滇西北野生观赏花卉调查

依据野外调查结果和有关文献资料,运用统计和比较的方法,对滇西北地区野生花卉的多样性进行了研究。结果表明,滇西北野生花卉有83科324属2206种。其中草本花卉1,163种,木本花卉。743种,滇西北特有野生花卉751种,珍稀濒危花卉35种。本文对滇西北地区野生花卉植物的种类、分布、观赏类型、花色、花期、受威胁状况以及特有现象进行了详细地统计分析。发现滇西北地区花卉植物的丰富度依次为丽江、中甸、贡山、德钦、维西、鹤庆、福贡、洱源、大理、兰坪。从垂直分布上看,海拔2400～3000m以及海拔3500m以上的地段花卉植物较为丰富,且特有和珍稀濒危野生花卉植物也较多地集中在这两个地段。按花色紫蓝、橙黄、红、白四大类型分类,则以紫蓝花种类最为丰富(约400种)、橙黄花次之(约230种)、红花较少(约170种)、白花最少(约140种)。     

In vitro propagation of Stackhousia tryonii Bailey (Stackhousiaceae): a rare and serpentine-endemic species of central Queensland, Australia

Stackhousia tryonii Bailey, a rare species whichhyperaccumulates nickel and with a potential to be exploited inphytoremediation/phytomining, is difficult to propagate via seeds. This studyinvestigated the development of a micropropagation protocol for the productionof large stocks of S. tryonii. Disinfested shoot tips andnodal buds were precultured on Gamborg's (B₅) basal medium toobtain aseptic shoots for the optimisation of the protocol. 6-Benzyl aminopurine(BAP) at 1.0 mg l^–1 produced the highest number ofshoots per explant in B₅ medium. Comparison betweenB₅ and MS media showed similar responses, but with marked influenceof BAP concentration on shoot numbers. Transfer of shoots from MS(multiplication) medium to MS medium supplemented with indole-3-acetic acid(IAA) and indole-3-butyric acid (IBA), individually or in combination, indicatedthat a combination of IAA and IBA (0.75 mg l^–1each) is required to produce roots on young shoots (75%) compared to IBA(15–45%) or IAA (0–10%) alone. This study demonstrated that by usingthis protocol, a high multiplication rate (up to 18 shoots per explant) could be produced within 4 weeks, andthey can be readily hardened (98% survival) in a glasshouse by transplantingthem into a potting mixture of sand and perlite (4:1).     

Promotion of indole alkaloid production in Catharanthus roseus cell cultures by rare earth elements

Production of the indole alkaloids, ajmalicine or catharanthine, in cell suspension cultures of Catharanthus roseus was enhanced by cerium (CeO₂ and CeCl₃), yttrium (Y₂O₃) and neodymium (NdCl₃). The yield of ajmalicine in these treated-cultures reached 51 mg l^–1 (CeO₂), 40 mg l^–1 (CeCl₃), 41 mg l^–1 (Y₂O₃) and 49 mg l^–1 (NdCl₃) while catharanthine production reached to 36 mg l^–1 (CeO₂) and 31 mg l^–1 (CeCl₃). A major portion of increased alkaloids was released into medium in these treatments. But Sm₂O₃, SmCl₃, La₂O₃, LaCl₃, complex of chromium (III)-titanium (IV) and NaSeO₄ treatments had little effect on alkaloid production of C. roseus cell cultures.     

Subpicogram analysis of sweat proteins using two-dimensional polyacrylamide gel electrophoresis

Sweat collected from six normal volunteers was analyzed to determine if reproducible protein patterns could be obtained using two-dimensional polyacrylamide gel electrophoresis of ¹²⁵I-labeled sweat proteins. This method has the capability of easily detecting picogram quantities of protein. Once the methods of collection of the sweat had been standardized, reproducible patterns were obtained from these volunteers. Over 100 discrete spots were revealed by a combination of fluorography and rare earth screen radioautography of dried two-dimensional gels. This method will allow analysis of sweat for qualitative and quantitative variations in protein content in pathologic conditions such as cystic fibrosis, renal failure, and diabetes.     

Presence and possible origin of positive Eu anomaly in shoot samples of Juncus effusus L

BackgroundThe rare earth elements (REE) are non-essential elements for plants. They stimulate plant growth at low doses, but at high levels are phytotoxic. There are differences in concentrations of REE in various organs of the same plant species, but the normalized REE patterns can be very similar in samples of the same species collected in different locations. Here we compare normalized REE curves in above-ground samples of Juncus effusus L. (common rush, soft rush) collected from sites with different land-use types.MethodsThe concentrations of rare earth elements were measured in 55 shoot samples of J. effusus L. The samples were collected from 15 sampling sites located in the Holy Cross Mts., south-central Poland and analyzed with the use of inductively coupled plasma mass spectrometry (ICP-MS). The results were normalized to the North American Shale Composite and anomalies of different elements were calculated.ResultsTotal REE concentrations varied from 0.028 mg/kg to 2.7 mg/kg. The samples were enriched in the light REE (from La to Eu) with the highest concentrations of La and Ce. The North American Shale Composite (NASC)-normalized REE curves were roughly similar in all samples except for two samples collected in the acid mine drainageaffected areas.ConclusionAll samples showed positive europium anomalies in NASC-normalized REE concentration patterns. The most probable explanation of this is that the uptake and translocation of Eu in J. effusus (and possibly in other wetland plants) is caused by a short-term decrease of the redox potential in a rhizosphere favoring reduction of Eu³⁺ to Eu²⁺ and thus enhancing Eu mobility in the soil-plant environment.     

