The real midlife crisis confronting many Americans

The way my mom imagined it, midlife was going to be great: counting down days until retirement, spending winters in Florida and checking off destinations on her bucket list. But it hasn't turned out that way.

Mystery behind striped barley solved

Plants with green leaves and stems are a common sight and are one of the most natural things on earth. But when considering that this colouring is achieved by small chlorophyll-filled organelles called chloroplasts, distributed ...

New leaf shapes for thale cress

Anyone who looks at their bowl of salad or at their garden can see how different the shapes of leaves can be. Spinach leaves, for example, have smooth edges and are comparatively simple in form, while parsley leaves are deeply ...

The conspicuous absence of women in India's labour force

India's rapid economic growth has been accompanied by falling fertility rates and higher educational attainment among women. These advances often lead to an increase in women entering the labour force, but there has been ...

Wax helps plants to survive in the desert

In 1956, Würzburg botanist Otto Ludwig Lange observed an unusual phenomenon in the Mauritanian desert in West Africa: He found plants whose leaves could withstand heat up to 56 degrees Celsius. At the time, the professor ...

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Leaf

In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin. There is continued debate about whether the flatness of leaves evolved to expose the chloroplasts to more light or to increase the absorption of carbon dioxide. In either case, the adaption was made at the expense of water loss. In the Devonian period, when carbon dioxide concentration was at several times its present value, plants did not have leaves or flat stems. Many bryophytes have flat, photosynthetic organs, but these are not true leaves. Neither are the microphylls of lycophytes. The leaves of ferns, gymnosperms, and angiosperms are variously referred to as macrophyll, megaphylls, or euphylls.

Leaves are also the sites in most plants where transpiration and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctly referred to as fronds. Furthermore, leaves are prominent in the human diet as leaf vegetables.

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