Coexistence of superconductivity and charge density wave instability in A15-Nb3Sn.

A15-type compound Nb3Sn has attracted much attention due to its relatively high critical temperature and critical field of superconductivity, making it a leading material for superconducting applications. In this study, we investigate the structural instability and superconductivity of Nb3Sn under hydrostatic pressure using first-principles calculations. We determine the electronic properties, phonon dispersion, electron-phonon coupling and the superconducting gap for Nb3Sn at pressures ranging from ambient to 9 GPa. Our results show that a significant electron density is present near the Fermi level due to the van Hove singularity, indicating the strong electron-phonon coupling. The phonon dispersion of Nb3Sn exhibits Kohn anomalies at three different wave vectors at a lower temperature. Moreover, above a pressure of 6 GPa, the charge density wave (CDW) instability disappeared, suggesting that pressure inhibits the CDW phase. The superconducting temperature is predicted to be TC = 18.62 K under ambient conditions, which is well consistent with the experimental results. We find that both the CDW and superconducting orders respond to pressure, with their transition temperatures decreasing as the pressure increases below 6 GPa. Above 6 GPa, the superconducting transition temperature increases slowly with pressure. Our results suggest that the instability in Nb3Sn is driven by the softening of the phonon modes due to the CDW caused by strong electron-phonon coupling. Therefore, the CDW phase and superconducting phase of Nb3Sn coexist at low pressure.

De novo assembly and discovery of genes involved in the response of Solanum sisymbriifolium to Verticillium dahlia.

Verticillium wilt, caused by the soil-borne fungus Verticillium dahliae, is a devastating disease of eggplant (Solanum spp.) and causes substantial losses worldwide. Although some genes or biological processes involved in the interaction between eggplant and V. dahliae have been identified in some studies, the underlying molecular mechanism is not yet clear. Here, we monitored the transcriptomic profiles of the roots of resistant S. sisymbriifolium plants challenged with V. dahliae. Based on the measurements of physiological indexes (T-SOD, POD and SSs), three time points were selected and subsequently divided into two stages (S_12 h vs. S_0 h and S_48 h vs. S_12 h). KEGG enrichment analysis of the DEGs revealed several genes putatively involved in regulating plant-V. dahliae interactions, including mitogen-activated protein kinase (MAPK) genes (MEKK1 and MAP2K1), WRKY genes (WRKY22 and WRKY33) and cytochrome P450 (CYP) genes (CYP73A/C4H, CYP98A/C3'H and CYP84A/F5H). In addition, a subset of genes that play an important role in activating V. dahliae defence responses, including Ve genes as well as genes encoding PR proteins and TFs, were screened and are discussed. These results will help to identify key resistance genes and will contribute to a further understanding of molecular mechanisms of the S. sisymbriifolium resistance response to V. dahliae.

Recognition and identification of active components from Radix Bupleuri using human neuroblastoma SH-SY5Y cells.

The aim of the study was to screen active components of Radix Bupleuri (a traditional Chinese herb) and discover novel anti-schizophrenic candidate drugs using human neuroblastoma SH-SY5Y cells. SH-SY5Y cells were used for preparation of the stationary phase in the cell membrane chromatography model. Retention components by the SH-SY5Y/CMC model were collected and then analyzed by GC/MS under the optimized conditions in offline conditions. After investigating the suitability and reliability of the SH-SY5Y/CMC method using amisulpride and haloperidol as standard compounds, this method was applied to screening active components from the extracts of Radix Bupleuri. Retention components of SH-SY5Y/CMC model were saikosaponin A, saikosaponin B1, saikosaponin B2, saikosaponin C and saikosaponin D, which were identified by the GC/MS method. In vitro pharmacological trials-MTT, saikosaponin B1, saikosaponin B2 and saikosaponin C could protect SY5Y cells. The protective effects of saikosaponin B1 and saikosaponin C were concentration dependent. Saikosaponin A and saikosaponin D inhibited cell viability at concentrations >30 µg/mL (p < 0.05). Via SH-SY5Y/CMC method and SH-SY5Y MTT trial, we rapidly detected target components from Radix Bupleuri, accurately identified them and determined their different effects on SH-SY5Y cells. Saikosaponin B1, saikosaponin B2 and saikosaponin C may be anti-schizophrenic candidate drugs.

Transcriptome differences between fiber-type and seed-type Cannabis sativa variety exposed to salinity.

