Myrica rubra plant growth，nodulation，and nitrogen fixation using a boron spray

Key words: 
• horticulture /
• Myrica rubra /
• boron /
• plant growth /
• nitrogenase activity

Abstract: Myrica rubra is a boron sensitive plant，and many research were focused on its growth and development，fruit production，fruit quality by boron fertilization，but no research on the relationship of boron and its nitrogen fixation. One-year-old Myrica rubra ‘Dongkui’ in a randomized complete-block design with five replications was sprayed with five treatments of boron［0（control），6.6，13.2，19.8，and 26.4 mg total boric acid per tree，each treatment divide into seven times，sprayed on 15th from May to November of 2005］in fruit tree greenhouse of Guangxi University to quantify plant growth，nodulation，and nitrogen fixation. Results showed that trees sprayed with boric acid had higher growth，nodule biomass，and nitrogenase activities as well as higher total nitrogen（TN） and soluble N in the soil than the control（P＜0.05）. With boric acid application over a year，as the concentration of boric acid increased，the growth，nodule biomass，nitrogenase activity of the trees along with TN and soluble N in the soil gradually improved（P＜0.05）. Compared to the control，over a year the 19.8 mg boric acid spray caused 1） maximum plant biomass（30.3%），tree height（64.6%），nodulation（62.0%），and nitrogenase activity（31.6%） and 2） increased TN（31.3%） and soluble N（9.2%）. Therefore，a proper supply of boric acid could improve nodulation and nitrogenase activity of Myrica rubra ‘Dongkui’ and promote its growth and development［Ch，3 tab. 10 ref.］