GENETIC VARIATION IN LEAF MORPHOLOGY DOES NOT AFFECT PLANT RESPONSE TO HIGH VAPOR PRESSURE DEFICIT IN OIL PALM

Résumé fourni par la source

Vapor pressure deficit (VPD) is a key driver of leaf transpiration and plays a crucial role in regulating water transport in plants. Elevated VPD often induces morphological, physiological, and biochemical responses that can impact plant performance and crop yields. This study aimed to investigate the genetic variability of oil palm responses to high VPD through two controlled experiments. Six oil palm progenies at an early growth stage were evaluated under low and high VPD conditions in glasshouses with tightly regulated air temperature, humidity, and irrigation to maintain non-limiting soil moisture, isolating the effects of VPD from soil water deficit. Phenological, morphological, ecophysiological, biochemical, and candidate gene expression analyses were conducted to assess progeny-specific responses. The results revealed distinct morphological differences in leaf traits among progenies that remained consistent under both VPD treatments, although total leaf area was similar across progenies. Significant effect of VPD on daily evapotranspiration was observed during both years, while the progeny effect was either absent or minimal. To limit water loss under high VPD, progenies reduced stomatal conductance, demonstrating a common adaptive response to elevated VPD. Biomass allocation patterns were progeny-specific and, along with carbon assimilation rates, remained stable regardless of VPD level. However, one progeny (G02) exhibited distinct behavior, with both stomatal conductance and water use efficiency not affected under high VPD, and a greater plasticity on carbon allocation to leaves. Overall, our results identify clear between-progeny morphological diversity and emerging progeny-specific responses to high VPD, but do not yet identify a single juvenile trait that reliably predicts whole-plant response.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.