Abstract:The vegetation types are described of Baishanzu National Nature Reserve in Qingyuan county, Zhejiang Province. The surveyed area covered 25 thousand hm² in which 27 sample plots with 20 m×20 m each were selected. Based on the importance value of plant species, six vegetation types were devided, viz, evergreen broadleaved forest, evergreen and deciduous broadleaved mixed forest, coniferous and broadleaved mixed forest, coniferous forest, mountain dwarf forest, and mountain shrub and herbosa. Floristic composition, community structure, and trend of community succession of each vegetation type are described.

Abstract:Studies of the distribution and contents of nutrients in 40-yr-old Cryptocarya concinna/Lindera chunii community of lower subtropical evergreen broadleaved forest in Dinghushan Biosphere Reserve showed that the total nutrient standing stock in the community was estimated to be 61.253 for P, 928.764 for K, 1 212.771 for Ca, and 79.349 kg hm^-2 for Mg. Nutrient allocation in different layers in the community was in the order of trees>lians>shrubs>herbs. In tree layer, 38.6%-61.7% of nutrient elements was in tree trunks and branches. Standing stock of nutrients in roots, trunks and barks was Ca>K>Mg>P, and that in other organs was K>Ca>Mg>P. Annual nutrient accumutations of P, K, Ca and Mg were 2.677, 41.550, 63.309 and 3.693 kg hm^-2, respectively. Nutrient use coefficients in the community were 0.18(P), 0.11(K), 0.09(Ca) and 0.28(Mg), the nutrient cycling coefficients being 0.76(P), 0.61(K), 0.41(Ca) and 0.84(Mg). Nutrient cycling period for P, K, Ca and Mg was 7.36, 15.12, 28.05 and 4.30 years, respectively. It is concluded that the community had greater nutrient reserve ability but lower nutrient use efficiency as compared to the previous study on Pinus massoniana community.

Abstract:Tree species diversity of a 40-yr-old secondary broadleaved forest which was destroyed by human cutting was invertigated for 18 sample plots (each 100 m^2) in Ailaoshan Nature Reserve, Yunnan Province. Measurements included species composition, tree height, diameter at breast height, and sprouting. The results revealed that the dominant species was Vaccinium duclouxii, and more than 2/3 of tree species and 72.7% of the total individuals (DBH≥3 cm) were regenerated by sprouting. Tree density in the forest decreased with the increases of height class and diameter class, whereas species abundance did not increase. Tree species diversity in the secondary forest was significantly lower than that in montane moist evergreen broadleaved forest at climax stage as compared by Shannon-wiener index, Simpson's diversity index, and Fisher's index.

Abstract:Fern flora was surveyed by selecting 108 sample plots with 5m×5m each in Gudoushan Nature Reserve of Xinhui City, Guangdong Province. Fifty-seven fern species in 41 genera of 22 families were recorded, which made up 60% of total fern species in the Reserve. Relative abundance, relative coverage, and relative frequency of fern species were calculated for getting the importance value for each species in the community. Physiognomical life form, leaf characteristics, and seasonal aspect of the community were also investigated. It is concluded that the dominant ferns are of tropical Asia elements. Due to random distribution of the population and heterogeneous habitat, species that are rare or with high relative abundance constitute only a small proportion. Five growth forms of pteridophytes, viz, basket, dendroid, creeping, climbing, and epiphytic forms are classified.

Abstract:Parasite Cuscuta campestris Yunker was examined for controlling the growth and spread of harmful weed Mikania micrantha H. B. K. The experiments were carried out to estimate biomass production by sowing the seeds of M. micrantha in sample plots in Shenzhen Xianhu Botanic Garden where this weed grew densely, and for physiological study by cultivation of both plants in pots. The result exhibited that the leaf number, stem length, and biomass dry weight of individual of the host M. micrantha began to decrease after the host was parasitized for about 30 days. Such decrease was obvious after 2 months of parasitism, so did the photosynthetic rate (P_n), transpiration rate (E), stomatal conductance (g_s), water use efficiency (WUE), chlorophyll content, and Fv/Fm. The parasite could spread rapidly extending to an area of 20 m² with longest distance of 5 m within 2 months. The parasite hampered the growth and reproduction of the host and depressed it even to die. It is suggested that C. campestris might be a promising plant for controlling this weed.

