Abstract:The flora and vegetation of the middle reaches of the Yangtze River (mainly Hunan and Hubei Provinces) were surveyed． On the basis of statistics of the lists of indigenous seed plants for Hubei and Hunan， there are 7 037 species of 1 476 genera in 202 famillies in this area， among which gymnosperm comprises 64 species，30 genera and 7 families,and angiosperm 6 973 species，1 445 genera and 1 96 families．Statistical analysis of the plant areal-types indicates that the flora of Central China including Hubei and Hunan Provinces，is rich inplant species with complicated types， and of ancient origin． This area possesses considerable amount of endemic species，genera and families．North temperate woody plants are hi ly concentrated in this area，which implies the characteristics of Early Tertiary and Boreal flora in middle reaches of the Yangtze River．There are numerous genera here which are endemic to East Asia and to China，and many genera with East Asian - North America disjunct distribution．The above mentioned components not only are the essence in the flora of Central China，but also of the whole China．In the mountain regions，the mixed forest dominated by Fagus lucida is virtually originated from Boreal-Tertiary mesophilous deciduous broadleaved forests. This area belongs to the evergreen broadleaved forest region， which includes two vegetation zones, i.e. north-subtropical evergreen broadleaved and deciduous broadleaved mixed forest zone，and mid-subtropical evergreen broadleaved forest zone．The latter can be further divided into mid-subtropical northern typical-evergreen broadleaved forest subzone and southern part of mid-subtropical southern evergreen broadleaved forest subzone with the floral components of South China．The natural vegetation includes 171 types(equivatent to formations)，mainly original vegetation types．Conservation strategies and suggestions are made from the aspects of the protection of species biodiversity，plant communities, and landscape

Abstract:The responses of diameter at breast height(DBH)in tree layer to nitrogen(N)additions were studied in three representative forest types in Dinghushan Biosphere Reserve：a pine(Pinus massoniana)forest，a pine— broadleaved mixed forest，and a broadleaved forest．Dissolved NH₄NO₃ was sprayed monthly with equal applications dose onto the forest floor of 10 m×20 m plots within a year to simulated elevated N deposition，Four treatments were established in the broadleaved forest：control，low N(50 kg N hm^-2a^-1 )，moderate N (100 kg N hm^-2a^-1 ) and high N(1 50 kg N hm^-2a^-1 )，and three treatments(control，low N and moderate N)，in mixed and pine forests．All the treatments were in three replicates. Annual increment rates of DBH in control plots were estimated to be 4.84％ , 4.09％ and 2.99％ for the pine, mixed and broadleaved forests， respectively. After treatment with N additions for one year， in the pine and mixed forest, the DBH increment rate in low N plots was similar to that in the control， while in moderate N plots the increment rates in pine forest and mixed forest were by 77．8％ and 105．6％， respectively， higher than those of the contro1． In contrast， in the broadleaved forest， all N addition treatments decreased the tree growth，though the treatment efect was not significant，and the increment rates in the low，moderate and high N plots were by 36．8％，28．5％ and 41.0％，respectively，lower as compared to the contro1．The efects of N addition on tree growth diferent in species. N additions stimulated the growth of Pinus massoniana both in pine forest and mixed forest， but decreased that of most broadleaved species in all the three forests.

Abstract:Net radiation and heat fluxes in a coniferous and broad—leaved mixed forest were monitored by a microclimate monitor system，an eddy covariance(EC)open-path system，and soil heat flux plates during January 9-23，2003 in Dinghushan Mountain，Southern China．The average net radiation(Rn)above the canopy was 53.14 W m^-2．The average latent heat flux(LE)and sensible heat flux(Hs)above the canopy were 57．18 W m and 43-40 W m^-2．while the LE and Hs below the forest canopy were 12.6l W m^-2 and 7.61 W m^-2．respectively．The LE and Hs flux es estimated by the EC and by the Bowen ratio energy balance method were very similar in daytime． but very diferent in the rest of the day．The diurnal changes of soil heat flux (Gt)were in an“S”shape．The average Gt was-1．50 W m^-2，which suggested that soil was one ofthe heat sources．The total Gt was only 84.0％ of the soil heat flux at 5 cm depth, which indicated that the heat stored by the soil should not be ignored in spite of the thin soil layers．A significant correlation (r=0．8517) between the amount of heat flux(LE+Hs)and available energy(Rn-Gt)with a slope of 0.9128 suggested that the LE and Hs measured by EC at the research site were within the reasonable range reported in the literature

