Study On The Anatomical Structure Of Two Species In Thalictrum

Thalictrum petaloideum L.and T.aquilegifolium L.belong to Thalictrum of Ranunculaceae.There are about 300 species of this genus.Both are distributed widely around the world.Most of them mainly exists in Liaoning Province,Jilin Province,Heilongjiang Province,Inner Mongolia and other places of China.T.petaloideum and T.aquilegifolium are perennial wild herbaceous flowers,which have high value and great utility in gardening,medicinal and edible.Current research mainly focuses on pharmacology and chemical composition.In this experiment,the roots,stems and leaves of T.petaloideum and T.aquilegifolium were selected,and dissected by paraffin sectioning and freehand sectioning.Meanwhile,the phenological period were observed,and based on the results of plant anatomy,the habitat,evolution status,introduction and domestication were discussed in detail.The research results are as follows:1.The leaves of T.petaloideum and T.aquilegifolium are heterofacial.The epidermal cells are deep wavy irregular polygons,and the upper epidermis has no stomata.The two palisade tissues are of 1-2 layers,and the sponge parenchyma is well developed with obvious intercellular space.The former has a stomatal density of 231/mm~2,the ratio of palisade tissue and spongy tissue is 95.64%,and a leaf structure density of 50.96%.The latter has a stomatal density of202/mm~2,and the ratio of palisade tissue and spongy tissue is 79.47%,and a leaf structure density of 55.15%.The leaf veins of T.petaloideum and T.aquilegifolium are all bulged at the distal axis,and T.aquilegifolium is more pronounced.There is a bundle of vascular bundles in the center of the vein,surrounded by a layer of vascular bundle sheath.The number of xylem vessels in the vascular bundle of T.petaloideum is 14-16,and the pipe diameter is 10.66±2.50?m.The number of xylem vessels of the vascular bundle of T.aquilegifolium is 10-12 and the pipe diameter is 8.95±1.57?m.The stomatal density,the ratio of palisade tissue and spongy tissue,the leaf structure density,the number of the vessel and pipe diameters indicate that the structure and the kinship of T.petaloideum and T.aquilegifolium is similar.Show that the two are close,but have inter species difference and the latter is more moisture-resistant than the former.2.Both plant stems are hollow and consist of epidermis,cortex,vascular bundle.The stem epidermis of T.petaloideum and T.aquilegifolium is of 1 layer,and the cortex has thick angle tissue inward.The vascular bundle has two rings,the inner ring and the outer ring;The inner ring is larger,and the outer ring is smaller.The number of vascular bundles in the inner and outer rings of T.petaloideum is basically the same as 18-23 bundles arranged in phase,and the inner vascular bundles of the inner ring of T.aquilegifolium are 13-14 bundles and more vascular bundles in the outer ring which are 21-23.As dicotyledonous plant,they show the characteristics of monocotyledonous,indicating that they have evolved.3.The xylem of the primary roots of T.petaloideum and T.aquilegifolium are two prototypes,and the developmental mode is the outer-initial type.The former primary and secondary xylem conduit type is reticulated catheter and threaded catheter,and the latter primary and secondary xylem conduit type is reticulated and ring-shaped catheter.The pipe diameter of the catheter in the secondary root of T.petaloideum is 19.87±5.13?m,and the pipe diameter of the secondary root catheter of T.aquilegifolium is 15.79±5.26?m.The number of bundles of thick-walled tissue in the secondary roots is basically the same,but single bundle of thick-walled tissue of T.aquilegifolium has a larger area and can obtain better mechanical support.It indicated that T.aquilegifolium is more resistant to negative and can obtain higher plant type.4.Both species of Thalictrum are middle-aged plants with good tolerance to negatives and posses strong vitality.The vascular bundles in the stems of T.petaloideum and T.aquilegifolium are in the anatomical features of the inner and outer rings,which proves the similar kinship and evolutionary basis of the two.This experiment also provides a theoretical basis for the introduction and domestication of the two,and thus is widely used for landscaping.