发根农杆菌诱导的决明毛状根与实生根的解剖结构比较

In order to find out the morphological and anatomical differences between the Agrobacterium rhizogenes induced hairy roots and the aseptic seedling roots of Cassia obtusifolia L., stereomicroscopic and light microscopic observation on the paraffin sections stained with safranine/fast green, and with polysaccharide periodate Schiff (PAS) reaction were used in this research to compare the morphology, anatomy and the distribution of starch granules in the hairy roots and the seedling roots. It was found that the hairy roots were more uniform in thickness, their root tips were thicker and more robust, and had more root hairs than the seedling roots; the smaller epidermal cells and the cortex cells of the hairy roots were more closely and irregularly arranged; the endodermal cells were more closely arranged with smaller intercellular space and no apparent Casparian strips; the protoxylem of the hairy root was diarch, while that of the seedling root was tetrarch; the cambial cells of the hairy roots were smaller, more closely arranged and had more layers of cells; the root caps of the hairy roots almost had no starch granules, whereas those of the seedling roots had quite a lot. This result shows that considerable differences existed in both the morphology and anatomy of the hairy roots and seedling roots of Cassia obtusifolia L..