Compartmentation and fluxes of carbon in leaf blades and leaf sheaths of<i>Poa annua</i>L. and<i>Poa x jemtlandica</i>(Almq.) Richt

Borland, Anne M.; Farrar, J. F.

doi:10.1111/j.1365-3040.1988.tb01792.x

Cited by 25 publications

(19 citation statements)

References 22 publications

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“…In Lolium perenne 64 % of total fructans are stored in the leaf sheaths and 36% in the elongating leaf bases (Morvan et al, 1997). It has been suggested that sheaths serve predominantly as thoroughfares for carbohydrates between leaf blades and other parts of the plant (Borland and Farrar, 1988). When carbon is fixed in excess relative to the overall plant demand, assimilates are unloaded along the path and stored mainly as storage carbohydrates.…”

Section: Resultsmentioning

confidence: 99%

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Sandrin

Domingos

Figueiredo-Ribeiro

2006

Braz. J. Plant Physiol.

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In temperate grasses, fructans are the major storage polysaccharides, being accumulated mainly in mature leaf sheaths, and also in the roots. The partitioning of carbohydrates within different organs regulates plant growth and development. The aim of the present work was to analyze the partitioning of water soluble carbohydrates in five different parts (elongating leaf blades, expanded leaf blades, upper and lower segments of the stubble, and roots) of plants of L. multiflorum cv. Lema, in order to contribute to an understanding of soluble carbohydrates distribution in these plants. Soluble carbohydrates and total fructose were analyzed in plants cultivated during 4 months in a glasshouse, by colorimetric, TLC and HPAEC-PAD techniques. Results showed that the greatest portion of total soluble carbohydrates was constituted of free and combined fructose, in all parts of the plants. The stubble contained the highest level of carbohydrates, followed by the elongating leaf blades, expanded leaf blades and roots. The leaf sheaths were not analyzed separately from the stubble, which explains the high levels of carbohydrates found in this part of the plant. The high metabolism of the elongating leaf blades, when compared to that of the expanded leaf blades, could explain the increased amounts of fructans stored in those tissues. Analysis by HPAEC-PAD showed that the elongating leaf blades and the roots had the highest proportions of low molecular weight fructans that could be readily mobilized, supplying the demand of growing tissues in other organs. Key words: fructan, grass, Italian ryegrass, sugars.Resumo: Partição de carboidratos solúveis em água em tecidos vegetativos de Lolium multiflorum Lam. ssp. italicum cv. Lema. Os frutanos são os polissacarídeos de reserva mais abundantes em gramíneas de clima temperado, sendo estocados principalmente nas bainhas de folhas adultas e também nas raízes. A partição de carboidratos entre os diferentes órgãos da planta regula seu crescimento e seu desenvolvimento. Visto que a partição de carboidratos solúveis ainda é desconhecida em Lolium multiflorum cv. Lema, o objetivo do presente trabalho foi verificar a partição desses carboidratos em cinco partes distintas (lâ-minas em alongamento, lâminas totalmente expandidas, segmentos superior e inferior do estolho e raízes) de plantas dessa espécie. Para isso, os carboidratos solúveis totais e a frutose total foram quantificados em plantas cultivadas durante quatro meses em Casa de Vegetação, por métodos colorimétricos e por TLC e HPAEC-PAD. Os resultados mostraram que grande parte da fração dos carboidratos solúveis totais é constituída por frutose, na forma livre e combinada, em todas as partes da planta. O estolho contém os maiores níveis de carboidratos, seguido pelas lâminas em alongamento, lâminas expandidas e raiz. No presente estudo, as bainhas foliares não foram diferenciadas do estolho, o que explica os altos teores de carboidratos solúveis encontrados nessa porção das plantas. As altas taxas de metabolismo das lâminas em alo...

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Section: Resultsmentioning

confidence: 99%

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Sandrin

Domingos

Figueiredo-Ribeiro

2006

Braz. J. Plant Physiol.

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“…After 7 d in the altered CO2, sucrose had reached a stable 6 near -51%o, indicating that the carbon in sucrose was completely exchanged by photosynthate originating from the altered CO2. Leafblade sucrose is known to be turned over rapidly by current photosynthate (Sicher et al 1984;Farrar and Farrar 1985;Borland and Farrar 1988).…”

Section: Resultsmentioning

confidence: 99%

Long-term steady-state labelling of wheat plants by use of natural 13CO2/12CO2 mixtures in an open, rapidly turned-over system

