Growth of Bauhinia forficata Link, Curcuma zedoaria Roscoe and Phaseolus vulgaris L. cell suspension cultures with carbon sources (original) (raw)
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Review: role of carbon sources for in vitro plant growth and development
Molecular Biology Reports, 2012
In vitro plant cells, tissues and organ cultures are not fully autotrophic establishing a need for carbohydrates in culture media to maintain the osmotic potential, as well as to serve as energy and carbon sources for developmental processes including shoot proliferation, root induction as well as emission, embryogenesis and organogenesis, which are highly energy demanding developmental processes in plant biology. A variety of carbon sources (both reducing and non-reducing) are used in culture media depending upon genotypes and specific stages of growth. However, sucrose is most widely used as a major transport-sugar in the phloem sap of many plants. In micropropagation systems, morphogenetic potential of plant tissues can greatly be manipulated by varying type and concentration of carbon sources. The present article reviews the past and current findings on carbon sources and their sustainable utilization for in vitro plant tissue culture to achieve better growth rate and development.
Planta, 1993
Metabolites and enzyme activities were measured in the phloem sap exuding from a cut hypocotyl of germinating castor-bean (Ricinus communis L.) seedlings. The sap contained considerable quantities of adenine nucleotides, uridine nucleotides, uridine diphosphoglucose (UDPGlc), all the major phosphorylated metabolites required for glycolysis, fructose-2,6-bisphosphate and pyrophosphate. Supplying 200 mM glucose instead of sucrose to the cotyledons resulted in high concentrations of glucose in the sap, but did not modify the metabolite levels. In contrast, when 200 mM fructose was supplied we found only a low level of fructose but a raised sucrose concentration in the sap, which was accompanied by a three-to fourfold decrease of UDPGlc, and an increase of pyrophosphate, UDP and UTP. The measured levels of metabolites are used to estimate the molar mass action ratios and in-vivo free-energy change associated with the various reactions of sucrose breakdown and glycolysis in the phloem. It is concluded that the reactions catalysed by ATP-dependent phosphofructokinase and pyruvate kinase are removed from equilibrium in the phloem, whereas the reactions catalysed by sucrose synthase, UDPGlc-pyrophosphorylase, phosphoglucose mutase, phosphoglucose isomerase, aldolase, triose-phosphate isomerase, phosphoglycerate mutase and enolase are close to equilibrium within the conducting elements of the phloem. Since the exuded sap contained negligible or undetectable activities of the enzymes, it is concluded, that the responsible proteins are bound, or sequesterd behind plasmodesmata, possibly in the companion cells. It is argued that sucrose mobilisation via a reversible reaction catalysed by sucrose synthase is particularily well suited to allow the rate of sucrose breakdown in the phloem to respond to changes in the metabolic requirement for ATP, and for UDPGlc during callose production. It is also calculated that the transport of nucleotides in the phloem sap implies that there must be a very considerable uptake or de-novo biosynthesis of these cofactors in the phloem.
Enzymic Assay of 10-7 to 10-14 Moles of Sucrose in Plant Tissues
PLANT PHYSIOLOGY, 1977
Procedures are desrbed for measuring sucrose in plant extracts or freeze-dried tissue in the range between 10-7 and 10-14 moles. The method is based on the destruction of pre-exbiting glucose and fructose, followed by the hydrolysis of sucrose and reduction of NADP+ by a series of coupled enzymic reactions. Depending on the senfitivity required, the NADPH is determined directly with a spectrophotometer or a fluorometer, or is ampliffed as much as 30,000 times before fluorometric assay. The procedures sugested for the macro level are simpler than current methods, and those suggested for microanalysis are severd orders of magnitude more sensitive. With this technique, single palisade parenchyma cells and single
The Potential of Carbohydrates in Plant Growth Regulation
Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues Vol. I, 2006
Attention was devoted to enzymes assumed to be involved in the elongation/cessation of growth after treatment with galactoglucomannan oligosaccharides (GGMOs). Endoglycanases, endo-(1-4)-ȕ-D-glucanase, endo-(1-3),(1-4)-ȕ-D-glucanase, endo-(1-4)-ȕ-D-mannanase, as well as XET, showed remarkable activity changes after GGMOs treatment indicating their role in cell wall remodeling and cell wall milieu stabilization during cessation of elongation growth. Studies on peroxidase-the enzyme participating in cell wall tightening-showed that elongation growth inhibited by GGMOs may be associated with the process of cell wall rigidification catalysed by peroxidase. Previously obtained results on glycosidases are also discussed.
Sucrose and the integration of metabolism in vascular plants
Plant Science, 2000
We consider the hypothesis that sucrose is a signal as well as a substrate. We suggest that the significance of sugar sensing in plants is the integration of whole-plant carbon flux so that the capacity of sources to produce sucrose matches the capacity of sinks to consume it. We pay particular attention to difficulties with this hypothesis and the areas where further or better evidence is needed. We conclude that there is strong correlative evidence for a link between sucrose metabolism and the level of expression of key genes, but that a number of different mechanisms may be involved.
