Abstract:Five new taxa of Myrsinaceae from China, Ardisia waitakii, A. linangensis, A. malipoensis, A. crassirhiza, Maesa consanguinea var. confusa are described and illustrated; Five names (Ardisia elegantissima Leveille, A. glauca pitard, A. corymbitera var. tuberifera C. Chen, A. kwangtungensis Walker, Maesa prodigiosa C. Chen,)are reduced to synonyms and several confused or misidentified species of Ardisia and Maesa are clarified and corrected.

Abstract:

Abstract:In the present paper, practical programs for the quantitative study of the seed plant flora of any a given region of China are worked out according to the areal-type classification of seed plants of China proposed by Professor C. Y. Wu. By use of these programs, the statistical data of the seed plant areal-types, composition of families, genera and species of any a given seed plant flora as well as the Jaccard's similarity coefficient of genera of this flora with another one can be readily and exactly obtained.

Abstract:A survey dealing with epiphyllous liverworts in Heishiding Natural Reserve, Guangdong Province, is first reported for epiphyllous liverworts in the west part of the province. Two families, 7 genera, 13 species and 1 variety of epiphyllous liverworts were found. The most common species of them are Leptolejeunea elliptica and Radula acuminata, and then Leptolejeunea hainanensis and Cololejeunea floccosa, which distribute in the evergreen broadleaved forests in ravines at 350m to 600m above sea level. From the viewpoint of bryoflora analysis, epiphyllous liverworts in Heishiding are similiar to that as in Wu yi Mt. (Fujian Province) , in Xishuangbanna and Taiwan. The similiar to each other species in these regions make up 50-70%, which are the major elements of South Asia and have significantly endemic to China species, amounting to 28. 5%.

Abstract:Karyotypes from the flower bud of nine tea (Camellia smensis (L. ) Kuntze) cultivars were studied. Somatic chromosome numbers of these cultivars were 2n = 30, i. e diploids, except culti-var 'Zhenghe Dabaicha' which was 2n = 45, a triploid. The characteristics of the karyotypes of all the cultivars were diferent to some extent. According to chromosome classification, karyotypes of those with tree form and large leaf were more symmetric, belonging to 2A type, and those with shrub form and smaller leaf were less symmetric, belonging to 2B type. The results indicated that the cultivars having tree form and large leaf were less developed in origin, which supported the result of other researchers, and that using flower bud as reaearch material in tea chromosome study was an effective and convenient way.

Abstract:Actin filaments were localized in the isolated generative cells of Allamanda schoteii and Hedyehir-um coranarium using fluorescence labeled phalloidin. In the generative cells of A. schuteii an actin cytoskeleton was revealed. This cytoskeleton was characterized by having a network consisting of thick bundles in the cytoplasm and around the nucleus. The pattern of organization of the actin filament cytoskeleton in the generative cell of H. coranarium was slightly different. It possessed a more well developed cytoskeleton consisting of an actin network and a more tightly packed mass of actin filaments around the nucleus. The pattern of distribution of the actin filaments in the dividing generative cells of A. schcteii was also followed. This was done by using immunofluo-rescence technique instead of fluorescence labeled phalloidin; because the fluorescence labeled phalloidin failed to stain the actin in the dividing cells. Using the immunofluorescence technique an actin network in the prophase cell was observed. When the cell entered metaphase the actin filaments reorganized into a spindle-shaped structure. In the anaphase and telophase cell, filaments were no longer seen. The cell became filled with punctate anti-actin fluorescence not unlike that seen in the root-tip cells of wheat by McCurdy and Gunning.

Abstract:Embryonic axes excsied from fresh lychee and longan seeds could be cultured and developed into plantlets in non-hormonal WPW medium with pH4. 8-8. 0. The addition of NAA and KT to the medium caused the inhibition on the normal growth of embryonic axes. The critical moisture contents of the embryonic axes of lychee and longan were about 30% and 23% respectively. Desiccation beyond these thresholds, the viability fell rapidly, and the embryonic axes could not produce normal plantlets after incubation for 25 days. The viability of embryonic axes desiccated by silica gel decreased more quickly than that of non desiccated ones after short-time storage , and the embryonic axes were easily infected by bacteria during incubating. The survival percentages of lychee and longan embryonic axes desiccated to about the critical moisture contents were 0 and 25-50%, respectivity, when they had been storaged in liquid nitrogen for 24 hours.

