![]() ![]() In contrast, the strands of internal metaphloem with giant sieve tubes, which are scattered among the metaxylem, were neither labeled nor did they show ATPase activity. In this region of the root, ATPase activity was concentrated on the plasmalemma and cortical cytoplasma of the sieve tubes, and on the tonoplast of the phloem parenchyma cells. Differentiating vessels were heavily labeled at sites where secondary walls were formed. In the region 5-6 cm from the root tip, in which the first metaelements differentiated, all parenchyma cells of the central cylinder and many cortical cells showed (14)C-label, in addition to the densely labeled protophloem. The activity of ATPase was recognized in many different cellular organelles of the meristematic phloem parenchyma. ![]() In the region 2-3 cm from the root tip, in which only protoelements of the vascular tissue were differentiated, (14)C-label was restricted to the protophloem. Vigorously growing aerial roots grew as fast as 26 mm d(-1), and zones of differentiation extended more than 10 cm from the root tip. ![]() In addition, histochemical localization of ATPase was carried out on similar aerial roots. Microautoradiographs of soluble and insoluble radioactivity were prepared from three different regions of the aerial root. pruned to exemplars with one leaf and one aerial root were labeled with 7.4 MBq (14)CO2 over the leaf blade. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |