7, 1.92×10⁶ and 3.35×10⁴ cfu·g^-1 relatively. Microorganism in the soil of reed plant community had obvious rhizosphere effect to some extent. The microorganism and soil organic carbon, total nitrogen, total phosphorus, total potassium, available nitrogen, available phosphorus and available potassium had a significant positive correlation. The rhizosphere effect of microorganism associated with microbial type, soil depth, monthly average rainfall and temperature channges, and it was non-significantly in winter as a whole. It had significant seasonal variations as well. The content of soil nutrition may be a major factor for the change of soil microbial quantity in Huixian Karst Wetland. Meanwhile, the dynamic changes of the number of soil microorganism may reveal the environmental effects of wetlands. The scientific data for the wetland sustainable management policy would be suggested for Huixian Karst Wetland.]]> 2017/7/2 22:58:41 *, SUN Ying-Jie, ZHANG De-Nan, YAO Yue-Feng, ZENG Dan-Juan]]> ZHOU Long-Wu, HUANG Yu-Qing, WANG Xin-Gui, XU Guang-Ping^*, SUN Ying-Jie, ZHANG De-Nan, YAO Yue-Feng, ZENG Dan-Juan 5true Excentrodendron hsienmu is the endemic species in tropical limestone area, and the second national key protected plant of China, and it widely distributes in the karst mountains of Southwest Guangxi, China. Exploring factors effecting the domiant arbor trees distribution has significant implication for effectively protecting the E. hsienmu population in the study area. Important value of the main arbor species and eight environmental factors were measured based on field surveys in the karst mountains of Southwest Guangxi. And then, correlation analysis was used to detect the relationships between topographic and soil factors. Canonical correspondence analysis(CCA)was used to explore the effects of environmental factors on the distribution of dominant arbor species. A total of 176 woody plant species with diameter at breast height ≥1.0 cm, and tree height ≥1.5 m were recorded, belonging to 50 families, 128 genera. E. hsienmu was absolutely dominant in tree layer, while Orophea anceps, Garcinia paucinervis, Walsura robusta, and Sterculia nobilis were the main accompanying species. Correlation analysis showed elevation was very significantly positively related to soil organic matter and total nitrogen. Except for soil pH, relationships between all soil factorswere markedly positive. Result of CCA revealed that soil total potassium had the most significantly effect and the soil total phosphorus had the second on the distribution patterns of dominant arbor species, while slope aspect and degree also played important roles in the spatial patterns of them. This study revealed the main factors influencing on the spatial patterns of dominant arbor trees of E. hsienmu community, and provides scientific information for the vegetation restoration in the study area.]]> 2017/7/2 22:58:41 1, OU Zhi-Yang^1*, PANG Shi-Long¹, HE Qin-Fei¹, LIANG Yan²]]> SHEN Wen-Hui¹, OU Zhi-Yang^1*, PANG Shi-Long¹, HE Qin-Fei¹, LIANG Yan² 4true Alternanthera philoxeroides around in our country since the widely spread, has an important impact on the production and life of the people. Plasticity is an important feature of invasive plants, we studied indexs of plasticity A. philoxeroides providing scientific basis for the prevention and cure in different habitats. The results were as follows:(1)There were obvious differences in internode length, leaf area per plant, total weight and leaf dry weight of A. philoxeroides in rock environment, road and aquatic habitats.(2)Asexual reproduction organs of stem biomass was the largest in rock environment, followed by the road and the river habitat.(3)Internode and leaf area of A. philoxeroides increased with the rock, road and aquatic environment.(4)In the lack of water rocks environment, A. philoxeroides increased reproduction by short internode and increase the mass.]]