The ultrastructural ontogeny of Commelina benghalensis minor-vein elements was followed. The mature minor vein has a restricted number of elements: a sheath of six to eight mestome cells encloses one ...

This is a preview. Log in through your library . Abstract Both thick- and thin-walled sieve tubes in leaf-blade veins of Hordeum vulgare L. exhibit a distinct, electron-opaque inner wall layer after ...

Figure 1: Model of protein/ribonucleoprotein transport through the microchannels of higher plant plasmodesmata. Figure 2: The plant vascular network and the development of the phloem sieve-tube system ...