Sucrose and starch metabolism during Fargesia yunnanensis shoot growth (original) (raw)
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Uptake of Carbohydrates by Suspension Cultured Cells of Bamboo Plants
Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues Vol. V, 2008
The genus Phyllostachys, a major bamboo found in Japan, provides useful resources for local economics. Recently it has been considered as a renewable bio-resource. We have established an efficient cell suspension culture system for bamboos, genus Phyllostachys. Uptake of carbohydrates by bamboo cells was characterized using this cell suspension culture system. In order to demonstrate the effect of cell densities on proliferation of bamboo suspension cells, a portion of maintained liquid suspension cells was re-suspended in fresh 50 ml of modified ½MS medium in 200-ml conical flasks at cell densities of 1, 10, 50 and 100 ml sedimented cell volume (SCV) per liter of the medium, respectively. Ten ml SCV l-1 was the most effective for proliferation of the cells (35.6-fold) while high-cell-density culture strongly suppressed their growth (2.6-fold). Osmolality in each liquid medium, which reflected consumption patterns of nutrients by the cells in a culture period, was measured and found that the value dramatically decreased in high-cell-density conditions (50-100 ml SCV l-1). In practice, no or less fructose, glucose, and sucrose contents in the media of high-cell-density conditions were detected by high performance liquid chromatography analysis suggesting that sucrose catabolism might be highly activated in bamboo suspension cells. A micro-plate cell culture method was employed for detailed analysis of growth and sugar uptake of bamboo plants. The unique characteristics of bamboo cells were discussed in comparison with that of rice Os cells and tobacco BY2 cells.
Journal of Plant Physiology, 2004
In monocots, the zygotic embryo is protected and nourished by an endosperm. In the present study starch deposition and amylase accumulation was noticed during somatic embryogenesis in stem callus of a bamboo, Dendrocalamus hamiltonii. SEM studies revealed that starch grains were clearly visible in the scutellum during the maturation stage of the somatic embryo. As the somatic embryo developed further, the scutellum got reduced with corresponding increase in amylase. The amylase activity was tested periodically at different developmental stages of embryos. The role of scutellum in somatic embryos for starch deposition and amylase accumulation is discussed. Abbreviations: BAP = benzylamino purine. -GA 3 = gibberellic acid. -2,4-D = 2,4-dichlorophenoxyacetic acid. -MS = Murashige and Skoog medium (1962). -NAA = α-naphthalene acetic acid. -SEM = scanning electron microscopy
PLANT PHYSIOLOGY, 1982
The control of photosynthetic starch/sucrose formation in leaves of soybean (Glyjine max L. Merr.) cultivars was studied in relation to stage of plant development, photosynthetic photoperiod, and nitrogen source. At each samplng, leaf tissue was analyzed for starch content, activities of sucrose-metabolizing enzymes, and labeling of starch and sucrose (by "4CO2 assimilation) in isolated cells. In three of the four varieties tested, nodulated plants had lower leaf starch levels and higher activities of sucrose phosphate synthetase (SPS), and isolated mesophyll cells incorporated more carbon (percentage of total "CO2 fixed) into sucrose and less into starch as compared to nonnodulated (nitrate-dependent) plants. The variation among cultivars and nitrogen treatments observed in the activity of SPS in leaf extracts was positively correlated with labeling of sucrose in isolated cells (r -0.81) and negatively correlated with whole leaf starch content (r = -0.66). The results suggested that increased demand for assimilates by nodulated roots may be accommodated by greater partitioning of carbon into sucrose in the mesophyll cells. We have also confirmed the earlier report (Chatterton, Silvius 1979 Plant Physiol 64: 749-753) that photoperiod affects partitoning of fixed carbon into starch. Within two days of transfer of nodulated soybean Ransom plants from a 14-hour to a 7-hour photoperiod, leaf starch accumulation rates doubled, and this effect was associated with increased labeling of starch and decreased labeling of sucrose in isolated cells. Concurrently, activities of SPS, sucrose synthase, and uridine diphosphatase in leaves were decreased.
