Przewalskia tangutica is an endangered alpine plant,found in the Qinghai-Tibet Plateau,contains tropane alkaloids as its main active ingredients.The roots,seeds and whole herb of P.tangutica are used in medicine and have significant medicinal value.The study was conducted to analyze the changes in the root exudates of P.tangutica induced by methyl jasmonate.The plants were treated with 0,150 μmol·L-1 methyl jasmonate for 3 d and 7 d,and the root exudates were analyzed using the non-targeted metabolomics technique of LC-MS/MS.The results were as follows:(1)There was a significant difference in the content of root exudates from P.tangutica after 3 d and 7 d treatments with 0,150 µmol·L-1 methyl jasmonate.(2)The amount of root exudate increased significantly with the 150 µmol·L-1 methyl jasmonate treatment compared to the control.(3)The KEGG pathways mainly involved in the root exudates of P.tangutica were α-linolenic acid metabolism pathway,plant hormone signal transduction pathway and lysine biosynthesis pathway.In summary,it was concluded that the induction of methyl jasmonate affected the metabolism and changed the content and quantity of induced exudates in the root system of P.tangutica.Through non-targeted metabolomics analysis,the study preliminarily reveals the key metabolites involved in the root exudate response to methyl jasmonate of P.tangutica,which provides a theoretical reference for further understanding of the changes in root exudate and metabolism mechanism of this alpine plant under methyl jasmonate.In addition,the results also offer a new way of thinking on the continuation of the resources.

Gentiana straminea Maxim. (Gentianaceae) is an important traditional Tibetan herb that is mainly distributed on the Qinghai-Tibetan Plateau. Despite its agricultural and pharmacological importance, there remains a paucity of microsatellite markers, particularly expressed sequence tag-simple sequence repeat (EST-SSR) markers, available for this local endemic species. In this study, based on previous Illumina transcriptome data of G. straminea, a total of 96 EST-SSR markers were initially designed and tested. Thirty-two of 96 loci (33.33%) were successfully amplified and verified for validation. Among them, 10 were polymorphic and had clear bands. The polymorphism information content values were 0.09-0.799, the number of alleles per locus ranged from 3 to 14, and the levels of observed and expected heterozygosity were 0.078-0.722 and 0.238-0.884, respectively, which suggested a high level of information. Moreover, cross-amplification was successful for 10 loci in two other related species, Gentiana macrophylla Pallas and Gentiana dahurica Fischer. These EST-SSR markers provide a valuable tool for investigating the genetic diversity related to quantitative traits and population genetic studies on G. straminea and related species in sect. Cruciata Gaudin.

Habenaria, a member of Orchidaceae family is the cosmopolitan distributions, which has significant medicinal and ornamental values. Regardless of morphology and molecular data that have been studied in recent times, the phylogenetic relationship is still under debate. Here, we sequenced, assembled, and annotated the whole chloroplast (cp) genome of two species (Habenaria aitchisonii Rchb.f. and Habenaria tibetica Schltr.ex Limpricht) of Habenaria grown on the Qinghai-Tibetan Plateau (QTP), and combined with seven already published cp genomes which may assist to uncover their genomic profiling. The two genomes ranged from 155259-155269 bp in length and both encoded 132 genes, including 86 protein, 38 tRNA and 8 rRNA. In the cp genomes, the tandem repeats (797), SSRs (2195) and diverse loci (3214) were identified. Comparative analyses of codon usage, amino frequency, microsatellite, oligo repeats and transition and transversion substitutions showed similarities among the species. Moreover, we identified 16 highly polymorphic regions with nucleotide diversity above 0.02, which may be suitable for robust authentic barcoding and inferring in the phylogeny of Habenaria species. Among the polymorphic regions, positive selection was significantly exerted on the several genes such as cemA, petA, and ycf1. This may suggest that the important adaptation stratagem for two Habenaria species on the QTP. The phylogenetic relationship displayed that H.aitchisonii and H. tibetica have closer relationship than others and the rest seven species clustered in the other three groups. Our findings also supported the idea that Habenaria could be divided into different sections. This study enriched the genomics resources of Habenaria, which may be helpful for the conservation efforts of these endangered species.