The industrial hemp varieties 'Yunma 5' and 'Bamahuoma,' which demonstrate growth vigor and environmental adaptability, have been primarily cultivated in Yunnan and Guangxi, China, respectively, for fiber and seeds. The results of physiological measurements showed the phenotypic differences between the two varieties in response to salt stress. RNA-Seq analysis was first performed on leaves of both varieties sampled at four time intervals (0, 2, 4, 6 days) after treatment with salt (500 mM NaCl) We identified 220 co-up-regulated differentially expressed genes (DEGs) in the two varieties, while 26 up-regulated DEGs and 24 down-regulated DEGs were identified exclusively in the single varieties after 2 days of salt stress. Among the 220 DEGs, we identified 22 transcription factors, including key transcription factors involved in salt stress, such as MYB, NAC, GATA, and HSF. We applied gene expression profile analysis and found that 'Yunma 5' and 'Bamahuoma' have variety-specific pathways for resisting salt stress. The DEGs of 'Yunma 5' were enriched in spliceosome and amino acid metabolism genes, while the DEGs of 'Bamahuoma' were enriched in fatty acid metabolism, amino acid metabolism, and endoplasmic reticulum protein processing pathway. Although there were common DEGs, such as genes encoding cysteine protease and alpha/beta-hydrolase superfamily, the two varieties' responses to salt stress impacted different metabolic pathways. The DEGs that were co-expressed in both varieties under stress may provide useful insights into the tolerance of cultivated hemp and other bast fiber crops to saline soil conditions. These transcriptomes also represent reference sequences for industrial hemp.

Antidepressant-like effects of magnesium lithospermate B in a rat model of chronic unpredictable stress.

CONTEXT: Magnesium lithospermate B (MLB), an active polyphenol acid of Danshen [Radix Salviae miltiorrhizae (Labiatae)], shows neuroprotective and anti-inflammatory effects in vivo and in vitro. OBJECTIVE: We hypothesized that MLB might exert antidepressant-like effects by targeting the neuroinflammatory signals. MATERIALS AND METHODS: Sprague-Dawley rats were subjected to the chronic unpredictable stress (CUS) protocol. Rats in the control group received no CUS during the whole experiment. In the model group, rats were exposed to CUS for 7 weeks. From the beginning of the 5th week, model group rats were randomly grouped and subjected to different treatments. In the experiment, control and model group rats were intraperitoneally (i.p.) injected with saline. MLB was dissolved in saline to give a final concentration, and the rats were injected (i.p.) with 15, 30, or 60 mg/kg MLB once a day for 3 weeks. RESULTS: MLB administration significantly reduced: (1) the immobility time in the forced swimming test (19 s, p < 0.05); (2) the immobility time in the tail suspension test (76.3 s, p < 0.05); (3) the corticosterone (CORT) concentrations in the serum (21.7 nmol/L, p > 0.05); (4) the pro-inflammatory cytokine levels in the serum - TNF-α (92.1 pg/ml, p < 0.05), IL-1ß (86.9 pg/ml, p < 0.05), and IL-6 (93.8 pg/ml, p < 0.05); (5) pro-inflammatory cytokine levels in tissue - TNF-α (3.2 pg/mg protein, p < 0.05), IL-1ß (1.5 pg/mg protein, p > 0.05), and IL-6 (6.3 pg/mg protein, p < 0.05); and (6) phospho-NF-κB (1.6, p < 0.05) and phospho-IκB-α (0.4, p < 0.05) expression in tissue. DISCUSSION AND CONCLUSION: The results suggested that MLB might exert therapeutic actions on depression-like behavior and the HPA axis hyperactivity in CUS rats, and the mechanisms underlying the antidepressant-like effects of MLB might be mediated by regulation of the expression of NF-κB and IκB-α in rats.

Exploratory quantum resonance spectrometer as a discriminator for psychiatric affective disorders.

The aim of this study was to evaluate reliability and psychiatric clinical value of quantum resonance spectrometer (QRS) in detection of affective disorders. We studied 1014 patients with schizophrenia and 248 patients with mood disorders (including 93 patients with major depression). Affective disorder symptoms of the same subjects obtained from the QRS test and psychiatrists' diagnoses were compared. In addition, three affective disorder symptoms of renumbered 93 patients with major depression were discriminated using QRS. Kappa values of affective disorder detection and diagnosis were more than 0.69 in all three symptoms of schizophrenia and more than 0.65 in six of seven symptoms of mood disorder. The same consistency could also be seen in receiver operating characteristic curve area under the curve. In the discriminated analysis, sensitivity, specificity, positive predictive value, and negative predictive value of hypothymia, anxiety, and irritability detected using QRS are more than 0.66 compared with psychiatrists' diagnoses. QRS could be an objective identification and diagnosis instrument and might promote psychiatric clinical diagnosis.

