Plant growth and development

In addition to inhibitory chemicals which enter the plant from the external environment, many endogenous inhibitors appear to function as regulators of seed germination and plant growth and development. The interrelationships between endogenous inhibitors and growth promoters such as the auxins, gibberellins, and kinins remain to be elucidated. 

Volatile Inhibitors. Of the volatile components that influence plant growth and development, ethylene has received the most attention. Literature concerned with the variety of effects produced by ethylene, factors which influence its production, and the mechanisms through which responses are expressed has been reviewed by Evenari (57). Other gaseous excretions with inhibitory effects considered by Evenari include hydrogen cyanide, ammonia, essential oils, and mustard oils (probably allyl isothiocyanate and /3-phenethyI isothiocyanate). 

Contemporary forest declines were initiated about 1950-1960, virtually simultaneously throughout the industrial world at the same time as damage to aquatic systems and structures became apparent. A broad array of natural and anthropogenic stresses have been identified as components of a complex web of primary causal factors that vary in time and space, interact among each other, affect various plant growth and development systems and may result in the death of trees in mountainous ecosystems. As these ecosystems decline, the alterations in forest ecology, independent of the initial causal complex, become themselves additional stress factor complexes leading to further alterations. 

In addition to the mechanisms of stress response so far considered, there are several others which have attracted the attention of plant ecologists. These include innate or environmentally determined forms of dormancy in seeds, spores, and vegetative buds, many of which represent adaptive responses restricting plant growth and development to favourable seasons or sites. Dormancy has been the subject of numerous publications and will not be considered here. Instead, opportunity will be taken to refer to two forms of plant response to stress which until recently have received only scarce attention. The first is the phenomenon of stored growth whilst the second involves the response of the developing shoot to mechanical impedance. 

We have noted how plant growth and development can be influenced by limited water availability in the soil. Direct effects of limited water supply are rather different in the leaves and the roots and it seems particularly important that continued growth of nodal and primary roots is... 

The observation that allelcpathic agents affect plant growth and development leads the physiologist to question the modes of action. While we know that diverse secondary plant products exhibit allelopathic activity, it is difficult to understand the mechanism of action of these plant products partly because of ... 

Leopold, A. C. Krledemann, P. E. "Plant Growth and Development" McGraw-Hill Book Co New York, 1975 111. 

In allelopathy studies, the allelochemicals first influence the physiological and biochemical processes in cells. Till now there is no book of methods to study allelopathic interactions in the cells. The activity of cells influence various important physiological processes like seed germination, plant growth and development, photosynthesis and respiration, senescence and abscission are included in this volume. To understand the basic mechanisms of various physiological processes, being affected by allelochemicals at the cellular level enzyme activity and metabolite studies are essential. 

WALDEN, R., FRITZE, K HAYASHI., H., MIKLASHEVICHS, E., HARLING, H., SCHELL, J., Activation tagging a means of isolating genes implicated as playing a role in plant growth and development, Plant Mol. Biol., 1994,26, 1521-1528. 

Brassinosteroids (BR) are a group of plant steroid hormones that help to regulate many aspects of plant growth and development. Several P450s have been... 

Fosket DE. Plant Growth and Development. A Molecular Approach, Academic Press, New York, 1994. 

Allelopathy is defined as biochemical interactions between one plant or microorganism (alga, bacteria, or virus) and another plant through the production of chemical compounds - secondary metabolites (allelochemicals), which influence, direct or indirect, harmful or beneficial, plant growth and development (Rice 1984). Allelochemicals are present in almost all plants and in many tissues, like leaves, stems, flowers, fruits, seeds, roots, or pollen and may be released from plants into the environment by volatilization, leaching, root exudation, and decomposition of plant residues (Chou 1990). 

Some studies indicated that exogenous zearalenone influences plant growth and development. For example, zearalenone stimulated the initiation of the vegetative bud in tobacco pith callus tissue (Mirocha et al. 1968), inhibited the cell membrane transport of maize roots (Vianello and Macri 1981) and enhanced the a-amylase and P-glucosidase activities of germinating maize seeds. 

Plant growth and development is a coordinated set of interrelated events. The growth of various plant parts can influence the growth of other parts through metabolic activities (I ). 

The flavonoids are a remarkable group of plant metabolites. No other class of secondary product has been credited with so many — or such diverse — key functions in plant growth and development. Many of these tasks are critical for survival, such as attraction of animal vectors for pollination and seed dispersal, stimulation of Rhizobium bacteria for nitrogen fixation. 

In order to understand fully the importance of these chemical factors, it is necessary to consider the processes which are probably responsible for their diversification. A mechanism of coevolution of insects and plants was set forth eloquently by Erlich and Raven (4). According to their hypothesis, angiosperms produced a series of chemical compounds which were not directly related to their basic (or primary) metabolic pathways, but which were otherwise not harmful to the plants growth and development. 

Rogers, L. A., and Campbell, M. M., 2004, The genetic control of lignin deposition during plant growth and development, New Phytol. 164 17-30. 

The effects of auxin upon the growth of plants were truly remarkable. As a result of the concerted effort and interest that plant scientists devoted to this highly fashionable and exciting field of research, much of what we know of the control of plant growth and development by auxin was discovered in these highly productive years. The hormone was derived from the aromatic amino acid tryptophan and was relatively abundant in the rapidly growing meristematic parts of plants such as apical buds and root tips. Inactive bound forms existed, as in seeds, where hydroly-... 

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