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Stem Reserve Mobilization and Sink Activity in Wheat under Drought Conditions  [PDF]
Anil K. Gupta, Kamaljit Kaur, Narinder Kaur
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.21010
Abstract: The effect of water deficit on stem reserve mobilization and sink activity in wheat (Triticum aestivum L.) cultivars, viz., C306 (drought tolerant) and PBW343 (drought sensitive) was studied. Drought was maintained in pot raised plants by withholding irrigation at 95 days after sowing (DAS), i.e. just five days before the initiation of anthesis. Drought induced a significant reduction in mean biomass of all the internodes of sensitive cultivar as compared to those of tolerant one. Mobilized dry matter and mobilization efficiency were observed to be higher in the internodes of tolerant cultivar, both under control and stress conditions, which resulted in enhanced translocation of stem reserves to the grains. Water soluble carbohydrates (WSC), which mainly occur as fructans, were observed to be higher in the internodes of tolerant cultivar than those of sensitive one. When drought was applied, fructans were mobilized more effectively from the internodes of tolerant cultivar. A significantly higher sucrose synthase activity in the grains of tolerant cultivar, under drought conditions, increased the sink strength by unloading the assimilates in the sink, thereby increasing further mobilization of assimilates to the grains. Grains of sensitive cultivar attained maturity much earlier as compared to the tolerant one, both under control and stress conditions. The longer duration of grain maturation in tolerant cultivar supported enhanced mobilization of stem reserves, thus restricting heavy decrease in grain yield, under stress conditions, as compared to the sensitive cultivar. It may, therefore, be concluded that certain characteristics viz., enhanced capability of fructan storage, higher mobilization efficiency, stronger sink activity and longer duration of grain maturation might help the drought tolerant cultivar in coping the stress conditions
Dynamics of reserve polyglucide mobilization under the action of alpha-amylase in various graminaceae species from cultivated and spontaneous flora  [cached]
Elena Ciornea,Gabriela Vasile,Dumitru Cojocaru,Sabina Ioana Cojocaru
Analele ?tiin?ifice Ale Universit??ii Alexandru Ioan Cuza din Ia?i,Sectiunea II A : Genetica si Biologie Moleculara , 2009,
Abstract: The investigations followed the mobilization of reserve polyglucides under the action of α-amylase, during the germination process, in some species of graminaceae from both cultivated and spontaneous flora (Panicum miliaceum, Sorghum vulgare and Bromus sterilis). The experimental results obtained showed that - under the action of amylases - starch gets hydrolyzed at an amazingly high rate, hydrolysis beginning as early as the first hours of germination; at the same time, major differences have been observed from one species to another.
On the mobilization of reserve starch under the action of glucanphosphorylase in Panicum miliaceum and Bromus sterilis  [cached]
Elena Ciornea,Gabriela Vasile,Dumitru Cojocaru
Analele ?tiin?ifice Ale Universit??ii Alexandru Ioan Cuza din Ia?i,Sectiunea II A : Genetica si Biologie Moleculara , 2008,
Abstract: The main objective of the study was the quantitative determination of the reserve starch and of the total soluble proteins, in correlation with the dynamics of the α-glucanphosphorylase activity from the caryopses, subjected to germination under laboratory conditions, belonging to two graminaceae species from the cultivated (Panicum miliaceum) and spontaneous (Bromus sterilis) flora. The experimental results obtained put into evidence a differentiated dynamics for both the enzymatic activity and protein and starch concentration, as a function of species - on one side - and germination time - on the other.
