Through field investigations it was observed that after Bursaphelenchus xylophilus (Steiner and Buhren) Nickle (pine wood nematode) invaded a pine forest, subsequently formed forest types would be significantly different from each other if two managing ways such as human removal and reserving damaged trees were taken before a natural regeneration, namely different disturbance measures taken for damaged trees would affect regeneration direction of understory vegetation of an infected pine forest. Based on the above observation, the dynamics of plant diversity under different managements of damaged trees were studied by choosing two Masson pine communities that were subjected to managements of removal and reserving damaged trees, respectively, after the invasion of pine wood nematode. α diversity index function-Rényi index was used as a measurement. The results showed that the species diversity of shrub and herb layers of the pine forest in which damaged trees were removed timely was higher than that in which damaged trees were reserved.

Microalgae Tetraselmis tetrathele was used as experimental materials. Two groups of experiments (A and B) were subjected to the treatments of short and long photoperiods, respectively. Group A of short photoperiod consisted of six treatments, ie. one, two, four, six, eight and ten hours of photoperiods, while Group B of long photoperiod also consisted of six treatments, ie. 14, 16, 18, 20, 22 and 23 hours of photoperiods. 12 h photoperiod was set as the control. The results showed that cell density, content of chlorophyll-a and intracellular protein of T. tetrathele in those treatments, ie. 6 h, 8 h, 10 h, 12 h, 14 h, 16 h and 18 h, were high but significantly low in the rest of treatments.

Because of its strong resistance to environmental stresses, Alternanthera philoxeroides, an alien invasive plant, has fast become a severe weed in China. In order to explore the mechanism of its strong resistance and invasiveness, we studied the properties of its chitinase, one of the pathogenesis-related proteins in plant. The protein was extracted from the leaves treated by ethylene, precipitated with 40～60% ammonium sulfate and isolated by Sephadex G-75 chromatography. An enzymatic assay showed that the optimum pH for this enzyme was about 5.7 and it was stable in the range of 4.0 to 8.0 pH. It would loss more than 50% of its activity when pH was lower than 4.0 or higher than 8.0 and almost had no activity when pH was 2.0 or 10.0. It had high endurance to wide range of temperatures and its activity was high from 30℃ to 80℃. Its optimum temperature was about 70℃ and it began to loss its activity when temperature was higher than 80℃. It was also found that the reaction velocity of this enzyme increased with the increase of its substrate concentration when the concentration was lower than 1.25%. All of these suggested that high endurance of this enzyme to temperature and acidity or alkalinity might have contributed to Alternanthera philoxeroid's strong resistance to environmental stresses.

In May and Nov 2005, the water quality and phytoplankton in a eutrophic reservoir, Henggang Reservoir, were investigated to analyze the species composition and abundance distribution of phytoplankton. In May, the average abundance of phytoplankton was 275.41×10⁶cells·L^-1, and the average biomass of phytoplankton was 31.07mg·L^-1. Merismopedia elgans and Merismopedia glauca were the only two dominant species, contributed over 90% of total phytoplankton abundance. In November, the composition of phytoplankton community had a significant change. The average abundance of phytoplankton decreased to 12.69 ×10⁶cells·L^-1, and the average biomass was 20.78 mg·L^-1. In the observed 16 species of Cyanophyta, the abundance of Merismopedia elgans and Merismopedia glauca decreased largely. Desmidiaceae, Pediastrum, Scenedesmus had high abundance, and the species numbers of Chlorophyta increased to 48. The biomass of large sized phytoplankton increased largely, especially the species which equivalent radiuses were over 20μm. In the November, the phytoplankton and nutrients were diluted with the increase in stored water. The seasonal change in precipitation caused by monsoon was the main physical factor affecting phytoplankton community in Henggang reservoir.

112 species of wetland vascular plants in Guangzhou area were recorded in an investigation, which belong to 42 families and 93 genera. Most of them are angiosperms including many species of Gramineae, Composita, Polygonum and Cyperus. Alternanthera philoxeroides (Mart.) Griseb., Solanum americanum Miller and Commelina communis Linn. are the species with higher appearance frequency. These three species were recorded in more than 70% of the investigating places. Of the 112 species recorded 15 species are hydrophytes, accounting for 13.39% of the total species, and most of them are monocot plants; 27 species are hygrophytes, accounting for 24.11%, and 70 hygrophilous species, accounting for 62.50%. Some of the species have already been widely used in wetland landscape gardens and artificial wetlands, and others have potential for future use.

