Ap Bio Plants

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1.)
Roots support photosynthesis and respiration by absorbing minerals and water and by storing organic nutrients. They also anchor the plant. Some roots have mycorrhizae, which increase the surface area and therefore increase the absorption. The endodermis, which is the innermost layer of cells in the root cortex, surrounds the vascular cylinder. It is the passage of minerals from the cortex into the vascular tissue. The stem has a system of nodes where leaves are attached. They have a waxy coating (epidermis) that prevents water loss. The stem and the roots are the 2 main axes in a vascular plant. Fluids are transported between the roots and the shoots through the stem by the phloem and xylem. Leaves are the main photosynthetic organ of vascular plants. They have a fattened blade, a stalk and a petiole. They have the chloroplast (with chlorophyll) and the gas exchange takes place here. 2.)

Intra-organism communication is possible through the xylem and the phloem. The transpiratinal pull is due to cohesion and adhesion. Evaporative cooling will result. A plant’s defense is due to its skin: the epidermis or periderm. Another line of defense is a chemical attack that kills pathogens. This is enhanced by the inherited ability to recognize certain pathogens. Plants respond to the environment. Examples are touch, light and gravity. Through photoreceptors they can detect light, its direction, intensity and wavelength. Most responses are triggered due to plant hormones. Tropism is any type of response that results in curvature of of organs toward or away from a stimulus (ex. Light). Plants reproduce by pollination, also called fertilization, which is the transfer of pollen from an anther to a stigma. A pollen grand produces a pollen tube. Eventually sperm will be discharged near the embryo sac and pollen develops. Products are seeds and fruits. Another way to reproduce is self-fertilization, which unfortunately is difficult for most plants due to...
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