Journal of Plant Physiology, 1993
A continuous culture of heterotrophic sugarcane (Saccharum sp.) suspension cells was established on a chemically defined medium. This allowed culture growth at constant, defined nutrient conditions including very low concentrations, where a particular nutrient is growth-limiting. Cells grown under nitrogen, phosphorus or carbon limitation were analyzed for cell components such as sucrose, amino acids, cations, anions and enzymes, which are involved in sucrose metabolism. Thereby, the influence of the particular nutrient on sucrose storage and solute composition of the cells was identified. High levels of sucrose storage were only reached under nitrogen starvation, i.e. at very low levels of amino acids, not under phosphorus or carbon starvation, indicating a direct regulation of sucrose metabolism by amino acids. The starch content was not correlated to sucrose storage. The amino acid content of cells, which was very high under optimal growth conditions, became low under carbon as well as under nitrogen limitation, whereas under phosphorus limitation a strong shift into amino acids deriving from pyruvate was observed. Phosphate and sulfate accumulation were inversely correlated in the sense that the decrease in cellular phosphate (e.g. under P-or N-limitation) led to an increase in sulfate. Highest phosphate levels were observed under carbon limitation. Accumulation of sulfate had the additional effect that it was accompanied by an increase in cellular sodium. The rate of net uptake of carbon was roughly correlated with the growth rate. The same was true for the respiration rate, except under nitrogen limitation, which strongly suppressed respiration. The ratio of carbon assimilation to carbon dissimilation therefore shifted significantly in favor of assimilation under nitrogen limitation, whereas carbon and phosphorus limitation had only a small effect on this ratio. Sucrose synthesis usually constituted only a very small portion of the assimilated carbon (1-6 %), except in the case of nitrogen limitation where it amounted to 37 %. Net sucrose storage is the result of a rapid cycle of sucrose synthesis and sucrose hydrolysis. The rates of the individual enzymes involved in sucrose metabolism were more related to the growth rate than to the rate of sucrose storage. Invertase activity neither correlated with growth nor with storage, but it responded immediately to changes of the growth rate. The metabolic background for the effect of particular nutrients, especially for the regulatory role of amino acids in sucrose storage, is discussed.
Intracellular site of sucrose synthesis in leaves
Phytochemistry, 1974
Improved condltlons for extraction and dssay increased rates of sucrose synthesis from urldme dlphosphate glucose (UDPglucose) plus fructose 6-phosphnte (F 6 P) cdtaiysed by leaf eXtrdCtS 20-fold Rates of 17 9 25 0,9 2 dnd 27 7 btmol,/hr/g fr wt respectively were obtained from pea shoots, spmach, wheat and bean leaves Chloroplasts isolated from pea shoots m which half the plastlds were mtact contdmed less than 4"" of the total UDPglucose-fructoaephosphate glucosvltran\ferase more than 30",, of the rlbulose dlphosphate (RuDP) cdrboxyldse, and more than 40':, of the total chlorophyll of the leaf Although some of the UDPglucose-fructosephosphate glucosyltranqferase wns assocldted with particles smaller than chloroplasts at least 85"" of the enzyme was not precipltdted at 38000 q UDPglucose pyrophosphorylase also thought to be essentldl for sucrose Fynthesis, was distributed between the cell fractions m d slmllar manner to UDPglucose-fructosephosphate glucosyltransferase It 1s concluded that sucrose synthesis m pea shoots and spinach leaves occurs mainly m the cytoplasm ' HFHER U SA"*TARII 5 K A Hr usox M A dnd HALII~R U W (1967) 7 htrrurfor xh 22b, I189 '
Carbon sources and their osmotic potential in plant tissue culture: does it matter
Scientia Horticulturae, 2003
Plant cell, tissue and organ cultures require a carbohydrate supply in order to satisfy energy demands. Experiments to define type and concentration of carbon source that allow culture establishment and development are usually conducted. Several studies published in the literature have inappropriately used percentages as reference concentrations to determine the quantities of the different types of sugars contained in the treatments leading to conflicting results and conclusions. The use of percentage references adds an undesirable osmotic variable among different treatments and some authors fail to consider this aspect. Therefore, molar concentrations should be used to carbohydrate concentrations reference because it isolates the osmotic variable influence that acts concomitantly with the nutritional variable. #
Sucrose Transport in Higher Plants
International Review of Cytology, 1997
of water and mineral salts taken up by the root system and transported via the xylem network, while non-green Sucrose as the major transported form of fixed carbon, tissues depend on the carbon supply deriving from metamust be translocated from the sites of synthesis, i.e.
Sucrose and starch metabolism during Fargesia yunnanensis shoot growth
Bamboo is one of the fastest growing plants in the world, but their shoot buds develop very slowly. Information about the sugar storage and metabolism during the shoot growth is lacking. In the present study, we determined the activity of sucrose and starch metabolizing enzymes during the developmental period of Fargesia yunnanensis from shoot buds to the young culms that have achieved their full height. The soluble sugars and starch contents were also determined and analyzed in shoot buds and shoots at different developmental stages. The results showed that there were higher sucrose contents in shoot buds than shoots, which coincides with the sweeter taste of shoot buds. As the shoot buds sprouted out of the ground, the starch and sucrose were depleted sharply. Coupled with this, the activity of soluble acid invertase (SAI), cell wall-bound invertase (CWI), sucrose synthase at cleavage direction (SUSYC) and starch phosphorylase (STP) increased significantly in the rapidly elongating internodes. These enzymes dominated the rapid elongation of internodes. The activities of SAI, CWI, SUSYC and STP and adenosine diphosphate-glucose pyrophosphorylase were higher as compared to other enzymes in the shoot buds, but were far lower than those in the developing shoots. The slow growth of shoot buds was correlated with the low activity of these enzymes. These results complement our understanding of the physiological differences between shoot buds and elongating shoots and ascertain the physiological mechanism for the rapid growth of bamboo shoots. In bamboos, like in other photoautotrophic and heterotrophic plants, sucrose, glucose and fructose constitute the major soluble carbohydrate fraction, and together with starch, these sugars represent the non-structural carbohydrates (Magel et al. 2005).