Abstract:Pometia tomentosa is a dominant uppermost canopy tree species of vallyland forest in Xishuangbanna tropical seasonal rainforest，China. Under different light intensities such as 100% natural sunlight (NS), 37.3% NS, 15.5%NS, 4.2% NS, 1.6% NS, 0.6% NS in shade house, growth characteristics were studied in early development stage and established seedlings. Light was an important environmental factor for the growth of P. tomentosa seedlings. During the early growth stage of seedlings, basal stem diameter and paripinnate number were decreased with the increasing of shade, taproot length, root : shoot ratio, total dry weight and leaf area per seedling were maximal under 37.3% NS, specific leaf area (SLA) was increased with the increasing of shade, but the relative growth rate was declined. Seedlings grew fastest under 0.6% NS, suggesting that nutrients stored in seeds played an important role at the early growth stage. The treatment of 37.3% NS was best for established seedlings in seedling height, basal stem diameter, paripinnate number, rachis length, the maximum sub-leaflet number of individual paripinnate, leaf area per seedling, relative growth rate and net assimilation rate. Light intensity was positively correlated to total dry weight, and negatively to specific leaf area. The maximum of SLA was observed under 15.5% NS. The fluctuations of SLA and root : shoot ratio in developmental established seedlings may be responsible for light intensity and soil moisture.

Abstract:The photosynthetic rate-light response curves, some morphological features of leaves and water relation parameters in leaves of eight common landscape climbing plants in South China: Mucuna birdwoodiana, Pyrostegia venusta, Passiflora edulis, Quisqualis indica, Clerodendron thomsonae, Pseudocalymma alliaceum, Illigera paviflora, and Cissus rhombifolia were investigated using one-year-old plant. The lower levels of maximum net photosynthetic rate (Pmax), light saturation point (LSP) and light compensation point (LCP), accompanied with no apparent photoinhibition under high light condition in all tested species revealed that their photosynthetic machinery had obvious plasticity in response to low and high light intensity. The instantaneous light use efficiency (ILUE), stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO2 concentration (Ci) varied with increasing light intensity. A positive correlation between Pn and Gs, and a negative correlation between ILUE and light intensity were observed in the range of light intensity from 500 μmol m-2s-1 to 1 700 μmol m-2s-1. Therefore, Gs and Ci are likely to be the main factors restricting net photosynthesis. However, no significant relationship was observed among leaf　thickness (LT) and water relation parameters (average water loss rate, rehydration rate, instantaneous water use efficiency). The values of Pmax, ILUE, IWUE, LT, leaf area and photosynthetic pigments (chlorophyll, carotenoid) contents differed pronouncedly among eight species. Three species, Mucuna birdwoodiana, Pyrostegia venusta and Passiflora edulis displayed an advantage in photosynthesis and water relations, whereas Illigera paviflora and Pseudocalymma alliaceum showed the lowest levels of these parameters.

Abstract:Effects of water stress on the diurnal changes of the net photosynthetic rate (Pn) in different seasons were investigated in 16-year-old trees of Litchi chinensis Sonn. cv. Nuomizi. In wet treatment the diurnal curves of Pn exhibited double peaks in autumn and summer, and a single peak in winter and spring, whereas in drought treatment they exhibited two peaks in winter and single peak in the other seasons. The maximum Pn or the first peak during daytime was generally the same in both treatments, which occurred at 9:00 in winter, 10:00 in spring and summer, 12:00 in autumn. The maximum Pn in wet- and drought-treated trees ranged from 6.25 μmol m-2s-1 to 8.14 μmol m-2s-1 and from 4.35 μmol m-2s-1 to 6.56 μmol m-2s-1, respectively. Moderate water stress could largely inhibit the photosynthesis of litchi tree, and the amount of daily Pn was decreased by 18.6%, 21.3%, 34.1% and 34.7% in winter, summer, spring and autumn, respectively. It was suggested that moderate water stress leads to Pn decrease by affecting stomatal conductance (Gs).