Histochemical analysis of seed reserve mobilization in Passiflora edulis Sims fo. flavicarpa O. Deg. (yellow passion fruit) during germination
Tozzi, HH.;Takaki, M.;
Brazilian Journal of Biology , 2011, DOI: 10.1590/S1519-69842011000400015
Abstract: in the present work, we analyzed the histochemical aspects of passiflora edulis seeds reserve mobilization during the first ten days of germination. our results showed that mainly lipids present in the endosperm are used as a reserve source, and their levels reduce at the same time the radicle protrudes, between the fourth and sixth day of sowing. furthermore, protein bodies are present in the cotyledons, which are degraded as germination occurs and are almost depleted by the time of radicle protrusion. starch grains also appear in the late germination period, and it is not clear if there is any reserve wall polysaccharide consumption in the endosperm.
Seed reserve composition and mobilization during germination and initial seedling development of Euphorbia heterophylla
SUDA, CECILIA N.K.;GIORGINI, JARBAS F.;
Revista Brasileira de Fisiologia Vegetal , 2000, DOI: 10.1590/S0103-31312000000300006
Abstract: seed composition and reserve mobilization were investigated in wild poinsettia (euphorbia heterophylla l.). lipids, around 60% of seed dry mass, are the major reserve. proteins, including albumins (49%), salt insoluble globulins (30%), salt-soluble globulins (21%) and prolamins (0.3%), comprise about a quarter of seed dry mass. soluble sugars comprise about 3.6% of seed dry mass, sucrose being the predominant sugar. starch was not detected in the endosperm of e. heterophylla. lipid depletion starts after initial imbibition, and is completed between 72 and 96 hours. protein fractions exhibit different degradation patterns, salt-soluble globulins being continuously degraded after the start of imbibition whereas salt insoluble fractions are degraded between 36 and 72 hours, and albumins between 60 and 84 hours. globulin depletion is accompanied by an increase in free amino acids in the endosperm whereas intense albumin depletion is not. this result suggests that during albumin depletion there is a rapid transfer of amino acids to the growing embryo. histochemical studies indicated that light accelerates protein degradation in the micropylar area of the seed. soluble sugars increase in the embryo with no concomitant decrease in the endosperm, suggesting that sugars are mostly originated from the catabolism of lipids.
Seed reserve composition and mobilization during germination and initial seedling development of Euphorbia heterophylla  [cached]
SUDA CECILIA N.K.,GIORGINI JARBAS F.
Revista Brasileira de Fisiologia Vegetal , 2000,
Abstract: Seed composition and reserve mobilization were investigated in wild poinsettia (Euphorbia heterophylla L.). Lipids, around 60% of seed dry mass, are the major reserve. Proteins, including albumins (49%), salt insoluble globulins (30%), salt-soluble globulins (21%) and prolamins (0.3%), comprise about a quarter of seed dry mass. Soluble sugars comprise about 3.6% of seed dry mass, sucrose being the predominant sugar. Starch was not detected in the endosperm of E. heterophylla. Lipid depletion starts after initial imbibition, and is completed between 72 and 96 hours. Protein fractions exhibit different degradation patterns, salt-soluble globulins being continuously degraded after the start of imbibition whereas salt insoluble fractions are degraded between 36 and 72 hours, and albumins between 60 and 84 hours. Globulin depletion is accompanied by an increase in free amino acids in the endosperm whereas intense albumin depletion is not. This result suggests that during albumin depletion there is a rapid transfer of amino acids to the growing embryo. Histochemical studies indicated that light accelerates protein degradation in the micropylar area of the seed. Soluble sugars increase in the embryo with no concomitant decrease in the endosperm, suggesting that sugars are mostly originated from the catabolism of lipids.
The social mobilization by social networks  [cached]
Abderrahmane AMSIDDER,Fathallah DAGHMI,Farid TOUMI
Essachess : Journal for Communication Studies , 2012,
Abstract: We will question the principle of mobilization by the ICT by analyzing the practices and uses of by the young Moroccans strongly mobilized after the Arab spring.