Abstract:The effects of soil fertility, soil moisture content and shade density on flowering and seed setting of Mikania microtha were investigated at different habitats in Dongguan City, Guangdong Province, during 2001 to 2002. The plants growing on less fertile soil caused fewer flowers, lower seed setting percentage, less 1000-grain weight and shorter flowering duration than those on more fertile soil. However, over-fertile soil also resulted in fewer flowers and low seed setting percentage. The plants growing in open habitat had more flowers with longer flowering duration, whereas under shade the 1000-grain weight was shown to have a slight increase. The seed setting percentage was highest at 10%-20% of shade density. Moist soil had no significant effect on 1000-grain weight, but obviously led to more flowers, high seed setting percentage and longer flowering duration.The effects of soil fertility, soil moisture content and shade density on flowering and seed setting of Mikania microtha were investigated at different habitats in Dongguan City, Guangdong Province, during 2001 to 2002. The plants growing on less fertile soil caused fewer flowers, lower seed setting percentage, less 1000-grain weight and shorter flowering duration than those on more fertile soil. However, over-fertile soil also resulted in fewer flowers and low seed setting percentage. The plants growing in open habitat had more flowers with longer flowering duration, whereas under shade the 1000-grain weight was shown to have a slight increase. The seed setting percentage was highest at 10%-20% of shade density. Moist soil had no significant effect on 1000-grain weight, but obviously led to more flowers, high seed setting percentage and longer flowering duration.

Abstract:Rice repetitive DNA sequence RRD3 and its six serial deletants were inserted into the promoter-capture vector of plants. Thus, gusA gene can be used to assess the promoter activity of inserted DNA. The promoter activities of serial deletants were detected after co-culture of rice calli with Agrobacterium LBA4404 containing different recombinant DNA by transient GUS (beta-glucuronidase) assay. The results indicated that total length of RRD3, 410 bp and 150 bp deletants had stronger promoter activities, while the promoter activities in 700 bp and 120 bp deletants were reduced. There are some positive/negative control elements in RRD3 sequence.

Abstract:Indica rice (Oryza saliva L.) varieties Yuexiangzhan, Yuefengzhan and Japonica rice (Oryza saliva L.) 998, 999, Bijing 38, which were treated by high hydrostatic pressure, as well as their mutants (Yuebianchang, Juwuba, Yuefengyabian 1 to 5, and Bixian), were used to study the effect of high hydrostatic pressure on the growth and agronomic traits of rice. The seeds of all varieties were soaked for 10 h at room temperate, then treated under 75 MPa for 12 h after the seeds germinated. The results showed that the plant height, panicle number of M₁ population of Yuexiangzhan and 998 increased obviously compared with the control, but no marked difference was observed in traits of Yuefengzhan, 999, and Bijing 38. Many traits including plant height, panicle number, grain number per panicle, grain length and 1 000-grain weight of Yuebianchang and Juwuba from M₂ to M₄ were different from the control, and all of the traits among M₂, M₃ and M₄ were stable. Plant height was segregated in M₃ population of Yuefengyabian 1 to 5 except Yuefengyabian 2. Some mutants with larger grain and/or longer awn were found in M₄ population of Yuefengyabian 4. Plant height, panicle length, grain length and grain number per panicle increased significantly in M₂ to M₄ of Bixian compared with Bijing 38, but seed setting percentage and 1000-grain weight obviously decreased. Twin or trine seedlings were observed from one seed when the treated seed of Yuefengzhan germinated in plate. This results indicate that high hydrostatic pressure not only influences rice growth and development, but also induces mutation.

Abstract:The chloroplast trnL intron and trnL-trnF intergenic spacer (IGS) sequences of one species in Dicksoniaceae (Cibotium barometz) and 11 species in Cyatheaceae were determined by sequencing cloned PCR products or amplified fragments directly (for Alsophila spinulosa and Cyathea tsangii, 9 and 2 individuals were sequenced, respectively). Sizes of the sequences of the 12 species ranged between 1004 bp to 1082 bp. The average contents of (A+T)% and (G+C)% were 60.9% and 39.1%, respectively. The base differences (transition/transversion) and Kimura's genetic distances were also computed between different species and intraspecific individuals. After sequence alignment, maximum parsimony, maximum likelihood and neighbor-joining methods were used to conduct phylogenetic analyses. The results indicated that Xia's classification of Chinese Cyatheaceae was supported, the dade consisting of Sphaeropteris brunoniana, Sphaeropteris hainanensis and Cyathea contaminans firstly diverged from the rest members of the family, and the latter was further separated into two subclades corresponding to the subgenus Alsophila and subgenus Gymnosphaera. Three monophyletic terminal clades, within each the pairwise genetic distances were less than 0.008, were formed separately by Cyathea gigantean-C. pseudogigantea-C. tinganensis-C. pectinata, C. contaminans-Sphaeropteris brunoniana-S. hainanensis, and Cyathea tsangii-Alsophia spinulosa, suggesting that these species could be combined as three separate species: Cyathea gigantean, Sepaeropteris brunoniana and Alsophila spinulosa. The genus Sphaeropteris was placed in the basal position of Cyatheaceae, whereas the genus Alsophila placed as the derived sister group, which supported Tryon's hypothesis accounting for the evolutionary relationships within Cyatheaceae and the derivation of their indusium.