> 2017/7/2 22:58:41 ZHANG Bao-Cheng, PENG Yan, ZANG Ling-Fei, QIN Kai-Nan, LI Xian-Bi, SUI Chang-Ling 3true Swida wilsoniana and Choerospondias axillaris. To exclude the influences from other confounding factors, each pot was filled with sand instead of soil. The seedlings were treated with five Ca levels, i.e., 5, 35, 70, 150, 300 mmol·L^-1. The growth and enzyme activities of the two plant species were measured. The results showed that the both species were the highest at 5 mmol·L^-1, and tended to decrease with the increase in Ca concentration. The biomass of roots, branches, leaf and total biomass of both species demonstrated a downward trend as Ca concentration increase, but those of C. axillaris showed a tendency to increase for the 300 mmol·L^-1 treatment. The biomass allocation ratio was in the order of root > branch > leaf for Swida wilsoniana, and root > branch > leaf for S. wilsoniana at 35 mmol·L^-1. The biomass allocation at other Ca levels showed a variation pattern of branch > root > leaf for both species. MDA content was the greatest at 150 mmol·L^-1 for both species. MDA content of Choeropondias axillaris was lower than that of Swida wilsoniana. The soluble sugar content and CAT activity of S. wilsoniana under calcium stress were higher than those of Choerospondis axillaris. The physiological indices reached optimum levels at the Ca concentrations of 5 and 150 mmol·L^-1 for both species, while were inhibited at the concentration 300 mmol·L^-1, which led to a decline of photosynthetic capacity. Our results also revealed that S. wilsoniana had better adaptability to high Ca concentrations relative to C. axillaris.]]> 2017/7/2 22:58:41 1,2,5, SONG Min^1,2,3, PENG Wan-Xia^1,2*, ZENG Fu-Ping^1,2, DU Hu^1,2, HU Fang^1,2,5, CHEN Li^1,2,4, SU Liang^1,2,4]]> ZHANG Fang^1,2,5, SONG Min^1,2,3, PENG Wan-Xia^1,2*, ZENG Fu-Ping^1,2, DU Hu^1,2, HU Fang^1,2,5, CHEN Li^1,2,4, SU Liang^1,2,4 2true Illicicum difengpi K. I. B. et K. I. M plants, which was a karst endemic medicinal plant. We investigated the photosynthetic variables, chlorophyll fluorescence variables and photosynthetic pigment content of I. difengpi under water stress and rewatering conditions. The results showed that withholding water for 10 d, the net photosynthetic rate(P_n), intercellular CO₂ concentration(C_i), stomatal limitation value(L_s)and stomatal conductance(G_s)of I. difengpi leaves decreased significantly under water stress, and stomatal limitation was the main reason for the decrease of P_n. Withholding water for 15 d, under water stress, the diurnal variation of P_n showed a gradual downward trend and the P_n values were close to zero after 9:30 am, which suggested that the depression of photosynthesis might be due to non-stomatal limitation. While the diurnal variation of P_n was dual-peaked in the leaves of control, and stomatal limitation was still the main reason for the decrease of P_n. The decrease of chlorophyll content and the increased of Chl _{(a/b )}under water stress conditions, which reduced the binding proteins(LHC Ⅱ)content, the captured light energy, and the risk of photosynthetic apparatus damage. Under water stress condition, the initial fluorescence(F_o)increased significantly, the maximum fluorescence(F_m), potential activity of photo-system Ⅱ(F_v/F_o)and maximal photochemical efficiency of photo-system Ⅱ(F_v/F_m)decreased significantly, which indicating that water stress could cause a certain degree of damage or fracture to its PS Ⅱ reaction center, therefore, the potential activity and maximal photochemical efficiency of PS Ⅱ were reduced. After re-watering for 5 d, the above-mentioned physiological and ecological parameters of I. difengpi could recover to the control level, indicated that the physiological repair capability of which is very strong after rehydration.]]> 2017/7/2 22:58:41 1, TANG Hui^1*, HAN Yu^1,2, ZHANG Jun-Jie^1,3, LIANG Hui-Ling¹]]> WANG Man-Lian¹, TANG Hui^1*, HAN Yu^1,2, ZHANG Jun-Jie^1,3, LIANG Hui-Ling¹ 1true