A multifunctional phenylphosphinamide additive for stable flexible inverted perovskite solar cells.

The multifunctional phenylphosphinamide additive is used in flexible inverted perovskite solar cells to release tensile strain and increase the toughness of the perovskite film, achieving enhanced device efficiency and stability.

Isolation and characterization of endophytic fungi from Camptotheca acuminata.

In this study, a total of 161 endophytic fungal isolates from Camptotheca acuminata were obtained and classified to 16 taxa according to morphological and molecular analysis. These taxa were composed of 2 frequent genera (Botryosphaeria and Fusarium) and 14 infrequent groups such as Xylaria, Diaporthe, Rhizopus, Epicoccum, and Preussia, demonstrating that fungal endophytes in C. acuminata were highly abundant and diverse. Antimicrobial activity screening using filter-paper diffusion method showed that 47.6 % of the tested isolates had antimicrobial activity against at least one of the test microorganisms. Screening of fungal endophyte-derived camptothecin analogues by TLC and LC-MS/MS³ demonstrated that a strain Botryosphaeria dothidea, X-4 could produce 9-methoxycamptothecin (9-MCPT) when cultured in Sabouraud's dextrose broth for 12 days under shake flask and bench-scale fermention conditions. This work showed that the fungal endophytes from C. acuminata could be an alternative source for the production of 9-MCPT and other natural antimicrobial compounds.

Effects of Gibberellin Pre-Treatment on Seed Germination and Seedling Physiology Characteristics in Industrial Hemp under Drought Stress Condition.

The present study aimed to explore the effects of exogenous gibberellins (GAs) on seed germination and subsequent seedling growth of hemp (Cannabis sativa L.) under drought stress. Seeds of two industrial hemp cultivars i.e., 'Yunma 1', (YM) and 'Bamahuoma', (BM) were treated with different concentrations of GA3 solution (0, 200, 400, 600, 800 mg/L) at 20 °C for 8 h. The effect of pre-treatment was assessed on germination characteristics and physiological indexes on subsequent exposure to drought stress using 20% (m/v) polyethylene glycol (PEG) for 7 days. The results revealed that seed germination in hemp was sensitive to drought stress, as the germination indexes (germination rate and germination potential) decreased significantly, and seedling growth (hypocotyl length and radicle length) was impeded under 20% PEG-6000 condition. GA3 pre-treatment affected germination rate, germination potential, hypocotyl length and radicle length. With increasing GA3 concentration, these indexes first increased and then decreased. For seedling physiology characteristics in hemp, GA3-pretreatment remarkedly increased the osmotic regulating substances (soluble sugar and soluble protein contents) and the activities of antioxidant enzymes (SOD, superoxide dismutase and POD, peroxidase), while sharply decreased the lipid peroxidation (malondialdehyde, MDA) in seedlings grown under PEG-6000 induced drought stress. These results suggested that seeds pre-treated with GA3 could enhance the drought tolerance of hempseeds, and the optimal effect of GA3 for seed pre-treatment of YM and BM could be obtained when the concentration of GA3 solution reached 400 mg/L and 600 mg/L, respectively.

Evaluation of hemp (Cannabis sativa L.) as an industrial crop: a review.

Rising human population has increased the utilization of available resources for food, clothes, medicine, and living space, thus menacing natural environment and mounting the gap between available resources, and the skills to meet human desires is necessary. Humans are satisfying their desires by depleting available natural resources. Therefore, multifunctional plants can contribute towards the livelihoods of people, to execute their life requirements without degrading natural resources. Thus, research on multipurpose industrial crops should be of high interest among scientists. Hemp, or industrial hemp, is gaining research interest because of its fastest growth and utilization in commercial products including textile, paper, medicine, food, animal feed, paint, biofuel, biodegradable plastic, and construction material. High biomass production and ability to grow under versatile conditions make hemp, a good candidate species for remediation of polluted soils also. Present review highlights the morphology, adaptability, nutritional constituents, textile use, and medicinal significance of industrial hemp. Moreover, its usage in environmental conservation, building material, and biofuel production has also been discussed.

