Abstract:Leaf epidermis of 17 species and 2 varieties of Calamus was oberserved under light microscope. The species studied are all reported for the first time, except C. simplicifolius, C. egregius and C. tetradactylus. The leaf epidermal structure of Calamus L. （Palmae） is of the same type： the stomatas are tetracytic with 4 subsidiary cells in which 2 are terminal and 2 lateral. The epidermal cells are oblong, longitudinally extended. There are 3 kinds of trichomes： single hair, multicellular, in single file （C. macrorrhynchus） ; single hair, multicellular, in 2-3 files （C. thysanolepis etc. ） ; ramose hair （C. tetradac tylus etc.）. The length and width of epidermis cells, the thickenss, undulatory depth and shape of cell wall, and the character of terminal subsidiary cells are different among species. Leaf epidermal morphology may verify the relationships of Calamus species and is of significance for classification and systematics of Calamus.

Abstract:The anther of an endangered species, A mmopiptanthus nanus （M. Pop.） Cheng f., is tetrasporangiate. The anther wall is of basic type in the development, which comprises epidermis, fibrous endothecium, middle layer and glandular tapetum. The microspore mother cells undergo meiosis, and the cytokinesis is simultaneous. The tetrads are tetrahedral. Mature pollen grains are two-celled at the dispersal stage. The abnormal development is not found in microsporogenesis and in development of microgametophyte of the species. It is suggested that the endangerment of the species is not related to the microsporogenesis and microgametophyte development.

Abstract:Leaf structure of Aquilaria sinensis （Lour.） Gilg （Thymelaeaceae） observed under light microscope shows that the leaves are of typically bifacial exhibiting xeromorphic characters. Epidermis consists of a row of irregular epidermal cells with thick horny layers and are closely arranged. The horny layers in upper epidermis are 1μm thicker than that in lower epidermis. Sunken stomata exist only in lower epidermis which is sparsely covered by unicellular hairs. The stomata are of anomocytic type. Mesophyll is well developed, in which many rectangular lithocyst arranged perpendicularly to the epidermis. Palisade parenchyma is composed of 1-2 layers of cylindrical cells. The cells in outer layer of palisade parenchyma are transformed into idioblasts. In spongy parenchyma there is a layer of hypodermis which is composed of idioblasts. The ratio of the thickness of palisade parenchyma to spongy is 1： 3. The micrib belonging to bicollateral bundle is well developed. The bundle sheath is composed of idioblasts. The leaves are rich in extraxylary fibres. The structural characteristics show that it is a xerophytic species adapted to arid environment.

Abstract:Twelve strains of endophytic diazotrophic bacteria were isolated from grain-straw-dual-purpose rice 201 popularized in Fujian Province. They were identified as： Enterobaeter cloacae, Enterococcus gallinarum, Bacillus purnilus, B. licheniformis, B. megaterium, B. sphaericus, B. cereus, Pirnelobacter, and Arthrobacter. Three strains with high acetylene reduced activity were selected to study the bacterial resistance to antibiotics, and results of Gram staining. The plasmids harboring the reporter gene lacZ fused to the promoters of nifH were transformed into Enterococcus gallinarum by triparental crossing. The inoculated rice roots were examined by β-galactosidase staining and observed under light and electron microscopes. The results indicated that the endophytic diazotrophic bacteria existed in epidermal cells, cortex cells, vascular tissue cells and intercellular spaces office roots.

Abstract:Gene-specific primers were designed according to the known sequence of mitochondrial phosphate transporter gene （MPT）, and the rice MPT （OsMPT） cDNA fragment of 1118 bp was cloned by One-step reverse transcription PCR （RT-PCR） from Cpslo17, a wide-compatibility variety of rice （Oryza saliva）. DNA sequencing analysis indicated that it carried an entire open reading frame and encoded a protein of 368 amino acid residues. The deduced amino acid sequence of OsMPT showed similarities of 93.5%, 85.6%, 83.8%, 83.7% and 81. 1% with those from maize, soybean, Lotus japonicus, Betula pendul and A rabidopsis thaliana, respectively. The hydropathy profiles of the deduced amino acid sequence predicted the existence of six membrane-spanning domains, which are highly conserved in the mitochondrial transporter family. The N-terminal amino acids were enriched with arginine, alanine and serine, and a signal peptide targeted in mitochondria was predicted by iPSORT. Further analysis of ecoding segment of OsMPT revealed that it contained 6 exons and 5 introns. The average length of introns and exons were 467 bp and 186.3 bp respectively; and the average GC content of introns and exons are 35.5% and 54.0% respectively. RT-PCR results showed relative high-level expression of OsMPT in leaves of both jopnica and indica rices, so was in both vegetative and reproductive tissues of Cpslo 17. Cloning and expression analysis of OsMPT will provide a base for the researches of its structure and biological function.

