Phenological and physiological performance of coconut varieties under water stress (Poster VIII 58)

Repellin Anne, Daniel Claude, Braconnier Serge, Sangaré A.. 1995. Phenological and physiological performance of coconut varieties under water stress (Poster VIII 58). In : Interdrought: integrated study on drought tolerance of higher plants. First international meeting. Proceedings = [Intersécheresse : étude intégrée de la tolérance à la sécheresse des plantes supérieures. Premier congrès international. Actes]. Belhassen E.. Montpellier : INRA, Résumé, 1 p. InterDrought I. 1, Montpellier, France, 31 Août 1995/2 Septembre 1995.

Autre titre : Comportement phénologique et physiologique de variétés de cocotier soumises au stress hydrique

Résumé : 9 variétés (8 hybrides Nain x Grand, et Grand Ouest Africain) ont été étudiées, parmi lesquelles le PB 121 a un bon comportement à la sécheresse. Les teneurs en lipides foliaires diminuent quand le stress hydrique s'intensifie, mais cette réduction est moins marquée chez PB 121 que chez ses 2 parents qui sont moins tolérants. La sécheresse semble entraîner une réduction du nombre de chloroplastes, mais sans que l'intégrité fonctionnelle des lipides des chloroplastes restants ne soit atteinte

Résumé (autre langue) : Coconut ( Cocos nucifera L.) is grown primarily on smallholdings, providing several tens of millions of people with income, food and manufactured goods. Water supply can be considered as one of the main factors limiting its yields and extension. Adapted crop techniques have their limits. It is possible to identify varieties more tolerant of drought than others. We therefore felt it would be worth attempting to gain a better understanding of the physiological mechanisms that determine palm performance under water stress so as to identify characters likely to influence the future performance of varieties. Of the 8 Dwarfx Tall hybrids and the West African Tall (WAT) studied, the PB121 (Malayan Yellow Dwarfx West African Tall, MYDxWAT) hybrid maintains high stomatal conductance for longer in the dry season, has a cuticular transpiration potential between that of its parents and maintains high yields after the dry season, although it apparently suffers greater leaf damage. This hybrid must therefore have greater protoplasmic tolerance than the other varieties. As regards protoplasmic tolerance, this study looked at leaf polar lipids. It was shown that coconut has good membrane tolerance of water deficits, since total lipid contents are low, as are the levels of galactolipids, such as monogalactosyl diacylglycerol (MGDG) and 18:3 linolenic acid in the MGDG, the target molecules of water stress. The leaf lipid contents of seedlings are lower the greater the water stress. This reduction is less marked in the PB 121 hybrid, which performs well in the field, than in its W AT and MYD parents, which are less drought-tolerant. During water stress,. membrane lipid losses primarily concern chloroplastic lipids and, in the PB 121 hybrid, the resulting reduction in galactolipids is less marked than in a Dwarf variety which performs poorly in the field. On the other band, the fatty acid composition of the MGDG does not change, which suggests that although drought leads to a reduction in the number of chloroplasts, it does not affect the functional integrity of the lipids in the remaining chloroplasts. The experimental results obtained will make it possible to characterize the varieties studied and determine an overall set of factors limiting photosynthesis in coconut and affecting membrane hardening and resistance. The way is open for immediate applications and new lines of research.

Mots-clés Agrovoc : Cocos nucifera, stress dû à la sécheresse, critère de sélection, résistance à la sécheresse, protoplasme, lipide, chloroplaste

Classification Agris : F61 - Physiologie végétale - Nutrition

Auteurs et affiliations

• Repellin Anne
• Daniel Claude
• Braconnier Serge
• Sangaré A.

Source : Cirad - Agritrop (https://agritrop.cirad.fr/388107/)

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