Abstract:Uptake，metabolism and toxicity of iron cyanide complex in trees were investigated． Pre-rooted weeping willows(Solix babylonica L．)were exposed to hydroponic solution spiked with ferrocyanide at 24.0±1℃ for 192 h．Four different treatment concentrations offerrocyanide were used(52.99，105.98，211.95 and 317.93 mg CN L^-1)．Cyanide in water， in tissues of aerial part of plants and in air was analyzed spectrophotometrically． Results from this study indicated less than 10.85％ reduction of the applied iron cyanide complex was detected in hydroponic solution in the presence of plants．Little amounts of cyanide were found in all parts of plant tissues， indicating the passage of ferrocyanide through the plants．Mass balance studies showed that iron cyanide complex moving into plants from hydroponic solution can be metabolized during transport． Phytotoxic efects were not found in all treatment groups，even at high doses of ferrocyanide within a 192-h exposure period．in conclusion，transport and metabolism of ferrocyanide in plants is most likely to happen and phytoremediation of this iron cyanide complex in field application may be possible．

Abstract:The dynamic responses of photosynthesis of Chaetoceros sp. to continuous high irradiance (1 000 μmol m^-2s^-1) for 12 h were demonstrated by measuring chlorophyll fluorescence. Both maximal photosynthetic rate (Pm, i.e. maximal relative electron transport rate) and maximal quantum yield ofphotosystem Ⅱ (Fv/Fm) decreased during 30 min of high light exposure, which showed obvious photoinhibition. Meanwhile, the initial slope α decreased while non-photochemical quenching (NPQ) increased, which means Chaetoceros sp. can reduce light absorption and dissipate more heat in order to protect their photosynthetic apparatus from damage. Chaetoceros sp. acclimated high light gradually and their photosynthetic activity recovered slowly during 1 000 μmol m^-2s^-1 exposure from 30 min to 8 h. α increased（although cannot reach the value before high light exposure）, Pm recovered to initial value at 4 h and even reached 2 times of the initial value at 8 h. Fv/Fm could only recover to half of the initial value during the acclimation. NPQ reached the maximum at 1 h, and then decreased. This result indicates that heat dissipation does not play major role in photoprotection after 1 h high light exposure. After exposure to high irradiance, there appeared transient post-illumination increase in chlorophyll fluorescence. The increase in chlorophyll fluorescence enhanced with increased duration of high irradiance, which reflects enhancement of cyclic electron transport around photosystem Ⅰ. Thus, after NPQ decreased, cyclic electron transport around photosystem Ⅰ may play important role in photoprotection.

Abstract:Algicides, bromogeramine（B）and isothiazolone（I），were used for removing Phaeoecystis globosa in the experiments in containers of 450 ml seawater with 109 cells L^-1 of algae collected in April 2005 from Zhanjiang Seaport, Guangdong Province, where red tide had happened in January 2004. The results showed that LC50 of isothiazolone was 0.54 mg L^-1 for the algae treated for 72 hours, which was more effective than that of bromogeramine （LC₅₀=0.96 mg L^-1）.　Alga-removal effects of both algicides used in combination showed synergistic action. The proportion ofbromogeramine to isothiazolone being 4.3 to 1 gave best result. Toxicity tests on little fishes （Mugil cephdus） showed that 2.0 mg L^-1 bromogeramine or 0.3 mg L^-1 isothiazolone were safe for fishes in the removal of algae in 72 hours.

Abstract:The determination of full-length 16S rDNA sequence and nifA gene segments of root nodule bacterium strain HJ06 isolated from Acacia crassicarpa showed that strain HJ06 had above 95% similarity with the genus Rhizobium. The nifA gene segments of HJ06 have 99.3% isogenesis with nifA genes of Klebsiella pneumoniae and 97.8% isogenesis with genes ofNifF, NifL, NifA and NifB proteins of K. oxytoca.