Abstract:The effects of sulfur and pH(5.0-8.0) on photohydrogen production was investigated in a unicellular green alga, Chlorella pyrenoidosa. Under continuous illumination of 165 μmol m-2s-1 conditions, in the TAP culture medium, changes of chlorophyll a content、Fv/Fm and ΦPSII indicated that growth of C. pyrenoidosa were very well at initialcultivation pH ranged from 6.0 to 7.0 and can form a temporary anoxic conditions in favor of H2 production. Maximum H2 production was obtained at initial cultivation pH 7.0 by C. pyrenoidosa. The maximum rate of H2 produced by C. pyrenoidosa was 0.10 ml mg-1 chl h-1 and the maximum total yield of H2 produced was 1.39 ml. In TAP-S culture medium, changes of chlorophyll a content、Fv/Fm and ΦPSII indicated that growth of C. pyrenoidosa were inhibited and can form a permanent anoxic conditions in favor of H2 production. The total yield of H2 production by C. pyrenoidosa in TAP-S culture was more than that in TAP culture. The Fv/Fm value of C. pyrenoidosa in pH 5.5 TAP-S culture was higher than the others culture. It indicated the residual PSII was more than the others. Under continuous illumination the electron of production H2 requirement mostly comes from PSII, so the maximum rate and total yield of H2 produced by C. pyrenoidosa appeared in pH 5.5 TAP-S cultures. The maximum rate of H2 produced by C. pyrenoidosa was 0.58 ml mg-1 chl h-1 and the total yield of H2 produced was 10.98 ml. The H2 production of C. pyrenoidosa was notable effected by sulfur and pH. In this test the best conditions for H2 production of C. pyrenoidosa was in pH 5.5 TAP-S cultures.

Abstract:Calcium distribution during the anther development of Jatropha curcas L. was observed under transmission electron microscopy by ultra-thin sectioning. At the sporogenous cell stage, very few calcium precipitates are found in the anther, but they are accumulated in the parenchymatous cells outside the vascular bundles. At the microspore mother cell stage, there are still few calcium precipitates in cytoplasm, but abundant calcium precipitates accumulate in the tapetal cell walls. After the tetrads form, abundant calcium precipitates appear in the cytoplasm of the microspores and tapetal cells. At the early microspore stage, numerous calcium precipitates accumulate in the microspore intine and abundant precipitates are found in the tapetal cells. At the late microspore stage, calcium precipitates accumulate on the vacuole membrane, but decrease in the tapetal cells. As starch grains accumulate in the mature pollen, very little calcium is found. At the same time, some calcium precipitates accumulate in the parenchymatous cells outside the vascular bundles. The character of calcium distribution during anther development of Jatropha curcas means that calcium plays some roles in biological significance during microspore development. Calcium precipitates are transported from the connective parenchyma cells into the tapetal cells, and they are transported into the pollen wall and cytoplasm. Quantity of calcium in the anthers during its whole developmental progress showed a changing tendency of few — increase — decrease.

Abstract:Twelve hybrid crosses among 3 cytoplasmic male sterile lines and 4 varieties of flue-cured tobacco popular in China were used to determine the heterosis in the following economic characters: yield, production value, average price, high class tobacco ratio, high and middle class tobacco ratio and tobacco class index. Results were as follows: (1) Heterosis from mid-parent was found in most crosses, and the yield and production value in 100.00％ crosses were significantly different at 0.05 or 0.01 levels, so were the other economic characters in 12.50％-83.33％ crosses; (2) Heterosis over higher-parent for yield and high class tobacco ratio was found in most crosses, and the heterosis of yield was in 75.00％ and high class tobacco ratio in 66.67％ crosses were significant at 0.05 or 0.01 levels, respectively. The others economic characters were in 8.33％-50.00％ of crosses with significance at 0.05 or 0.01 levels respectively. (3) The cross of MsYZ203-6 × Honghuadajinyuan showed significant heterosis over higher-parent in all economic characters expressed above, and cross of MsYZ206-9 × Yunyan87 showed significant heterosis over higher-parent in all economic characters above except average price.

