Studies On Root System And Fleshy Root Structure Of Cycas

The method of anatomy is used to study the root system and fleshy root structure of 9 species of wild Cycas and 1 species of cultivated Cycas in Guangxi. The results show that: (1) Cycas belong to fibrous root system but not taproot system. This finding is contrary to the conclusion that Cycads belong to taproot system for a long time, and is a new discovery in Cycads research. (2) All of the fibrous roots of Cycas tend to develop into fleshy roots, whose cortex consists of 80 layers of biggish parenchyma cells that contain abundant starch grain and tannin. (3) There are 2~n primary xylems in the vascular cylinder, and the numbers are gradually increasing from the tine to the top in the fleshy root of Cycas. (4) There are pitted vessels and reticulated vessels in fleshy root of 10 species of Cycas. Reticulated vessels vary in sizes and are small in diameter, while pitted vessels are long and big in diameter. (5) Nucleus and cytoplasm can be seen in parenchyma cells of secondary structure of 10 species of Cycas. It was never reported in anatomy research of vegetative organ of Cycads previously. (6) C.longiconifera, C. acuminatissima and C.multifida are not appropriate to incorporate in to one species according to the characteristics of existence of crystal or not, the...