Abstract:SDS, CTAB and modified CTAB methods were used to extract DNA from the leaves of Cymbidium hybridium cv. Hiroshima Golden Cup “Sunny Moon” and cv. Fortissimo “Pianist”. The results showed that modified CTAB method was best for DNA quality and production. The optimal reaction of RAPD in C. hybridium was studied with primer 5'-GGTGCTCCGT-3' for cv. Hiroshima Golden Cup “Sunny Moon”. The optimum concentration of five important components such as Mg²⁺, Taq DNA polymerase, primer, template DNA, and dNTP in 25 μl RAPD reaction system were 2.0 mmol/L, 1.0 U, 0.20 μmol/L, 25 ng, and 0.20 mmol/L, respectively. Modified thermal profile consisted of an initial denaturation step at 94℃ for 4 min, followed by 40 cycles of 94℃ for 30 s, 37℃ for 1 min and 72℃ for 1 min and a final exposure to 72℃ for 7 min.

Abstract:The combining ability and heritability were estimated in progenies of 12 cross combinations of sugarcane （Saccharum officinarum L.） hybridized by using a incomplete diallel cross design for four female and three male parents. Six parameters were used for the analyses of quality characters in sugarcane juice, i.e. brix （percentage of total soluble solids）, polarilneter reading （PR）, pol in juice （Pol）, sucrose content （SC）, apparent purity （AP）, and gravity purity （GP）. The results showed that the heredity of quality characters was induced mainly by additive gene effects. The changes in brix, PR, Pol and SC were affected by male parents. Parents with high sugar-yielding and good combining ability appeared in CP72-330, HoCP93-750, GT91-116 and YT92-1287 which presented high and positive general combining ability （gca）. Whereas for progenies of crosses, CP72-330×GT91-1 10 and HoCP93-750×YT92-1287 showed high and positive special combining ability （sea）. The gca variances in male parcnts were greater than those in female ones. The gca variances in parcnts were grcater and sea variances in crosses by 7 to 28 times. The heritability in broad sense （h_B²） in quality characters were from 58% to 68%, and that in narrow sense （h_N²） 56%-60%. These results indicated that the data of quality characters had better heritability.

Abstract:Based on field survey and specimen examination, Ptcridophytes in Fenghuangshan in Chaozhou, Guangdong Province werc studied floristically. The flora comprises 96 species of 58 genera in 31 families, of which tropical and subtropical elements consist of 52 specics, 36 genera and 13 families. Temperate elements amount to 36 species and 8 genera. Most of the ferns arc geophilic, follow by lithophytes （25%） and epiphytes （9.38%）, Conservation and utilization of fern rcsource are discussed.

Abstract:Endemic plants occurring in limestone of Hainan Province consist of 63 species in 52 genera and 37 families, of which 18 species are restricted to Hainan only. About 84% of the species are of tropical elements. Changjiang County of western Hainan is considered to be the centre of the distribution of endemic plants on the island. However, endemism in the limestone flora of Hainan is not obvious as compared to that of neighboring Provinces. A list of endemic species distributed in limestone region on Hainan is tabulated.

Abstract:Axillary buds and aseptic adventitious buds of vetiver （Vetiveria zizanioides （L.） Nash） were used as explants to investigate the factors that affected somatic embryogenesis and plant generation. The explants were cultured on MS medium supplemented with 2,4-dichlorophenoxyacetic acid （2,4-D） or and 6-benzyladenine （6-BA）. The results showed the explants could regenerate via somatic embryogenesis when the medium contained only 2,4-D without or with little content of 6-BA. Callus induction frequency in different cultivars was significantly varied, eg:cv. Zomba had highest induction frequency, up to 96.7%, but cv. Malaysia the lowest, less than 30%, whereas that in cv. Kandy and cv. Sunshine was almost the same. Regeneration ability in embryonic calli could be maintained for a long time, the regeneration frequency being still over 80%, regardless of subculture times from 0 to 23.The differentiation ability of embryonic calli was inhibited at temperature of 3-7 ℃, under which only 40.5%-50.0% of them could regenerate.