Abstract:Seven ecdysteroids,20-hydroxyecdysone(1),podecdysone C(2),3-O-acetyl-20-hydroxyecdysone(3),20-hydroxyecdysone-20,22-butylidene acetal(4),shidasterone(5),atrotosterone C(6)and carthamosterone(7),were isolated from the roots of Serratula chinensis S.Moore.All compounds except compound1were isolated from this plant for the first time,and compound4was found to be a new ecdys-teroid.

Abstract:Compared to variety Shanyou 63, super high-yielding hybrid rice Pei'ai 64S/E32 had higher activities of ascorbate peroxidase and glutathione reductase, higher antioxidant contents (Vc, total Vc, reduced glutathione, and β-carotene), and higher capacity of scavenging organic free radical, but less content of malondialdehyde (a product of membrane-lipid peroxidation) in flag leaves at late development stage. It was shown that the flag leaves of Pei'ai 64S/E32 at late stages have strong antioxidant capacity, which coincided with the lower degradation of chlorophyll and protein contents in this hybrid at late seed setting stage.

Abstract:The role of calcium ion in kinetin (KT) signal transduction was studied with etiolated mung bean (Phaseolus radiatus L) hypocotyl protoplasts. The volume of protoplasts maintained at a constant osmotic potential at 20±2℃ began to swell 10 minutes later when treated with 1 μmol/L KT in the present of CaCl₂, and reached their maximum at 30 minutes, then declined to the same level as the control one (CaCl₂ only) at 60 minutes. The swelling of protoplasts induced by KT could be significantly inhibited by Verapamil (Ca²⁺ channel blocker) or LaCl₃ (Ca²⁺ channel competitive inhibitor) respectively. Calmodulin antagonists TFP, CPZ and W₇ could obviously inhibit protoplasts swelling induced by KT. CaM levels in protoplasts reached their peaks at 30 minutes whether treated with or without KT, the CaM content of the treated one being about five times more than that in treatment without KT. However, when KT and CaCl₂ solutions were added with 5μmol/L CPZ, TFP or 0.5μmol/L W7, CaM level in protoplasts declined greatly. It is suggested that calcium acts as the second messenger in KT-induced swelling of protoplasts in this system and Ca²⁺-CaM may play an important role. The present study did not exclude the possibility of involvement of other cellular signaling system.

Abstract:Nitrogen, phosphate and potassium fertilizers with various proportion and in combination with conventional agricultural chemicals were applied to Cymbidium Golden E1f 'Sundust' for controlling anthracnose disease caused by Colletotrichum orchidearum f. cymbidii. Fertilizers used were a compound fertilizer of N:P₂O₅:K₂O=15:15:15(C), and on the basis of which additional K and P were supplied as N:P:K=15:15:30 (A) and 15:30:15 (B), respectively. No agricultural chemical was applied in D for control. The results indicated that increasing K and P contents in fertilizer significantly enhanced the resistance to the anthracnose, the controlling effects being 76.54% and 73.71%, respectively, whereas in treatment C being 47.79%.

Abstract:The growth and development of Cymbidium sinense in vitro were observed under scanning electron microscopy. The cells in mesophyll near midrib are often elongated as palisade-liked tissue in young leaves. With the development of the plantlets, cells in mesophyll near midrib of leaf base are found to be gradually rounded or elliptic, but those in leaf apex and near midrib are still arranged as palisade-liked tissue. The development of the stem goes through protocorm, rhizome and pseudobulb stages. There are a large number of starch grains in most cells of protocorm and in cells of cortex parenchyma of rhizome, but almost no starch grain is found in pseudobulb. In young roots, medullas are absent and starch grains scatter in cortex parenchyma. In mature roots, there are medullas with starch grains. Generally, of the four axillary buds, only the outmost floral bud and the innermost leaf bud are developmental.