Endophytic fungi are a crucial microbial resource that can influence plant growth and development through their interactions with host plants. Gentiana straminea Maxim. is an important traditional Tibetan herb used to treat a range of diseases in the Qinghai-Tibetan region. However, the diversity and community structure of endophytic fungi in the species remain poorly understood. In this study, a total of 944 strains of endophytic fungi were isolated from the roots, stems, and leaves of G. straminea from four different altitudes. A total of 87 OTUs were identified through sequence alignment, comprising 6 classes, 15 orders, 25 families, and 44 genera. The colonization rate and diversity of endophytic fungi were affected by tissue type and altitude. With the exception of Xining, the endophytic fungi colonization rate of tissues was roots>leaves>stems. Moreover, the α-diversity of endophytic fungi among different tissues was leaves>stems>roots. Notably, the phylogenetic diversity index in leaves was significantly higher than that in roots. In addition, the colonization rate and diversity of endophytic fungi in leaves and stems demonstrated a decline with the increasing altitude. The β-diversity analysis revealed significant differences in the endophytic fungi of G. straminea at varying altitudes. In roots, geographical factors, such as latitude and longitude, were the primary drivers of variation, whereas environmental factors, including temperature and precipitation, had a greater influence on endophytes in leaves and stems. In addition, the results of the endophytic fungi association preference, linear discriminant analysis effect size (LEfSe), and co-network analysis indicated that these differential endophytic fungi may play a significant role in the authenticity and stress resistance of G. straminea.

Habenaria, a genus in the family Orchidaceae, are the nearly cosmopolitan orchids, and most species have significant medicinal and ornamental values. Despite the morphological and molecular data that have been studied in recent years, the phylogenetic relationship is still unclear. We sequenced, assembled, and annotated the chloroplast (cp) genomes of two species (Habenaria aitchisonii Rchb.f. and Habenaria tibetica Schltr.ex Limpricht) of Habenaria grown on the Qinghai-Tibetan Plateau (QTP), and compared them with seven previously published cp genomes which may aid in the genomic profiling of these species. The two genomes ranged from 155,259–155,269 bp in length and both included 132 genes, encoding 86 proteins, 38 tRNAs and 8 rRNAs. In the cp genomes, the tandem repeats (797), SSRs (2195) and diverse loci (3214) were identified. Comparative analyses of codon usage, amino frequency, microsatellite, oligo repeats and transition and transversion substitutions revealed similarities between the species. Moreover, we identified 16 highly polymorphic regions with a nucleotide diversity above 0.02, which may be suitable for robust authentic barcoding and inferring in the phylogeny of Habenaria species. Among the polymorphic regions, positive selection was significantly exerted on several genes, such as cemA, petA, and ycf1. This finding may suggest an important adaptation strategy for the two Habenaria species on the QTP. The phylogenetic relationship revealed that H. aitchisonii and H. tibetica were more closely related to each other than to the other species, and the other seven species were clustered in three groups. In addition, the estimated divergence time suggested that the two species separated from the others approximately 0.39 Mya in the Neogene period. Our findings also suggest that Habenaria can be divided into different sections. The results of this study enriched the genomics resources of Habenaria, and SSR marker may aid in the conservation management of two endangered species.