Abstract:The plant’s growth, litterfall, soil bulk density, soil organic matter, pH and plant diversity were investigated in two oil shale waste dumps in Maoming, Guangdong Province. The south dump was afforested for 18 years, and the north for 3 to 5 years. The results showed that in the south dump, the standing litterfall production increased by 1.39 times, organic matter in soil at 0-20 cm depth by 52.39%, at 20-40 cm by 50%, and soil pH by 0.28 unit, as compared to the north dump. The pH in south and north dumps increased by 0.99 and 0.71 units, respectively, compared to the bare dump. The invading wild plants on the south dump amounted to 138 species in 118 genera of 48 families since oil shale waste dumping 45 years ago, and the north dump amounted to 66 species in 63 genera of 24 families since dumping 28 years ago.

Abstract:Shannon-wiener index, Levins index and comparability proportion formula were used to study niche breadth and niche overlap of dominant species in Tsuga longibracteata forest gaps at different stages. Tsuga longibrocteata, an endemic to China species of Pinaceae, is distributed at the uppermost layer of forest, which makes it difficult to regenerate naturally. The study of ecological niche in gaps of T. longibracteata forest is to understand the change in population number of some species, the regeneration of which depends on gaps, and to protect the forest resource more effectively. The sites studied were located in Tianbaoyan National Nature Reserve in Fujian Province. Twenty one gaps, with quadrats of 80 m2 each were investigated, The results revealed that niche breadth of main trees in gaps varied at different stages of gap development. At early stage, niche breadth of tree species declined in the following order： Tsuga longibracteata, Castanopsis carlesii, Schima superba, Castanopsis eyrei, Michelia maudiae, Cinnamomum subavenium, Cyclobalanopsis glauca, Rhododendron iniarum, Symplocos sumuntia, Cyclobalanopsis myrsinaefolia； at the middle stage, in the descending order of： Castanopsis carlesii, Schima superba, Tsuga longibrctcteata, Cinnamomum subavenium, Michelia maudioe, Symplocos sumuntia, Castanopsis eyrei, Rhododendron iniarum, Cyclobalanopsis glauca, Cyclobalanopsis myrsinaefolia； while at the late stage, Castanopsis carlesii, Schima superba, Tsuga longibracteata, Cyclobalanopsis glauca, Cyclobalanopsis myrsinae, Cinnamomum subavenium, Michelia maudiae, Cyclobalanopsis myrsinaefolia, Castanopsis eyrei,Rhododendron iniarum. High values of niche overlap were shown in all trees in gaps with different stages, but then the values declined with the gap development. Less niche overlap values were shown in T. longibraeteata compared to those species with higher niche breadth, but more to those with lower niche breadth.

Abstract:A new species of Syndiclis in Lauraceae, S. hongkongensis N. H. Xia, Y. F. Deng ＆ K. L. Yip, is described and illustrated. The new species is similar to S. chinensis Allen, but differs in 6 perianth-lobes, 6 （rarely 7） eglandular fertile stamens.

Abstract:A new species of Beilschmiedia of Lauraceae, B. glondulosa N. H. Xia, F. N. Wei ＆ Y. F. Deng, is described and illustrated. The new species is similar to B. delicata S. Lee ＆ Y. T. Wei and B. tsongii Merr., but differs in its short inflorescences. glandular shotted on upper surface of leaves and smooth fruits.

Abstract:The production of toxin is a feature in red tide. More than 70 species of microalgae produce toxins. As a secondary metabolite, the synthesis of algal toxin may be considered as an inhibition or rejection response to other phytoplanktons in the competition among communities and species. There is little understanding about the synthesis pathway of these toxins because the factors （algal species, sources, environment, conditions, etc.） that affect the production of toxin are complicated. In this review, the following aspects in studies on algae which from red tide are presented： ecological significance of red tide algae producing toxins, factors affecting the production of toxins by algae, possible biochemical pathway of toxin synthesis, and molecular aspects of toxin biosynthesis in study of marine algae.

Abstract:This review focuses on anaerobic respone in gene expression pattem, signal transduction in higher plants and regulation mechanism under anaerobic stress.