Abstract:GAI gene was transferred to calli from anther culture ofHevea brasiliensis by particle bombardment to develop dwarf rubber trees. Plant material was bombarded with plasmid PBI121 containing kanamycin resistant, GUS and GAI genes. Kanamycm concentration at 50 mg L^-1 was used as selection pressure alter concentration gradient experiments. The experiments showed that each plate of Hevea calli, which was bombarded once by gold particles coated with the plasmid and the distance between particles and target cells at 9 cm, had good results, the embryoid induction rate reaching to 1.87%. It was confirmed that GAI gene had been inserted into Hevea genome as detected by histochemical staining using X-gluc and PCR analysis.

Abstract:Phytoplankton, water quality and hydrology in Feilaixia reservoir, Guangdong, were investigated to understand temporal pattern ofphytoplankton community. The reservoir, located in the southern tropic region, is a typical riverine reservoir with a short residence time, averaging 15 days a year. Total cell abundance of phytoplankton was measured to be less than 10⁶ cells L^-1, and the concentration of chlorophyll a varied between 1 and 5 μg L^-1. In total, 140 taxa were observed in all samplings in various seasons, in April 83 taxa, in July 92, in September 96 and in December 51. The variation in species composition of phytoplankton was mainly contributed by green algae and diatoms. In the dry season, diatoms were the important groups, which were mainly composed of Melosira variant, Cyclotella menighiniana and Syaedra spp.. Cryptophyta were the most important groups,dominated by Cryptomonas erosa and Chroomonas acuta, which appeared in relatively long residence time of water in reservoir （67 days） in December. Green algae, cyanophyta and diatoms were rich in flood season with high water temperature and high nutrient concentration. However, there was no significant differences in seasonal composition of green algae, in which no obvious dominant species were observed. Such green algae were Dictyosphaerium pulchellum. Actinastrum hantzschii and Scenedesmus bijuga. The cyanophyta were dominated by Gloeocapsa sp.. Merismopedia elegans and Pseudoanabaena sp..

Abstract:The habitats and biological characteristics of Dysosma versipellis （Hance） M. Cheng （Berberidaceae）, an endangered medicinal plant endemic to China, was investigated. Two or three sampling plots with 5 m × 5 m each were surveyed for each of the five populations. The sampling sites were distributed in five provinces, i.e. Sichuan, Hunan, Hubei, Jiangxi and Anhui. D. versipellis grows mainly under evergreen and deciduous broadleaved mixed forest or in bamboo forest. Most trees in upper layer were dominant local species. The soil was yellow brown earth, pH 5.40-6.59, with rich organic matter （19.36%）, and high available N, P, K and total N, P, K contents （840, 46, 310 mg kg^-1 and 9 970, 1 217, 2 603 mg kg^-1, respectively）. Propagation disturbance and human overexploitation cause the plant to be endangered. Ex-situ in combination with in-situ protection is thought to be a conservation strategy for this plant.

Abstract:To understand the characteristics of the community with dominant species of a invading injurious weed, Eupatorium odoratum, which is widely distributed in Guangxi Province, the floristic composition, geographic elements, life forms, species diversity in the community as well as community structure were investigated. There are 62 species of 58 genera in 38 families in seven plots with total area of 175 m^2. Most of the genera are of pantropical and Asian tropical comprising 15 and 8 genera, respectively. According to Raunkiaer＇s life-form classification, micro- and nanophanerophytes （48.39%）, therophytes （17.74%） and hemicryptophytes （12.90%） are the dominants. Leaf characters in the community are mostly herbaceous, microphyllous, and of simple leaves or with entire margin. The community structure is simple, having only shrub and herb layers. Both probability of interspecific encounter index and Shannon-Wiener index of diversity in shrub layer are relatively high, suggesting that this community is relatively stable, and E. odoratum is at the stage of population establishment.

Abstract:The seeds of Impatiens balsamina L. （Balsaminaceae） were carried by spacecraft Shenzhou 4 on December 30, 2004 which flew for 6 days and 19 hours. The changes in cotyledons were observed in the third generation of the plants. The experiments showed that there were differences in number, size and shape of cotyledons. Four types of cotyledons were found： dicotyledons, tricotyledons, syncotyledons and funnel-shaped cotyledons. The growth period, flowering and fertility were also observed. Whether the variations in cotyledons are caused by physiological or genetic factors must await more research.