Aims Kobresia pygmaea is a perennial cushion herb from the Cyperaceae family with a height of 1–3 cm and small linear leaves about 1 mm wide. It is mainly distributed on the low slopes of the high mountains ranging from 3 000 m to 5 960 m on the Qingzang Plateau, China. Its habitat is harsh, and extreme climate conditions such as low temperature, strong wind, and high sunlight intensity are the main abiotic stresses during plants growing season. The objectives of this study were to analyze the photochemical and non-photochemical energy distribution of the photosystem II（PSII） reaction center in K. pygmaea leaves, and their quenching protection mechanism after nocturnal low-temperature（NLT） treatment. Methods Kobresia pygmaea meadow turfs（30 cm × 15 cm） were collected from the Alpine Grassland Ecosystem Research Station of the Resource of Three Rivers. The turf blocks were separated into two groups, one group was kept in a culture room with a temperature of 24/18 °C（day/night） as a control treatment, and another was kept in an artificial climate chamber with 0 °C in the evening as an NLT treatment. During the daytime, the NLT group was moved back to the culture room and irradiated together with the control group. On day 0, day 1,day 3, and day 5 after NLT treatment, the chlorophyll fluorescence of K. pygmaea leaves including, the light-response curve, PSII photochemical efficiency at 400 and 1 500 μmol·m -2 ·s -1 steady-state light intensities, and dark relaxation were monitored using CF imager. Then, based on the “Lake Model”, the variation of the PSII actual photochemical efficiency(Φ PSII ), the quantum yield of non-regulated energy dissipation(Φ NO ) and regulated energy dissipation(Φ NPQ ) were explored. Additionally, the fast and slow relaxation components of PSII non-photochemical quenching were determined. Important findings Nocturnal low temperature had limited effects on the rapid light-response curves of PSII relative electron transfer rate through PSII（rETR）, the fraction of open PSII centers（q L ）, and PSII non-photochemical quenching coefficient(q NP ). The comparison of chlorophyll fluorescence between 400 and 1 500 μmol·m -2 ·s -1 steady-state light intensities confirmed that NLT treatment did not affect the activity of the PSII reaction center and the process of non-photochemical quenching of K. pygmaea. On the third day after NLT treatment, under high light intensity, the ratios of Φ PSII :Φ NO :Φ NPQ were 36:19:45 and 38:19:43 in the control and NLT groups, respectively; while under lower light intensity, they were 66:22:12 and 66:23:11, respectively. The fast relaxation component（NPQ f ） was the main component in non-photochemical quenching（NPQ）; the proportion of the slow relaxation component in non-photochemical quenching was 11% and 10% on day 1 and day 3 in control group, and 13% and 12% in NLT group, respectively. Our results indicated that the probability of photoinhibition of the PSII reaction center in K. pygmaea was increased after NLT treatment; low light intensity and NLT led to the prolongation of photosynthetic induction time. Overall, the NLT treatment did not increase the tendency of excess excitation energy to be difficult to regulate and dissipate in K. pygmaea leaves, since PSII photochemical energy dissipation and protective regulation mechanism still effectively distributed the absorbed light energy.

