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2008 - 501 p.

Water stress effects on perennial grasses growth and behaviour

Kallida R., Al Faïz C., Shaimi N.

In a glasshouse experiment, six cultivars of perennial grasses were tested under imposed water stress. The aim of the trial was to analyse some drought effects on grasses behaviour and water use efficiency. Some physiological indicators associated with drought were used (such as osmotic regulation and sugar accumulation). Differences in varieties response under water constraints were highlighted. Dry matter production was higher for festuca cultivars, followed by phalaris and then cocksfoot. Correlation between dry matter production and water consumption was highly significant. Moderate water stress gave the best results. Festuca cultivars were the most water efficient. The phalaris Atlas and cocksfoot Kasbah had the lowest WUE. In contrast, Lutine fescue had the highest WUE followed by Fraydo, Medly and Sirolan, which gave comparable values. The two cocksfoot, Medly and Kasbah, and the phalaris Sirolan seemed to maintain their leaf relative water content while experiencing drought conditions, assuming some traits of drought tolerance. The varieties Atlas, Sirolan and Medly made better adjustments by maintaining their osmotic potentials almost unchanged over the drought period and then by decreasing their osmotic potential more quickly afterwards.

Une expérimentation conduite en conditions contrôlées a été conçue pour analyser de près certains effets directs du stress hydrique sur le comportement de 6 variétés de graminées pérennes. Dans les conditions expérimentales imposées, des différences de comportement variétal vis-à-vis de la contrainte hydrique ont été mises en évidence. Lorsque l'offre en eau est réduite, les fétuques Lutine et Fraydo présentent un avantage de production de biomasse. L'effet dépressif du stress hydrique a été exprimé chez les variétés testées. Les dactyles Medly et Kasbah et le phalaris Sirolan ont pu maintenir leur teneur en eau relative en passant des conditions d'eau non limitantes aux conditions de stress et peuvent être considérés comme ayant un potentiel de tolérance à la sécheresse. Les variétés Atlas, Sirolan et Medly s'ajustent mieux, d'abord en maintenant leur potentiel osmotique presque inchangé en régimes hydriques stressés et ensuite en diminuant leur potentiel osmotique plus vite.

Mots-clés    

DEFICIT HYDRIQUE DU SOL, EXPERIMENTATION, GRAMINEE FOURRAGERE, PRESSION OSMOTIQUE, STRESS DU A LA SECHERESSE, VARIETE

Citer cet article    

Kallida R., Al Faïz C., Shaimi N. Water stress effects on perennial grasses growth and behaviour. In : Porqueddu C. (ed.), Tavares de Sousa M.M. (ed.). Sustainable Mediterranean grasslands and their multi-functions . Zaragoza : CIHEAM / FAO / ENMP / SPPF, 2008. p. 309-313. (Options Méditerranéennes : Série A. Séminaires Méditerranéens; n. 79). 12. Meeting of the Sub-Network on Mediterranean Forage Resources of the FAO-CIHEAM Inter-regional Cooperative Research and Development Network on Pastures and Fodder Crop, 2008/04/09-12, Elvas (Portugal). http://om.ciheam.org/om/pdf/a79/00800667.pdf