Cell growth rate, chlorophyll a content, carotenoid content, dry weight, and astaxanthin content were measured to study the effects of nitrogen and phosphorus nutrients on the growth of green vegetative cells of Haemalococcus pluvialis CG-11 that was cultivated in BBM medium. The experiments were carried out separately as three single factor tests. It was found that both NaNO₃ and NH₄NO₃ were suitable nitrogen sources for the cell growth. Suitable N concentration for the algae growth was 41.2 mg·L^-1. Suitable P concentration for the algae growth was 5.33~53.3mg·L^-1.

Accurate measurement of leaf area is a foundation for evaluating energy flux, carbon flux, and water using of ecosystem. Current methods for measuring leaf area have various limitations and scope of use. Some of them are easy-to-use and accurate, but can only be used for small batches. It is very difficult for most methods to measure leaf areas in large batches in a relatively short period of time. In this study, we took Spartina alterniflora as an example to discuss a method based on scanner and dry-leaves weight, combined with Photoshop image processing technology, which can measure leaf areas instantly in large batches. Tested by a known power function relation between leaf length (y) and leaf pixel (x), ie. y=419.85x^1.9693 (R≈1.00), our new method only yielded 3.651% (n=30) relative error. There were no significant difference between this method and a classic square method (P=0.473). It is concluded that this method can be used to measure leaf area in large batches in a relatively short period of time, and to measure various shapes of leaves with little change in the vein.

Growth of Botryococcus braunii 764 and Botryococcus braunii 765 that were cultured in three media (Chu10, Chu13×2 and SE) was studied and compared. Cell density (OD₆₈₀), biomass(dry weight), total lipids, and total hydrocarbons were measured. The following results were reported:(1) total lipids and total hydrocarbons of B. braunii 764 were 19.4% and 23.4% respectively, which were significantly higher than those of B. braunii 765; (2) cell density, biomass, total lipids and total hydrocarbons of B. braunii 764 that was cultured in medium Chu10 were higher than those cultured in media Chu13×2 and SE, whereas only cell density, biomass and total lipids of B. braunii 765 cultured in medium Chu10 were higher than those cultured in Chu13×2 and SE, total hydrocarbons in Chu13×2 was higher than those in Chu10 and SE.

Regeneration polarity of Chondria crassicaulis was studied in solid medium. We used three different liquid medium and three different temperatures to explore the effects of some external factors to the cultivation of chopped tissues of Chondria crassicaulis. We found that under artificial culture environment there was no obvious polarity in the regeneration of fragments. When cultured in PES, modified ASP1, modified ES culture media and under 10℃, 15℃, 22℃, it was found that the formations of buds were abundant and best in the segments under 15℃ in modified ES liquid media. We also found that there were two kinds of sporangia, cruciform and four conical, in the cultivation, and tetraspore of Chondria crassicaulis could develop into four kinds of seedlings.

Ecological Footprint (EF) theory has an important guiding significance for urban ecosystem research and ecological construction of a city. In this paper, we report an assessment on dynamic change of EF in Guangzhou based on data from 2001 to 2005. Our results show that EF demand per capita was 3.95527 hm²·person^-1 in 2005, which was much greater than supply. During 2001～2005 EF percapita tended to increase and the demand for fossil fuel EF was ranked as top one that took up 72.67% of the EF demand in 2005, while EF per ten thousand Yuan GDP tended to decrease. By the means of STELLA it is forecasted that the tendency of EF demand per capita in Guangzhou till 2025 would be going up. It is concluded that the demand for fossil fuel EF is a key contributing factor for increased demand of EF in Guangzhou.

