Polarity - Root and Shoot Morphogenesis

Polarity is defined as having a difference (morphological, physiological or both) between the two ends of an axis or cells. This is largely determined by the position. In an embryo sac located in an ovule, egg cells and synergids are located at one end and antipodals at the opposite end. This is a kind of polarity. In an eucaryotic unicellular organism like chlamydomonas-flagellae are situated at anterior end. In higher plants, right after division of the zygote, the radicle end and plumule end are well defined. The location of cotyledons is also established very soon. The auxin transport is polar basipetal.

Cytokinins move from roots to shoot apex. Polarity is a common phenomenon observed in plant body right from embryo up to fully grown plant. You should know that Genotype contains information to control polarity. Genes control this process through hormones i.e. gradient of all the growth regulating hormones control and regulate phenotypic expression of polarity.