Abstract:To investigate the potential allelopathic effect of Alexandrium tamarense on the growth of Prorocentrum donghaiense, experiments were designed to co-culture both algae or to culture P. donghaiense with cell-free filtrate from A. tamarense under N- and P-limited and nutrient-sufficient （normal） conditions. The results showed that the growth of P. donghaiense was inhibited when semi-continuously cultured in cell-free filtrate of A. tamarense. Under N-limited condition, cell density of P. donghaiense was significantly lower than the control （without addition of filtrate） after 5 days of culture, the cell density being 1.02×10⁷ cells L^-1, buf that of control was 1.7× 10⁷ cells L^-1. Under the P-limited condition, there was no obvious difference in cell density between treated alga and the control, the cell density of treated alga being 1.44× 10^7 cells L^-1. Under nutrient-sufficient condition, there was no difference in cell density between P. donghaiense and the control. In co-culture, the inhibitory effect ofA. tamarense on P. donghaiense was more obvious. Under N- and P-limitied conditions, P. donghaiense was entirely killed by A. tamarense after 4 days, the former gathered into groups and sank. However, a few P. donghaiense survived （cell density at 3.3 × 10⁴ cells L^-1） under nutrient-sufficient conditions. The results suggested that A. tamarense have allelopathic effect on P. donghaiense, and the production ofallelochemicals would be stimulated under N- and P-limited conditions. Thus, the inhibitory effect of A. tamarense might be one of the causes that suppresses the growth of P. donghaiense.

Abstract:The effect of 10 mg L^-1 Zn²⁺ together with various concentrations of glutathione （GSH） on the changes in activity of protective enzymes （ SOD, CAT, POD）, generation rate of O₂·-, and the contents of GSH, soluble protein, chlorophyll and H₂O₂ in leaves of Hydrocharis dubia were determined. The results showed that the addition of endogenous GSH in treatments obviously increased the content of GSH in leaves by 10.71% to 35.71%, generation rate of O₂·- was lowered to 78.2% and H₂O₂ was scavenged to 62.7% as compared to the treatment with 10 mg L^-1 Zn²⁺ alone without GSH. The content of soluble protein increased at most by 74.2%, and the activities of CAT, SOD, POD increased at most by 108.2%, 61.4%, 19.5%, respectively. It is obvious that GSH relieve the toxic of Zn²⁺ to some extent. The most effective concentrations of GSH against Zn²⁺ stress are 20-40 mg L^-1 in culture solution.

Abstract:Changes of alcohol-insoluble solids （AIS）, water-soluble pectic substances （WSP）, acid- and alkalisoluble pectic substances （HP, OHP） were determined during banana （Musa acuminata cv. Brazil） fruit softening. Results showed that the contents of AIS decreased continuously with the fruit ripening, and declined rapidly at climacteric stage. The contents of water-soluble pectic substances （WSP） were found increased, while those of acid- and alkali-soluble pectic substances （HP, OHP） decreased. Such changes were little at the beginning of fruit storage, but became more obvious when firmness declined rapidly. It was shown that changes of cell wall substances played an important role in banana fruit softening.

Abstract:Leaves and petioles of seven varieties of Gerbera jamesonii Bolus （Compositae） cultured on MS medium supplemented with 0.5, 1.5 and 2.0 mg L^-1 2,4-D could produce and proliferate calli in all the varieties. The callus induction by leaf explants is better than by petioles, although there are differences among varieties. No callus could be induced from leaf or petiole explants of varieties F30 and Ⅱ cultured on MS medium if supplemented alone with 6-bezyladenine （6-BA） or thidiazuron （TDZ）, or kinetin （KT）. However, the calli were induced on MS medium containing 2.0 mg L^-1 6-BA and 0.5 mg L^-1 NAA （α-naphthaleneacetic acid）, and the calli derived from petioles of variety Ⅱ could produce redifferentiated shoots, but of variety F30 could not. The later could only produce shoots directly from the base of the petioles. It is obvious that callus induction and proliferation of gerbera need growth regulators, and are influenced by varieties and explants of different parts of the plants.

Abstract:The experiments of the effects of Ganoderma lucidum （Leyss. ex Fr.） Karst. extract （GLE） on bacterial inhibition in tissue culture of common banana was carried out by adding various concentrations of GLE into MS medium containing 2 mg L^-1 BA and 0. 1mg L^-1 NAA. Explants from absorptive buds of common banana （Musa sapientum L.） were used to observe the inhibition of bacteria （Escherichia coli I, Saccharomyces cerevisiae, Staphylococcus aureus, Streptomyces griseus and Agrobacterium tumefacierts）, the shooting and the growth of plantlets. It was indicated that best bacterial inhibition concentrations of GLE in primary culture and subcultures were 5 or 10 g Ganoderma pieces boiled in 1 000 ml distilled water for two hours. However, GLE showed certain inhibitory effect on shooting, but there was no influence on rooting.