Abstract:Variations in β diversity of forest communities along an altitudinal gradient were studied in Nanling National Nature Reserve, China. A horizontal transect (10 m × 120 m) was established at each 100-m altitudinal interval from an elevation of 300 m up to 1 900 m a.s.l. Correlation analysis, regression analysis and ANOVA were used to determine altitudinal patterns of β diversity and its relationship with environmental factors. Results were as follows: the Cody index and species turnover rate βC showed linearly and significantly negative correlations with altitude (P＜0.05) in base and adjacent belt transects. Shared species of community, canopy stratum, understory stratum decreased with increasing species turnover rate βC (P＜0.05). The Cody index could better reveal the species differences along altitude among communities, canopy stratum and understory stratum, based on analysis of one-way ANOVA, Fish’s LSD and Tukey’s HSD. Compared with community dissimilarity, the Bray-Curtis index, the Morisita-Horn index, species turnover rate Sβ and species turnover rate t, the Cody index and species turnover rate βC were useful to characterize the β diversity of forest communities along an altitudinal gradient in Nanling National Nature Reserve.

Abstract:Phenolic compounds are toxic allelochemicals widely distributed in agriculture and natural ecosystems. They accumulate largely in plant soils, inhibit plant growth and pollute environments. Oxidative degradation of phenolic allelochemicals by Fenton’s reagent was studied under natural conditions. In a 1.0 ml reaction solution containing 8×10-3 mol/L (0.028%) of hydrogen peroxide (H2O2), 5.4×10-4 mol/L (0.075%) of FeSO4, and 10-3 mol/L of phenolics or 160 μg ml-1 of soil extracts, p-coumaric acid was oxidized by 55% and 74% in 10 and 30 minutes, respectively; p-hydroxybenzoic acid was oxidized by 90% within 10 minutes; juglone was completely oxidized within 10 minutes. p-Coumaric acid, the main allelochemical in extracts of soil beneath forest of bamboo (Bambusa chungii), was oxidized by 75% in 2 h. Direct application of 0.1% or 1% of H2O2 of Fenton’s reagent to the soil from bamboo forest resulted in a 32% or 37% degradation of p-coumaric acid in the soil. Activities of antioxidant enzymes of catalase and peroxidase, but no superoxide dismutase, were detected in the bamboo soil. These enzymes may decompose H2O2 employed to soil and reduced its function in soil. Meanwhile, they are responsible for decomposition of surplus H2O2 in the soil. Results indicated that Fenton’s reagent might be a potential reagent for degradation of toxic allelochemcials in plant soils and cultural solutions.

Abstract:Using semi-quantitative method, we investigated the adaptabilities of 81 rare and endangered limestone plant species introduced to acidic soil in Guilin Botanical Garden, China. The adaptive ones accounted for 54%, moderate adaptive ones accounted for 27% of the total, less adaptive ones for 11%, unadaptive ones for 8%. Most introduced rare and endangered limestone plants are found adaptive or moderate adaptive to the habitat condition of the Garden. Of those unadaptive and less adaptive species, only a small portion were affected by soil condition, whereas others were affected by the difference of climate condition.