Aims Kobresia pygmaea is a typical low temperature-tolerant arid mesophyte,and mainly distributes at low slope and high mountains ranging from 3 000 to 5 960 m on the Qingzang Plateau.Low temperature is a frequently occurring abiotic stress factor during the plants growing season on the Qingzang Plateau.The objectives of this study were to analyze the photochemical and non-photochemical energy distribution characteristics of the photosystem Ⅱ(PSⅡ)reaction center of K.pygmaea leaves,and explore their quenching protection mechanism in response to low temperature stress. Methods Turf blocks(30 cm × 30 cm)of K.pygmaea meadow were collected from the Alpine Grassland Ecosystem Research Station of the Resource of Three Rivers,moved and kept in a culture room with air temperature of 24 ℃/18 ℃(day/night)at a diurnal photoperiod of 12 h and relative humidity of 45％;being irradiated with artificial LED light source of 500 μmol·m-2·s-1light intensity.When the turf black had been kept in culture room for one day,the measurements of chlorophyll fluorescence were performed immediately using chlorophyll fluorescence imager with built-in protocol.The trial of light response curves at different leaf temperatures,temperature response at a steady-state light intensity and light-temperature interaction effects were performed at controlled temperature using thermostatic control instruments.Based on the"Lake Model",the relative variation of the PSⅡ actual photochemical efficiency(ΦPSⅡ),the quantum yield of regulated energy dissipation(ΦNPQ)and non-regulated energy dissipation(ΦNO)were investigated.Furthermore,the interaction effects of low temperature and high light intensity was analyzed by two-way ANOVA of the general linear model(GLM). Important findings The maximum quantum efficiency of PSⅡ photochemistry(Fv/Fm and 1/Fo-1/Fm)were higher at 10 ℃ and their coefficient of variation(CV)was smaller relative to other temperatures.The rapid light-response curves of the PSⅡ relative electron transfer rate(rETR)showed a downward as a whole with the decreasing of temperature,and their initial slope(a)also decreased accordingly.Low temperature caused a decrease in ΦPSⅡ and ΦNO,and an increase in ΦNPQ,accompanied with enhancement of CV values.Under 1 000μmol·m-2 s-1 steady-state light intensity,the relative ratios of ΦPSⅡ∶ΦNPQ∶ΦNO at the temperature of 20,10,5,0,and-5 ℃were in turn 23:57:20,18∶63∶19,15∶68∶17,11∶75∶14,and 8∶80∶12,showing remarkable decrease inΦPSⅡ and increase in ΦNPQ The relative limitation of PSⅡ photochemical efficiency(LPPFD)increased gradually with the increase of light intensity,and also with the decrease of temperature.The two-way ANOVA of GLM showed that there were no interaction effects of low temperature and high light intensity in both PSⅡphotochemical and non-photochemical energy dissipation processes.Therefore,the excited energy absorbed by PSⅡ antenna pigments can be transferred and dissipated effectively by the photochemical energy conversion ofΦPsn and protective regulatory mechanisms of ΦNPQ avoiding the exacerbation of ΦNO,which exhibited a strong tolerance and adaptation to alpine habitats.However,the increased instability of photosynthetic activities at low temperatures indicated that the photosynthetic apparatus of K.pygmaea still suffer the stress while maintaining normal operation.It can be inferred that the low temperature is an important factor affecting the photosynthetic physiological process and limiting growth and development and its distribution.

[目的]探究低温逆境对高山植物叶片PSⅡ反应中心光化学效率的影响,明确光合机构的适宜运行温度.[方法]应用叶绿素荧光图像分析手段,以青藏高原典型寒冷中生植物小嵩草(Kobresia pygmaea)为材料,研究低温对叶片PSII光化学效率和非光化学猝灭的影响.[结果]PSⅡ最大光化学量子效率(Fv/Fm)在5℃至15℃时较高(P<0.05).低温可影响PSⅡ光化学效率和非光化学猝灭的光响应过程,引起稳态作用光强下PSⅡ运行效率(Fq′/Fm′)和PSⅡ效率因子(Fq′/Fv′)的降低,以及非光化学猝灭(NPQ)的增高,并导致PSⅡ反应中心光化学效率的变异系数(CV)升高.低温对PSⅡ最大效率(Fv′/Fm′)和NPQ总变异的贡献较强光明显,但Fq'/Fm'、Fv′/Fm′、Fq′/Fv′和NPQ均没有呈现低温和强光的交互效应,即使模拟-5℃的低温也未能完全抑制光合机构的活性.[结论]低温可导致小嵩草叶片PSⅡ光化学效率的不稳定性增高,植株在承受逆境胁迫的同时,又表现出对高寒生境的极强适应性和耐性,是形成高寒小嵩草草甸地带性分布的重要因素.