[Effects of stand structure on understory biomass of the Quercus spp secondary forests in Hunan Province, China]. / æž—åˆ†ç»“æž„å¯¹æ¹–å—æ Žç±»å¤©ç„¶æ¬¡ç”Ÿæž—æž—ä¸‹æ¤è¢«ç”Ÿç‰©é‡çš„å½±å“.

We examined biomass characteristics and the potential driving factors of different forest types of Quercus spp. secondary forest in Hunan. A total of fifty plots were divided into five forest types: Castanopsis eyri - Rhododendron latoucheae mixed forest (CR), Fagus lucida - Fargesia spathacea mixed forest (FF), Lithocarpus glaber - Damnacanthus indicus + Camellia japonica mixed forest (LDC), C. eyri + Quercus serrata - R. latoucheae mixed forest (CQR), Cyclobalanopsis glauca - Camellia oleifera + R. latoucheae mixed forest (CCR). The biomass of understory vegetation was low in the five forest types, being smaller than 2.3 t·hm-2. There was no significant difference in the biomass of understory shrubs among the five forest types. The biomass of herbage layer in CR was significantly lower than that of the other four forest types. The factors affecting the biomass of understory vegetation varied in different forests types. In CR, biomass of herbaceous layer was negatively correlated with canopy and uniform angle index, whereas total understory biomass was positively correlated with opening degree index. In FF, biomass of shrub layer was negatively correlated with stand canopy density and uniform angle index, while herbaceous biomass and total understory biomass were positively correlated with stand closure. In LDC, herbaceous biomass was positively correlated with the stand aggregation index. In CQR, shrub biomass was negatively correlated with stand mingling index, while herbaceous biomass was positively related with stand density. In CCR, there was no significant correlation between stand structure and understory biomass. To adjust the understory biomass, we should first adjust the horizontal distribution pattern of stand and then adjust the degree of forest cover and tree species structure.

Identifying Modifiable Risk Factors for Relapse in Patients With Schizophrenia in China.

BACKGROUND: Preventing relapse of schizophrenic patients is really a challenge. The present study sought to provide more explicit evidence and factors of different grades and weights by a series of step-by-step analysis through χ2 test, logistic regression analysis and decision-tree model. The results of this study may contribute to controlling relapse of schizophrenic patients. METHODS: A total of 1,487 schizophrenia patients were included who were 18-65 years of age and discharged from 10 hospitals in China from January 2009 to August 2009 and from September 2011 to February 2012 with improvements or recovery of treatment effect. We used a questionnaire to collect information about relapse and correlative factors during one year after discharge by medical record collection and telephone interview. The χ2 test and logistic regression analysis were used to identify risk factors and high-risk factors firstly, and then a decision-tree model was used to find predictive factors. RESULTS: The χ2 test found nine risk factors which were associated with relapse. Logistic regression analysis also showed four high-risk factors further (medication adherence, occupational status, ability of daily living, payment method of medical costs). At last, a decision-tree model revealed four predictors of relapse; it showed that medication adherence was the first grade and the most powerful predictor of relapse (relapse rate for adherence vs. nonadherence: 22.9 vs. 55.7%, χ2 = 116.36, p < 0.001). The second grade factor was occupational status (employment vs. unemployment: 19.7 vs. 42.7%, χ2 = 17.72, p < 0.001); the third grade factors were ability of daily living (normal vs. difficult: 28.4 vs. 54.3%, χ2 = 8.61, p = 0.010) and household income (household income ≥ 3000 RMB vs. <3000 RMB: 28.6 vs. 42.4%, χ2 = 6.30, p = 0.036). The overall positive predictive value (PPV) of the logistic regression was 0.740, and the decision-tree model was 0.726. Both models were reliable. CONCLUSIONS: For schizophrenic patients discharged from hospital, who had good medication adherence, more higher household income, be employed and normal ability of daily living, would be less likely to relapse. Decision tree provides a new path for doctors to find the schizophrenic inpatient's relapse risk and give them reasonable treatment suggestions after discharge.

A glutamatergic insular-striatal projection regulates the reinstatement of cue-associated morphine-seeking behavior in mice.