Abstract:Single chromosome of papaya （Carica papaya L.） was isolated by glass needles, and the chromosomal DNA was amplified by LA-PCR （Linker Adapter PCR）. The PCR products were a smear ranged from 80 to 700 bp. Southern blot showed that the PCR products were homogeneous with the papaya genomic DNA, indicating that DNAs from the single chromosome had been successfully amplified. The PCR products were cloned into pGEM-T-Easy vector and about 1.18×10⁵ recombinant clones were obtained. The size of the inserted fragments of clones ranged from 100 to 400 bp.

Abstract:Based on the sequences of racy genes from Microcystis, a specific primer pair was determined. PCR-mediated detection of mcyB gene was developed and applied to the identification of potential microcystin produced from Microcystis strains in natural water bodies. The sensitivity of PCR method was investigated, and the detection limit was as few as 100 cells per reaction. The method does not require extraction of the genomic DNA of Microcystis, and does not need large volume of water samples. It is simple, sensitive, rapid and economical, which can be used for the detection of the toxic Microcystis strains in water sources for human consumption.

Abstract:An in vitro protocol for rapid propagation of medicinal plant Dioscorea zingiberensis C. H. Wright was optimized. Nodal segments with buds cultured obtained from vessels were used as explants which were the ncultured on bulbil induction medium. The explants started to appear emergence from basal segments after 15 days. Three to five bulbils with roots developed from each segment were obtained after another 15 days. The optimal culture conditions for bulbil formation were 26±2℃ at 1 500-2 000 lx illuminated for 14 hours per day on MS medium supplemented with 4.0 mg L1 BA and 1.0 mg L^-1 IBA in addition of 6%-9% sucrose, 0.5% active charcoal, and 7% agar. The bulbil induction rate was 100%, and the plantlet survival rate being above 90%.

Abstract:By spraying β-aminobutyric acid （BABA） or/and leaf wounding treatments, the activities of defenserelated enzymes were determined to investigate the interaction effects of BABA and wounding on the resistance of tobacco （Nicotiana tabacum L. cv.Yunyan 85） to tobacco mosaic virus （TMV）. The results showed that wounding or BABA treatment caused a significant increase of phenylalanine ammonia-lyase （PAL） and polyphenol oxidases （PPO） activities, which were associated with BABA concentrations and timing of induction. However, leaf wounded by pruning in combination with addition of BABA decrease the activities of PAL and PPO, resulting in obviously more TMV symptoms than BABA treatment alone. The results suggest that BABA and wounding exhibit antagonistic effect. It is likely that BABA and other SA-dependent chemical inducers should not be applied to the wounded tobacco seedlings.

Abstract:The alterations of papain activity and conformation were studied in condition of pretreatment with ethanol solutions at different concentrations, different pretreatment times, and in condition of various reaction concentrations. The result showed that the papain activity was obviously increased and the Km value was declined when treated with ethanol. Ultraviolet difference spectra showed that the secondary structure ofpapain altered in ethanol solutions. Fluorescence emission spectra showed that the peak of fluorescence emission was not shifted but the fluorescence intensity in papain increased in ethanol solutions.

Abstract:Changes in mineral element contents in young seedlings of Citrus maxima cv. Pingshanyou and C. reticulata cv. Fuju cultured in plastic pots and treated with various salt concentrations were studied. Na⁺ and CIcontents in roots and shoots of Pingshanyou and Fuju seedlings increased with the increase of NaCl concentration. The contents of Na⁺ and Cl in roots and shoots of Fuju seedlings were higher than those of Pingshanyou under the same salinity. 40 mmol/L of NaCl significantly decreased Ca²⁺, Mg⁺ and Zn contents in roots and K⁺ and Fe contents in shoots of Pingshanyou and Fuju seedlings, whereas markedly increased the contents of Fe in roots and Zn in shoots. As salt concentration increased, K⁺ in roots and Ca²⁺, Mg²⁺ in shoots of Pingshanyou seedlings exhibited little change, but the above-mentioned mineral ions in Fuju seedlings significantly decreased when the salinity was higher than 160 mmol/L. It was shown that the contents of K⁺ in roots and Ca²⁺, Mg²⁺ in shoots were related to citrus varieties, which might be used as indices for evaluating the salt tolerance. Under salt stress, P, Mn in roots and shoots of Pingshanyou and Fuju seedlings decreased, but Cu increased obviously at high salt concentration. The value of K⁺/Na⁺, Ca²⁺/Na⁺ and Mg²⁺/Na⁺ decreased significantly in shoots of Pingshanyou and Fuju seedlings under NaC1 stress, of which the value of K⁺/Na⁺ could be considered as an index for evaluating the salt tolerance of citrus seedlings.