Haloxylon ammodendron is a preferred shrub species for buffering against wind and fixing sand in arid sandy areas of northwest China. To determine whether sandstorms cause damage to H. ammodendron seedlings, we investigated the effects of wind-blown sands on the photosynthetic function of H. ammodendron by simulating sand-carrying wind in the wind tunnel. The results showed that photosystem II (PSII) non-photochemical quenching ( NPQ ) was sensitive to wind erosion, and sustained blowing of sand-carrying winds enhanced NPQ reduction. The rapidly relaxing quenching NPQ f made up the majority component of NPQ ; the NPQ f / NPQ ratio was approximately 64.4% in the sand-free wind group and nearly 56.2% in the sand-carrying wind group. The distribution of the quantum efficiency of the excitation energy indicated that the relative proportions of the quantum yield of PSII photochemistry Φ PSII , the quantum yield of quenching due to light-induced Φ NPQ , and non-light-induced Φ NO were influenced by both wind erosion and light intensity; the sand-carrying wind resulted in a relative decrease in Φ NPQ and a corresponding increase in Φ NO . The maximum quantum efficiency of PSII photochemistry F v / F m was relatively stable in the sand-free wind group, with an average value of approximately 0.81. Compared to sand-free wind, sand-carrying winds caused remarkable decreases in F v / F m . Light intensity was the main factor affecting Φ PSII , Φ NPQ , and relative electron transport rate ( rETR ); there was no interaction effect between the duration of sand-carrying wind and light intensity. Taken together, wind-blown sands cause irreversible damage to the photosynthesis of H. ammodendron seedlings, which is the main factor restricting population regeneration in shelterbelts.

Kobresia pygmaea Clarke is mainly distributed in the alpine region from 3800 to 4500 m elevation on the Qinghai-Tibet Plateau. It is excellent in low-temperature tolerance and trampling resistance and plays an important role in maintaining the stability of regional ecological environments. Mainly based on the chlorophyll fluorescence imaging technique, using grass sods blocks with a size of 20 × 20 cm 2 collected from K. pygmaea forb meadow, simulated a low-temperature treatment in cultural room with 8 °C/4 °C (day/night) at diurnal photoperiod, we analyzed the effects of low temperature on PSII photochemical efficiency and non-photochemical quenching, as well as the interaction between low temperature and light intensity. The results showed that low temperature could significantly decrease the maximum quantum efficiency of PSII photochemistry ( F v / F m ) and inhibit the leaf growth of K. pygmaea . The light response curve of PSII relative linear electron transport rate was reduced by low temperature, while it recovered to almost normal level after two days of removing adversity. Further experiments under steady-state actinic light confirmed that light intensity was the main factor affecting the PSII photochemical efficiency, and its reduction caused by the low temperature showed a certain degree of reversibility. The non-photochemical quenching (NPQ) was significantly affected by light intensity, and its fast and slow components (NPQ f and NPQ s ) in NPQ accounted for 36% and 64% of NPQ, respectively. The decrease in NPQ f and corresponding increase in NPQ s slowly recovered after relieving from low-temperature condition. The relative inhibition of photosynthesis ( P inh ) was significantly enhanced by low temperature and reduced after removal of adversity. Strong light intensity could intensify the adverse effect of low temperature on PSII operating efficiency F q ′/ F m ′ and efficiency factor F q ′/ F v ′, as well as NPQ. In conclusion, low temperature was one of the main reasons limiting the photosynthetic performance of K. pygmaea on the Qinghai-Tibet Plateau and could aggravate photosynthetic photoinhibition. The adversity of low temperature frequently occurring in the plant growing season on the Qinghai-Tibet Plateau was constituted of the main factor of the low productivity level in alpine meadow.

Enhanced UV-B radiation resulting from stratospheric ozone depletion has been documented both globally and on the Qinghai-Tibet Plateau in China. The response of Kobresia humilis, an important alpine meadow plant species, to enhanced UV-B radiation was experimentally investigated at the Haibei Alpine Meadow Ecosystem Research Station (37°29′–37°45′ N, 101°12′–101°23′ E; alt. 3200 m). K. humilis was exposed to UV-B radiation including ambient UV-B and enhanced UV-B (simulating a 14% reduction in the ozone layer) in a randomized design with three replications of each treatment. Enhanced UV-B radiation resulted in a significant increase of both leaf area and fresh weight chlorophyll and carotenoid but had no effect on UV-B absorbing pigments. Similarly, enhanced UV-B radiation did not significantly change the photosynthetic O2 elevation rate while leaf thickness, width, and length significantly increased (p < 0.01). The enhanced UV-B radiation was associated with 2–3 days earlier flowering and a larger number of flowers per spikelet. The enhanced UV-B generally resulted in larger leaves and more flowers but earlier phenology. In summary, these findings suggest that alpine species of K. humilis have adapted to the strong solar UV-B radiation intensity presented on the Qinghai-Tibet Plateau, but the interspecies differences and their influence on trophic level should be more concerning.

