Abstract

African violets (Streptocarpus ionanthus), originally native to the Eastern Arc Mountains of Africa and adjacent submontane or montane forests in Kenya and Tanzania, are commonly grown as ornamental plants and have been extensively studied by horticulturists. However, there is a lack of laboratory data regarding their ecophysiology. Given the growing interest in conserving African violets in their threatened natural habitats, it would be beneficial to establish baseline data on their physiological ecology, helping to document their response to changing environmental conditions in their natural environment. To address this need, we conducted an analysis of the net photosynthesis rate, respiration rate, and leaf fluorescence of mini and standard strains of African violet plants within a controlled laboratory setting. Additionally, we examined variations in the photosynthesis rate, respiration rate, and leaf fluorescence data for leaves of different ages (phenology) in the standard strain. The results showed that the mean net photosynthesis rate in the older whorl of leaves was approximately 50% of the rate observed in the younger leaves. Furthermore, the mature leaf respiration rate accounted for about 25 to 30% of the net photosynthesis. This particular metric, the ratio of respiration to net photosynthesis, is significant in estimating the carbon balance of the plants. It helps us understand how much carbon (C) is gained through photosynthesis compared to the amount of carbon lost through respiration.

Key words: Environmental carbon balance, leaf relative chlorophyll content analysis, leaf chlorophyll fluorescence analysis, photosynthesis rate, respiration rate, specific leaf area.