Ettore Pacini – författare

Nectar is the most important reward offered by plants to pollinating animals. This book is a modern and interdisciplinary text on nectar and nectaries, prompted by the expansion of knowledge, especially in the more ecological and now molecular fields, and the strong recent interest in pollination biology. The topics covered vary widely: they include historical aspects, the structure and ultrastructure of nectaries and relationships to plant systematics, the dynamics of nectar secretion, nectar chemistry and the molecular biology of defence proteins, adaptations to insect and vertebrate nectar consumers and consequences for pollination ecology, and broad-scale studies of nectar resources at the community level.

The anther tapetum, present in all land plants, is a highly specialized, transient tissue surrounding the (micro-)spores and/or pollen grains during their development. Any tapetum malfunction causes male sterility. The exact knowledge of tapetum form and function therefore is indispensable not only for basic research, but also and especially in plant breeding and plant genetics. In fourteen contributions by reknown experts, a comprehensive account of the various characters and functions of the tapetum is provided, covering the areas of cytology, cytophysiology, biochemistry, tapetum development and function.

The identification of pollen is widely used in the reconstruction of vegetation, the climate of the past, and plant biodiversity. Studies concerning pollen structure, size, and form are key issues in basic sciences as plant taxonomy and evolution. But they also play an important role in applied fields as plant breeding. In pollination studies pollen is generally used to identify food sources of visitors and to reconstruct their foraging routes. The 16 papers in this volume consider the functional ecology of pollen in relation to its structure and constituents as a framework towards a better understanding of evolutionary processes that mold pollination biology. They can be roughly classified into three main topics: pollen structure and constituents, pollen evolutionary ecology, and the pollen-pollinator interface. Floral reward, such as pollen and nectar, are only one aspect of the multidimensional pollination caleidoscope. Other aspects include the various mechanisms in distributing or collecting pollen, the question of pollen longevity, or the convergence of evolution in angiosperm pollination.

Pollen, the plant structure most widely used by humans, is a key structure in plant reproduction giving rise to fruits and seeds. Moreover, the biotechnological use of pollen is of great importance for plant breeders since it allows to obtain varieties with better utilization and yield. In the first part, the successive steps of pollen development in the anther from floral induction to pollen germination and fertilization are thoroughly examined; the second part is devoted to pollen behaviour in vitro.

Based on papers presented at the International Symposium on Sexual Reproduction in Higher Plants, this volume covers the topics: micro- and macrosporogenesis, the activation and recognition of mature pollen, pollen germination and tube emission in vivo and in vitro, pollen and pollen tube cytoskeleton, stigma and style morphology, pollen/stigma interactions, incompatibility mechanisms and gene expression. The reinvestigation of classical topics using modern methods such as immunofluorescence, micromanipulation, freeze-substitution, electron microscopy, etc., is the common basis of all results presented. Especially applied aspects of sexual reproduction important e.g. for crop improvement, are discussed in detail.

Pollen studies make important contributions nature, into three main themes: pollen struc­ to our knowledge in many interdisciplinary ture and constituents, pollen evolutionary arenas. Pollen identification is widely used in ecology and the pollen-pollinator interface. reconstruction of, e.g., vegetation, the climate Several papers overlap somewhat or are of the past, and plant biodiversity. Studies perhaps even somewhat contradictory and concerning pollen structure, size and form are reflect the author's own ideas and experience. key issues in basic sciences, as, e.g., plant Some could be understood more deeply by taxonomy and evolution, but are also of consulting other closely related articles. The importance in applied fields as, e.g., plant reader is strongly referred to the respective breeding. In pollination studies pollen is literature list of each article. generally used specifically to identify food ofanther ripening and pollen The last steps development (Pacini) and the mature pollen sources of visitors and to reconstruct their foraging routes. Fewer have been devoted to wall structure (Hesse) are key factors to pollen collection mechanisms and to the struc­ understand pollen dispersal mechanisms in ture and content of pollen in relation to its biotic pollination (Stroo) as well as abiotic pollination (Ackerman). Pollen size, shape, function.

The anther tapetum, present in all land plants, is a highly specialized, transient tissue surrounding the (micro-)spores and/or pollen grains during their development.Any tapetum malfunction causes male sterility. The exact knowledge of tapetum form and function therefore is indispensable not only for basic research, but also and especially in plant breeding and plant genetics.In fourteen contributions by reknown experts, a comprehensive account of the various characters and functions of the tapetum is provided, covering the areas of cytology, cytophysiology, biochemistry, tapetum development and function.