Introductory Plant Biology
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This introductory text assumes little prior scientific knowledge on the part of the student. It includes sufficient information for some shorter introductory botany courses open to both majors and nonmajors, and is arranged so that certain sections can be omitted without disrupting the overall continuity of the course. Stern emphasizes current interests while presenting basic botanical principles.
organic compounds are burned, the energy is released very rapidly in the form of heat and light, and much of the usable energy is lost. Living organisms, however, “burn” their energy-containing compounds in numerous, small, enzyme-controlled steps that release tiny amounts of immediately usable energy. The released energy is usually stored in ATP molecules, which allows the available energy to be used more efﬁciently and the process to be controlled more precisely. 1. The Essence of Respiration
the ﬁrst to understand the signiﬁcance of cells, but they explained them more clearly and with greater insight than others before them had done. They are generally credited with developing the cell theory, beginning with their publications of 1838 to 1839. This theory, in essence, states that all living organisms are composed of cells and that cells form a unifying structural basis of organization. In 1858, another German scientist, Rudolf Virchow, argued persuasively in a classic textbook that
5.17 Root nodules on the roots of bur clover (Medicago polymorpha). The somewhat popcornlike nodules contain bacteria that convert nitrogen from the air into forms that can be used by the plant, ×5. root nodules that are clearly visible when such plants are uprooted (Fig. 5.17). The nodules contain large numbers of nitrogen-ﬁxing bacteria. A substance exuded into the soil by plant roots stimulates Rhizobium bacteria, which, in turn, respond with another substance that prompts root hairs to bend
sapwood, resin canals, bark, laticifers, and vascular bundles. Next, there is a survey of specialized stems (rhizomes, stolons, tubers, bulbs, corms, cladophylls, and others). The chapter concludes with a discussion of the economic importance of wood and stems. Some Learning Goals 1. Know the tissues that develop from shoot apices and the meristems from which each tissue is derived. Distinguish between primary tissues and secondary tissues. 2. Learn and give the function of each of the
discussed are given in Appendix 1. Summary 1. Leaves are similar to solar panels in that they are covered with a transparent epidermis that admits light to the interior, and many twist on their petioles so that their ﬂat surfaces are inclined to the sun throughout the day. 2. All leaves originate as primordia. Most leaves consist of a blade and a petiole that may have paired stipules at the base. Leaves may be simple or compound, and all are associated with leaf gaps. 3. The lower and often the