Ion homeostasis in the Chloroplast

peer reviewedThe chloroplast is an organelle of high demand for macro- and micro-nutrient ions, which are required for the maintenance of the photosynthetic process. To avoid deficiency while preventing excess, homeostasis mechanisms must be tightly regulated. Here, we describe the needs for nutrient ions in the chloroplast and briefly highlight their functions in the chloroplastidial metabolism. We further discuss the impact of nutrient deficiency on chloroplasts and the acclimation mechanisms that evolved to preserve the photosynthetic apparatus. We finally present what is known about import and export mechanisms for these ions. Whenever possible, a comparison between cyanobacteria, algae and plants is provided to add an evolutionary perspective to the description of ion homeostasis mechanisms in photosynthesis

The impact of maternal mental health and child's behavioural difficulties on attributions about child behaviours

The effects of maternal mental health and child's behavioural difficulties upon mothers' attributions for negative child behaviour were examined. A community sample of 70 mothers of children aged about 9 years were interviewed in depth and the interviews transcribed. Transcripts were analysed for spontaneous attributions which were subsequently coded on the dimensions of internality, controllability, stability, universality and globality. Mothers with mental health problems made the same number of attributions about negative behaviours as normal mothers. However, more internal-to-self and global attributions were made by the group with mental health problems. This pattern was demonstrated regardless of the child's level of behavioural difficulties. The increase in negative attributions by mothers with mental health problems is not the result of the association between maternal mental health and child's behavioural difficulties. Mothers with mental health problems do not explain their child's negative behaviours in a way that is typical of normal mothers, and reasons for this are discussed

A simple method for quantification of protochlorophyllide in etiolated <i>Arabidopsis </i>seedlings

Etiolated seedlings accumulate the chlorophyll biosynthesis intermediate protochlorophyllide (Pchlide) and measuring Pchlide can be important for characterizing photomorphogenic mutants that may be affected in chloroplast development. In this chapter we outline a simple and sensitive method for quantifying Pchlide in extracts of Arabidopsis seedlings using fluorescence spectroscopy. This method can be easily adapted to study chloroplast development in a wide range of plant species.</p