Apical¿basal polarity: why plant cells don't standon their heads

The anatomical terminology that is used to describe the orientation and polarity in the plant body (for distinction indicated here in italics) is based on the consensus agreement that the transition zone between the aerial and the soil-borne part (the rootshoot junction) is defined as the base of the plant, and the ends of a body axis root and shoot tips are defined as apices. For embryos, another terminology is equally well established (indicated here by underlining), which defines the root embryo pole as the base and its opposite end as the apex. Over the past few years, studies dealing with issues of cellular polarity in plants have used either anatomical or embryological terminology to describe the upper and lower side of individual cells. Recently, this confusion in terminology was highlighted, and it was proposed that the anatomical terminology should be used in all cases. However, we believe that the anatomical terminology, when used for the description of cellular polarity, has important deficiencies. Here, based on a number of arguments, we propose what we consider to be a suitable compromise.