Reserve mobilization during imbibition of stored Gliricidia sepium (Jacq.) Steud. (Leguminosae - Papilionoideae) seeds
Reis, Renata Conduru Ribeiro;Dantas, Bárbara Fran?a;Castro, Renato Delmondez de;Antunes, Cimille Gabrielle Cardoso;Silva, Fabrício Francisco Santos da;Pelacani, Claudinéia Regina;
Revista Brasileira de Sementes , 2011, DOI: 10.1590/S0101-31222011000300018
Abstract: gliricidia sepium is a drought-tolerant species, easily multiplied by seeds, and has been exploited by farmers as a source of forage in the semi-arid region of northeast brazil. the objective of the present study was to evaluate the effect of seed storage on the mobilization of reserves during imbibition of "gliricidia" seeds. freshly-harvested seeds were packed in kraft paper bags and stored for three and six months in the laboratory under ambient conditions (25 o c ± 3 t and 75% ± 3 rh). cotyledons were isolated from imbibed seeds and macerated for the extraction and quantification of total soluble sugars, reducing sugars, sucrose and starch, as well as of proteins, amino acids and for amylase activity. storage under these conditions resulted in an increase in seed water content although germination remained at relatively high levels (86%). seed macromolecule levels showed significant variation with the storage period and imbibition and these variations were associated with a loss in seed viability due to inadequate storage conditions.
The role of seed size in the non-genetic variation exhibited in salt tolerance studies involving the bread wheat cv. chinese spring
P. K. Martin,R. M.D. Koebner
Acta Societatis Botanicorum Poloniae , 1995, DOI: 10.5586/asbp.1995.048
Abstract: The intention of this study was to confirm the role of seed size in the non-genetic variation exhibited during salinity tolerance experiments involving the bread wheat cv. Chinese Spring. The nutrient film/rockwool hydroponics technique was utilised. This study concluded that seed size does not play a significant role in the non-genetic variation generated during a study of salinity tolerance of the bread wheat cv. Chinese Spring.
Complete PHB mobilization in Escherichia coli enhances the stress tolerance: a potential biotechnological application
Qian Wang, Hongmin Yu, Yongzhen Xia, Zhen Kang, Qingsheng Qi
Microbial Cell Factories , 2009, DOI: 10.1186/1475-2859-8-47
Abstract: The successful expression of PHB biosynthesis and PHB depolymerase genes in E. coli was confirmed by PHB production and 3-hydroxybutyrate secretion. Starvation experiment demonstrated that the complete PHB mobilization system in E. coli served as an intracellular energy and carbon storage system, which increased the survival rate of the host when carbon resources were limited. Stress tolerance experiment indicated that E. coli strains with PHB production and mobilization system exhibited an enhanced stress resistance capability.This engineered E. coli with PHB mobilization has a potential biotechnological application as immobilized cell factories for biocatalysis and biotransformation.A wide variety of microorganisms are able to accumulate polyhydroxyalkanoates (PHAs) as intracellular carbon/energy storage compounds or reducing power for coping with changing, often oligotrophic environments [1,2]. Various PHAs, as well as the best-known poly 3-β-hydroxybutyrate (PHB), were found to be accumulated and degraded as required under environmental conditions by most natural PHAs producing bacteria [3]. When the environment is sufficient with carbon source or the C/N ratio is quite high (>20), the PHAs accumulation is much faster than degradation [4,5]. While facing different stresses, such as low nutrient availability and detrimental physical, chemical, or biological factors, these bacteria begin to mobilize PHAs to conquer those unfavorable environments. The biosynthesis and degradation of PHAs is a cyclic mechanism that has already been found in many bacteria, such as Ralstonia eutropha, Azotobacter beijerinckii and Hydrogenomonas eutropha [6-8]. The in vivo PHB biosynthesis pathway is conducted by the successive action of β-ketoacyl-CoA thiolase (phbA), acetoacetyl-CoA reductase (phbB) and PHB polymerase (phbC). However, PHB degradation, which has been investigated for years, was divided into intracellular mobilization and extracellular degradation. Intracellular PHB mo
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