Effects of chlorine deficiency in the field on leaf gas exchanges in the PB 121 coconut hybrid

A study of leaf gas exchanges during the dry season and rainy season confirmed the importance of the Cl- ion in coconut. In the dry season, compared to a control, chloride deficiency led to lower stomatal conductance in coconut, hence a reduction in leaf gas exchanges. This resulted in less intense net photosynthesis and transpiration, which accounted for the poorer drought tolerance of Cl- deficient palms. During the dry season, even if not very intense, coconut palms that were not Cl- deficient maintained and even increased their stomatal conductance. This enabled them to increase leaf transpiration, hence responding to the increase in evaporative demand and maintaining a high level of net assimilation. Conversely, deficient palms reduced their stomatal conductance, leading to a drop in transpiration and in net photosynthesis. Observations during the rainy season failed to reveal any effect of chloride deficiency on intrinsic photosynthesis. The Cl- ion therefore seems to act primarily during the dry season, and in stomatal regulation.

Bibliographic Details

Main Authors:	Braconnier, Serge, Bonneau, Xavier
Format:	book_section biblioteca
Language:	eng
Published:	CIRAD-CP
Subjects:	F60 - Physiologie et biochimie végétale, F61 - Physiologie végétale - Nutrition, P35 - Fertilité du sol, Cocos nucifera, hybride, résistance à la sécheresse, carence minérale, chlorure, photosynthèse, transpiration, échange gazeux, stomate, conductance stomatique, http://aims.fao.org/aos/agrovoc/c_1716, http://aims.fao.org/aos/agrovoc/c_3707, http://aims.fao.org/aos/agrovoc/c_2392, http://aims.fao.org/aos/agrovoc/c_4849, http://aims.fao.org/aos/agrovoc/c_1567, http://aims.fao.org/aos/agrovoc/c_5812, http://aims.fao.org/aos/agrovoc/c_7871, http://aims.fao.org/aos/agrovoc/c_11098, http://aims.fao.org/aos/agrovoc/c_7423, http://aims.fao.org/aos/agrovoc/c_37253, http://aims.fao.org/aos/agrovoc/c_3840,
Online Access:	http://agritrop.cirad.fr/390467/
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