Seasonal Variation of Photosynthetic Carbon Flow Rate into Young Walnut and its Partitioning among the Plant Organs and Functions

Lacointe, André; Kajji, Abdellah; Daudet, F.A.; Archer, P.; Frossard, J.S.

doi:10.1016/s0176-1617(11)82045-6

Cited by 20 publications

(17 citation statements)

References 26 publications

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“…From 5 d after assimilation through leaf fall and winter, the total label incorporated in the structural fraction exhibited no change in most tree parts, namely the roots or the main stem . This is consistent with previous results (Lacointe et al . 1995b) showing that leaf export, which was the limiting step for the final pattern of spatial and biochemical partitioning of current assimilates, was completed by 90% within 5 d. In the present experiment, however, there was an increase in the structural fraction of branches, both between September and leaf fall, and even more after leaf fall.…”

Section: Discussionsupporting

confidence: 94%

“…The use of isotopic tracers revealed another, major, effect: the carbon losses from the shaded branch‐assimilated carbon were significantly higher than those from the sunlit branch‐assimilated C. At this time scale, i.e. within 5 d after assimilation, carbon losses can be ascribed to respiration (Lacointe et al . 1995b), so this denotes higher relative respiratory losses in the former than in the latter case.…”

Section: Discussionmentioning

confidence: 99%

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Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches

Lacointe

Deléens

Améglio

et al. 2004

Plant Cell & Environment

100

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The impact of a heterogeneous within-crown light environment on carbon allocation was investigated on young walnut trees trained on two branches: one left in full sunlight, the other shaded until leaf fall resulting in 67% reduction in photosynthetically active radiation. In September, the two branches were separately labelled with 14 CO 2 and 13 CO 2 , respectively, so that the photosynthates from each branch could be traced independently at the same time. Although some carbon movements could be detected within 5 d in both directions (including from the shaded branch to the sun branch), between-branch carbon movements were very limited: approximately 1% of the diurnal net assimilation of a branch. At this time of the year branch autonomy was nearly total, leading to increased relative respiratory losses and a moderate growth deficit in the shaded branch. The ratio of growth to reserve storage rate was only slightly affected, indicating that reserves acted not as a mere buffer for excess C but as an active sink for assimilates. In winter, branch autonomy was more questionable, as significant amounts of carbon were imported into both branches, possibly representing up to 10% of total branch reserves. Further within-plant carbon transfers occurred in spring, which totally abolished plant autonomy, as new shoots sprouted on each branch received significantly more C mobilized from tree-wide reserves than from local, mother-branch located reserves. This allowed great flexibility of tree response to environment changes at the yearly time scale. As phloem is considered not functional in winter, it is suggested that xylem is involved as the pathway for carbohydrate movements at this time of the year. This is in agreement with other results regarding sugar exchanges between the xylem vessels and the neighbouring reserve parenchyma tissues.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches

Lacointe

Deléens

Améglio

et al. 2004

Plant Cell & Environment

100

View full text Add to dashboard Cite

show abstract

“…At the end of the season, C is essentially used for respiration. This sharing out shows no discrepancy with biological observations [31,35].…”

Section: Tree Photosynthesissupporting

confidence: 68%

SIMWAL: A structural-functional model simulating single walnut tree growth in response to climate and pruning

