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Background Atractylodes lancea is a traditional Chinese medicine, which typically requires more than 3–4 years of continuous cropping to obtain the underground medicinal components. With continuous cropping years, the quality and yields of A. lancea medicinal materials decrease, while pests and diseases increase. These aspects are intimately correlated with rhizospheric microorganisms. Methods This research paper employed high-throughput sequencing for its detection in soil that was cultivated for three years and never cultivated to clarify the relationship between the microbial diversity of the rhizosphere and continuous A. lancea cropping. Results The rhizosphere microbial community was altered following the continuous cropping of A. lancea. The bacterial diversity and richness were observed to decrease, while the fungal community diversity increased, and richness decreased. The total OUTs of the soil bacteria and fungi of unplanted and planted A. lancea were 59.58% and 37.65%, respectively. At the phylum level, the relative abundance of Proteobacteria, Gemmatimonadetes, Acidobacteria and Chloroflexi decreased, whereas the relative abundance of Mortierellomycota increased. At the genus level, Bradyrhizobium, Striaticonidium, Dactylonectria, Sphingomonas, Burkholderiaceae, Rhodanobacter, Arthrobacter, Scleroderma, Mortierella and Penicillium were significantly different between the two sample groups. Conclusions Our results revealed that following the cultivation of A. lancea, the rhizospheric microbial community was altered. This study preliminarily determined the

We quantified the water use of Phyllostachys pubescens using 10 mm TDP. Water use of P. pubescens was affected by culm age rather than its size. Rhizome system has a strong transfer function. To accurately quantify the water use of bamboo forest stands, the applicability of a modified TDP (10 mm long) for measuring the sap flow of bamboo culms was verified. We also investigated the effects of culm age and rhizomes on water use. To this end, we designed two experimental systems, an induced hydraulic pressure and sap flow changing device and a whole-culm pot weighing method to validate the sap flow equation in Phyllostachys pubescens. The results showed that the modified 10 mm long TDP was a valid means of measuring the sap flow of P. pubescens. The verified probes and the corrected Granier’s empirical equation were applied to monitoring and calculating the sap flow density of P. pubescens. The results showed that stand transpiration changed significantly across the wet and dry seasons. Culm transpiration decreased with culm age whether in winter or in summer. Juvenile bamboo had the highest daily transpiration, and more than 20 % of compensative water was imported from other culms by rhizomes in summer. The water potential of the rhizome-cut culms was lower than that of normal culms. It is concluded that the rhizome system has a strong transfer function and that the water consumed by juvenile culms includes water self-absorbed directly from soil and water transferred from other culms via rhizomes.

Elevated tropospheric ozone(O3) and enhanced atmospheric nitrogen(N) deposition exert great impact on the physiology of forest trees.The respective effects of these two pollutants have been studied thoroughly during the past couple of decades.However,little information is available concerning their combined effects on the physiology of subtropical evergreen trees.In the present study,O3 effects on Cinnamomum camphora,a native evergreen tree species,widely distributed in subtropical region,were investigated under enhanced N loads.One-year-old seedlings were adopted and the experiment was carried out in open-top chambers(OTCs).O3 fumigation regimes were set at ambient air(AA),ambient air plus 60 nmol/mol(AA+60) and ambient air plus 120 nmol/mol(AA+120);N load levels were set at 0(CK),30 and 60 kg · hm-2 · a-1,designated as N0,N30 and N60,respectively.Membrane lipid peroxidation,foliar chlorophyll and ascorbic acid contents as well as the total antioxidant capacity were examined after treatments for one growing season(May 5-September 10,2009).Foliar MDA(malondialdehyde) concentration was significantly enhanced by AA+120 treatment,but changed little in AA+60.Neither N30 nor N60 affected foliar MDA concentration significantly.Chlorophyll a content significantly decreased under both AA+60 and AA+120 treatments,and was significantly lower in the latter than in the former.Both N30 and N60 significantly increased chlorophyll a content,and the increment under N60 was significantly greater than that under N30.Chlorophyll b was also significantly increased by both N30 and N60,while was only significantly decreased by AA+120 rather than by AA+60.AA+120,as well as N60,significantly decreased chlorophyll a/b,which,however,was affected by neither AA+60 nor N30.The effects of elevated O3 and enhanced N on foliar carotenoid content were similar to those on Chlorophyll a content: significant treatment effects(O3 and N) with significant differences between treatment levels(AA+60 and AA+120,or N30 and N60).Besides,AA+120 significantly increased the total antioxidant capacity,on which,however,the effect of AA+60 was not significant.Significant difference of the total antioxidant capacity was not found either between AA+60 and AA+120,or among the N treatments.There were no significant interactions detected between O3 and N on foliar MDA,chlorophyll content and the total antioxidant capacity in our study.However,the effects of elevated O3 on the reduced(ASC) and total ascorbic acid() content were significantly modified by N loads.Under N0,both AA+60 and AA+120 significantly reduced the foliar ASC content,which,however,was significantly increased by AA+120 under N30 and N60.AA+60 also tended to increase the ASC content under enhanced N,although its effect was not significant.The effects of elevated O3 on under different N loads were similar to those on ASC,although they were of no statistical significance.Enhanced N loads strengthened the tolerance of C.camphor to O3 through increasing the foliar ASC content.