Progressive Water Deficit Modulates Growth, Photosynthetic Pigments, and Proline Accumulation in Theobroma cacao L. Seedlings
José G. Joya Dávila1,*, Federico A. Gutiérrez Miceli2, Leslie A. Serrano Gómez1, Olivia Tzintzun Camacho1, Dagoberto Durán Hernández1, Alexis Salazar Navarro1, David Cervantes-García1, Ulin Antobelli Basilio Cortes1, Anayancy Lam Gutiérrez3, Daniel González Mendoza1
1 Instituto de Ciencias Agrícolas, Universidad Autónoma de Baja California, Carretera al Delta, Ejido Nuevo León s/n, Mexicali, Baja California, México
2 Tecnológico Nacional de México/I.T. Tuxtla-Gutiérrez, Carretera Panamericana Km 1080, Tuxtla Gutiérrez, Chiapas, México
3 Tecnológico Nacional de México/IT Superior de Cintalapa, Carretera Panamericana Km 995, Cintalapa, Chiapas, México
* Corresponding Author: José G. Joya Dávila. Email: 
Phyton-International Journal of Experimental Botany https://doi.org/10.32604/phyton.2026.087160
Received 11 June 2026; Accepted 27 July 2026; Published online 03 August 2026
Abstract
Water deficit is one of the major constraints to the establishment and early growth of cacao (
Theobroma cacao L.), particularly under increasingly frequent and intense drought conditions. The objective of this study was to evaluate the morphological and physiological responses of cacao seedlings subjected to progressive water deficit under nursery conditions. Plants were evaluated over a 45-day period without irrigation and compared with well-watered plants maintained at 60% of substrate field capacity. Growth variables, photosynthetic pigment concentrations, and proline accumulation in leaves, stems, and roots were evaluated. Stem length showed no significant differences between treatments, whereas root length and fresh biomass decreased as the water deficit was prolonged. Dry biomass remained unchanged under moderate stress but was significantly reduced when the irrigation-free period was extended, indicating that stress duration was the primary factor influencing plant growth. Water-stressed seedlings maintained higher chlorophyll concentrations throughout the experimental period, whereas proline accumulation increased, reaching a maximum after 30 days of water deficit, with increases of approximately 119%, 71%, and 147% in leaves, stems, and roots, respectively, before declining under prolonged stress. Stress duration was identified as the main factor determining the magnitude of the physiological responses, revealing a distinct temporal- and organ-dependent pattern of proline accumulation. Overall, these findings demonstrate that the morphological and biochemical responses of cacao seedlings to water deficit occur in a coordinated manner and are primarily determined by stress duration, providing new insights into the temporal dynamics of proline accumulation and associated physiological responses during the early developmental stages of cacao.
Keywords
Osmotic adjustment; abiotic stress; drought; tropical perennial species
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