Science of the Total Environment, 2022
Regional increases in atmospheric O 3 , mainly produced photochemically from anthropogenic precursor gases, have phytotoxicity due to its strong oxidizing properties. To determine the response of bamboo physiology to elevated O 3 levels, three-year-old dwarf bamboo (Indocalamus decorus) clones were exposed to three O 3 concentrations (Ambient-AA, 21.3 to 80.9 ppb in the daytime; −AA+70, 70 ppb O 3 above ambient; −AA+140, 140 ppb O 3 above ambient) in open-top chambers for one growing season in Beijing, China. Gas exchange, biomass, growth, soluble sugar, and starch contents were examined at the end of the experiment. Our findings indicated that: (1) elevated O 3 treatments decreased the photosynthesis rate, total biomass, and bud numbers but increased individual bud biomass and rhizome bud to rhizome biomass ratio. The most severe reduction was observed in new rhizome biomass (35.9% reduction in AA+70 and 57.2% reduction in AA+140), whereas individual bud biomass increased by 50% and 75% in the AA+70 and AA+140 groups compared with AA, respectively; (2) the starch contents in the rhizome decreased by 28.4%, whereas soluble sugar increased by 38.1% in the AA+140 rhizome buds compared to AA; (3) only the culm numbers of pachymorph rhizomes (clumped) decreased, whereas no changes in leptomorph rhizomes were observed. However, the mean distance between two ramets was lengthened by 49.4% and 86.5% in AA+70 and AA+140, respectively. In conclusion, Indocalamus decorus allocated more nonstructural carbohydrates (NSCs) from the rhizome to the buds to
Sucrose Synthase in Rice Plants : Growth-Associated Changes in Tissue Specific Distributions
PLANT PHYSIOLOGY, 1990
Different parts of the rice (Oryza sativa L.) plant at different growth stages were analyzed for sucrose synthase (SS) by enzyme activity assay and enzyme-linked immunosorbent assay directly on the extracts or on the eluates from a gel filtration column. On a dry matter basis, the amount of soluble protein and SS activity decreased significantly, but the amount of enzyme protein changed little in growing leaves. In the grain, the SS activity was the highest at the early ripening stage and decreased later, but the amount of SS protein increased with the increase in maturity. In the root, a low activity of SS was detectable only in
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.
Carbon allocation in developing spruce needles. Enzymes and intermediates of sucrose metabolism
Physiologia Plantarum, 1994
In lyophilized needles of Norway spruce {Picea abies [L.] Karsten) and starting from bud break, we determined enzyme activities (sucrose phosphate synthase [SPS: EC 2.4.1.14). sucrose synthase [SS: EC 2.4.1.13]. acid invertase [AI: EC 3.2.1.26]) and intermediates (starch, sucrose, glucose, fructose: fructose 6-phosphate, fructose 2,6bisphosphate [F26BP1) of carbohydrate metabolism together with needle weight, shoot length, chlorophyll and protein. For up to 110 days after bud break, samples were taken twice a week from about 25-year-old trees under field conditions. At least three periods can be distinguished during needle maturation. During the first period (up to 45 days after bud break) Al showed the highest escractable activity. This coincided with terj high levels of F26BP (up to II pmoi [mg dry weight] ') and a transient increase of starch in parallel to a decrease of sucrose. The interval between 45 and 70 days after bud break was characterized by high SS activity (ratio of fructose/glucose >11, much decreased le\els of F26BP (down to below 1 pmol [mg dr> weight] '). and a pronounced increase in the dry w-eight/fresh weighl ratio. In parallel, starch declined and soluble carbohydrates increa.sed. Finally, needle maturation was characterized by decreasing SS and continuously increasing SPS acti\ities, so that the ratio of SPS/SS increased more than 6-fold. ,\l. however did not decline with maturation. Changes in poo) siz.es of metabolites and enzyme acti\'iiies (AI, SPSi are consisteni with current concepts on sink/.source transition. SS is obviously important with regard to the synthesis of structural polysaccharides. Key words-.Acid invertase. carbon partitioning/alkx;ation. fructose 2.6-bisphosphate, metabolite pools, needle development, Picea ahies. .sucrose pho.sphate synthase. sucrose synthase.