为了研究风沙流胁迫环境对梭梭Haloxylon ammodendron植株冠型特征的影响和适应机制,以2a生梭梭为研究对象,在风沙环境风洞中分别模拟5、8、10、13、16和18m·s-1风沙流胁迫环境,定量分析风沙流胁迫对梭梭的生长和冠型特征的影响.结果 表明:(1)不同强度风沙流胁迫后,梭梭枝条外表产生的伤害特征表现不一,植株恢复正常生长所需的时间也不同.18m·s-1风沙流胁迫20 min已达到致死风速,梭梭枝条恢复困难,永久死亡.(2)梭梭冠幅和植株体积大小随风沙流胁迫强度的增加呈先升高后降低的趋势.梭梭冠幅和植株体积累计增加量大小排序分别为:轻度风沙流胁迫＞中度风沙流胁迫＞重度风沙流胁迫.(3)梭梭枝条长度、分枝数量和枝条直径大小随风沙流胁迫强度的增加呈二项式曲线变化,新生枝长度累加量呈直线方程快速减少,表明梭梭具有较强的形态可塑性与变异性.

Solanum japonense Nakai. (Solanaceae) is a traditional Chinese medicine and animal fodder in Asian continent. Here, the complete chloroplast genome sequence of S. japonense was determined by the Illumina Hiseq technology. The complete chloroplast genome of S. japonense was 155,415 bp and the GC content was 37.81%. The typical circular quadripartite structure was composed with two inverted repeat (IR) regions with 25,588 bp, a large single-copy (LSC) region (85,931 bp) and a small single-copy (SSC) region (18,344 bp). The chloroplast genome of S. japonense contained 132 unigenes, which contained 86 protein-coding genes, 37 tRNA and 8 rRNA genes and one pseudo-gene. Moreover, 183 SSRs were identified and 65% (119)of them located at LSC region. A Maximum-Likelihood (ML) phylogenetic analysis based on chloroplast genomes indicated that S. japonense was closely related to S.dulcamara, S.nigrum. Our results would provide a valuable resource for resource utilization and the phylogenetic studies of species of Dulcamara sect. in Solanaceae.

Ethnobotanical relevance: Gentiana straminea Maxim. is a well-known Tibetan traditional herb, which has been used to treat rheumatic arthritis, iceteric hepatitis, and other diseases for thousands years. However, there is still lack of comprehensive active constituents profiling of this species throughout the Qinghai-Tibet Plateau (QTP). Aim of study: This study was designed to provide a comprehensive quality map of G.straminea germplasm based on twelve active constituents (loganic acid, gentiopicroside, swertiamarin, sweroside, 6-O-beta-D-glucosylgentio-picroside, oleanic acid, morroniside, trilobatin, isoorientin, isovite, Shanzhisidemethylester and quercetin) on the QTP. Materials and methods: G.straminea root samples collected throughout QTP in the flowering period were analyzed by the LC-MS/MS. Statistics analysis methods PCA, clustering and ecological regions analysis for G.straminea constituents differentiation was demonstrated. Results: The active constituents varied greatly across the QTP; the majority of constituents were secoiridoid derivatives, with gentiopicroside being the most abundant compound. Most constituents were significantly affected by the latitudes and altitudes other than longitudes. PCA and hierarchical clustering analysis showed that all samples could be separated into six distinct groups, and 15 populations showed the highest constituent abundances. Further, geographical region analysis showed that the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas. Additionally, correlation analysis showed that there were relationships among genetiopicroside, loganic acid, and other compounds, which might be related to the enzymatic pathways involved in the metabolism of these constituents. Conclusion: LC-MS/MS method allowed separation of quality profiling of G.straminea on the QTP, 15 populations showed the highest constituent abundances. In six geographical groups, the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas, which may be due to the climate caused by the westerlies and Indian Ocean monsoons in the QTP.