Abstract:Based on 5-year from 2001 to 2005 located observation in different types of forests in karst mountainous area in center of Guizhou Province, China, the annual surface runoff was from 1.765 to 22.934 mm in different forest types and from 10.553 to 11.699 mm in different observed years, with an average of 11.108 mm. The forest surface runoff changed in the order of young forest returned farmland (22.934 mm)＞ coniferous forest (17.236 mm)＞needle and broad-leaved mixed forest (10.770 mm)＞evergreen and deciduous broad-leaved forest (8.876 mm), which is similar to forests in the same or another bio-climate zones. And it is the common character of karst and nonkarst mountainous forests. The karst shrub forest was different from nonkarst in surface runoff due to mother rock properties. Surface runoff of the types was Summer＞Spring＞Autumn＞Winter, coincided with seasonal distribution of precipitation. Seasonal changing rule of surface runoff coefficients in young forest returned farmland was as same as seasonal distribution of surface runoff, and the rule in coniferous forest and needle and broad-leaved mixed forest was Summer＞Spring＞Winter＞Autumn, and the rule in shrub forest and evergreen and deciduous broad-leaved forest was Spring＞Summer＞Winter＞Autumn, and this difference was made by species composition and precipitation distribution. There existed remarkable correlation, accorded to line, between surface runoff in ten days and hydrological factors include precipitation,evaporation and relative humidity, and temperature factors include Max. and Min. and average temperature in air and surface and soil deepth in 5 cm, 10 cm, 15 cm and 20 cm. Results of contribution ratio to surface runoff from multi-variances regression analyses was that temperature is higher than hydrology, and this indicated temperature affected flow of air mass near surface, and influenced further precipitation and forested surface runoff. Influence of layer characteristics in different forest types on annual surface runoff had mutual beneficent and repellency based on community component, structure and development. Annual surface runoff was affected complexly by micro-habitat and surface soil characteristics of plots, and increased by slope of plots rising, and decreased by altitude of plots rising, there had remarkable negative correlation between annual surface runoff and total porosity and capillary pore, and contribution ratio of volume weight to annual surface runoff was -96.54%, based on multi-variances regression analyses.

Abstract:A quantitative survey was conducted to investigate the biodiversity characteristics of bryophytes in Heishiding Nature Reserve，Guangdong, China. 50 species of bryophytes in the five 2 500 m2 transects were found in which 30 were liverworts and 20 were mosses. Forty species of bryophytes occurred on trunks, which was much more than those on floor (only 24 species). Bryophyte coverage on trunks and floor was very low. Species richness of floor bryophytes in each plot was between 8 and 13 and the coverage was from 0.59%to 1.12%. The distribution and species richness of floor bryophytes were strongly affected by slope and micro-environments. Epiphytic bryophytes in each plot ranged from 12 to 20 species and the coverage was from 0.63% to 1.63%. This suggested that the species richness and coverage of bryophytes in 30-year-old secondary broadleaved forest have restored to the level of mature broad-leaved forest. Similarity analysis of bryophyte communities indicated that species composition of the mature forest was similar to that of the mixed pine and broad-leaved forest and young secondary forest, but community structure of the former was quite different from the latter. More studies are needed to understand the mechanism of low coverage of floor and epiphytic bryophytes.

Abstract:The moss Neckeropsis moutieri (Broth. & Par. in Par.) Fleisch. (Neckeraceae) is reported herein new to the moss flora of China, representing the first record of the species newly discovered outside southeast Asia. It differs from the closely related species Neckeropsis takahashii Higuchi et al. in its filamentous pseudoparaphyllia and weaker intra-marginal borders. The species is illustrated and described based on the Chinese material. A key to the 11 species of Neckeropsis Reichardt in China is presented.

Abstract:Rungia sect. Stoloniferae C. M. Gao & Y. F. Deng, a new section in the genus Rungia Nees of Acanthaceae is described. It is characterized by the spike not secund, both bracts at each node fertile, homomorphic.

Abstract:A new variety, Ardisia lindleyana var. angustifolia C. M. Hu & X. J. Ma is described. It differs from the type variety by its leaves being linear-lanceolate, 7-13.5 cm long, only 4-7 mm broad. Superficially, it strikingly resembles A. ensifolia E. Walker and A. quinquegona Blume var. salicifolia (E. Walker) C. M. Hu & J. E. Vidal, but can be easily distinguished by its rusty puberulent branchlets, inflorescences terminal on leafy branchlets, and leaves with marginal glands.

Abstract:Berberis jinshajiangensis X. H. Li nom. nov. is suggested to replace Berberis micropetala T. S. Ying (1999)，a later homonym of Berberis micropetala C. K. Schneid. (1939).

Abstract:Longan germplasm resources are very important for the breeding study. The genetic relationships of germplasm resources are the scientific basis for longan’s origin, evolution, classification, breeding and application. The research advances in genetic relationships of longan germplasm are reviewed in the following aspects:morphology, palynology, biochemistry and genetics. The prospects of longan germplasm resources are also discussed.