Abstract:Gas exchange and chlorophyll fluorescence were investigated in young Chinese strawberry tree （Myrica rubra var. astropurea Tsen.） leaves treated with different chilling temperatures （12℃. 6℃ and 2℃） under differentirradiance levels （0, 70 and 350 μmol m^-2s^-1） for 12 hours by a portable photosynthesis system HCM-1000 and a portable modulation fluorometer PAM-2000. The results showed that exposure of strawberry tree leaves to various low temperature and light resulted in the increases in Ci/Ca （internal/external CO₂ concentration）, Fo （initial fluorescence）, qN （non-photochemical quenching） and （Fi-Fo）/（Fp-Fo） （amount of inactive PS Ⅱ centers）, butdecreases in Pn （net photosynthesis rate）, Gs （stomata conductance）, Fv/Fm （maximal photochemical efficiency of PSⅡ）, qP （photochemical quenching） and ФPSⅡ （quantum yield of PS Ⅱ ）. At the same levels of low temperature, moderate irradiance （350 μmol m^-2s^-1） enhanced the inactivation or damage of PSⅡ reaction centers which needed longer time for recovery. It was shown that the inhibition of photosynthesis in treated plants induced by low temperature under light condition can be attributed to the loss of activity in photosynthetic apparatus. It is suggested that the accumulation of QQ_A^- and non-reducing Q_B is a possible cause for the inactivation or damage of PSⅡ reaction centers, and non-radiative energy dissipation probably plays an important protective role against the photoinhibition induced by chilling.

Abstract:A nthurium andraeanum cv. Arizona was potted in three plastic greenhouses with top open. In each of the greenhouse, CO₂ was adjusted respectively to 360±30 μmol CO₂ mol^-1 （Control）, 700±100 μmol CO₂ mol^-1 （T1）,and 1 000±100 μmol CO₂ mol^-1 （T2）. Plant growth, net photosynthetic rate, activity of photosynthetic enzyme, and other physiological and biochemical characteristics were determined. The results showed that the plants grown under treatment T1 for 30 days increased in plant height, leaf area, and fresh weight by 12.8%, 2.39%, and 29.2%, respectively, and by 8.7%, 1.81% and 27.2% for treatment T2, respectively, compared to the Control. However, net photosynthetic rate （Pn） in treatments T1 and T2 measured under treatment conditions at that time were 27.0% and 33.8% higher, respectively, than those grown under the Control. Pn in T1 and T2 treatment measured in Control condition were also higher than that of the Control. Elevated CO₂ caused a marked increase in soluble sugar and starch accumulations in leaves, but significantly reduced their stomatal conductance and transpiratory rate, there is no evident difference in chlorophyll content between the Control and the treatment. In addition, elevated CO₂ had positive effect on Rubisco activity, and glycolate oxidase activity apparently decreased in leaves.

Abstract:Using microclimatic dada recorded from 2002 to 2003 in litchi （Litchi chinensis） forest in Huadu, the relationship between the microclimate and macroclimate was studied. The results indicated that average monthly air temperature in litchi forest canopy was lower by 0.35-0.75℃ than that obtained at meteorological station in Huadu. This was particularly obvious in winter and spring, and at night. Temperature in the canopy was by 0.2-0.4℃ higher than that above the canopy, which was more obvious in summer and autumn and in the daytime. Average monthly relative humidity in litchi forest increased by 7% compared to that in macroclimate, indicating that the humidification in litchi forest always causes diseases and pests.

Abstract:Flowering characteristics and pollination ecology of Tamarix chinensis were investigated in the Nature Reserve of Yellow River Delta in Shandong Province. The flowering phase and dynamics, insect visitors and their behavior and visiting frequency were observed, and the breeding system, pollen-ovule ratio （P/O） and pollen viability were determined. The results showed that T. chinensis was self-compatible requiring pollinators. Syrphid flies （Syrphus） were the most common visitors. The duration of single flower of this plant lasted only one day, the P/O was 390.9±81.0. The fruits matured within 15 days. In natural condition, the fruit setting rate reached 95.23%. The population had a flowering period of several months （from May to September）, which produced a large amount of seeds that would germinate and form a large area of Tamarix shrub.

Abstract:Fern flora of Mt Wutongshan in Shenzhen of Guangdong Province comprises 126 species and two varieties of 63 genera in 33 families. The species-rich families are Polypodiaceae, Thelypteridaceae, Dryopteridaceae, Selaginellaceae, Athyriaceae and Pteridaceae, each of the six families contains over eight species. Phytogeographically, the pteridophyte species of Mt Wutongshan can be divided into nine areal types and six subtypes, and the main elements are of Tropical Asia distribution and Eastern Asia distribution. The fern flora is of tropical nature about 67% are tropical species.

Abstract:A taxonomic treatment of Polyspora Sweet （Theaceae） from China is given, based on the latest available data on DNA and morphology. It is revealed that Gordonia Ellis s. 1. is not a monophyletic group. The species from North America and from East Asia should be separated into two different genera, Gordonia Ellis s. str. and Polyspora Sweet, respectively. All Chinese species formerly placed in Gordonia are transferred to Polyspora and seven new combinations are proposed.

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