Catálogo de publicaciones - libros

Terrestrial life forms made their move on land about 400 million years ago. Plants crossed the barrier between life in water to life in the atmosphere. With the invention of stable stems, plants overcame hydrological and mechanical problems. The construction of plant stems is the focus of this book. It demonstrates that nature created a framework in which plant stems evolved—annual herbs as well as century-old, 100 m-tall trees, from tropical to arctic environments.

As the title of this book suggests, the main objective of the book is to explain anatomical structures on the basis of microscopic slides. Since comparability is one of its major goals, most micro-photographs are based on recently prepared microscopic slides. Gärtner & Schweingruber 2013 explain sample design and preparation techniques in detail.

Life forms and growth forms are principally synonymous terms. The image on the following page shows that the currently existing plant forms are based on a principle that was invented 400 million years ago.

Single cells can only be observed through microscopes. The cell is anatomically and physiologically complex. It principally consists of protoplasts, which contain various organelles, the vacuole and the cell wall. The following section introduces elements that are visible under normal and polarized light without special microscopic equipment.

The cell wall of seed plants principally consists of several layers: the middle lamella, the primary, secondary and tertiary wall, a concept presented by Evert 2006. Secondary walls consist of macro-fibrils.

Meristems initiate longitudinal growth on tips of shoots and roots of plant bodies. Meristematic tissues consist of living cells, which produce new cells.

This chapter describes the anatomy of major stem-forming taxa within the taxonomic hierarchic system.

Writing a comprehensive story about stem evaluation is difficult because evidence of only few early plants has been preserved over millions of years. Samples exist of plants which were fossilized under anaerobic conditions, enclosed in resin (amber) or carbonized. The majority of plants from sites with aerobic soil conditions are not preserved.

All wood anatomy classification books describe the structure of so-called “normally grown” specimens. Nature, however, also produces a few giants, and many dwarfs. Here the question is raised to which degree local environmental factors modify the morphology and anatomy of stems of individual species. Exemplarily presented are the xylem structures of a few large (giants) and small individuals (dwarfs) of trees and herbs. Larger-thanaverage individuals have experienced mostly favorable growing conditions when they were young, and during their lifetime escaped the effects of extreme growth-limiting factors such as lack of nutrients, water or light, frost, or injury. In contrast, limiting and extreme factors negatively affected growth in small individuals. Giants are the winners, and dwarfs are the losers of competition.

Two principal capacities characterize seed plants. Primarily, cell formation pathways determine the basic structure of plant bodies, and the formation of different cell types.