The Regrowth of Grass Swards

Davies, Alison

doi:10.1007/978-94-009-1187-1_3

Cited by 102 publications

(110 citation statements)

References 106 publications

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“…The ability of perennial grasses to grow following defoliation and to tolerate stress depends on their ability to accumulate carbohydrate reserves in leaf sheaths and to transport them to growing tissues (White, 1973 ;Davies, 1988). Exposure to drought increases sugar contents of grasses (and of many other species) because growth is reduced more than assimilation (Arcioni et al, 1985 ;Nicolas et al, 1985 ;Thomas & Evans, 1989 ;Busso et al, 1990 ;Chaves, 1991).…”

Section: mentioning

confidence: 99%

“…Previous work (Thomas, 1991) on changes in sugar pools in perennial ryegrass during drought was concerned with events in mature leaves and growing leaf bases. The first aim of the present work was to complete the study by describing changes in sugars : in the laminae of the growing leaves, since they are the source of assimilates nearest the growing tissue and may respond differently to drought than do mature leaves (Wardlaw, 1969) ; and in the mature leaf sheaths, which are the major storage site for sugar reserves (Davies, 1988).…”

Section: mentioning

confidence: 99%

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Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Thomas

James

1999

New Phytologist

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Simulated swards of perennial ryegrass (Lolium perenne) growing in 1-m$ soil blocks in the glasshouse were either well watered or deprived of water for 57 d and then rewatered. The first aim was to measure effects of drought on sugar (water-soluble carbohydrate) composition of laminae and sheaths of mature laminae, and bases and laminae of young (growing) leaves. The second aim was to use pulse labelling with "%CO # to follow the partitioning of recently-fixed assimilates, and the assembly and consumption of reserve sugars (fructans). Over the last 7 d of drought growth almost stopped, old leaves died faster than they were replaced, and total sugar (which had doubled in concentration during drought) was rapidly consumed. Leaf laminae had lower content of total sugars and of large fructan (DP 5) than did growing bases and sheaths. Drought greatly reduced the rate at which sugar was exported from the laminae to the sheaths and growing leaf bases, and the rate at which it was converted to fructan. Nevertheless, fructan accumulated over the first 50 d of drought. Rewatering did not result in depolymerization and remobilization of sugars that had been formed during the last 7 d of drought, but stimulated their further assembly into high-DP fructans. Our hypothesis, that accumulation of neo-kestose (a DP-3 fructan) in droughted laminae was a symptom of sugar remobilization just before death, was disproved. It is concluded that sugar reserves contribute to drought resistance only under extreme conditions. The specific role of fructan in dry environments might be to improve regrowth when drought is relieved, rather than to enhance growth during drought.

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Section: mentioning

confidence: 99%

Section: mentioning

confidence: 99%

Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Thomas

James

1999

New Phytologist

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“…Carbohydrate reserves are depleted and may even become limiting for initial regrowth after severe defoliation (Davies 1988;Richards 1993). Consequently, increased C availability at elevated Pco-, ^ê xpected to stimulate regrowth (Nijs et al 1988).…”

Section: Tntroductionmentioning

confidence: 99%

Source‐sink relations in Lolium perenne L. as reflected by carbohydrate concentrations in leaves and pseudo‐stems during regrowth in a free air carbon dioxide enrichment (FACE) experiment^*

Fischer

Frehner

Hebeisen

et al. 1997

Plant Cell & Environment

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The effect of an elevated partial pressure of CO2 (pCO2) on carbohydrate concentrations in source leaves and pseudo‐stems (stubble) of Lolium perenne L. (perennial ryegrass) during regrowth was studied in a regularly defoliated grass sward in the field. The free air carbon dioxide enrichment (FACE) technology enabled natural environmental conditions to be provided. Two levels of nitrogen (N) supply were used to modulate potential plant growth. Carbohydrate concentrations in source leaves were increased at elevated pCO2, particularly at low N supply. Elevated leaf carbohydrate concentrations were related to an increased structural carbon (C) to N ratio and thus reflected an increased C availability together with a N‐dependent sink limitation. Immediately after defoliation, apparent assimilate export rates (differences in the carbohydrate concentrations of young source leaves measured in the evening and on the following morning) showed a greater increase at elevated pCO2 than at ambient pCO2; however, replenishment of carbohydrate reserves was not accelerated. Distinct, treatment‐dependent carbohydrate concentrations in pseudo‐stems suggested an increasing degree of C‐sink limitation from the treatment at ambient pCO2 with high N supply to that at elevated pCO2 with low N supply. During two growing seasons, no evidence of a substantial change in the response of the carbohydrate source in L. perenne to elevated pCO2 was found. Our results support the view that the response of L. perenne to elevated pCO2 is restricted by a C‐sink limitation, which is particularly severe at low N supply.

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“…O número de folhas vivas por perfilho é um valor relativamente constante para uma dada espécie (Davies, 1977;Yang et al, 1998;Carnevalli & da Silva, 1999 .…”

Section: Ar F P Iafunclassified

“…O princípio de compensação tamanho/densidade populacional de perfilhos (CTD) em pastagens tem sido verificado e estudado com intensidade crescente nos últimos anos (Langer, 1963;Bircham & Hodgson, 1983;Davies, 1988;Chapman & Lemaire, 1993;Matthew et al, 1995;Sackville Hamilton et al, 1995;Hernández Garay et al, 1999). Há muito tempo sabe-se que plantas crescendo em comunidade possuem um mecanismo de auto-compensação (Puntieri, 1993).…”

Section: Ar F P Iafunclassified

Compensação tamanho/densidade populacional de perfilhos em pastagens de Cynodon spp.

Sbrissia¹

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The Regrowth of Grass Swards

Cited by 102 publications

References 106 publications

Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Source‐sink relations in Lolium perenne L. as reflected by carbohydrate concentrations in leaves and pseudo‐stems during regrowth in a free air carbon dioxide enrichment (FACE) experiment^*

Compensação tamanho/densidade populacional de perfilhos em pastagens de Cynodon spp.

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The Regrowth of Grass Swards

Cited by 102 publications

References 106 publications

Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Partitioning of sugars in Lolium perenne (perennial ryegrass) during drought and on rewatering

Source‐sink relations in Lolium perenne L. as reflected by carbohydrate concentrations in leaves and pseudo‐stems during regrowth in a free air carbon dioxide enrichment (FACE) experiment*

Compensação tamanho/densidade populacional de perfilhos em pastagens de Cynodon spp.

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Source‐sink relations in Lolium perenne L. as reflected by carbohydrate concentrations in leaves and pseudo‐stems during regrowth in a free air carbon dioxide enrichment (FACE) experiment^*