Osmotic Adjustment, Induced by Drought, in Seedlings of Three Eucalyptus Species

Myers, BA; Neales, T. F.

doi:10.1071/pp9860597

Cited by 47 publications

(34 citation statements)

References 12 publications

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“…Water deficits reduced tree growth and affected carbon metabolism, increasing the concentration of soluble sugars in the bark tissues. Similar results were found for other eucalyptus trees [24] and in several Mediterranean species [9,22,29].…”

Section: Discussionsupporting

confidence: 75%

Positive effect of drought on longicorn borer larval survivl and growth on eucalyptus trunks

Caldeira¹,

Fernandéz²,

Tomé³

et al. 2002

Ann. For. Sci.

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-Phoracantha semipunctata (F.) larvae attack and kill trees in Eucalyptus globulus (Labill.) plantations in Mediterranean countries. To test the hypothesis that these attacks are more likely in arid environments, we examined the effects of water deficits in the host trees of E. globulus on the mortality and growth of P. semipunctata larvae. Trees subjected to water stress during two subsequent years were compared with rainfed and irrigated trees. Larvae of P. semipunctata were artificially introduced in the bark of trees of either treatment. Larvae mortality was lower and weight gain was higher in water stressed trees than on rainfed trees. There was no larvae survival in irrigated trees. These results were related to changes in moisture content and concentration of soluble sugars in the bark of the trees. The results of this study suggest that water stress had a major role on the survival and growth of the larvae.Cerambycidae / Phoracantha semipunctata / plant-insect interaction / water-deficit / bark borer Résumé -Effets positifs de la sécheresse du sol sur la survie et la croissance des larves de Phoracantha semipunctata sur l'eucalyptus. Le Phoracantha semipunctata (F.) (Coleoptera : Cerambycidae) est un ravageur commun des plantations d'Eucalyptus globulus (Labill.) des milieux méditerranéens, particulièrement dans les régions les plus arides. La mortalité et la croissance des larves de P. semipunctata ont été comparées in vivo sur des arbres d'E. globulus soumis à trois traitements : stress hydrique durant deux années consécutives, irrigation et témoins. Des larves de P. semipunctata ont été artificiellement introduites dans l'écorce des arbres soumis aux trois traitements. Une plus faible mortalité et une augmentation de la biomasse des larves ont été obtenues chez les arbres stressés, comparativement aux arbres témoins. Chez les arbres irrigués la mortalité de larves était totale. Les effets de la teneur en eau et de la concentration en sucres solubles de l'écorce sur la mortalité larvaire ont aussi été testés. Nos résultats permettent de conclure que le stress hydrique est un facteur déterminant dans la réussite de la colonisation de l'arbre par les larves de P. semipunctata. Cerambycidae / Eucalyptus globulus / Phoracantha semipunctata / interaction plante-insecte / contrainte hydrique Ann. For. Sci. 59 (2002) [99][100][101][102][103][104][105][106] 99

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Section: Discussionsupporting

confidence: 75%

Positive effect of drought on longicorn borer larval survivl and growth on eucalyptus trunks

Caldeira¹,

Fernandéz²,

Tomé³

et al. 2002

Ann. For. Sci.

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“…These responses can be many and varied, even within the one genus. In the case of the large Eucalyptus genus, for example, responses to water stress include changes in biomass allocation (Rawat and Banerjee 1998), stomatal control (Macfarlane et al 2004), cell wall reinforcement (Ladiges 1975), cell wall water storage (Tuomela 1997) and cellular osmolarity (Myers and Neales 1986;LemcoV et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Changes in gas exchange versus leaf solutes as a means to cope with summer drought in Eucalyptus marginata

