Xylem Cells Of Different Shoot Types. Spur-type Apple Anatomical Structures And Branches Nutrients Study

Studies on the correlation between the cyto-anatomy structure of the secondary xylem of different branches and their mineral nutrition contents in spur-type apples Abstract The cyto-anatomy structure of the vessel members of the secondary xylem of different branches of two apple strains, Starking and Golden delicious(including spur-type trees Starkrimson and Golden Spur Delicious, standard-type trees Starking and Golden Delicious), were studied with scanning electron microscope and optical microscope ; Moreover, the contents of mineral nutrition (K. Ca-. Mg-. Cu Fe Mn. Zn)of different branches were measured with atomic absorber. The results indicate as follows: (1). The vessel members of all apple varieties are pitted vessel, the pits possess border, and there exists the perforation and the shorter (or longer) tail on the end wall. The density of the pits on the sidewall of vessel members of spur-type apples is obviously smaller than that of the standard-type trees in the same kind of branch. In every variety, the tendency of the dimension of vessel members in different branches is very similar: the mean length and diameter of the vessel members of extending branches or splindling branches are the longest and widest; and the vessel members of fruit branches and fruit-born branches are shorter and narrower than that of the extending branches. (2). The contents of mineral nutrition of different branches in different varieties are different with each other during dormant period. In varieties, the contents of K, Ca, Mg, Cu, Fe, Mn and Zn are all higher in fruit branches and fruit-born branches than those of extending branches in spur-type trees or in standard-type trees, the content of K in spur-type trees is higher than that of standard-type trees, but other elements are irregular. (3). There is the negative correlation between the dimension of vessel member and the contents of K, Ca. Mg, Cu, Fe, Mn, Zn of different branches in any variety (except the content of Cu in Golden delicious). This means that the level of mineral nutrition content in branches is reduced as the dimension of their vessel member increases. In every variety, there is the positive correlation among the seven mineral elements in different branches except the correlation between Mg and Cu in Golden spur delicious. Those results provided new reference material of cyto-anatomical physiology and nutritional physiology for the further study of spur-type apples.