Leaf — The Source of All Food

Duration: 4 hours

Target Audience: Anyone who is interested in science, life, joy, nature and the cosmos

Brief:

Mankind cannot survive without the nutritional and medicinal properties of plants. Not only that, but there are many other reasons. The number of plant species on Earth has been estimated at around 400,000, with many of these species remaining unknown to humans. Plants can breath, see, communicate, travel, count, adjust, strike, capture, digest, imprison, repel, impersonate, collect, respond (to light, touch and sound/music), feel, struggle, make decisions, and adapt to variety of environments. All life on Earth depends on plants. Plants depend on leaves.

Life begins at the leaf of a plant. Leaf is life-giving, life-sustaining, and life growing. Leaves feed us and cure our ailments. They come in infinite variety of sizes, shapes, colors, patterns, and textures. A leaf is Nature’s masterpiece, a work of art, a wonder of science. Nature perfectly fused art and science into a leaf—art that is beautiful, and science that is extremely complex. Walt Whitman said,  “I believe a leaf of grass is no less than the journey-work of the stars.”

A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants. Typically a leaf is a thin, flattened organ borne above ground and specialized for photosynthesis. Plants manufacture about 300 billion tons of food every year. This food feeds all animals including humans. As the Old Testament puts it pithily  “All flesh is grass.”  All animals, including the most determined carnivores, eat plants, if not firsthand, then at second, third or fourth. By leaves, we live.

Saul Bellow said, "I've never turned over a fig leaf yet that didn't have a price tag on the other side." Turn a leaf and see, there is neither a barcode nor a price tag! Nature gave it free. We must be thankful to Nature. Besides food, trees also deliver oxygen that is vital to life. A single mature tree can absorb carbon dioxide at a rate of 22 kg or 48 lb per year and release enough oxygen back into the atmosphere to support 2 human beings. Leaves give life, promise resurrection and demonstrate beauty. Martin Luther said,  “Our Lord has written the promise of resurrection, not in books alone, but in every leaf in springtime.”  About the beauty, Albert Camus said,  “Autumn is a second spring when every leaf is a flower.”  About sense of wonder, Albert Schweitzer said,  “Never say there is nothing beautiful in the world anymore. There is always something to make you wonder in the shape of a tree, the trembling of a leaf.”

Animals have to search and find food, whereas plants make it themselves. An invisible but splendid work done by the leaf is photosynthesis. Photosynthesis is a process used by plants and other organisms to convert the light energy captured from the sun into chemical energy that can be used to fuel the organism's activities and benefit other animals. Leaf runs on the diet of light. In a trillionth of a second, leaf reconfigures six molecules of carbon-dioxide and six molecules of water into one molecule of glucose and twelve molecules of oxygen. A leaf pushes the carbon absorbed from carbon-dioxide, through more than thirty steps before it becomes part of glucose molecule. Each of these thirty steps is a complex chemical reaction.  Photosynthesis is an unimaginably complex process! After more than a century of intense research, still black-boxes remain in understanding this process. About thirty Nobel prizes were awarded in the last hundred years, to scientists for deciphering some secrets of this process, or for discovering the inner architecture of the leaf that enables it. Leaf does not lend its secrets easily. If it does, joy would evaporate quickly. That is one of the reasons why Nature loves to hide.

The Outline of Lecture:

This lecture will cover:
(1) Leaf anatomy, (2) Leaf chemistry (Food manufacturing and Oxygen delivery by Photosynthesis; Communication), (3) Leaf physics, (4) Leaf arrangement (Phyllotaxis), (5) Leaf deployable mechanism, (6) Friends and foes of leaves, (7) Leaf life cycle, (8) Medicinal properties of leaves, (9) Modern technologies imitating the science of leaves.

Leaves give us not only food, oxygen, and medicines, but also make us feel beauty and joy. More knowledge of Nature can give us more joy, magnifying and multiplying our sense of wonder. Sense of wonder is the root of joy, the essence of life.

Let me take liberty to say this:  Let your life lightly dance on the edges of Time like dew on the tip of a leaf  (Rabindranath Tagore). In this lecture, I will show the beautiful photographs of trees and leaves that  have shot with Nikon D3200 at Hawaii Islands, Chicago Botanic Garden, Edinburgh Botanical Gardens, Huntington Botanical Gardens in Pasadena, CA, and Sai Geetha Ashramam at Hyderabad (A small group of us visited this Ashramam on Dec 2, 2012 along with SRI RAM ‘SIR’, saw some amazing trees that could cure not only physical infirmities but also mental illnesses).