Abstract:Natural environment of the growth of Huperzia serrata populations were investigated in Zhejiang and adjacent area．The water content，organic matter content，conductivity and pH in soils．and the content of K、Ca、 Mg、Fe、Zn、CU、Mn、Na、Al、Pb and Cd in soils and plants as well as the content of huperzine A in plants were determined． The results showed that Huperzia serrata mostly grew under closed forests or in ravine with wet soils at altitude 350-l 700 m，with over l 500 mm annual rainfall，78％ relative humidity，l 0％-30％ soil water content． 4.57-5.3l soil pH，0.06l-0.385 ms cm^-1 soil conductance．and 6.18％-9.75％ organic matter．This plant absorbed more K，Ca，Zn and Na than other elements，meanwhile，the accumulation level of Pb，Cu and Cd Was higll，to which more attention should be paid in cultivation. It is suggested that shady habitats with SHfficient rainfall and high relative humidity，and with soils of lower conductance，4.75-5.3l pH，are good for the cultivation of the plant． The scater plot produced using Detrended Correspondence Analysis (DCA) based on the soil indices showed that the environm ental vailables for Pan’an population are distinctly difierent from those for the other sites，revealing the special environm ental conditions having some impacts on the huperzine A content in the plant．

Abstract:The membrane leakage rate and chloroplast ultrastructure were investigated in the fronds of two duckweeds，Lemna minor L．and spirodela polyrrihiza(L_)Schleid，cultured in distilled water and in diferent pH values(5.5，4.5，3.5，2.5)of simulated acid rain for 48 h．The membrane leakage rate and alteration of chloroplast ultrastructure in tw o duckw eeds were enhanced with the decreasing pH value． A diferent sensitivity to acid rain and changing paaem of injured chloroplast morphology were found between two species．In L．minor，the damages of chloroplast and membran e system began at pH 4.5， subsequently， severe plasmolysis， circular dilated chloroplast and the confused structure of grana with numerous vesicles were observed， as pH value of acid rain was dropped down to 3.5．However，in S.polyrrihiza under pH 3.5，less membrane leakage rate (17％) was accompanied by partial break in the outer envelope of chloroplast， while the structures of grana and stroma thylakoid showed no obvious change．The evident damage of chloroplast ultrastructure in S．polyrrihiza appeared at pH 2.5， but no severe plasmolysis and chloroplast swelling were seen． It is postulated that in the freshwater body，S．polyrrihiza may exhibite a stonger ability of existence competition to acid pollution than L．minor，and L． mino r may be used as a sensitive plan t indicator for water body with pH value less than 4．5．

Abstract:The effects of ABA priming, both alone and in combination with GA3, KT and NAA on germination of Matthiola bicornis seeds were investigated. The best priming was to treat seeds in 2.5×10^-5 mol/L ABA solution at 20℃ for 7 d. This treatment significantly reduced mean germination time and increased germination index compared with the control. Combined treatment by ABA with NAA showed no further effect on germination of the seeds, but all the other combined treatments significantly increased the percentage of normal seedlings. The treatment in combination with KT and NAA increased the germination index compared to the treatment with ABA or PEG priming alone. There were quite differences in the seed relative water absorption between treatments with PEG and ABA priming. The potential and the mechanisms for using ABA priming to improve seed germination are discussed.

Abstract:IEF-SDS-PAGE(isoelectric focusing electrophoresis-sodium dodecyl sulfate-polyacrylamigel electro-phoresis)technique was applied to comparing and analyzing the changes in protein component during embryo differentiation and development of longan (Dimocarpus longan Lout．CV．Wulongling)．The results showed that major components of proteins were generally similar at different development stages，but some changes also took place． The 7 new specific proteins were observed at different stages of the embryo development．They were TE₁(27.1 kD，pI 7.3)，TE₂(17.5 kD，pI 8.2)on 38 days after anthesis(DAA)；TE₃(11.4 kD，pI7.6)，TE₄(13.2 kD， pl 9.9)on 45 DAA；TE₅(22.6 kD，pI 7.2)，TE₆(18.6 kD，pI 8.3)，TE₇(23.5 kD，pI 3.6)on 52 DAA．These specific proteins showed good repeatability in the experiments． The number of protein points were comparatively higher on 31 DAA gel electrophoretogram． which indicated that rich synthesis and accumulation of proteins appeared at the stage of 31 DAA， and coincided with the results of the protein contents determined． The appearance or disappearance of the specific proteins might play an important role in longan’s embryo differentiation and development．