The Geomagnetic Field Is a Compass Cue in Cataglyphis Ant Navigation

1. Download high-res image (135KB)
2. Download full-size image

     

Molecular and cellular basis of ornithine δ-aminotransferase deficiency caused by the V332M mutation associated with gyrate atrophy of the choroid and retina

Gyrate atrophy (GA) is a rare recessive disorder characterized by progressive blindness, chorioretinal degeneration and systemic hyperornithinemia. GA is caused by point mutations in the gene encoding ornithine δ-aminotransferase (OAT), a tetrameric pyridoxal 5′-phosphate-dependent enzyme catalysing the transamination of l-ornithine and α-ketoglutarate to glutamic–γ-semialdehyde and l-glutamate in mitochondria. More than 50 OAT variants have been identified, but their molecular and cellular properties are mostly unknown. A subset of patients is responsive to pyridoxine administration, although the mechanisms underlying responsiveness have not been clarified. Herein, we studied the effects of the V332M mutation identified in pyridoxine-responsive patients. The Val332-to-Met substitution does not significantly affect the spectroscopic and kinetic properties of OAT, but during catalysis it makes the protein prone to convert into the apo-form, which undergoes unfolding and aggregation under physiological conditions. By using the CRISPR/Cas9 technology we generated a new cellular model of GA based on HEK293 cells knock-out for the OAT gene (HEK-OAT_KO). When overexpressed in HEK-OAT_KO cells, the V332M variant is present in an inactive apodimeric form, but partly shifts to the catalytically-competent holotetrameric form in the presence of exogenous PLP, thus explaining the responsiveness of these patients to pyridoxine administration. Overall, our data represent the first integrated molecular and cellular analysis of the effects of a pathogenic mutation in OAT. In addition, we validated a novel cellular model for the disease that could prove instrumental to define the molecular defect of other GA-causing variants, as well as their responsiveness to pyridoxine and other putative drugs.     

Combined effects of heat shock, smoke and darkness on germination of Epacris stuartii Stapf., an endangered fire-prone Australian shrub

Epacris stuartii (Epacridaceae) is an endangered heathland shrub in which seedling recruitment occurs almost exclusively after fire. Seed viability and multiple seed dormancy mechanisms were examined to explore why levels of seedling recruitment were low after some fires, despite high rates of pre-fire seed production. The individual and combined effects of heat shock, smoke derivatives and darkness on germination were tested in the laboratory using an orthogonal logit-linear model, a form of analysis ideally suited to hypotheses concerning multiple germination cues. Seed viability (56%) was found not to be limiting. After 89 days of incubation, germination was significantly enhanced by heat shock, smoke treatment and continuous darkness but there were no significant interactions. These effects were equal in magnitude and additive such that maximum germination (42% of viable seeds) was stimulated when all three treatments were combined, significantly less germination occurred in response to any two treatments combined (22–23%), any single treatment stimulated germination at levels (10–11%) significantly less than two treatments and the lowest levels of germination occurred among untreated seeds (4%). Relative to the untreated control, germination was stimulated by smoke derivatives in high concentrations but not in low concentrations. The effect of darkness diminished with time so that after 270 days of incubation darkness had no significant effect on germination, while heat and smoke still enhanced germination significantly, additively and interchangeably. More prolonged germination of seeds exposed to light on the soil surface than buried seed may spread the risk of desiccation of emerging seedlings over multiple rainfall events. The role of heat and smoke derivates suggests that fire management is a crucial tool for influencing seedling recruitment and hence the survival of E. stuartii at its only known location. Received: 3 November 1996 / Accepted: 15 June 1997     

不同温度下稀土元素对展萼花臂尾轮虫的影响

15℃时,稀土元素对轮虫种群增长具有明显的促进作用,随着稀土元素含量的增加,轮虫种群密度随之上升,后代混交百分率呈逐渐上升趋势,稀土浓度为0.005mgL-1时,种群平均携卵率量高于其它浓度组,混交率居中。25℃和30℃时,稀土适宜浓度为0.001mgL-1,在该浓度下种群密度最大、混交率较低,平均携卵量居中。30℃时,0.010mgL-1对种群增长具抑制作用。       

香港珍稀濒危植物的分布及保育

在第一批共３８８种中国重点保护的珍稀濒危植物中,有１４种分布于香港特别行政区。其中蕨类植物２种,裸子植物２种,被子植物１０种。此１４种珍稀濒危植物,除了狭叶瓶尔小草外,亦分布于广东省。而其中被列为国家级渐危种类的土沉香及白桂木,在香港则较为常见。本文阐述了此１４种珍稀濒危植物在香港的分布情况及其保育工作。