Abstract:Chinese Wampee seed which is very sensitive to desiccation is a typical recalcitrant seed. Initially, the mean moisture contents of seeds were about 51% (wmb). The viability and germination index of seeds were lost completely when moisture content decreased to 22. 4%. As seeds dry naturally, the content of soluble sugar in seeds increased and the content of starch in seeds decreased. In the meantime, the activities of phosphorylase and isocitrate lyase in seeds, and that of α-and β-amylase in embryonic axes rose initially, and then declined. These changes were very similar to those occured in the germinating seeds of Chinese Wampee and pea. It is considered that the reason why Chinese Wampee seeds are sensitive to desiccation might be that the seeds germinate at their shedding. As these germinationrelated events proceed, the seeds become increasingly sensitive to desiccation, water becomes a limiting factor and the viability of seeds is lost.

Abstract:Oxygen consumption of mitochondria isolated from mung bean seeds and leaves was determined with an oxygen electrode in the dark or light. In mitochondria isolated from mung bean leaves, strong light (40 000 Ix) suppressed the NADH oxidation by 11. 8% through cytochrome pathway, and the capacity of the alternative pathway was increased by 71. 5 %. This suggested that illumination caused part of the electrons diverting from the cytochrome pathway to the alternative pathway. It was postulated that one of the physiological functions of the alternative pathway was to regulate the balance between levels of NADH and high-energy phosphate in green cells. The mechanism of this light effect on the change in respiratory pathway still remains unknown. The mitochondria from germinated seeds of mung bean, however, were different to that from leaves of mung bean, it showed no response to light.

Abstract:Phosphoenolpyvate carboxykinase (PEPCK, EC 4. 1. 1. 49) from pineapple leaf was puri-fied by the procedures including amm-onium sulfate precipitation, chromatography on Sephadex G-200 and DEAE-cellulose. The purified enzyme showed a homo-genous band oh polyacry-lamide gel electrophoretogram. The conformation of PEPCK protein was studied by ultraviolet absorption difference spectrum and fluorescence spectrum. The binding of enzyme with substrate and Mn2+ resulted in the changes of ultraviolet absorption difference spectra at peak sharpness, height and orientation. Substrate OAA induced a broad negative band at 268-280nm, but two negative bands at 242. 5nm and 273. 5nm were observed when another substrate ATP was bound alone to PEPCK. By addition of both ATP and OAA, the spectrum showed two positive peaks at 252nm and 268nm. The changes of spectra orientation and shift of wavelength were found in the presence of Mrt2+ either with ATP or ATP+OAA. The enzyme protein solution showed a maximum fluorescence emission at 323nm, OAA markedly enhanced the emission, whereas ATP or ATP + Mn2+ declined the fluorescence. The combination of OAA+ATP+Mn2+ with PEPCK induced the further decrease of fluorescence. These results suggest that the alternative conformation states was generated during the binding of PEPCK to its substrate and metal ion. The difference conformation state between PEPCK + OAA and PEPCK + ATP indicated that these two compounds were bound to different sites of PEPCK protein. Mn2+ might bind together with ATP on the same site of enzyme. The changes of spectra orientation caused by Mn2+may be explained as a beneficial conformation for catalysis of PEPCK.

Abstract:When mung bean seedlings were grown under natural condition for 12 days, leaves were cut off and floated on water. These detached leaves were treated with dark, white light and blue light respectively. The light intensity was 10 ± 2 μmol· m-2s-1. Some physiological parameters were determined during 8 days of treatment. As compared with the treatment in the dark, the treatments with blue and white lights were more effective in retarding the losses of chlorophyll and protein. However, there were no sig nif-icant difference in contents of these two substances under white and blue lights. In addition, blue light led up to the obvious opening of stomata and the increase of transpiration rate. After blue light illumination, SOD activity was maintained at a higher level and the increase of relative permeability of plasmalemma was retarded. The results indicate that blue light is able to retard the senescence in detached leaves of mung bean seedling.

Abstract:DCMU-enhanced chlorophyll fluorescence ratio of marine algae [Halymenia sinensis (red alga), Ulva pertusa (green'alga), Underia pinnatifita (brown alga) and Spirulina platensis (blue-green alga)] was studied. It was found that the red alga had the highest ratio (3. 9) among these species. The green one and blue-green alga had the value of 2. 5 and 2. 8 respectively. The ratio for U. pinnatifida (collected in summer season) was as low as 1. 7. FD/FN values declined obviously under the effects of stresses (dehydration or heat). If also reduced when the algae senesced. So this ratio can be used as a sensitive index of photosyhthetic capacities of marine algae. In addition, the FD/FN values of two phytoplanktons (red tide species) Prarocentrum micans and Chaetoceras minutissmus both in batch culture, and their relation to growth rate were investigated. The resnlts indicated that both FD/FN value and U changed with the time of culture, but the important fact was that the maximum value of fluorescence ratio was reached always prior to the appearing of the maximum of growth rate. This results presented a good prospect for using fluorescence in vivo in the research of red tide occurence.

