The Change of Chlorophyll Content and Chlorophyll Efficiency in Epipremnum aureum by Water and pH

Abstract

Epipremnum aureum (pothos) is an herbaceous species and is originated to tropical or subtropical South East Asia and Solomon islands. This study investigated the effect of excessive moisture on chlorophyll content and photosynthesis efficiency on E. aureum. The chlorophyll a, b, and total (chlorophyll a + b) contents were measured by using spectrophotometer.  Fluorescence analysis for chlorophyll efficiency was measured with the PAM Chlorophyll Fluorometer. The chlorophyll content increases when moisture increases to 30%, but gradually decreases when it exceeds 40%.  When the soil moisture was 80%, the values of chlorophyll a and b were 0.317 mg/g and 0.126 mg/g, respectively. This decreased the chlorophyll a, b, and total contents by 38.1%, 46.6%, and 36.8%, respectively, compared to 30% in 80% moisture.  The chlorophyll content was highest at pH 6.5 of the soil. The content for chlorophylls a, b, and total were 0.471, 0.219, and 0.446 mg/g at pH 6.5, respectively. The correlation coefficients were subjected of the chlorophyll efficiency as a function of moistures. The change of chlorophyll efficiency in the quenched state (Fv) was also increased at 30% of moisture and then decreased steeply. The maximal possible value for fluorescence (Fm) was varied from 4310 (40% moisture) to 4220 (80% moisture).  The Fm was varied from 4098 (pH 4.0) to 4356 (pH 6.5). The maximum quantum yield of photosynthesis (Fv/Fm) was varied from 0.798 (30% moisture) to 0.810 (60% moisture). The slope factors of Fo, Fm, Fv, and Fv/Fm for chlorophyll efficient indicators were 0.938, -0.806, 0.013, and 0.846, respectively. Excess watering decreased chlorophyll a, chl b, and chl (a + b) contents, and the chl a/b ratio in the E. aureum. The growth of this species was not as sensitive to pH compared to moisture.