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Author: H.-D. Behnke Publisher: Springer Science & Business Media ISBN: 3642744451 Category : Science Languages : en Pages : 311
Book Description
This detailed overview of the structure of the sieve elements of the major plant groups, from algae to flowering plants, includes extant and extinct groups, revealing both common and divergent solutions to the problem of long-distance assimilate transport.
Author: H.-D. Behnke Publisher: Springer Science & Business Media ISBN: 3642744451 Category : Science Languages : en Pages : 311
Book Description
This detailed overview of the structure of the sieve elements of the major plant groups, from algae to flowering plants, includes extant and extinct groups, revealing both common and divergent solutions to the problem of long-distance assimilate transport.
Author: S. Aronoff Publisher: Springer Science & Business Media ISBN: 1468486586 Category : Science Languages : en Pages : 631
Book Description
Ten years ago, at the International Botanical Congress in Edinburgh, a group of us from various countries discussed the difficulty of pursuing academic problems in depth at such meetings. In particular, we were discouraged at the poverty of time for phloem transport. From long association, we were conscious of the extraordinary breadth of the problem, from developmental through anatomical, to biophysical and physiological. Only by a reasonable understanding of all these components could one hope to come to some kind of understanding. We decided to establish common plant material so that data would have a common source. Similarly, we resolved to exchange information by circulating pre-publication manuscripts. For awhile, after the meeting was a pleasant memory, the plan seemed to be working; but, as is so often the case, human infirmities and foibles played early and, subsequently, predominant roles. Some became administrators (a punishment for good behaviour); others concentrated on alternative rings in their academic circuses. The next Congress (in Seattle) proved similar to its predecessor in its neglect and, consequently, succor was sought elsewhere. A little known, but remarkably understanding group becoming visible was the Science Committee and the Division of Scientific Affairs of N. A. T. O. Its sponsorship of Advanced Study Institutes including phytochemistry and phytophysics, was unusual both in the generosity of its funding and in the requirements for academic quality.
Author: M.H. Zimmermann Publisher: Springer Science & Business Media ISBN: 3642661610 Category : Science Languages : en Pages : 548
Book Description
When WILHELM RUHLAND developed his plan for an Encyclopedia of Plant Physiol ogy more than three decades ago, biology could still be conveniently subdivided into classical areas. Even within plant physiology, subdivisions were not too difficult to make, and general principles could be covered sufficiently in the two introductory volumes of the Encyclopedia on the physical and chemical basis of cell biology. But the situation changed rapidly even during the 12-year publication period of the Encyclopedia (1955-1967). The new molecular direction of genetics and structural research on biopolymers had an integrating effect on all other biological fields, including plant physiology, and it became increasingly difficult to keep previously distinct areas separated. RUHLAND'S overall plan included 18 volumes and about 22,000 pages. It covered the entire field of plant physiology, in most cases from the very beginning. But, as each volume appeared, it was clear that its content would soon be outdated.
Author: Ray F. Evert Publisher: John Wiley & Sons ISBN: 0470047372 Category : Science Languages : en Pages : 623
Book Description
This revision of the now classic Plant Anatomy offers a completely updated review of the structure, function, and development of meristems, cells, and tissues of the plant body. The text follows a logical structure-based organization. Beginning with a general overview, chapters then cover the protoplast, cell wall, and meristems, through to phloem, periderm, and secretory structures. "There are few more iconic texts in botany than Esau’s Plant Anatomy... this 3rd edition is a very worthy successor to previous editions..." ANNALS OF BOTANY, June 2007
Author: Daniel Leroy Mullendore Publisher: ISBN: 9781267671424 Category : Languages : en Pages :
Book Description
The distribution of photosynthetically derived assimilates through plants occurs in specialized cells called sieve elements that are connected to each other forming a microfluidic system within the plant. Sieve elements were discovered over 150 years ago, however their in vivo structure and complete assimilate transport properties eludes clarification. Microscopic investigation of sieve elements requires tissue manipulations that disrupt the natural state of translocating sieve elements resulting in interpretations of sieve element ultrastructure. Construed sieve element structures accommodate the osmotic pressure flow hypothesis. Assimilates are postulated to passively flow through sieve elements as a result of osmotically generated pressure differences from source to sink. The assimilate stream characteristics are considered to adhere to physical parameters of the sieve element geometry. For this theory to hold the sieve elements must be free major of obstructions. Presented below is a five year compilation on the investigations on sieve element structure and how the structure may relate to function. Cell wall geometries of the sieve elements were investigated with newly developed microscopy methods and the geometries were compared to phloem flow, implicating that phloem flow may not adhere to the dogma of osmotic pressure flow hypothesis. Sieve element occlusion mechanisms were also reviewed and investigated. Sieve element occlusion related proteins were investigated by means of newly developed microscopic methodologies. One new microscopic method demonstrates unprecedented preservation of sieve element ultrastructure that has never been witnessed.