为研究持续干旱处理对紫斑牡丹(Paeonia rockii)光合生理特性的影响,本研究.以实生苗为材料进行盆栽控水试验,设置对照(compared,CK)、轻度胁迫(light stress,LD)、中度胁迫(moderate stress,MD)、重度胁迫(Severe stress,SD)4个水分处理,研究随着干旱胁迫的加剧,叶片水分生理以及光合生理参数的变化.结果 表明:在CK、LD、MD水分梯度下,紫斑牡丹生长正常,但在SD胁迫下受影响明显,植株叶片变黄且萎蔫;各胁迫阶段叶厚、叶水势下降明显,相对含水量(relative water content,RWC)降低幅度小,差异不明显,饱和水分亏(water saturation deficit,WSD)有在MD胁迫下有所升高;干旱胁迫抑制了光合色素合成,叶绿素a(Chlorophyll a,Chla)、叶绿素b(Chlorophyll b,Chlb)、叶绿素总含量(total chlorophyll content,Chla+b)、类胡萝卜素(Carotenoids,Car)显著依次下降,叶绿素比值(Chlorophyll ratio,Chla/b)则相反;干旱胁迫导致叶片净光合速率(net photosynthetic rate,Pn)、气孔导度(Stomatal conductance,Gs)以及蒸腾速率(transpiration rate,Tr)呈现下降趋势,但胞间二氧化碳浓度(intercellular carbon dioxide concentration,Ci)则表现为上升后下降,其中水分利用效率(water use efficiency,WUE)在逐渐上升.在轻度和中度干旱的紫斑牡丹表现出一定的适应性和耐旱能力,而长期重度干旱则对紫斑牡丹影响较为严重,在重度干旱地区栽植需考虑水分供给.本研究为干旱地区和城市的园林绿化植物的选择提供理论支持.

以青海省海北站、德令哈、河北乡、下藏科和班玛县5个地理种源麻花艽种子为材料,检测干旱胁迫、盐胁迫和混合胁迫下麻花艽幼苗的生长和生理特性.结果显示,胁迫下麻花艽材料的生长受到明显抑制,但不同地区受胁迫的影响不同,干旱胁迫下德令哈地区幼苗的株高最高,为2.36 cm;盐胁迫和混合胁迫下河北乡地区幼苗的株高最高,分别为2.49 cm和2.28 cm.不同胁迫下不同地区的幼苗生理特性也存在一定的差异,与对照相比,仅干旱胁迫下德令哈地区幼苗的MDA含量降低了69.07％,其可溶性蛋白增加了46.52％;单纯干旱胁迫下,海北站地区幼苗的POD和CAT活性分别增加了234.39％和86.39％;单纯盐胁迫处理下,海北站地区幼苗的POD和CAT活性分别增加了340.53％和127.86％;混合胁迫下德令哈地区幼苗的SOD和CAT分别增加了6.44％和51.20％.通过隶属函数法进行综合分析发现,5个地理种源麻花艽的抗旱性综合评价顺序为:德令哈>海北站>下藏科>河北乡>班玛县,耐盐性顺序为:海北站>下藏科>德令哈>班玛县>河北乡,混合胁迫抗性顺序为:德令哈>下藏科>河北乡>海北站>班玛县.结果表明,不同地理种源麻花艽对胁迫的响应存在一定的差异,德令哈和海北站地区麻花艽对胁迫的耐受性更强,推测可能与长期生长的自然环境有关.

