Phosphorus Uptake by Plants: From Soil to Cell

P is an important plant macronutrient, making up about 0.2% of a plant's dry weight. It is a component of key molecules such as nucleic acids, phospholipids, and ATP, and, consequently, plants cannot grow without a reliable supply of this nutrient. Pi is also involved in controlling key enzyme reactions and in the regulation of metabolic pathways (Theodorou and Plaxton, 1993). After N, P is the second most frequently limiting macronutrient for plant growth. This update focuses on P in soil and its uptake by plants, transport across cell membranes, and compartmentation and redistribution within the plant. We will concentrate on P in higher plants, although broadly similar mechanisms have been shown to apply in algae and fungi.