Author: Yan Liu Publisher: ISBN: Category : Sieve elements Languages : en Pages : 155
Book Description
The phloem in vascular plants transports photoassimilates and other macromolecules from source organs to distant sink organs for growth, storage and development. Mature sieve elements, which are the transporting cells, are void of major organelles, such as nuclei and vacuoles. The unobstructed sieve elements allow the rapid, long distance transport of photosynthates at a low resistance. Despite the essential role of phloem in plants, little is known about the function of the remaining sieve element components, such as the structural phloem proteins (P-proteins), sieve element plastids, endoplasmic reticulum (ER) and mitochondria. The work presented in this dissertation is a compilation on the investigations of sieve element components. One of the few sieve element organelles with known function are forisomes, which are spindle-shaped P-protein bodies present exclusively in Fabaceae species. Forisomes are capable of occluding sieve tubes due to their unique, reversible Ca2+-dependent but ATP- independent contractility. Using bioinformatic tools and site-directed mutagenesis, we studied the structure and function of the forisome-like bodies in yeast, and more importantly, identified three aspartate residues critical for Ca2+-responsiveness, and two more that were required for forisome-like bodies assembly (Chapter Three). We have investigated non-dispersive P-protein bodies in Populus trichocarpa, the homologous proteins of forisomes, to evaluate if they have a similar function. The non-dispersive P-protein bodies have been characterized at a molecular level and we found that the P-protein bodies in P. trichocarpa did not respond to wound of the sieve tube or Ca2+ (Chapter Two). In addition, to investigate other components in sieve elements, we have developed a novel methodology to isolate intact sieve elements in Nicotiana tabacum and performed proteomics analysis. We discovered three novel sieve element specific proteins that are likely localized in a new, undescribed compartment in sieve elements (Chapter Four).
Author: N. Michelle Holbrook Publisher: Elsevier ISBN: 0080454232 Category : Science Languages : en Pages : 597
Book Description
Vascular Transport in Plants provides an up-to-date synthesis of new research on the biology of long distance transport processes in plants. It is a valuable resource and reference for researchers and graduate level students in physiology, molecular biology, physiology, ecology, ecological physiology, development, and all applied disciplines related to agriculture, horticulture, forestry and biotechnology. The book considers long-distance transport from the perspective of molecular level processes to whole plant function, allowing readers to integrate information relating to vascular transport across multiple scales. The book is unique in presenting xylem and phloem transport processes in plants together in a comparative style that emphasizes the important interactions between these two parallel transport systems. Includes 105 exceptional figures Discusses xylem and phloem transport in a single volume, highlighting their interactions Syntheses of structure, function and biology of vascular transport by leading authorities Poses unsolved questions and stimulates future research Provides a new conceptual framework for vascular function in plants
Author: František Baluška Publisher: Springer Science & Business Media ISBN: 0387469575 Category : Science Languages : en Pages : 331
Book Description
he biological sciences are dominated by the idea that cells are the functionally autonomous, physically separated, discrete units of life. TThis concept was propounded in the 19th century by discoveries of the cellular structuring of both plants and animals. Moreover, the ap parent autonomy of unicellular eukaryotes, as well as the cellular basis of the mammalian brain (an organ whose anatomy for a long while defied attempts to validate the idea of the cellular nature of its neurons), seemed to provide the final conclusive evidence for the completeness of *cell theory', a theory which has persisted in an almost dogmatic form up to the present day. However, it is very obvious that there are numerous observations which indicate that it is not the cells which serve as the basic units of biological life but that this property falls to some other, subcellular assemblage. To deal with this intricate problem concerning the fundamental unit of living matter, we proposed the so-called Cell Body concept which, in fact, devel ops an exceedingly original idea proposed by Julius Sachs at the end of the 19th century. In the case of eukaryotic cells, DNA-enriched nuclei are intimately associated with a microtubular cytoskeleton. In this configuration—as a Cell Body—these two items comprise the fundamental functional and struc tural unit of eukaryotic living matter. The Cell Body seems to be inherent to all cells in all organisms.