ON THE POLARITY OF GREENING IN PRIMARY LEAVES OF DARK AND LIGHT‐GROWN SEEDLINGS OF Triticum aestivum*

— In primary leaves of four-day-old dark-grown wheat seedlings the capability to accumulate chlorophyll under white light is highest in the tissues of the apical region. It declines though, as the dark-grown seedling ages and the primary leaf grows longer. This decrease is lower in the basal than in the apical regions of a leaf, which results in an inverted polarity of the capability to accumulate chlorophyll If the seedlings are grown under continuous white light applied from four different directions, the high capability of greening observed in the apical tissues of young leaves stays at that level even in old seedlings: the polarity does not change during culturing. The saturation-level of greening is much higher in the tissues taken from the apical region of a primary leaf than in those from the basal region.