Abstract:Semi-parasitism in the sandalwood(Santalum album L．) seedlings was studied on the basis of propagation of different host plant species． The sandalwood plants can grow normally without host plant during seed germ ination and early seedling stage． However， the subsequent growth needs suitable host plant for roots to be parasitized． The experiment indicated that host plant species had great impact on the growth of sandalwood seedlings and their root haustoria， which revealed the differences in haustorium number， size and adhesiveness．Based on our preliminary study， host plants species， such as Hibiscus rosa—sinensis and Phyllanthus reticulatus were found good for the growth of sandalwood seedlings． It was observed that the sandalwood roots lacked root hairs， but its vessels were well developed， which is benefit for absorption of water an d nutrition from the host roots．The process ofroot semi-parasitism ofsandalwood in Hibiscus was also investigated．

Abstract:The tobacco calli were cultured on MS or MS containing 0.1 mmo／L 2-aminoindan-2-phosphonic acid (AIP，inhibitor of SA synthesis，gift from Professor B．Mauch．Mani)or l mmol／L aminoxyacetic acid(A0A，inhibitor of ethylene synthesis)in dark(25±2℃)，while methyl jasmonate(MJ) were sprayed to the calli．After treatment，the contents of malondialdehyde(MDA)，active oxygen，hydrogen peroxide(H₂O₂)and the activities of superoxide dismutase(SOD)，lipoxygenase(L0X l and LOX3)，catalase(CAT)，ascorbate peroxidase(APX)were determined during 2-l0 days． MJ largely decreased the content ofM DA，H，O，。and the activities ofSOD，CAT， APX．By contrast，MJ increased the activity of LOX1 and the content of active oxYgen．However．MJ had little effects on the activity of L0X3． The treatment of A0A completely inhibited the effects Of MJ on M DA。active oxygen，SOD and CAT，but，AIP had 1ittle eriects on that substances and enzymes． AIP and AOA differed in the effects on the activity of APX and the MDA content，and had different efects on promoting the LOX activity induced by MJ．The results indicate there are different pathways of signal transduction in the activities of some enzymes and some metabolized substances that involved in the active oxygen burst and lipid peroxide． Ethylene plays a main role in inducing M DA，active oxygen and SOD，but SA had little efects on the induction of these substances． Thus，the effects of MJ are mainly induced by the ethylene pathway． However，SA is essential to the production of MDA and has a particular efect on modulating the activity of SOD under the condition of ethylene deficiency

Abstract:In order to select suitable Hevea accessions for extending genetic base of Chinese rubber tree in future breeding schemes, the genetic diversity of 14 wild accessions and 37 cultivated clones were detected by RAPD and ISSR. Thirty-one reliable primers (19 RAPD primers and 12 ISSR primers) were chosen. Based on RAPD, a total of 132 bands were generated, polymorphic bands accounted for 88.6%, and similarity coefficient ranged from 0.432 to 0.947 among all accessions. Otherwise based on ISSR, 101 bands were produced, polymorphic bands accounted for 87.1%, and similarity coefficient was 0.505 to 0.941. The wild accessions showed higher polymorphism than cultivated clones according to the average heterozygosity. Based on ISSR, the 51 accessions were divided into 2 clusters according to unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis: Cluster Ⅰ contained 9 wild accessions and Cluster Ⅱ consisted of 37 cultivated clones and 5 wild accessions. But all of the accessions can not be divided into wild cluster and cultivated cluster according to RAPD.Some cultivated clones, i.e. PR107, Re yan 217, could be screened from 51 accessions. The significantly high correlation between RAPDs and ISSRs among 51 accessions was observed (r = 0.574), although the differences between the RAPD and ISSR dendrograms were observed. It is proven that all of the results can be used in Hevea breeding programs, and RAPD and ISSR can be used in clonal identification and diversity study of Hevea.

