Physiological and biochemical responses of sugar palm (Arenga pinnata Merr.) at different elevation levels

Altitude influences the physiological and biochemical responses of sugar palm due to changes in weather and climatic conditions. In this study, sugar palms were observed at low (427 masl), medium (620–700 masl), and high (1,011–1,026 masl) altitudes. The results revealed that altitude had no significant effect on chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, proline, anthocyanin reductase (ANR), superoxide dismutase (SOD), peroxidase (POD), and malondialdehyde (MDA) levels. However, a trend of increasing stress with altitude was observed, indicated by a negative correlation between SOD and POD activities with chlorophyll content and ANR activity. As SOD and POD activities increased, chlorophyll content and ANR activity decreased, suggesting an adaptive response to oxidative stress at higher altitudes. Overall, sugar palms exhibited more favorable physiological and biochemical profiles when cultivated at low to medium altitudes. These findings indicated that sugar palms grow optimally in lower elevation environments and may experience increasing physiological stress with altitude, providing important insight for their conservation and potential development as a sugar-producing crop.