Estimation of potential productivity of agricultural land for a region could gain information on climatic productivity, harmony degree of agricultural resources and regional differences. This paper reports that a universal model for evaluation of land potential productivity was chosen and revised as an evaluation model for agricultural land resources of Northeast China. With this model and GIS technology, climate potential productivity of main crops, such as maize and soybean, in Northeast China was calculated. In addition, spatial differences of use ratio of agricultural natural resources in Northeast China were also analyzed. The results showed that there was no significant difference between photosynthetic potential productivities of different areas. However, the differences between photosynthetic and thermal potential productivities in different locations were very significant. Photosynthetic and thermal potential productivities were increasing from northern to southern part because of the large latitude span of the study area. Zonal distribution of rainfall in growing season of different locations led to comparatively big discrepancies between climatic potential productivities. Climatic potential productivity was increasing from western to eastern gradually. There were big differences among use ratios of agricultural natural resources in the whole Northeast plain. The resource use ratios of western part of Northeast China were lower than that of eastern part, which means that there may be a big potential to increase crop yields in western part.

Distribution, accumulation and transfer dynamics of TCCA in water, sediments, and biota in a simulated micro-cosmos system were studied by HPLC. The results showed that once TCCA was released into water body, some were hydrolyzed in aqueous solutions; some were assimilated by aquatic organisms or precipitated into sediments. There were differences in distribution, accumulation and transfer dynamics of TCCA among different aquatic organisms. Echinodorus amazonicus adsorbed TCCA mainly by its leaf instead of its roots and reached to an equilibrium quickly; Allogynogenetic crucian carp and Corbicula fluminea had obvious ability to accumulate TCCA, which could retain in these organisms for a long time. Significant differences of TCCA bioaccumulation existed between visceral and muscle, and higher concentration of TCCA was found in visceral tissues. It was found that bioaccumulations of TCCA varied with species, and the order was Echinodorus amazonicus>Corbicula fluminea>Allogynogenetic crucian carp.

Elements Boron and Cadmium play important roles in the yield and quality of canola crop. Boron is an essential trace element for plant growth, and in order to benefit canola growth, we need to apply Boron to it. While Cadmium is one of the nonessential elements for plant growth, it tends to accumulate in canola plant and may effect people's health through food chains. From the point view of Cadmium concentration and food safety of canola, this paper illustrated a mechanism of canola enduring and accumulating cadmium. A brief literature review on effects of boron on seed yield and quality of canola was also made. Based on the field conditions of our research region Guangxi, where effective Boron is low and total Cadmium is high in soil, and boron-cadmium interaction theory, we propose to apply adequate Boron fertilizer in field to help improve yield and quality of canola, and minimize potential hazard of Cadmium.

Soil health is a foundation of agricultural product safety and human health, and a new concept endowed with the epoch of 21st century characteristics. Development of health pedology has predicted a new era of soil science. In this paper connotation of soil health was elucidated as a new concept. The close relationship among soil health, human diseases and agricultural product safety was expounded. From the aspect of ecological indicators of soil animals, microorganisms, plants and soil enzymes, it is proposed that soil health indexes should have features with a high degree of ecological sensitivity, a wide range of usage, applicable analysis and measurable method. Current research status and future development of ecological indication of soil health both in China and abroad were summarized. It is also proposed that in addition to further in-depth research into some problems related with soil health, soil health research should also be conducted from the aspect of hydraulics characteristics and aquatic ecological processes in order to make evaluation system of soil health more valuable.

To describe the trends and regularity of a discipline from a point of bibliometric view is a necessary supplement for the development of a new discipline. We selected 37 sub-disciplines of ecology as Keyword and searched for relevant literatures of past 15 years in 《VIP. Chinese Scientific and technological Journal Database》. It was found that the number of ecological literatures showed an exponential increase and the majority of literature increase was concentrated in six sub-disciplines. However, the proportion of literature in eco-economy and agriculture ecology was declining yearly. The number of literature in five sub-disciplines was small but increased rapidly in recent years. The number of authors in the literature showed a power function. A high-yield author could be defined by the publication of 10 papers. Main organizations that were affiliated with ecological publications were agricultural and forestry universities, universities, and institutes of Chinese Academy of Sciences. The distribution of ecological literatures in periodicals followed the Bradford Regularities.