Biocatalysis and Biotransformation, 2006
Since the initial discovery showing that ADPglucose (ADPG) serves as the universal glucosyl donor in the reaction catalyzed by starch synthase, the mechanism of starch biosynthesis in both leaves and heterotrophic organs has generally been considered to be an unidirectional process wherein ADPG pyrophosphorylase (AGPase) exclusively catalyzes the synthesis of ADPG and acts as the major limiting step of the gluconeogenic process. There is however mounting evidence that ADPG linked to starch biosynthesis is produced de novo in the cytosol by means of sucrose synthase (SuSy). In this review we show and discuss the numerous pitfalls of the 'classic' view of starch biosynthesis. In addition, we describe many overlooked aspects of both ADPG and starch metabolism. With the overall data we propose an 'alternative' model of starch biosynthesis, applicable to both photosynthetic and heterotrophic tissues, according to which both sucrose and starch biosynthetic processes are tightly interconnected by means of an ADPG synthesizing SuSy activity. According to this new view, starch metabolism embodies catabolic and anabolic reactions taking place simultaneously in which AGPase plays a vital role in the scavenging of starch breakdown products. Sucrose UDPG G1P UDP Fru SuSy UGPase PPi UTP G6P PGM Starch ATP PPi G1P ADPG AGPase G6P PGM ADP Amyloplast Cytosol ADP ATP Sucrose UDPG G1P UDP Fru UGPase PPi UTP G6P PGM ATP PPi G1P G6P PGM Amyloplast Cytosol Sucrose UDPG G1P UDP Fru UGP PPi UTP G6P PGM ATP G1P G6P PGM t l ADP ATP ADP ATP 2Pi APPase Figure 2. Schematic representation of the classic model of Suc-starch conversion in heterotrophic tissues of di-cotyledonous plants.
Tropical Plant Biology, 2015
Sucrose, glucose and fructose concentrations, and sucrolytic enzyme activities were measured in the developing shoots and internodes of sprouting sugarcane setts (Saccharum spp, variety N19). The most striking change during the sink-source transition of the internode and germination of the axillary bud is a more than five-fold induction of cell wall invertase in the germinating bud. In contrast, soluble acid invertase is the main sucrose hydrolytic activity induced in the internodal tissue. A cycle of breakdown and synthesis of sucrose was evident in both the internodes and the shoots. During shoot establishment, the sucrose content decreased and the hexose content increased in the internodal tissues while both sucrose and hexoses continuously accumulated in the shoots. Over the sprouting period internode, dry mass was reduced by 25 and 30 % in plants incubated in a dark/light cycle or total darkness, respectively. Sucrose accounted for 90 % of the dry mass loss. The most significant changes in SuSy activity are in the synthesis direction in the shoots resulting in a decrease in the breakdown/synthesis ratio. In contrast the SuSy activity in the internodal tissue decrease and more so in the synthesis activity resulting in an increase in the breakdown to synthesis ratio. Keywords Sugarcane (Saccharum spp). Sucrose. Germination. Cell wall invertase. Invertases sucrose synthase Abbreviations CWI Cell wall invertase (EC. 3.2.1.26) NI Neutral invertase (EC 3.2.1.26) SAI Soluble acid invertase (EC. 3.2.1.26) SuSy Sucrose synthase (EC 2.4.1.13) Bq Becquerel V max Maximum catalytic activity HEPES N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid EDTA Ethylenediaminetetraacetic acid NAD β-nicotinamide adenine dinucleotide HK Hexokinase G6PDH Glucose-6-phosphate dehydrogenase (EC 1.1.1.49) ATP Adenosine 5′-triphosphate PGI Phosphoglucose isomerase (EC 5.3.1.9) UDP Uridine 5′-diphosphate ATP Adenosine 5′-triphosphate PVPP Polyvinyl polypyrrolidone Communicated by: Ray Ming