Intracellular pH in one-cell mouse embryo differs between subcellular compartments and between interphase and mitosis.

The pH-sensitive dual-emission fluorophore SNARF-1 coupled with a laser confocal microspectrofluorimeter was used to measure the internal pH (pHi) in different subcellular and subnuclear compartments of early mouse embryos. By this method we analysed the first cell cycle of naturally fertilised embryos in order to detect possible pHi changes correlated to cellular events, particularly the onset of replication or transcription and the first mitosis. Throughout interphase, significant differences of pHi were observed between cytoplasm and pronuclei, and, even more striking, between these compartments and nucleolus precursor bodies, whose pHi was systematically lower.

Carbon Fluxes in Plant-Soil Systems at Elevated Atmospheric CO2 Levels.

The flow of carbon from photosynthesizing tissues of higher plants, through the roots and into the soil is one of the key processes in terrestrial ecosystems. An increased level of CO in the atmosphere will likely result in an increased input of organic carbon into the soil due to the expected increase in primary production. Whether this will lead to accumulation of greater amounts of organic carbon in soil depends on the flow of carbon through the plant into the soil and its subsequent transformation in the soil by microorganisms.

Diurnal changes in the flux of calcium toward meristems and transpiring leaves in tomato and maize plants.

Tomato (Lycopersicon esculentum Mill. cv. Moneymaker) and maize (Zea mays L.

Transport of divalent cations: cation exchange capacity of intact xylem vessels.

The cation exchange capacity of the intact xylem vessels in cut shoots of papyrus (Cyperus papyrus spec.) has been determined. The cation exchange capacity is independent of the cation concentration in the transpiration stream, and is equal for Ca and Co.

Mobility and ionic form of silver as related to longevity of cut carnations.

The mobility of different ionic forms of silver ((110m)Ag) has been studied using semiconductor radiation detectors. Silver, applied as silvernitrate (2mM), moves upward in the stems of cut carnations (Dianthus caryophyllus L.) at about 3 cm day(-1).