Anatomy Study On Primary Tissues And Organs Of ’Dangshansuli’ Pear

The terminal buds, young roots, stem, and leaves were used as test materials toexplore the developmental roles of main tissues and organs of ‘Dangshansuli’ pear andprovide basis for improving fruit output and quality in production. The period of the flowerinitiation was determined by method of intermittent leaves removal, and the process ofmorphological differentiation of flower organs was observed under microscope byhand-slice. The structure difference between the leaves of external and internal tree canopyon same plant and the structure of young roots and stem were also observed at some time.The Casparian strip form on endodermis of root was observed under transpirationelectronic microscope.The main results gained were as follows.1. Flower initiation began at first June and lasted to mid-late July, when thedevelopment of flower organs started. The stamen primordia begin to form inmid-September and the pistil primordia initiate in mid-late October. In late March nextyear, flower buds begin to swell, and then experienced cluster bud, finger bud, white bud,bulb bloom, first open bloom, half open flowers, full bloom and petal fall stages, theflowering phenology of ‘Dangshansuli’ pear ended in mid-April.2. It was found that the primary structure of young root from downside to upside wasroot cap, root hair zone, primary and secondary structure, and from external to internal wasroot hair, epidermis, exodermis, endodermis, casparian strips, pericycle, primary phloem,primary xylem, cambium and cord observed under microscope. The secondary structure ofyoung root included epidermis, cortex, endodermis, pericycle, primary phloem, primaryxylem, cambium, secondary phloem, secondary xylem, periderm, primary vascular lineand secondary vascular line.3. The result of observation of the stem primary and secondary structure showed thatthe development from the primary to secondary structure was a process from the growthcone to the completely secondary structure.4. The observation of microstructure differences between the leaves of external andinternal tree canopy on same plant showed that the palisade tissue and spongy mesophyll inthe former were thicker than the later.