Abstract:Eight phenolic compounds were isolated from the aerial parts of Merremia boisiana （Convolvulaceae）. On the basis of the spectral data, they were identified as scopoletin （1）, esculetin （2）, paprazine （3）, 3,5-di-O- caffeoylquinic acid methyl ester （4）, 3,4-di-O-caffeoylquinic acid methyl ester （5）, 3,4,5-tri-O-caffeoylquinic acid methyl ester （6）, quercetin （7）, and kaempferol 3-β-D-galactopyranoside （8）. They were all obtained from Merremia plants for the first time.

Abstract:Heliconia plants including 38 taxa were introduced to South China Botanical Garden in the early 1980s from Australia and in 1997 to 1999 from Thailand, Australia, Singapore, the United States, etc. This paper presents the growth, phenological phase and cold resistance of heliconias introduced. Results of the cultivation showed that Heliconia bourgaeana Petersen had longest growth period lasting 13 to 15 months from budding to blooming, while H. densiflora Vedot cv. Fire Flash lasted only 3 to 4 months. The longest flowering period （with more than 6 months） was observed in individual H. angusta Vellozo cv. Holiday. Most heliconias had flowering time of 1 to 3 months only. Many heliconias could be used as good materials for cut flowers, such as H. latispatha Bentham cv. Orange Gyro, H. rostrata Ruiz ＆ Pavon, H. bourgaeana Petersen, H. hirsuta L. f. cv. Darrell, H. aurantiaca Ghiesbreght ex Lemaire, H. librata Griggs, etc. A list of introduced heliconias taxa with phenological phases and cold resistance under Guangzhou conditions is tabulated.

Abstract:Four species are reported as new records for Hainan Island, China. They are A ristolochia fangchi Y. C. Wu ex L. D. Chow et S. M. Hwang, Begonia cathayana Hemsl., Lysimachia capillipes Hemsl., Galeola lindleyana （Hook. f. et Thorns.） Rchb. f.. All the voucher specimens cited in this paper are preserved m Herbarium of South China Botanical Garden, the Chinese Academy of Sciences （IBSC）.

Abstract:Bulb scale segments of Lilium longiflorum were used as original explants and shoot sections excised from shoot clusters arosed from the first explants as the secondary explants. The effects of different concentrations of BA （benzyladenine） and different parts of plant segments on shoot formation were studied. After roots formed, plantlets were treated at 4℃ for 0, 7 and 30 days. The results indicated that MS medium supplemented with 1.0 mg L^-1 BA and 0.1 mg L^-1 NAA was optimum for shoot formation and proliferation by using short basal stem segment as the second explant. Moreover, cold treatment had little effect on flowering stage. About 54 000 new plantlets could be obtained from one bulb. It took only 8 months from bulb scale to flowering.

Abstract:DNA of Lilium brownii was extracted from the fresh leaves, silica gel dried leaves and scales. The optimized reaction system and programme of RAPD for Lilium brownii are as follows. The reactions were performed in a volume of 20 μl containing 20 ng of DNA, 2.0 mmol/L Mg²⁺, 0.2 mmol/L dNTPs, 1.5 U Taq DNA polymerase, 0.3 μmol/L primer （S1519）. Thermal cycling was programmed by 1 cycle for 5 min at 94℃, followed by 35 cycles for 30 sec at 94℃, 50 sec at 38℃, and 1 min at 72℃ and finally, by 1 cycle for 10 min at 72℃, storing at 4℃.

Abstract:Cytokinins are important plant hormones and can delay plant senescence, In this review three approaches in study of the effects of cytokinins on plant senecence are presented： the analysis of endogenous cytokinins during senescence； the application of exogenous cytokinins； and the research on transgenic plants with cytokinin biosynthesis or biodegradation genes. The mechanisms of cytokinins in retarding of senescence was discussed in relation to saccharides, lipid oxidation, as well as to other hormones.

Abstract:Plant plasma membrane H⁺-ATPase plays important roles in regulation of pH in cells, in enhancement of nutrient uptake and in transportation of assimilates. This paper reviews plant plasma membrane H⁺-ATPase under the following headings： structure, function and molecular machenism, signal transduction events; response of plant plasma membrane H⁺-ATPase to environmental stresss. Future prospects are presented as well.