Recently, the insular cortex (IC) was identified as part of the neuronal circuit responsible for the reward expectations in cue-triggered behaviours. Moreover, there are evidences that connections between the IC and the ventral striatum, particularly with the nucleus accumbens (NAc), may mediate the retrieval and performance of actions based on incentive memory. However, the precise role of the IC-NAc connections in cue-related drug-seeking behaviour remains unclear. We used the morphine-induced conditioned place preference (CPP) paradigm to assess the formation and relapse of cue-related drug-seeking. cFos immunostaining was used to determine the activation of the brain regions. Chemogenetic and optogenetic methods were used to manipulate the activity of IC-to-NAc projection neurons. The result showed that neurons in IC and NAc core but not NAc shell were activated following cue-induced morphine-seeking behaviour. Negligible effect of inhibition of IC-to-NAc core projection (IC→NAc core) on morphine CPP expression, whereas chemogenetic inactivation of this projection potently blocked the reinstatement of expressed morphine CPP. Furthermore, optogenetic inhibition of glutamatergic IC→NAc core inputs significant suppressed the CPP reinstatement without significant effect on CPP expression. We demonstrated here, for the first time, that IC→NAc core glutamatergic projection is required for the reinstatement of cue-associated drug seeking behaviour in mice. The present study provide insights into modulations of relapse of cue-associated drug-seeking behaviour following repeated overexposure to opioids in humans.

Effectiveness of Electroacupuncture and Electroconvulsive Therapy as Additional Treatment in Hospitalized Patients With Schizophrenia: A Retrospective Controlled Study.

Electroacupuncture (EA) and electroconvulsive therapy (ECT) are often used in the management of schizophrenia. This study sought to determine whether additional EA and ECT could augment antipsychotic response and reduce related side effects. In this retrospective controlled study, 287 hospitalized schizophrenic patients who received antipsychotics (controls, n = 50) alone or combined with EA (n = 101), ECT (n = 55) or both (EA + ECT, n = 81) were identified. EA and ECT were conducted for 5 and 3 sessions per week, respectively, with a maximum of 12 sessions for ECT during hospitalization. The Scale for the Assessment of Positive Symptoms (SAPS) and Scale for the Assessment of Negative Symptoms (SANS) were used to assess the severity of psychotic symptoms. Clinical response on SAPS and SANS, weight gain, and adverse events were compared. Survival analysis revealed that the ECT and EA + ECT groups had markedly greater clinical response rate than controls on SAPS [72.7 and 90.1% vs. 64.0%; relative risk (RR), 1.974 and 2.628, respectively, P ≤ 0.004] and on SANS (67.3 and 70.4% vs. 42.0%; RR, 1.951 and 2.009, respectively, P ≤ 0.015). A significantly greater response rate on SANS than controls was also observed in the EA group (64.4% vs. 42.0%; RR = 1.938, P = 0.008). EA-containing regimens remarkably reduced weight gain and incidences of headache, insomnia, dry mouth, and electrocardiographic abnormalities. These results suggest that EA and ECT can serve as additional treatment for enhancing antipsychotic response and reduce the side effects in hospitalized patients with schizophrenia. Clinical Trial Registration: http://www.chictr.org.cn/showprojen.aspx?proj=38901, identifier ChiCTR1900023563.

Rapid purification of truncated Taq DNA polymerase Stoffel fragment by boiling lysis of bacterial expression cultures.

A simplified and low-cost method, boiling lysis, was developed and used to purify the truncated DNA polymerase Stoffel fragment after overproduction of the enzyme in Escherichia coli. The method is based on the thermostable properties of the Stoffel fragment. Conditions such as the boiling time and number of cycles employed were identified as determinants with which to achieve a high yield and activity of this truncated Taq enzyme. Under established conditions, a period of 8 min consisting of two cycles of boiling and centrifuging was ideal for the purification of the Taq protein, followed by dibasic phosphate and ethanol extraction in a single type of storage buffer to remove contaminating nucleic acid. The whole purification process could be achieved within 1 or 2 h. A total yield of 80 mg of truncated Taq enzyme with an activity of 1.6x10(7) units was purified from l litre of bacterial culture. The purified Taq enzyme had a molecular mass of 61 kDa, a value consistent with the truncated DNA polymerase Stoffel fragment reported previously.

[Cloning and expression of atp6 and atp9 genes from ramie (Boehmeria nivea (L.) Gaud.) and their relationship with cytoplasmic male sterility].