Abstract:Inter-simple sequence repeats 0SSR)marker was used to analyze the genetic diversity and diferentiation of 137 individuals within and among 7 populations of Orchidantha chinensis，an endan gered species，in Guangdong Province．Ten ISSR primers generated 101 bands，ofwhich 58(57.43％)were polymorphic．ISSR diversity within the population was lower than that among the populations(at species level：P=57.43％，H=0.1254，I=0.2000；at population level：P=18.24％，H=0.057，I=0.0876)．Based on Nei’s G_ST value calculated by POPGENE1．3 1，gene diversity within populations was 0.1 254±0.1686．Shannon information index was 0.2000±0.2429．Variation coeficient among populations was O.5481, and that within population was O.4519．The ranger ofgentic identity among populations was from 0.8855 to 0.9511. Based on the gene diversity inform ation available for Orchidantha, two management strategies are proposed．A conservation area is suggested to be established in Honghuatan(HHT) where is considered to be an optimal habitat for O.chinensis growth．And because ofthe diferentiation among the populations， cross transplan tation is suggested in order to enhan ce the gene flow among the populations． By this means，the genetic diversity resources of the species could be preserved to the greatest extent.

Abstract:Thirty hybrids from ll parent sugarcance varieties in a incomplete diallel cross model were obtained．The seedling biomass of all F₁S were analysed by a model of additive-dominance-random environment effect．The results indicated that the inheritance of sugarcane biomass was determined jointly by additive，dominance，and both additive and environm ent interaction effects, in which the additive effect was the most important one．The genetic effect of phenotypic characters from parents on the progenies was influenced mainly by female parent．Both broad-sense and narrow-sense heritabilities in biomass traits were relatively high． and the form er was higher than the latter，suggesting that the selection of biomass traits is effective in early generation．The analyses of additive and dominant effects predicted for parents and cross combinations showed that five parents, viz．YT72／426，YT79／177，YT85／177，ROC24 and ROC25 were accounted to have higher additive effect，and four crosses to have higher dominant effect，which could be used in sugarcane breeding for high biomass．

Abstract:The seeds of 18 taxa including 16 species and 2 forms of genus iradiclis B1．were examined．The seeds ofspiradiclis have small(0．2-0．3 mm) or medium size (0.3-2 mm)，irregular shape，alveolate surface，slightly prominent hilum．Seed testa consists of exotesta and endotesta．The projections on periclinal wall of epidermis cells can be classified into two types：the projections are either distributed consistently on slightly concave periclinal walls，which can be seen in 6 taxa，viz．：S. bifida，S. caespitosa，S. caespitosa f. cylindrca，S. caespitosa f. subimersa，S. emeiensis and S. 1ongzhouensis，or around the fovea formed by deeply concave periclinal walls，which can be found in 12 taxa，viz.：S. coccinea，S. cordata，S. fusca，S．guangdongensis， S. hainanensis，S. howii，S. laxiflora，S．1eptobotrya，S．1oana，S. microphylla，S. petrophila and S．purpureocaerulea．The seed morphology in spiradiclis can play an important role in distingu ishing infra-genus taxa．

Abstract:Seed oiI from Camellia oleifem extracted with different methods(supercritical CO₂，microwave，ultrasonic，and squeezing)was analyzed by GC-MS．Chemical composition ofthe seed oil extracted with the three methods was similar except squeezing． However, vitamin E and squalene were not found in the constituents extracted by squeezing．It is suggested that the extraction with supercritical CO₂ is an ideal method by which the oil is up to the first degree of national standard． Physical and chemical properties， and the constituents of the oil extracted by these methods are tabulated．

Abstract:Four species and four varieties are newly recorded from Yunnan Province，namely Wikstroemia pilosa，Saurauia napaulensis var．omeiensis Erythropsis kwangsiensis，Reevesia pubescens vat．kwangsiensis，Berberis francisci-ferdinandii，Berberis kongboensis，Bennettiodendron brevipes var．margopaterise，and A chyranthes biden-tara var. japonica.