Growth and development

Occasionally the membrane is seen attached to cells in suspension culture (Fig. 5.1.2B). This membrane is associated with a variety of unusual structures containing phenolic residues and tannin. The role of these membranes or skins in osmotic phenomena, filtration, gas exchanges, lectin and enzyme partitioning, and energy transduction at or on surfaces is unknown. Lectins are associated usually with juvenile tissues, such as embryos and seeds, rather than with mature tissues (19, 20). However, lectins that bind manganese and zinc have been isolated from the bark of Robinia pseudoacacia (68). 

It is possible that a proteinaceous residue derived from the breakdown of cytoplasmic membranes contributes to the membrane that covers the lumen surface of xylem cells in softwoods and hardwoods (84). Deposited nitrogenous constituents may be eluted subsequently by the transpiration stream (27). In Pistacia vera, zinc deficiency contributes to the immobility of the nitrogenous storage compound arginine where it builds up inside leaves (Durzan 1985, unpublished). The redistribution of amino acids is mediated by lignified transfer cells (105, 109). 

During the life cycle of trees, hormone action involving the release of hormones from conjugates may involve the soluble and insoluble compartments of the cell wall (21). How oligosaccharins derived from cell walls contribute and relate to the control of morphogenesis and extracellular nitrogenous compounds remains unknown (3). 

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The mode of action is by inhibiting 5-enolpymvyl-shikimate-3-phosphate synthase. Roundup shuts down the production of the aromatic amino acids phenylalanine, tyrosine, and tryptophane (30). Whereas all these amino acids are essential to the survival of the plant, tryptophane is especially important because it is the progenitor for indole-3-acetic acid, or auxin, which plays an important role in growth and development, and controls cell extension and organogenesis. 

R. M. Sacher, "Strategies to Discover Plant Growth Regulators for Agronomic Crops," in Chemical Manipulation of Crop Growth and Development 1982, p. 167. 

J. L. Bema and co-workers. Growth and Developments in Einear Alkylbenyene Technology. Thirty Years ofilnnovation and More to Come, Petresa and UOP Pre-Pubhcation Communication, 1994. 

Because of the great importance of phosphorus and its compounds in the chemical industry, several books and reviews on their preparation and uses are available.Some of these applications reflect the fact that P is a vital element for the growth and development of all plants and animals and is therefore an important constituent in many fertilizers. Phosphorus compounds are involved in energy transfer... 

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. 

Various assay methods have been used to detect the presence of inhibitory substances. These include some of the classical tests used by investigators of growth-promoting substances—i.e., the various Avena coleoptile assays which utilize intact, decapitated, or isolated cylinders and the split pea stem test. Effects on seed germination and seedling shoot or root growth and development have also been measured in addition to other visible expressions of inhibition. Details of many of these tests have been compiled by Mitchell et al. (99). Tests have been carried out in Petri dishes, with various solution culture techniques, and by sand and soil culture. Effects so measured may or may not be similar to those obtained under field situations— i.e., the establishment of inhibition under controlled conditions pro-... 

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). 

The estrogens are secreted by the ovarian follicle and in smaller amounts by the adrenal cortex. Estrogens are important in the development and maintenance of the female reproductive system and the primary and secondary sex characteristics. At puberty, they promote growth and development of the vagina, uterus, fallopian tubes, and breasts. They also affect the release of pituitary gonadotropins (see Chap. 50). 

Southwest Foundation for Research and Education, Division of Biological Growth and Development, Department of Biochemistry, San Antonio, Texas 78284. 

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. 

Value and satisfaction. Mentors tend to gain immense personal satisfaction from knowing that they have contributed greatly to another individual s growth and development. Some also... 

The key to successful mentorhood is the commitment to the growth and development of another individual. 

Saunders et al. 1995), osteometry (Saunders and Hoppa 1995 Saimders and Sawchuk 1995) and growth and development (Saunders and Hoppa 1993 Saimders et al 1993). 

Murphy SD. 1982. Toxicity of hepatic metabolism of organophosphate insecticides in developing rats. In Hunt VR, Smith MK, Worth D, eds. Banbury report, Vol. II. Environmental factors in hiunan growth and development symposium, November 1-4, 1981. Cold Spring Harbor, NY Cold Spring Harbor Laboratory, 125-136. 

Hi) Poly amines. In many respects the role of poly amines in plant functioning is still mysterious after many years work. They are almost certainly involved in the control of growth and development through their interactions with nucleic acids and membranes (Smith, 1985). There is increasing circumstantial evidence for their involvement, especially of putrescine, in plant responses to a wide range of stresses including pH, Mg deficiency, osmotic shock, cold, SO2 pollution, and cadmium and ammonium toxicity (Smith, 1985). It remains to be determined, however, how, and indeed whether, putrescine accumulation in response to these diverse stresses is beneficial. 

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. 

Regulation of growth and development of plants growing with a restricted supply of water... 

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