Leaf Shape

Fig. 15.3 Changes in leaves shape and height of soybean plants after soaking of seeds in zearalenone solution, (a) The picture of the field with plants grown from seeds treated with zearalenone (left side) and non-zearalenone treated (control, right side), (b) Dark-green leaves of soybean plants which were grown from zearalenone-treated seeds, (c) Control plants with visible light-green leaves...

Species of passion vines Passiflora spp. family Passifloraceae) that twine upward in tropical, subtropical, and some temperate regions of the world. They occur most often in wet forests, though some species may occur in drier, more open places. These vines have glossy leaves shaped like rounded human hands, and their flowers are often sweetly scented and packed with a ring of colorful filaments. The tendrils of passion vines hold the... 

Epiglottis Leaf-shaped cartilage which closes larynx during swallowing. 

To find the equilibrium form of a crystal, the following Wullf construction [20] can be used, which will be explained here, for simplicity, in two dimensions. Set the centre of the crystal at the origin of a polar coordinate system r,6. The radius r is assumed proportional to the surface tension 7( ), where 6 defines the angle between the coordinate system of the crystal lattice and the normal direction of a point at the surface. The anisotropy here is given through the angular dependence. A cubic crystal, for example, shows in a two-dimensional cut a clover-leaf shape for 7( ). Now draw everywhere on this graph the normals to the radius vector r = The... 

Blatter erde, /. potassium acetate. Oba. erz, n. foliated tellurium (oagyagite). blatterformig, a. in the form of leaflets or flakes laminated leaf-shaped. 

The ground term of the cP configuration is F. That of is also F. Those of and d are " F. We shall discuss these patterns in Section 3.10. For the moment, we only note the common occurrence of F terms and ask how they split in an octahedral crystal field. As for the case of the D term above, which splits like the d orbitals because the angular parts of their electron distributions are related, an F term splits up like a set of / orbital electron densities. A set of real / orbitals is shown in Fig. 3-13. Note how they comprise three subsets. One set of three orbitals has major lobes directed along the cartesian x or y or z axes. Another set comprises three orbitals, each formed by a pair of clover-leaf shapes, concentrated about two of the three cartesian planes. The third set comprises just one member, with lobes directed equally to all eight corners of an inscribing cube. In the free ion, of course, all seven / orbitals are degenerate. In an octahedral crystal field, however, the... 

Edible landscaping offers the creative gardener the opportunity to try out all sorts of unusual planting combinations. Vegetables may be chosen for color, leaf shape and texture, and overall form, and as visual statements. They can be trained up screens, trellises, or other plants... 

In contrast to DNA, RNAs do not form extended double helices. In RNAs, the base pairs (see p.84) usually only extend over a few residues. For this reason, substructures often arise that have a finger shape or clover-leaf shape in two-dimensional representations. In these, the paired stem regions are linked by loops. Large RNAs such as ribosomal 16S-rRNA (center) contain numerous stem and loop regions of this type. These sections are again folded three-dimensionally—i.e., like proteins, RNAs have a tertiary structure (see p.86). However, tertiary structures are only known of small RNAs, mainly tRNAs. The diagrams in Fig. B and on p.86 show that the clover-leaf structure is not recognizable in a three-dimensional representation. 

Fig. 76. A skeletal drawing of the large supercage of the framework structure showing the clover-leaf-shaped windows and the pockets at the corners of the cage [471]...

The sensitive plant (Mimosa pudica) also undergoes a remarkable change in leaf shape triggered by mechanical touch (Fig. 2). A light touch or vibration produces a sudden drooping of the leaves, the result of a dramatic reduction in turgor pressure in cells at the base of each leaflet and leaf. As in the Venus flytrap, the drop in turgor pressure results from K+ release followed by the efflux of water. 

Find a flowering plant that interests you. Look at the root formation, leaf shapes and how they are attached to the stem, and the shape of the flower. Draw these different shapes. Find molecules that resemble these different shapes. Remember that group 3A elements form trigonal planar shaped molecules, group 4A elements form tetrahedral shaped molecules, group 5A elements form pyramid shaped molecules and group 6A elements form bent shaped molecules. Carbon chains have a zigzag shape and the DNA molecule is a double helix. You will see that these molecular shapes are duplicated in natural objects. See how many molecular shapes you can find in an ordinary flower. 

For cutting the leaf shape out of sugar paste, use a small, sharp knife to create leaves that are irregular—and more true to nature. If you use a cutter, look for an elongated-leaf cutter or a rosebud-leaf cutter. These shapes are not so plump and squat and tend to harmonize nicely with most flowers. 

I also suggest that you buy a couple of leaf veiners, too, which are molded silicone leaves with protruding veins. After you cut out a leaf, place it on the veiner and press it lightly with the roller to create realistic veins. I love the look of a rough, hand-cut leaf shape detailed with the veiner—it s like a leaf plucked from a bush. 

Fig. 10 Four common types of crystal habit in polyethylene and long alkanes (a) rhombic lozenge bounded by 110 facets (b) lozenge truncated by curved 100 faces (Toda s type B) (c) leaf-shaped crystal bounded solely by curved 100 faces (step propagation rate v equals h = Gno/sin(

The trematodes (flukes) are leaf-shaped flatworms that are generally characterized by the tissues they infect. For example, they may be categorized as liver, lung, intestinal, or blood flukes. 

Fig. 2.4. The flow reactor as a device for RNA structure optimization. RNA molecules with different shapes are produced through replication and mutation. New sequences obtained by mutation are folded into minimum free energy secondary structures. Replication rate constants are computed from structures by means of predefined rules (see text). For example, the replication rate is a function of the distance to a target structure, which was chosen to be the clover leaf shaped tRNA shown above (white shape) in the reactor. Input parameters of an evolution experiment in silico are the population size N, the chain length X of the RNA molecules as well as the mutation rate p.

As we have indicated, Sbl represents an average thickness of the unstirred air layer adjacent to a leaf (or to leaflets for a compound leaf). The main factors affecting Sbl are the ambient (local) wind speed and the leaf size, with leaf shape exerting a secondary influence. Partly for convenience, but mainly because it has proved experimentally justifiable, we will handle the effect of leaf size and shape on boundary layer thickness by the characteristic dimension /, which is the mean length of a leaf in the direction of the wind. Based on hydrodynamic theory for laminar flow adj acent to a flat surface as modified by actual observations under field conditions, an approximate expression for the average thickness of the boundary layer next to a flat leaf is... 

Instead of estimating the boundary layer conductance or resistance based on fibl calculated by Equation 7.10, which cannot account for all of the intricades of different leaf shapes, it is often more expedient to construct a filter-paper replica of the leaf. If this leaf is then moistened, the observed Jwv from it for a certain Acbl will indicate or rbl (Eq. 8.2) because water vapor then crosses only a boundary layer. 

Leaf Shape—Herbicides tend to bounce or run off narrow, upright leaves. Broad, flat leaves tend to hold the herbicide longer. 

The maidenhair tree or ginkgo Ginkgo biloba) is said to be named after this group of ferns because of the similarity of leaf shape. However, the ginkgo is a conifer tree, and is not related to the maidenhair ferns. 

Palmate—Refers to a leaf shape in which the lobes or veins appear to radiate from one central point, as is typical of the foliage of maples. 

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