2007

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Two of the ways in which plants cope with water deficits are stomatal closure and "osmotic adjustment". We sought to assess the contributions of these processes to maintenance of leaf hydration in field-grown, 7-year-old Eucalyptus marginata. Plants were exposed to their normal summer drought (controls) or supplied with additional water (irrigated). Irrigation increased photosynthesis by 30% in E. marginata. These increases in photosynthesis were related to an 80% increase in g (s). However, there was no difference in substomatal CO(2) concentrations between treatments, or in chloroplast CO(2) concentrations, as indicated by carbon isotope composition of leaf soluble sugars. This suggests that impaired mesophyll metabolism may partially explain slower rates of photosynthesis in plants exposed to their normal summer drought. There was no difference in concentrations of solutes or osmotic potential between non-irrigated and irrigated individuals, perhaps because relative water content was the same in non-irrigated and irrigated plants due to stomatal sensitivity to water deficits. Irrespective of the absence of osmotic adjustment, analysis of leaf solutes gave a clear indication of the major groups of compounds responsible for maintaining cell osmotic potential. Soluble sugars were three times as abundant as amino acids. Proline, a putatively osmotically active amino acid, contributed less than 1% of total solutes. These patterns of solutes in E. marginata are consistent with a growing body of literature arguing a greater role for carbohydrates and cyclitols and lesser role for amino acids in maintaining osmotic potential. Our data suggest the primary mechanism by which E. marginata coped with drought was partial stomatal closure; however, we cannot discount the possibility of osmotic adjustment under more severe water deficits.

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“…For eucalypts, the adjustment of internal osmotic potential in response to saline and/or dry conditions has been demonstrated across many species (ClaytonGreene, 1983;Lemcoff et al, 1994;Li, 1998;Myers et al, 1986;Pita et al, 2001;Tuomela, 1997;White et al, 2000). Variation among eucalypt species in the capacity to modify osmotic potential has been proposed to explain differing salt (Grieve et al, 1999) and drought (Li, 1998) tolerances, leading to suggestions of its use as a selection criterion (Lemcoff et al, 1994;van der Moezel et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Variations saisonnières des hydrates de carbone, des cyclitols et des relations hydriques chez 3 espèces d’Eucalyptus de taxonomie contrastée, en plein champ et poussant sur un site commun

et al. 2010

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Abstract• Alterations in plant chemistry underpin a suite of physiological adaptations to arid conditions. Qualitative and quantitative differences in leaf chemistry are found in the genus Eucalyptus correlating with physiological adaptation to aridity.• Here we investigate seasonal water relations of three field grown eucalypt species grown at a common site known to differ in their ability to accumulate the cyclic sugar alcohol, quercitol.• We show that quercitol contributes significantly to osmotic relations in field grown trees of Eucalyptus melliodora but is present only in trace amounts in E. rubida and E. obliqua.• Measured concentrations of quercitol account for the difference in osmotic potentials between species and can be interpreted as a mechanism for adaptation to low water availability. Mots-clés :Eucalyptus / potentiel hydrique / pression volume / ajustement osmotique Résumé -Variations saisonnières des hydrates de carbone, des cyclitols et des relations hydriques chez 3 espèces d'Eucalyptus de taxonomie contrastée, en plein champ et poussant sur un site commun.• Des altérations dans la chimie des plants soutiennent une série d'adaptations physiologiques à l'aridité. Des différences qualitatives et quantitatives dans la chimie des feuilles sont trouvées chez le genre Eucalyptus en corrélation avec les adaptations physiologiques à l'aridité.• Ici, nous étudions les relations hydriques saisonnières de 3 espèces d'Eucalyptus de plein champ, poussant sur un site commun, connues pour être différentes au plan de leur capacité à accumuler le quercitol.• Nous montrons que le quercitol contribue de manière significative aux relations osmotiques chez Eucalyptus melliodora mais est seulement présent à l'état de trace chez Eucalyptus rubida et Eucalyptus obliqua.• Les concentrations de quercitol qui ont été mesurées rendent compte des différences de potentiel osmotique observées entre les espèces et peuvent être interprétées comme un mécanisme d'adaptation à la faible disponibilité en eau.

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Osmotic Adjustment, Induced by Drought, in Seedlings of Three Eucalyptus Species

Cited by 47 publications

References 12 publications

Positive effect of drought on longicorn borer larval survivl and growth on eucalyptus trunks

Positive effect of drought on longicorn borer larval survivl and growth on eucalyptus trunks

Changes in gas exchange versus leaf solutes as a means to cope with summer drought in Eucalyptus marginata

Variations saisonnières des hydrates de carbone, des cyclitols et des relations hydriques chez 3 espèces d’Eucalyptus de taxonomie contrastée, en plein champ et poussant sur un site commun

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