[Root microstructure and distribution of the endophytic fungi in Taxus chinensis var. mairei].
OBJECTIVE
To study the root microstructure and the distribution of the endophytic fungi in Taxus chinensis var. mairei.


METHODS
The roots of Taxus chinensis var. mairei at nature were cut with paraffin, dyed and observed by microscope.


RESULTS
The secondary structure of the roots of Taxus chinensis var. mairei consisted of the periderm and vascular cylinder (stele). Axial and radial systems formed the secondary xylem of the roots. Tracheids and xylary parenchyma cells constituted the axial system, and xylary radial formed the radial systems. The secondary phloem consisted of sieve cells and phloem parenchymas. Only a small quantity of phloem fibers were distributed in the secondary phloem, and the phloem ray was unconspicuous. Many endophytic mycelia penetrated in the velamina.


CONCLUSIONS
The secondary structure of the root of Taxus chinensis var. mairei accords with that of other gymnosperms and dicotyledons, although its secondary xylem is constituted with tracheids and sieve cells. The endophytic mycelia exists in the local cells of velamina in the roots of Taxus chinensis var. mairei.
Tan
Xiao-Ming
XM
Mycorrhizal Department, Institute of Medicinal Plant Development, CAMS and PUMC, Beijing 100094, China.
Cuo
Shun-Xing
SX
D005658:Fungi / Q000302:isolation & purification*; D018517:Plant Roots / Q000382:microbiology / Q000648:ultrastructure; D020946:Taxus / Q000382:microbiology* / Q000648:ultrastructure