Qualitatively anatomic characteristics of vegetative organs of juvenile hop plant (Humulus lupulus L.), the family Cannabaceae
2007
Jurcak, J.,Univerzita Palackeho, Olomouc (Czech Republic). Katedra Botaniky | Stranc, P.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Rostlinne Vyroby | Stranc, J.,ZEPOR, Zatec (Czech Republic) | Stranc, D.,ZEPOR, Zatec (Czech Republic)
The roots have the primary structure (rhizodermis with root hairs, primary bark, and actinostele with radial, mostly tetral vascular bundle) at a distance of 15-20 mm from the growing point. The lateral root was established exogenously. The roots pass soon to the secondary structure by activities of phellogen and cambium. Their tissues manifested minimal to zero lignification of cell walls and high presence of starch (amyloplast). The stem has a primary structure, too (epidermis, primary bark, collateral vascular bundles, pith), only on a short section behind the growing point. Cambium is applied functionally at a distance of 10 mm from the growing point and internal structures pass into the secondary structure. The secondary xylem of arising growth cylinder has a character of homoxylous porously scattered deuteroxylem. Phellogen was not recorded. Excretory (latex) channels have been already established in undifferentiated zone and are present in all internodes. Lignification of cell walls of mechanical tissues was very low, vascular walls of deuteroxylem components are more lignified. The stem has a character of woody species. The internal structure of petiole (the system of cover, conductive and basal tissues) reminds the stem structure. The secretory channels placed among phloem sections penetrate from the stem through the leafstalk into the main vein of the leaf blade. The blade is significantly thin among the veins and has a typical bifacial structure. Stomata and huge trichomes are present only in abaxial epidermis. Mostly the cell walls are not lignified. The resistance is provided by xylem segments of vascular bundle and subepidermal layer of tissues with mechanical function (collenchyma and sclerenchyma) in the leafstalk and thick veins.
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