Evidence for the Cell Wall Involvement in Temporal Changes in Freezing Tolerance of Jerusalem Artichoke {Helianthus tuberosus L.) Tubers during Cold Acclimation

Murai, Mari; Yoshida, Sbizuo

doi:10.1093/oxfordjournals.pcp.a029295

Cited by 30 publications

(25 citation statements)

References 29 publications

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“…Interestingly, the results shown in Figure 5 further revealed that the freezing tolerance of Arabidopsis leaf sections is considerably dependent on the osmolarity of the solution around leaf sections: in the presence of 1 mM calcium, survival of cells in leaf sections immersed in a solution without sorbitol was ;56% at -38C ( Figure 5A), but much greater (;70%) even at -128C when immersed in a solution containing 0.6 M sorbitol ( Figure 5B). This is consistent with the results of Murai and Yoshida (1998), who showed that the freezing tolerance of Jerusalem artichoke tuber tissues is remarkably lower in water than in an isotonic solution.…”

Section: Calcium-dependent Freezing Tolerance Of Leaf Sectionssupporting

confidence: 93%

Calcium-Dependent Freezing Tolerance in Arabidopsis Involves Membrane Resealing via Synaptotagmin SYT1

et al. 2008

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Plant freezing tolerance involves the prevention of lethal freeze-induced damage to the plasma membrane. We hypothesized that plant freezing tolerance involves membrane resealing, which, in animal cells, is accomplished by calcium-dependent exocytosis following mechanical disruption of the plasma membrane. In Arabidopsis thaliana protoplasts, extracellular calcium enhanced not only freezing tolerance but also tolerance to electroporation, which typically punctures the plasma membrane. However, calcium did not enhance survival when protoplasts were exposed to osmotic stress that mimicked freeze-induced dehydration. Calcium-dependent freezing tolerance was also detected with leaf sections in which ice crystals intruded into tissues. Interestingly, calcium-dependent freezing tolerance was inhibited by extracellular addition of an antibody against the cytosolic region of SYT1, a homolog of synaptotagmin known to be a calcium sensor that initiates exocytosis. This inhibition indicates that the puncture allowing the antibody to flow into the cytoplasm occurs during freeze/ thawing. Thus, we propose that calcium-dependent freezing tolerance results from resealing of the punctured site. Protoplasts or leaf sections isolated from Arabidopsis SYT1-RNA interference (RNAi) plants lost calcium-dependent freezing tolerance, and intact SYT1-RNAi plants had lower freezing tolerance than control plants. Taken together, these findings suggest that calcium-dependent freezing tolerance results from membrane resealing and that this mechanism involves SYT1 function.

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Section: Calcium-dependent Freezing Tolerance Of Leaf Sectionssupporting

confidence: 93%

Calcium-Dependent Freezing Tolerance in Arabidopsis Involves Membrane Resealing via Synaptotagmin SYT1

et al. 2008

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“…However, this does not exclude the possibility of plasmolysis sensu stricto occurring in species where the rigidity of the cell wall does not allow folding in response to dehydration (Webb and Arnott 1982) or to extra-protoplasmic freezing (Murai and Yoshida 1998). Electron microscopy revealed that the plasmalemma maintains its trilaminar structure, continuity, and apposition against cell walls even at the very low water content of 0.08 g of water per g of dry mass.…”

Section: Discussionmentioning

confidence: 95%

Freeze-substitution of dehydrated plant tissues: Artefacts of aqueous fixation revisited

Wesley-Smith

2001

Protoplasma

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This investigation assessed the extent of rehydration of dehydrated plant tissues during aqueous fixation in comparison with the fine structure revealed by freeze-substitution. Radicles from desiccation-tolerant pea (Pisum sativum L.), desiccation-sensitive jackfruit seeds (Artocarpus heterophyllus Lamk.), and leaves of the resurrection plant Eragrostis nindensis Ficalho & Hiern. were selected for their developmentally diverse characteristics. Following freeze-substitution, electron microscopy of dehydrated cells revealed variable wall infolding. Plasmalemmas had a trilaminar appearance and were continuous and closely appressed to cell walls, while the cytoplasm was compacted but ordered. Following aqueous fixation, separation of the plasmalemma and the cell wall, membrane vesiculation and distortion of cellular substructure were evident in all material studied. The sectional area enclosed by the cell wall in cortical cells of dehydrated pea and jackfruit radicles and mesophyll of E. nindensis increased after aqueous fixation by 55, 20, and 30%, respectively. Separation of the plasmalemma and the cell wall was attributed to the characteristics of aqueous fixatives, which limited the expansion of the plasmalemma and cellular contents but not that of the cell wall. It is proposed that severed plasmodesmatal connections, plasmalemma discontinuities, and membrane vesiculation that frequently accompany separation of walls and protoplasm are artefacts of aqueous fixation and should not be interpreted as evidence of desiccation damage or membrane recycling. Evidence suggests that, unlike aqueous fixation, freeze-substitution facilitates reliable preservation of tissues in the dehydrated state and is therefore essential for ultrastructural studies of desiccation.

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“…Além do dano físico, podem ocorrer modificações na composição química da parede celular e na permeabilidade da membrana plasmática, que podem também influenciar na quantidade e qualidade do extrato final obtido (Palta et al, 1977;Olien & Smith, 1977;Chen & Gusta, 1978;Weiser et al, 1990;Murai & Yoshida, 1998).…”

Section: Armazenamento De Extratos E De Raízesunclassified

“…Em muitos estudos, a extração de sorgoleone tem sido feita a partir de raízes recém-coletadas, e o extrato é usualmente armazenado em baixas temperaturas antes da sua utilização em testes de atividade e do seu fracionamento (Einhelling & Souza, 1992;Rasmussen et al, 1992;Nimbal et al, 1996;Souza et al, 1999;Kagan et al, 2003;Czarnota et al, 2003b;Hejl & Koster, 2004). Alguns estudos mostram que o armazenamento de órgãos vegetais antes da extração pode acarretar alterações no extrato final obtido (Palta et al, 1977;Olien & Smith, 1977;Chen & Gusta, 1978;Weiser et al, 1990;Murai & Yoshida, 1998). Além disso, as condições de armazenamento de extratos vegetais podem influenciar na estabilidade e degradação dos compostos químicos presentes (Srivastava et al, 2007;Tabart et al, 2007).…”

Section: Introductionunclassified

Quantificação de sorgoleone em extratos e raízes de sorgo sob diferentes períodos de armazenamento

Franco

Machado²,

Takahashi³

et al. 2011

Planta daninha

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RESUMO -Neste trabalho, foi realizada a purificação, a obtenção do padrão de sorgoleone (2 -hidroxi -5 -metoxi -3 -[(8'Z,11'Z)-8',11',14'-pentadecatrieno]-p-benzoquinona) e a quantificação desse marcador em raízes primárias de sorgo. As sementes de sorgo foram desinfectadas, colocadas em placas gerbox opacas e acondicionadas em câmara de germinação a 30 o C durante sete dias no escuro. Posteriormente, a extração foi feita mergulhando-se as raízes por 5 min em solução de ácido acético glacial em diclorometano 0,0025% v/v. A quantificação de sorgoleone nos extratos obtidos foi feita por cromatografia líquida de alta eficiência (HPLC), utilizando-se uma curva de calibração. Foi avaliado o efeito do armazenamento de extratos e de raízes, utilizando-se três repetições para cada tratamento. Os extratos de raízes recém-coletadas foram armazenados a -20 o C por 0, 1, 3, 5, 7, 14 e 21 dias. As raízes foram coletadas e imediatamente congeladas (20 o C) e armazenadas pelo mesmo período, quando foram submetidas à extração. Não foi observada diferença significativa entre a quantidade de sorgoleone em extratos armazenados e a de não armazenados, sendo observado o mesmo resultado em extratos obtidos de raízes frescas e armazenadas. Os resultados obtidos mostram que o armazenamento por até 21 dias não altera o conteúdo de sorgoleone nos extratos.Palavras-chave: Sorghum bicolor, BR 007, alelopatia, purificação, padronização.ABSTRACT -Sorgoleone (2 -hydroxy -5 -methoxy -3 -[(8'Z, 11'Z)-8',11',14'-pentadecatriene]-pbenzoquinone) was purified, identified by NMR, and quantified in primary roots of sorghum. The seeds were disinfected and stored in dark gerbox plates inside germination chambers at 30 o C for seven days. Extraction was made by immersing the roots during 5 minutes in a glacial acetic acid/ dichloromethane solution 0, 0025% v/v. Sorgoleone quantification in the extracts was achieved by using a calibration curve made with the data obtained through High Performance Liquid Chromatography (HPLC). The effect of storing the extracts and roots was verified using three repetitions. The extracts of freshly collected roots were stored at -20 o C for 0, 1, 3, 5, 7, 14 and 21 days. No significant difference was observed between the amount of sorgoleone present in the stored and non-stored extracts. The same result was found for the extracts obtained from fresh and stored roots. The results obtained showed that storage up to 21 days does not alter the content of sorgoleone in the extracts.

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Evidence for the Cell Wall Involvement in Temporal Changes in Freezing Tolerance of Jerusalem Artichoke {Helianthus tuberosus L.) Tubers during Cold Acclimation

Cited by 30 publications

References 29 publications

Calcium-Dependent Freezing Tolerance in Arabidopsis Involves Membrane Resealing via Synaptotagmin SYT1

Calcium-Dependent Freezing Tolerance in Arabidopsis Involves Membrane Resealing via Synaptotagmin SYT1

Freeze-substitution of dehydrated plant tissues: Artefacts of aqueous fixation revisited

Quantificação de sorgoleone em extratos e raízes de sorgo sob diferentes períodos de armazenamento

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