et al. 2000

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-SIMWAL (SIMulated WALnut) is a structural-functional tree model developed for single young walnut tree (Juglans sp.). It simulates the 3D structure dynamics of the tree, and biomass partitioning among its different organs, for a period ranging from a few months to several years, according to climatic conditions (temperature, radiation and air CO 2 concentration) and pruning. The aerial part of the tree is represented by axes split into growth units, inter-nodes, buds and leaves. The root system is described very coarsely by three compartments (taproot, coarse root and fine root). Only carbon-related physiological processes, i.e., radiation interception, photosynthesis, respiration, photosynthate allocation, and reserve storage and mobilisation are taken into account. Water and mineral nutrients are assumed to be optimal. We describe the model, and present preliminary tests of its ability to simulate tree architecture dynamics and carbon balance compared with field observations. Data requirements, and limits and improvements of the model are discussed.structure / function / model / Juglans / pruning Résumé -SIMWAL : un modèle d'arbre structure-fonction simulant la croissance d'un noyer en fonction du climat et de la taille. SIMWAL est un modèle d'arbre structure-fonction développé pour le jeune noyer (Juglans sp.). Il simule l'évolution de la structure 3D de l'arbre et la répartition de la biomasse entre ses différents organes, pour des périodes allant de quelques mois à quelques années, en fonction des conditions climatiques (température, radiation, concentration dans l'air du CO 2 ) et des opérations de taille. La partie aérienne de l'arbre est représentée par des axes, eux-mêmes divisés en unités de croissance, entrenoeuds, bourgeons et feuilles. Le système racinaire est plus grossièrement décrit en trois compartiments : pivot, racines moyennes et racines fines. Seuls les processus physiologiques relatifs au carbone sont pris en compte : interception lumineuse, photosynthèse, respiration, répartition carbonée, et stockage et mobilisation des réserves. L'eau et les éléments minéraux sont considérés à l'optimum. Nous décrivons en détail le modèle et présentons quelques tests préliminaires visant à vérifier sa capacité à simuler l'évolution de l'architecture d'un arbre et son bilan de carbone en comparaison à des observations de terrain. Le manque de certaines connaissances, les limites et les améliorations possibles du modèle sont discutés. structure / fonction / modèle / Juglans / tailleAnn.

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“…In 3-year-old English walnut, C accumulated as starch in the taproot in late summer and fall can be hydrolyzed to sugar in winter and remobilized by growing organs in spring (Frossard and Lacointe 1988;Lacointe et al 1993). Lacointe et al (1995) also reported that recent (up to 5 days old) C fluxes allocated toward respiration did not exceed 25% of total plant respiration as measured in August and October using 14 CO 2 labeling in young English walnut trees. While changes in temperature and demand from sink organs are thought to be important causal mechanisms in walnut C remobilization, the relative importance of each mechanism is still uncertain (Lacointe 2000).…”

Section: Carbon Dynamicsmentioning

confidence: 88%

Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change

Gauthier

Jacobs

2011

Annals of Forest Science

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Context Walnuts (Juglans spp.) are ecologically and commercially important trees, yet synthesis of past and current research findings on walnut ecophysiology is lacking, especially in terms of potential acclimation to climate change.• Aims This study aims to (1) investigate walnut ecophysiology by comparing its attributes to associated deciduous angiosperms, (2) address potential acclimation of walnut to climate change, and (3) identify areas for prioritization in future research.• Results There is considerable uncertainty regarding the magnitude of potential effects of climate change on walnut. Some studies tend to indicate walnut could be negatively impacted by climate change, while others do not. Walnut may be at a disadvantage due to its susceptibility to drought and frost injury in current growing regions given the projected increases in temperature and extreme climatic events. Other regions that are currently considered cold for walnut growth may see increased establishment and growth depending upon the rate of temperature increase and the frequency and severity of extreme climatic events.• Conclusion Research investigating a combination of environmental factors, such as temperature, carbon dioxide, ozone, water, and nitrogen is needed to (1) better project climate change effects on walnut and (2) develop management strategies for walnut acclimation and adaptation to climate change.

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Seasonal Variation of Photosynthetic Carbon Flow Rate into Young Walnut and its Partitioning among the Plant Organs and Functions

Cited by 20 publications

References 26 publications

Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches

Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches

SIMWAL: A structural-functional model simulating single walnut tree growth in response to climate and pruning

Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change

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Seasonal Variation of Photosynthetic Carbon Flow Rate into Young Walnut and its Partitioning among the Plant Organs and Functions

Cited by 20 publications

References 26 publications

Testing the branch autonomy theory: a 13C/14C double‐labelling experiment on differentially shaded branches

Testing the branch autonomy theory: a 13C/14C double‐labelling experiment on differentially shaded branches

SIMWAL: A structural-functional model simulating single walnut tree growth in response to climate and pruning

Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change

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Product

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Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches

Testing the branch autonomy theory: a ¹³C/¹⁴C double‐labelling experiment on differentially shaded branches