Effect of Cultivar Variability on Physiological Response of Oil Palm to Drought Stress

Abstract

Drought stress presents a daunting challenge to oil palm cultivation, provoking a number of morphological and physiological responses that impact growth and development. In this study, the effects of drought stress on three cultivars of oil palm, namely GH500 (GH), Yan-gambi (YM) and Carlix (CX) were investigated by subjecting them to varying degrees of drought conditions. Morphological alterations, including leaf drying and necrosis, along with reduced root mass and volume, were observed in drought-stressed seedlings compared to well-watered controls. Additionally, chlorophyll content exhibited distinct patterns among cultivars under different drought intensities, with GH showing pronounced sensitivity even to mild stress. Chlorophyll reduction was accompanied by diminished transpiration rates, indicating the plant's adaptive response to conserve water under stress conditions. Interestingly, the decline in chlorophyll concentration preceded the onset of severe drought, highlighting its potential as an early indicator of stress. Concurrently, photosynthesis exhibited a decreasing trend with increasing drought severity, reflecting the pivotal role of chlorophyll and intracellular CO₂ concentration in sustaining photosynthetic activity. Despite reduced transpiration, CX and YM cultivars displayed a balance between photosynthesis and transpiration, indicating their adaptive capacity to maintain essential physiological functions. Based on these observations, it can be inferred that the YM and CX cultivars may possess higher resistance or tolerance to drought stress compared to the GH cultivar. The complex interplay between physiological parameters emphasize the multifaceted nature of oil palm's response to drought stress, with implications for its long-term viability and resilience in changing environmental conditions. Our findings shed light on the mechanisms underlying oil palm's response to drought stress and provide valuable insights for enhancing its stress tolerance and sustainability in the face of climate variability. Exploring the proteomics and metabolomics governing the plant response will go a long way in providing effective clues for interventions efforts to mitigate the effects of drought on oil palm.