Abstract:The meiosis of Ammopiptanthus nanus, an endangered species of Leguminosae, was observed under Olympus Vanox microscope. The materials collected from Wuqia County in Uygur Autonomous Region of Xinjiang were fixed in Carnot's fluid, then washed in absolute ethanol and preserved in 75% ethanol. Slide specimens were prepared by smear method and enzyme-disaggregated method. There are nine bivalents in pollen mother cells at late diplotene or early diakinesis, and the homologous chromosomes essentially arrange on the equatorial plate at late metaphase Ⅰor early anaphase Ⅰ, then the two homologous chromosomes of each bivalent separate from each other and move to two opposite poles drawn by spindle fibers. Nine chromosomes at each pole are observed, therefore the basic chromosome number of this species should be x=9. In addition, abnormal behavior of chromosome is not found in the process of meiosis, so the development of microspores is regarded as normal. It is suggested that the endangerment of the species is not related to the chromosome behavior.

Abstract:

Abstract:Eleven species of Annonaceae were reported as new records to6provinces in China,i.e.Dasymaschalon rostratum for Fujian,Artabotrys hainanensis for Guangdong,Fissistigma shangtzeense and F.tientangense for Hainan,A.hainanensis,A.rhynchocarpus,Orophea yunnanensis,Polyalthia nemoralis and P.simiarum for Guangxi,F.tientangense,O.hainanensis and Uvaria kweichowensis for Yunnan,Miliusa tenuistipitata for Xizang.

Abstract:Different volumes of Tris-HCl buffer (0.1 mol/L, pH 8.8) in combination with different contents of PVP40 were employed to study the embryo protein extracted from Litchi chinensis varieties "Huaizhi", "Guiwei" and "Heiye". It was shown that the volume of Tris-HC1 buffer being 5 times the fresh wieght of embryo and added with 15% PVP40 (g g^-1 FW) was adapted to obtain a satisfactory result. Homogenate containing 15% PVP40 (g g^-1 FW) could be used directly for determination of soluble protein content by Coomassie Brilliant Blue G-250 and 10% PVP40 (g g^-1 FW) for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Endosperm protein could be extracted with equal volume of Tris-HCl containing 2% PVP40. Precipitation of embryo and endosperm proteins with ethanol of 10 times the volume of protein extraction gave best SDS-PAGE pattern.

Abstract:Three cultivars of Narcissus tazetta var. chinensis and three cultivars of N. poeticus have been studied by RAPD (randomly amplified polymorphic DNA). Twelve 1 0-bp arbitrary primers were screened and 119 DNA bands were amplified, among which 84.86% were polymorphic. Genetic similarities were calculated using simple matching coefficient, and the phenogram was constructed by using UPGMA method. Three cultivars of N. tazetta var. chinensis were very closely related, while the three cultivars of N. poeticus were clustered together, indicating that there is a distance in relationship between the first three and the latters. It is suggested that molecular marker technique is helpful for the breeding and variety identification of Narcissus.

Abstract:Gene trap is a system that allows gene activity to be monitored by creating gene fusions with a reporter gene. Gene traps provide a powerful tool for isolating genes and determining gene functions. Reporter genes can be used to construct three basic types of gene traps: enhancer trap, promoter trap and gene trap. In an enhancer trap, the reporter gene is fused to a minimal promoter that is unable to drive reporter gene expression alone but can be activated by neighboring enhancer elements. Promoter traps and gene traps contain a promoterless report gene, so that reporter gene expression can occur only when the reporter gene inserts within a transcribed chromosomal gene, creating a transcriptional fusion. In this review, we describe how gene traps were developed, how to construct gene trap system, how gene traps were adopted to isolate genes and determine gene functions, what is the present status about applications of gene traps on plant molecular biology and why gene traps are likely to play an increasing important role in the future.

Abstract:Recent studies on plant responses to elevated CO₂ is reviewed. Increase in atmospheric CO₂ concentration affects not only global climate but also plant morphology, water use, protein synthesis, photosynthesis, resistance, growth, biomass and so on. Elevated CO₂ has effects of promoting the growth of plant roots and seedlings, making the leaf thick, lowering the stomatal density, stomatal conductance and transpiration, enhancing the water use efficiency, crop yield and biomass, intensifying the biosynthesis of ethylene and antioxygen competence. High CO₂ concentration together with other environmental factors affect plants. Plants with different photosynthetic pathways (C₃, C₄ and CAM) and different vegetation types (natural and artificial vegetation) exhibite different responses to high CO₂ concentration. Short-term exposure to elevated CO₂ enhances photosynthesis while long-term inhibits. Experimental conditions such as air pressure, temperature, water availability, nutrition status, oxygen, light intensity even growth space also have great effect on the results of the experiments.