Abstract:Along with ent-kauran-16β, 17-diol, a new diterpene, paraquilegin was isolated from the non-basic fraction of Paraquilegia anemmoides and its structure was determined by spectroscopic analysis and chemical correlation.

Abstract:The EtOH extract of the root of the Chinese herb Achyranthes bidentata B1. was subjected to column chromatography to obtain abidenine (1), a new isoquinoline alkaloid. 1 is bright needle crystals, m. p. 200℃ (dec). Its structure was elucidated through spectroscopic methods as 5,6-dihydro-2,3,10,11-tetramethoxy-dibenzo [a,g] quino-lizinium (1).

Abstract:The chemica1 constituents of 171essential oil samples of Artemisia L. in China were analysed and 305 compounds were identified. In the samples analysed , 64 species were included and 47 of which were from the sections of Subgen. Artemisia and the rest were from the sections of Sub gen. Dracomcubre (Bess. ) Peterm. According to the analyses, there is a regularity for the distribution of these compounds in above two subgenera. The major constituents of the essential oils from Subgen . Artemisia are monoterpenoids and sesquiterpenoids, while that from Subgen. Dracumculus (Bess. ) Peterm. are sesquiterpenoids and aromatic compounds. It means that the distribution of chemical constituents is correlated with the classification of Artemisia L. , in which the species from more primitive to advanced can be divid ed into 7 sections as follows. Subgen. Artemisia: Sect. Absinthium DC. (monoterpenoids) - Sect. Abrotanum Bess. ( monoterpenords ) - Sect. Artemisia (monoterpenoids) - Sect. Viscidipubes Y. R. Ling (monoterpenoids and sesquiterpenoids)-Sect. Albibractea Y. R. Ling (sesquiterpenoids). Subgen, Drameulus (Bess. ) Peterm. : Sect. Dracunculus Bess, (sesquiterpenoids and aro matic compounds)-Sect. Latilobus Y. R. Ling (sesquiterpenoids and aromatic compounds).

Abstract:Diurnal changes of transpiration rate and stomatal conductance in Rhizophora stylusa Griff. mangrove forest and some ecological factors were determined by porometer in Hainan. In the sunny day in December, transpiration rate of the forest canopy reached its peak between 10 to 11 o'clock at 4. 27 - 4. 34μg · cm-2s-1, and decreased at noon. It was shown that the complex correlation between transpiration rate of community and ecological factors, i. e. , photosynthetic active radiation (PAR), leaf-air vapour pressure difference, air temperature, relative humidity and leaf temperature, was very significant. The critical factors affecting transpiration rate of the community were PAR, relative humidity and leaf-air vapour pressure difference. The everage of total transpiration rate of R. stylosa forest was 2502 g H2O · m-2d-1, of which the transpiration rate of the canopy accounted for 63%.

Abstract:Litterfall and its monthly variation, litter standing crop, and the litter decomposition rate in the lower subtropical evergreen broad- leaved forest of Heishiding Natural Reserve, Province Guangdong, were studied from Aug. 1989 to Aug. 1991. the forest is at 400 m above sea level , which was dominated by Ixonanthes chinensis, Artocarpus styracifolins, Ormosia glaberrima, Crypto-carya cancinna, Calamus rhabdocladus, Cibotium, barametz, etc. As measured, amount of small litter-fall including leaves, branches less than one centimeter in diameter, flowers and fruits, and trash was 5. 230 t · ha-1 per year (mean for 2 yrs. ) among which leaves, branches, and flowers and fruits were 3. 550(68. 22%), 0. 837(15. 81%), and 0. 582(10. 97%) respectively. It was obvious that the litterfall varied monthly. Greater leaf litterfall occured in the wet season, with a peak in April, while flower and fruit litterfall was more in Autumn and Winter. Big branch (diameter over 1 cm) litterfall was 0. 34 t · ha-1per year (mean for 2 yrs. ), with significant yearly variation. Litter standing crop amounted to 5. 545 t · ha-1, among which leaves, branches, and flowers and fruits were 3.275 (59.06%), 1. 618(29. 18%), and 0. 131(2. 36%) respectively. Leaf litteffall and standing crop of leaf litter were about 1/4 and 1 /5 of the leaf biomass respectively. It took about 5 months for the litter to lose half of its weight in wet season. The lit ter decreased to 19 % of the original weight in 18 months.

Abstract:A new method has been developed to introduced foreign DNA into rice cells. Gene delivery occurs when a low-voltage electrophoresis at long pulse applied to a mixture containing partially digested SCG (small cell groups) and plasmid DNA. Gene-transfer efficiency is evaluated by a detection of GUS activity resulting from the chimeric plasmid DNA. The optimal combination of voltage and pulse produces a frequency of up to 8. 2% for transformation of SCG. The results demonstrates that electrophoretic drive is applicable to introduce foreign genes into plant cells.