Schnyder

1992

Planta

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A photosynthate labelling method is presented which takes advantage of the natural difference in carbon-isotope composition (δ Carbon-isotope composition of a sample is conventionally presented as δ (‰) = [(RP/RS) -1] · 1000, where RP and RS are the molar abundance ratios, (13)C/(12)C, of the sample and of the standard (PDB carbonate), respectively ) which exists between atmospheric CO2 (δ≈-8‰) and commercially available compressed CO2. Carbon dioxide with δ-4.0 and -27.9%., respectively, has been used for labelling. A plant growth cabinet served as the labelling compartment. CO2-free air was continuously injected at a rate of up to 54m(3)·h(-1). Dilution of cabinet CO2 by CO2-free air was counterbalanced by addition of CO2 with known constant δ. Since the labelling-cabinet atmosphere was continuously exchanged at a high rate, photosynthetic carbon-isotope discrimination was fully expressed. In order to study the distribution of carbon acquired by the plant during a defined growth period, the δ of CO2 was modified by replacing, for example, atmospheric CO2 by CO2 with δ -27.9%. and the weight and 5 of plant carbon pools was monitored over time. In such an experiment the δ change of CO2 was followed by a rapid change of the δ of sucrose in mature flag-leaf blades of wheat (Triticum aestivum L.). The 5 of sucrose stabilized near -51%., indicating complete exchange by current photosynthate. In contrast 83% of the total carbon in mature flag-leaf blades was not exchanged after 14 d continuous labelling. Differential labelling of pre- and post-anthesis photosynthate indicated that 13% of grain carbon originated from pre-anthesis photosynthesis. Carbon-isotope discrimination and its consideration in experimentation and labelling data evaluation are discussed in detail. Since the air supplied to the labelling cabinet is dry and free of CO2, carbon-isotope discrimination and carbon turnover and partitioning can be studied over a wide range of CO2 concentrations (0-2600 cm(3) · m(-3)) and vapor-pressure deficits.

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“…The dynamics of fructan turnover are less clear. Its half-life was found to be in the range of 2 to 5 h in leaf blades of Hordeum distichum and two Poa species (Borland and Farrar, 1988;Farrar, 1989) and 14 to 18 h in leaf sheaths of Poa (similar to a 9-to 15-h half-life of vacuolar Suc; Borland and Farrar, 1988). Fructan stored in wheat stems did not turn over during the storage phase (Winzeler et al, 1990).…”

Section: Discussion the Identity Of Respiratory Substrate Poolsmentioning

confidence: 98%

Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic ¹³C Labeling and Compartmental Analysis of Tracer Kinetics

et al. 2008

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The substrate supply system for respiration of the shoot and root of perennial ryegrass (Lolium perenne) was characterized in terms of component pools and the pools' functional properties: size, half-life, and contribution to respiration of the root and shoot. These investigations were performed with perennial ryegrass growing in constant conditions with continuous light. Plants were labeled with 13 CO 2 / 12 CO 2 for periods ranging from 1 to 600 h, followed by measurements of the rates and 13 C/ 12 C ratios of CO 2 respired by shoots and roots in the dark. Label appearance in roots was delayed by approximately 1 h relative to shoots; otherwise, the tracer time course was very similar in both organs. Compartmental analysis of respiratory tracer kinetics indicated that, in both organs, three pools supplied 95% of all respired carbon (a very slow pool whose kinetics could not be characterized provided the remaining 5%). The pools' half-lives and relative sizes were also nearly identical in shoot and root (half-life , 15 min, approximately 3 h, and 33 h). An important role of short-term storage in supplying respiration was apparent in both organs: only 43% of respiration was supplied by current photosynthate (fixed carbon transferred directly to centers of respiration via the two fastest pools). The residence time of carbon in the respiratory supply system was practically the same in shoot and root. From this and other evidence, we argue that both organs were supplied by the same pools and that the residence time was controlled by the shoot via current photosynthate and storage deposition/mobilization fluxes.

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Compartmentation and fluxes of carbon in leaf blades and leaf sheaths ofPoa annuaL. andPoa x jemtlandica(Almq.) Richt

Cited by 25 publications

References 22 publications

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Long-term steady-state labelling of wheat plants by use of natural 13CO2/12CO2 mixtures in an open, rapidly turned-over system

Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic ¹³C Labeling and Compartmental Analysis of Tracer Kinetics

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Compartmentation and fluxes of carbon in leaf blades and leaf sheaths ofPoa annuaL. andPoa x jemtlandica(Almq.) Richt

Cited by 25 publications

References 22 publications

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Partitioning of water soluble carbohydrates in vegetative tissues of Lolium multiflorum Lam. ssp. italicum cv. Lema

Long-term steady-state labelling of wheat plants by use of natural 13CO2/12CO2 mixtures in an open, rapidly turned-over system

Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic 13C Labeling and Compartmental Analysis of Tracer Kinetics

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Root and Shoot Respiration of Perennial Ryegrass Are Supplied by the Same Substrate Pools: Assessment by Dynamic ¹³C Labeling and Compartmental Analysis of Tracer Kinetics