关键词: 杨梅, 硫, 钴, 分布, 生长

Abstract: Sulphur contents of soil where three years old Myrica rubra trees were planted for one year without the application of fertilizers decreased by 37.7% indicating that there is a st ronger capability of S absorption in this plant which is mainly accumulated in leaves and root nodules. It has been observed that
sulphur contents in leaves or root nodules is about two times as much as that of roots. That cobalt contents in root nodules and roots are 4.88 and 4.48 times as much as that of leaves respectively showed that cobalt is mainly accumulated in root nodules and root s of M. rubra. Below 30 mg CoSO₄·7H₂O per tree , sulphur or cobalt can be preferentially transported and accumulated into root nodules. Sulphur content s in root nodules and in leaves were 3.38 - 4.58 times and 2.75 - 3.72 times as much as that of roots respectively,
Moreover sulphur contents in root nodules were 1.23 times as much as that of leaves. Similarly , when CoSO₄·7H₂O below 30 mg per tree was used , cobalt contents in root nodules were 1.39 - 1.90 and 3.53-4.55 times as much as that of roots and leaves respectively. When CoSO₄·7H₂O below 30 mg per tree was used , biomass , tree height , amount of root nodules and nit rogenase activities of M. rubra were increased remarkably and nitrogenase activities of root nodules in treatment were 8-18.35 times as much as that of control. A hypothesis is put forward that sulphur may have relation to symbiotic nitrogen fixation of Frankia and can promote formation of root nodules and nit rogen fixation.

Key words: Myrica rubra, Sulphur, Cobalt, Distribution, Growth