In vitro leaching of two sclerophyllous fynbos plants

Abstract

In vivo leaching is described for dried leaf litter of Berzelia lanuginosa (Bruniaceae) and dried stem material of Elegia thyrsifera (Restionaceae), two species of sclerophyllous fynbos (Cape 'macchia') plants. The process in B. lanuginosa was characterised by darkening of the water owing to the release of humic substances, which were quantified as polyphenols using the Folin-Ciocalteau reaction. Very little leaching or colouration of the water took place during the immersion period of E. thyrsifra. After an initial decrease in both species, the pH of the water containing B. lanuginosa increased to slightly above the initial level. Early (< 12 h) pulses of ammonium were detected from both species and of phosphorus from B. lanuginosa, while in both species, nitrate levels began to rise only after about 48 h. Subsequent trends in nutrient releases substantiated our hypothesis that little or no decomposition (as opposed to leaching) took place during the experiment.

Review: Water quality in non-perennial rivers (with erratum)

“…pH may vary naturally from time to time. Streams in the southwestern Cape, for example, tend to be more acidic during winter (Britton et al, 1993) 493 humic substances from the soil and groundwater during winter rains (Raubenheimer and Day, 1991). In productive ecosystems, on the other hand, as a result of removal of CO 2 during the process of photosynthesis, pH may reach values of 10 or more during the day, falling to 8 or less at night (Sweeting, 1994).…”

Erratum: Water quality in non-perennial rivers [Water SA 45 (3) 487–500]

“…pH may vary naturally from time to time. Streams in the southwestern Cape, for example, tend to be more acidic during winter (Britton et al, 1993) (Raubenheimer and Day, 1991). In productive ecosystems, on the other hand, as a result of removal of CO 2 during the process of photosynthesis, pH may reach values of 10 or more during the day, falling to 8 or less at night (Sweeting, 1994).…”

Erratum: Water quality in non-perennial rivers [Water SA 45 (3) 487–500]

“…humic substances from the soil and groundwater during winter rains (Raubenheimer and Day, 1991). In productive ecosystems, on the other hand, as a result of removal of CO 2 during the process of photosynthesis, pH may reach values of 10 or more during the day, falling to 8 or less at night (Sweeting, 1994).…”