海南鹦哥岭自然保护区的珍稀濒危植物与保育

对鹦哥岭的珍稀濒危植物进行野外调查表明,本区共有野生分布的珍稀濒危植物79种,隶属于47科71属。其中属于1999年国家重点一级保护4种,如海南苏铁(Cycas hainansis)、坡垒(Hopea hainansis)、台湾苏铁(Cy-cas taiwaniana)和伯乐树(Bretschneidera sinensis),国家二级保护14种。建议将18种列入国家保护名录中,20种列入省级保护名录,其中有30种为海南特有种。鹦哥岭珍稀濒危植物面临的威胁主要有原始森林面积的减少、人为毁林开荒和分布区限制。针对珍稀濒危植物的现状和受到的威胁,提出了应重点加强保护的6个地点及相应的保护对策和建议。     

华西银腊梅挥发油化学成分的研究

用水蒸气蒸馏法提取华西银腊梅挥发油,并用气相色谱-质谱(GC-MS)联用技术对其挥发油的化学成分进行分析,结果共鉴定了其中的39种成分,所鉴定成分含量约占总检出量的87.83%。其化学成分主要为(Z,Z)-9,12-十八碳二烯酸甲酯(9.00%),壬醛(5.83%),二十一烷(5.69%),二十烷(5.08%),辛炔酸(4.50%),2,6,10,15-四甲基十七烷(3.93%),(Z)-6-十八烯酸甲酯(3.65%),3,8-二甲基十一烷(3.52%),1-十六碳炔(3.31%),肉豆蔻酸(2.86%),月桂醛(2.81%),壬酸(2.23%),5,6,7,7α-四氢-4,4,7α三甲基-2(4H)-苯并呋喃酮(2.18%)等。     

Aerotaxis and chemotaxis ofAzospirillum brasilense: A note

Azospirillum brasilense was attracted to capillaries containing either phosphate buffer, distilled water, or saline. The number of bacteria in these capillaries was 3–4×10⁴, after 1 h of incubation. In the presence of phosphate buffer + attractants, the number of cells accumulated in the capillary increased only to 5×10⁴–1.1×10⁵ cells. It was not possible, therefore, to measure chemotaxis inA. brasilense as distinct from aerotaxis by the capillary method. Chemotaxis was observed in semi-solid agar plates and was determined by a growth band oriented towards the attractant. Positive chemotactic response was obtained with peptone, tryptone, yeast extract, amino acids, organic acids, arabinose and galactose.     

Isolation and characterization of microsatellite markers in Koompassia malaccensis (Leguminosae), an important tropical timber species

This paper reports the isolation and characterization of 24 polymorphic microsatellite markers in an important tropical timber species, Koompassia malaccensis (Leguminosae). The primers were designed from a genomic library enriched for dinucleotide (CT) repeats and screened on 24 samples from a natural population. The number of alleles detected per locus ranged from two to 13 while the observed heterozygosity ranged from 0.042 to 1.000. Significant departure from Hardy–Weinberg equilibrium (P < 0.05) was detected in two loci. These microsatellite markers were tested across 13 timber species of the same family. The amplification success appeared to be associated with taxonomy classification at the genus but not subfamily levels.     

Construction of a cross-species cell landscape at single-cell level

Individual cells are basic units of life. Despite extensive efforts to characterize the cellular heterogeneity of different organisms, cross-species comparisons of landscape dynamics have not been achieved. Here, we applied single-cell RNA sequencing (scRNA-seq) to map organism-level cell landscapes at multiple life stages for mice, zebrafish and Drosophila. By integrating the comprehensive dataset of > 2.6 million single cells, we constructed a cross-species cell landscape and identified signatures and common pathways that changed throughout the life span. We identified structural inflammation and mitochondrial dysfunction as the most common hallmarks of organism aging, and found that pharmacological activation of mitochondrial metabolism alleviated aging phenotypes in mice. The cross-species cell landscape with other published datasets were stored in an integrated online portal—Cell Landscape. Our work provides a valuable resource for studying lineage development, maturation and aging.     

Effects of Exhaustion and Calcium Supplementation on Adrenocorticotropic Hormone and Cortisol Levels in Athletes

The present study was performed to investigate the effects of strenuous exercise and calcium supplementation on cortisol and adrenocorticotropic hormone levels in athletes at rest and exhaustion. Thirty male athletes, ages 17–21 years, were enrolled in the 4-week study. They were divided into three groups as follows: group 1 (n = 10): training without supplementation; group 2 (n = 10): training and calcium supplemented, and group 3 (n = 10): calcium supplemented without training. Venous blood samples were obtained for determination of the hormones. One-month supplementation with calcium does not influence the cortisol and adrenocorticotropic hormone in athletes, but strenuous exercise results in a significant increase in their levels with or without supplementation (p < 0.05).     

An Ultrastructural Investigation of 180°-Rotated Ciliary Meridians in Tetrahymena pyriformis*

SYNOPSIS. An ultrastructural investigation has been carried out on 180°-rotated ciliary meridians (inverted meridians) in Tetrahymena pyriformis temperature-sensitive mutant (mol^b/mol^b), syngen 1, strain B. The longitudinal, transverse and postciliary microtubular bands, the kinetodesmal fiber, and the parasomal sac, are shown to be disposed at a 180° angle to their normal positions or orientations. Other abnormalities are as folows: the first 2 basal bodies of the inverted meridian fail to organize into “couplets” and the inverted meridian intrudes into the anterior pole region; an extra longitudinal microtubular band is found in one of the cell lines.     