[目的]通过不同种源麻花艽的光合特性比较,分析其光合机构的驯化适应能力,为优质种质资源的筛选与引种培育提供科学依据.[方法]源自青藏高原地区不同海拔的五类麻花艽类群,栽培于青海省湟中县多巴镇实验苗圃,经1a引种栽培驯化后,比较分析了其叶片光合色素、叶绿素荧光和光合气体代谢参数.[结果]较高海拔碌曲类群的叶绿素a、叶绿素b和类胡萝卜素含量最高;低海拔互助与同仁类群的胡萝卜素、叶绿素b含量低于碌曲和达日类群,而叶绿素a/b则高于碌曲和达日类群.源自高海拔的类群,光合速率(Pn)较高,而气孔导度(Gs)和胞间CO2浓度(Ci)则相对较低;蒸腾速率(Tr)除低海拔互助显著较高外,其余不同类群间无明显差异.叶绿素荧光测定表明,PSⅡ有效光化学效率(Fv′/Fm′)和实际光化学效率(ΦPSⅡ)在达日和碌曲类群略低,光化学猝灭系数(qP)在各个类群间几乎无差异,但非光化学猝灭系数(NPQ)则达日和河南类群显著高于同仁类群.叶绿素荧光的光响应曲线显示,qP随光强增高而降低,而NPQ随光强增高而增高,两者均为高海拔达日和碌曲类群较高;相对光合电子传递速率(ETR)随光强增大而增高,高光强呈光抑制现象,且达日、碌曲与河南驯化类群的ETR高于互助和同仁类群,也具有较高初始斜率α、ETRm和EK值.[结论]经过1 a的驯化适应,不同种源麻花艽类群的光合特性存在着差异,与其起源地海拔有密切关系,其中源自高海拔达日、碌曲和河南麻花艽类群的Pn,Ci和叶绿素荧光特征均呈现较高的适应性和光合潜力,在引种栽培中具有较大利用空间.

The complete chloroplast genome sequence of traditional Tibetan herb, Rheum pumilum Maxim. was analyzed. The complete chloroplast genome of R. pumilum is 162,213 bp in size and has a 27.27% GC content. In the typical circular quadripartite structure, there was a pair of inverted repeat (IR) regions with 31,023 bp in length, which separated by a large single-copy (LSC) region (87,424 bp) and a small single-copy (SSC) region (12,743 bp). The chloroplast genome of R. pumilum contained 131 unigenes, which was composed of 86 protein-coding genes, 37 tRNA and 8 rRNA genes. Moreover, 238 SSRs were identified and 58.8% of them existed in LSC region. A maximum likelihood (ML) phylogenetic analysis based on chloroplast genomes indicated that R. pumilum was closely related to R. pulmatum, R. tangutica, and R. officinale. Our results would provide a valuable resource for resource utilization and the phylogenetic studies of Rheum in Polygonaceae.

为研究土壤干旱和风沙流交互胁迫对紫斑牡丹(Paeonia rockii)光合生理特性的影响,选取对照(CK)和重度胁迫(SD)2个水分处理的盆栽紫斑牡丹进行风沙流胁迫模拟试验.结果表明,12 m/s胁迫处理下紫斑牡丹叶片SD的Pn、Gs、Ci较CK低,SD的Tr较CK高,CK的WUE较SD高;CK的Chla、Chlb、Chla+b、Car、Yield、qP及ETR较SD高,SD的NPQ较CK低;同一胁迫处理SD下,紫斑牡丹不套袋处理的Ci、Fv/Fm、Fv/Fo及NP较套袋低.这说明紫斑牡丹对胁迫响应明显,为河西走廊等干旱风沙环境的防风固沙植物、城市园林绿化植物的选择提供理论依据以及干旱荒漠区的经济发展提供更多可能.

秦艽是我国传统的中藏药材,为龙胆属Gentiana (Tourn.) L.秦艽组植物,主要分布在青藏高原及周边地区,在多种疾病的治疗方面具有显著疗效.对近20年国内外秦艽组植物的形态多态性、生化多态性及分子多态性的研究进展进行综述与展望,以期为秦艽的种质资源保护、鉴定及进化适应等研究提供借鉴.