to support right and truth, is a most blessed step taken toward God. Every step taken in that direction, however small it is, will play a part in the new, expected reform world-wide. Such steps may be thought of as drops, fallen into our present, from the blue ocean of the future. In that future, mankind will enjoy true happiness. We live now upon the dream of that blessed time to come.