Growth-regulator Interactions in the Growth of the Shoot System of Avena sativa Seedlings: I. THE GROWTH OF THE FIRST INTERNODE

1. Segments, 3.5 mm. long, cut from the first internode of Avenasativa seedlings grown in complete darkness respond to bothauxins and gibberellic acid by accelerated extension. 2. The optimum concentration of indole-3-acetic acid (IAA) is10 p.p.m. and of gibberellic acid (GA) is 0.1 p.p.m. 3. The degree of stimulation relative to the growth of controlsegments is affected by the inclusion in the segement of thenode between the internode and coleoptile. Thus the gibberellineffect is greatly increased while the IAA effect is decreased.The optimal concentrations are not affected by inclusion ofthe node. 4. These results can best be explained in terms of the supplyby the node tissue of an endogenous auxin which is necessaryfor the expression of GA action. 5. Numerous factorial experiments demonstrated that there isno detectable interaction between applied IAA and GA in thepromotion of first-internode extension. This implies that thepostulated endogenous auxin which synergized GAA action in (4)is either an active form of IAA produced only in the node tissueor is a completely different auxin. 6. No synergism of growth-promotive action can be detected betweenGA and the two synthetic auxins I-naphthylacetic acid and 2,4-dichlorophenoxyaceticacid. 7. p-chlorophenoxy-iso-butyric acid (PCIB) anc 2,4,6-trichlorophenoxyaceticacid (2,4,6-T) act as weak auxins and thus antagonize competitivelythe promotive action of GA. 8. The anti-auxin -(I-naphythyl-methyl-sulphide)propionic acid(NMSP) antagonizes competitively the promotive action of bothIAA and GA. 9. The facts under (5)–(8) suggest that auxins and GAare acting at the same growth-promotion centres and may competefor them. 10. Growth inhibitions are induced by high concentrations ofPCIB, 2,4,6-T and NMSP. The inhibitions produced by PCIB and2,4,6-T are both synergized by supra-optimal concentrationsof IAA while that of NMSP is synergized by supra-optimal concentrationsof both IAA and GA. This similarity of the effects of IAA andGA suggests that their inhibition actions also are of a closelysimilar nature.     

Response of plant species richness and primary productivity in shrublands along a north–south gradient in Europe to seven years of experimental warming and drought: reductions in primary productivity in the heat and drought year of 2003

We used a nonintrusive field experiment carried out at six sites – Wales (UK), Denmark (DK), the Netherlands (NL), Hungary (HU), Sardinia (Italy – IT), and Catalonia (Spain – SP) – along a climatic and latitudinal gradient to examine the response of plant species richness and primary productivity to warming and drought in shrubland ecosystems. The warming treatment raised the plot daily temperature by ca. 1 °C, while the drought treatment led to a reduction in soil moisture at the peak of the growing season that ranged from 26% at the SP site to 82% in the NL site. During the 7 years the experiment lasted (1999–2005), we used the pin‐point method to measure the species composition of plant communities and plant biomass, litterfall, and shoot growth of the dominant plant species at each site. A significantly lower increase in the number of species pin‐pointed per transect was found in the drought plots at the SP site, where the plant community was still in a process of recovering from a forest fire in 1994. No changes in species richness were found at the other sites, which were at a more mature and stable state of succession and, thus less liable to recruitment of new species. The relationship between annual biomass accumulation and temperature of the growing season was positive at the coldest site and negative at the warmest site. The warming treatment tended to increase the aboveground net primary productivity (ANPP) at the northern sites. The relationship between annual biomass accumulation and soil moisture during the growing season was not significant at the wettest sites, but was positive at the driest sites. The drought treatment tended to reduce the ANPP in the NL, HU, IT, and SP sites. The responses to warming were very strongly related to the Gaussen aridity index (stronger responses the lower the aridity), whereas the responses to drought were not. Changes in the annual aboveground biomass accumulation, litterfall, and, thus, the ANPP, mirrored the interannual variation in climate conditions: the most outstanding change was a decrease in biomass accumulation and an increase in litterfall at most sites during the abnormally hot year of 2003. Species richness also tended to decrease in 2003 at all sites except the cold and wet UK site. Species‐specific responses to warming were found in shoot growth: at the SP site, Globularia alypum was not affected, while the other dominant species, Erica multiflora, grew 30% more; at the UK site, Calluna vulgaris tended to grow more in the warming plots, while Empetrum nigrum tended to grow less. Drought treatment decreased plant growth in several studied species, although there were some species such as Pinus halepensis at the SP site or C. vulgaris at the UK site that were not affected. The magnitude of responses to warming and drought thus depended greatly on the differences between sites, years, and species and these multiple plant responses may be expected to have consequences at ecosystem and community level. Decreases in biodiversity and the increase in E. multiflora growth at the SP site as a response to warming challenge the assumption that sensitivity to warming may be less well developed at more southerly latitudes; likewise, the fact that one of the studied shrublands presented negative ANPP as a response to the 2003 heat wave also challenges the hypothesis that future climate warming will lead to an enhancement of plant growth and carbon sequestration in temperate ecosystems. Extreme events may thus change the general trend of increased productivity in response to warming in the colder sites.