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A close examination of the veins of a leaf reveals a branching pattern similar to the whole tree. Also, the overall profile of a given tree resembles the overall profile of one of its leaves. This is yet another way in which fractals show up in the structure and function of plants.
Many leaves have a midrib, which travels the length along the center of the leaf. The midrib contains the main vein (primary vein) of the leaf as well as supportive ground tissue (collenchyma or sclerenchyma). Figure \(\PageIndex{1}\): A typical eudicot leaf. Many leaves consist of a stalk-like petiole and a wide, flat blade (lamina). The ...
1 lis 2013 · The first is netted venation, where the leaf veins form a lace-like skeleton of veins. This can be palmate netted venation , where the veins spread form one central point like fingers from a hand (think of a nasturtium or geranium).
The leaf blade is (usually) the flat, photosynthetic part of the blade. In eudicots, the leaf will have a central midvein (also called the midrib), with smaller veins branching off from there. This type of vein organization is called netted venation. The edge of the blade is the margin.
Veins are lateral extensions that develop from the midrib of the leaf and extend towards the leaf margin. Veins contain the conducting tissues called the xylem and phloem. Leaf veins are present throughout the leaf lamina which supports the structure of the leaf.
2 lut 2023 · The leaf veins are small channels or capillaries that transport water and minerals to and from the leaf of a plant. They are vascular tissues composed of xylem and phloem cells embedded mainly in the parenchyma and sometimes sclerenchyma cells.
The venation differs in the two examples below. The oak leaf is pinnate, with a major vein heading down the midrib of the leaf. The maple leaf is palmate, with major veins that radiate from the point of attachment to the petiole. Oak leaves have pinnate venation (L), while maple leaves have palmate venation (R).
