Leaves213-page9

Leaves213-page9 - reproductive bud Reproductive buds are “terminal” in the sense that no apical meristem is preserved in a shoot bud for new

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Leaves - 9 Other Leaf Variations Phase changes As discussed in our section on genetic controls of development, the leaf shapes in some plants change from the juvenile regions of the plant compared to those in areas that are more mature, changes that are controlled by gene signals in the meristem. Because plants have modular growth, the originating meristem exerts genetic control over meristems derived from it, so plants may have juvenile and mature leaves at the same time. All meristems derived from an originating bud, for example, will have the genetic phase shape of that original bud. Phase changes are also responsible for submerged and above the water differences in leaf shape. Other phase changes occur when a shoot transitions from a vegetative to a
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Unformatted text preview: reproductive bud. Reproductive buds are “terminal” in the sense that no apical meristem is preserved in a shoot bud for new bud primordia. Shade/Sun Leaves Leaves in the shade have thinner blades and a larger surface area compared to those exposed to full sun, which have thicker mesophyll and epidermis, and greater vascular tissue development. Shade leaves have a lower photosynthetic rate in full sun, but in low light levels, because they have more surface area, shade leaves have similar rates of photosynthesis to sun leaves. These leaf developmental differences are good examples of the influence of environmental conditions on developmental processes. Leaf in full sun, xs Leaf in shade, xs...
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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