Macronutrients and allocations to different organs in one-to three-year-old Taxus chinensis var. mairei

Key words: 
• botany /
• Taxus chinensis var. mairei /
• nutrient elements /
• seedling

Abstract: Taxus chinensis var. mairei,a rare and endangered species,both is a beautiful garden tree and a good timber tree,especially,its extract(taxol) can be used for medicine to treat cancers. This trial studied the macronutrients and allocations to different organs in T. chinensis var. mairei seedlings in order to improve its cultivation level. T.chinensis var. mairei were planted in Tonglu County,Zhejiang Province,treated with fertilizer (N∶P2O5∶K2O=16∶16∶16) in the end of March every year. The N,P,K,Ca,and Mg contents in leaf,root,and branch organs of T. chinensis var. mairei and the organs' drought weight for one- to three-year-old seedlings were analyzed in November 2006 by random sampling with three replications. Results showed that drought weight of the three different organs increased 10 times every year first three years,and the root/crown ratio also increased. Nutrient elements for one- and two-year-old seedlings were in the order of leaf > root > branch,while in three-year-old seedlings the order was leaf > branch > root. As the seedlings grew,leaf N,P,K,and Ca increased,but Mg decreased; branch N and Mg increased,whereas P,K,and Ca decreased; and root nutrient elements all decreased. Of the five nutrient elements in the three organs,N and Mg accumulated faster increasing about 10 times each year. Accumulation in the first year was: N > K > Ca > P > Mg,whereas in the second and third years the order was N > K > Mg > Ca > P. A shading treatment(25% shading from April to November in 2006) increased N in leaves but decreased N in branches and roots; increased P in leaves,branches,and roots; increased K in roots and leaves but decreased K in branches: and had little influence on Ca and Mg content. For the shading treatment,accumulation of the 5 nutrients in T. chinensis var. mairei decreased 6.8%.