Study On Morphological Anatomy Of Rhus Typhina

Rhus typhina, belonging to Rhus Anacardiaceae of Rhus and growing natively in North America, which is also named lujiao qi or huoju qi. The growth characteristic, stress tolerance, acitve composition and biological invasion had been researched a lot.This article selected root, stem and leaf of Rhus typhina as the research objects, which were collected from the botanical garden in Jilin Agricultural University. The anatomical structure in each part of Rhus typhina had been researched deeply by the micro-anatomic method. And then we could explore and discuss the relationship among the unique anatomical structure, eco-physiological function and evolutionary status. The results show that:1. Primary root: Casparian strip in the cortex is not clear. The column type is actinostele, which is more primitive. The xylem is polyarch.2. Secondary root: There are lenticels in the periderm. The xylem type is ring porous xylem. The stubby reticulate vessels among the secondary xylem is a little thickening in the vessel wall. The tilt degree of the end wall is small and the type of perforation plate is simple. The tracheid is the spiral tracheid. The xylem parenchyma is faraway from the vessel. Most of the xylem parenchyma is diffuse parenchyma. The type of xylem ray is heterogeneous I.3. Primary stem: There is large amount of epidermal hair in the surface of epidermis. From the outside to the inside, epidermis, cortex parenchyma cell, primary phloem, vascular bundle and pith are lined orderly, indicating the type of vascular bundle is the typical collateral vascular bundle. There are 34-41 small and large secretary canals in the area between cortex parenchyma cell and primary phloem. These secretary canals are squeezed into oval on the transverse section. Primary xylem are made up of vessels, tracheids, xylem fibers and xylem parenchyma cells. The vessels in the vascular bundle one-way lined radially and orderly. Pith is developed, in the central position.4. Secondary stem: Secondary xylem are made up of vessels, tracheids, xylem fibers and xylem parenchyma cells. The vessels distributed intensively nearby the growth rings, which looks like a concentric-ring. The xylem type is ring porous xylem. The reticulate vessels with modest roughness and length is a little thickening in the vessel wall. The tilt degree of the end wall is modest and the type of perforation plate is simple.The spiral tracheids exist in early and late wood. The xylem parenchyma is faraway from the vessels. Most of the xylem parenchyma is apotracheal banded parenchya. Besides, diffuse parenchyma is existent at the same time. The type of xylem ray is heterogeneous I.5. Leaf: The leaf is the bifacial type. The type of stomatal apparatus is irregular and the shape of stomatal apparatus is elliptical. The stomatal apparatus are sunken and only on the lower epidermis of leaf. The average stomatal density is 318 per square millimeter,so Rhus typhina belongs to drought tolerant species. The palisade tissue is a single layer. The Ratio of palisade tissue and spongy tissue is 1.17. There are large amounts of epidermal hair on the lower epidermis of leaf, petiolule and petiole,which is one kind of multicellular and single-row non-glandular hair. In addition, secretory ducts can be seen in the leaf, petiolule and petiole of Rhus typhina.6. The results above suggest that: Rhus typhina is advanced on the whole due to lots of evolutional characteristics. But, some original features exist simultaneously. Rhus typhina has strong stress tolerance and soil adaptability, so we must be attentive while using it for afforestation.