Physiological Effects of Drought Stress on Seedlings of Different Coffee Varieties

Abstract

To elucidate the impact of drought stress on the physiological characteristics of seedlings from different coffee varieties, seedlings of the small-bean varieties 'Tipica', 'Geisha', 'Central America', and 'Ethiopia' were used as experimental materials. This study compared the physiological changes of seedlings from these four different coffee varieties under three levels of drought stress (75%–80%, 55%–60%, 35%–40%). Physiological indicators such as chlorophyll content, soluble sugar content, proline content, peroxidase (POD) activity, and malondialdehyde (MDA) content were measured. The results indicated that with the increase in the degree of water stress, the contents of soluble sugars, proline, chlorophyll, POD activity, and MDA content all showed varying degrees of initial decline followed by an increase; suggesting that the intensification of drought stress has a certain impact on plant drought resistance. Under moderate stress (55%–60%) compared with mild (75%–80%) and severe (35%–40%) stress, the overall growth rate of indicators among varieties was higher, indicating better plant stress resistance. Based on comprehensive analysis of drought resistance indicators, principal component analysis, and subordinate function comprehensive evaluation, the drought resistance capability of the varieties was ranked from highest to lowest as follows: Tipica coffee > Geisha coffee > Ethiopian coffee > Central American coffee.