The atp6 and apt9 gene fragments associated with cytoplasmic male sterility (CMS) were cloned from the mitochondrial DNA of a ramie (Boehmeria nivea (L.) Gaud.) cytoplasmic male sterile line and its maintainer and restorer lines using PCR and degenerated primer strategy. The primers were designed according to the reserved sequences in the encoding region of mitochondrial genes atp6 and atp9 of some dicotyledons from GenBank. These fragments did not have complete encoding region but showed the homology of 94% and 85% with atp6 and atp9 genes from the referred dicotyledons in GenBank. The complete atp6 and atp9 genes including the complete open reading frames were cloned by means of amplifying the 3' and 5'end unknown sequences of these gene fragments using DNA Walking method. The atp6 gene showed no difference among ramie male sterile line, maintainer and restorer lines at mtDNA sequence, transcription and translation control and protein level. However, compared to the maintainer and restorer lines, the atp9 gene of the male sterile line was different and deletion in several bases at the 3' end of the encoding region. An abnormally high expression of atp9 gene in the male sterile line at the budding stage and full-bloom stage was analyzed by RT-PCR analysis. These results indicated that the variation in DNA sequence and/or abnormality in expression of atp9 gene in the male sterile line maybe closely related to ramie CMS.

De novo transcriptome assembly and characterization of the 10-hydroxycamptothecin-producing Xylaria sp. M71 following salicylic acid treatment.

In the present study, we identified genes that are putatively involved in the production of fungal 10-hydroxycamptothecin via transcriptome sequencing and characterization of the Xylaria sp. M71 treated with salicylic acid (SA). A total of 60,664,200 raw reads were assembled into 26,044 unigenes. BLAST assigned 8,767 (33.7%) and 10,840 (41.6%) unigenes to 40 Gene Ontology (GO) annotations and 108 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. A total of 3,713 unigenes comprising 1,504 upregulated and 2,209 downregulated unigenes were found to be differentially expressed between SA-induced and control fungi. Based on the camptothecin biosynthesis pathway in plants, 13 functional genes of Xylaria sp. M71 were mapped to the mevalonate (MVA) pathway, suggesting that the fungal 10-hydroxycamptothecin is produced via the MVA pathway. In summary, analysis of the Xylaria sp. M71 transcriptome allowed the identification of unigenes that are putatively involved in 10-hydroxycamptothecin biosynthesis in fungi.

Morphological and Transcriptomic Analysis Reveals the Osmoadaptive Response of Endophytic Fungus Aspergillus montevidensis ZYD4 to High Salt Stress.

Halophilic fungi have evolved unique osmoadaptive strategies, enabling them to thrive in hypersaline habitats. Here, we conduct morphological and transcriptomic response of endophytic fungus (Aspergillus montevidensis ZYD4) in both the presence and absence of salt stress. Under salt stress, the colony morphology of the A. montevidensis ZYD4 changed drastically and exhibited decreased colony pigmentation. Extensive conidiophores development was observed under salt stress; conidiophores rarely developed in the absence of salt stress. Under salt stress, yellow cleistothecium formation was inhibited, while glycerol and compatible sugars continued to accumulate. Among differentially expressed unigenes (DEGs), 733 of them were up-regulated while 1,619 unigenes were down-regulated. We discovered that genes involved in the accumulation of glycerol, the storage of compatible sugars, organic acids, pigment production, and asexual sporulation were differentially regulated under salt stress. These results provide further understanding of the molecular basis of osmoadaptive mechanisms of halophilic endophytic fungi.

Photosynthetic Response of an Alpine Plant, Rhododendron delavayi Franch, to Water Stress and Recovery: The Role of Mesophyll Conductance.

Rhododendron delavayi Franch is an evergreen shrub or small tree with large scarlet flowers that makes it highly attractive as an ornamental species. The species is native to southwest China and southeast Asia, especially the Himalayan region, showing good adaptability, and tolerance to drought. To understand the water stress coping mechanisms of R. delavayi, we analyzed the plant's photosynthetic performance during water stress and recovery. In particular, we looked at the regulation of stomatal (g s) and mesophyll conductance (g m), and maximum rate of carboxylation (Vcmax). After 4 days of water stress treatment, the net CO2 assimilation rate (AN) declined slightly while g s and g m were not affected and stomatal limitation (SL) was therefore negligible. At this stage mesophyll conductance limitation (MCL) and biochemical limitation (BL) constituted the main limitation factors. After 8 days of water stress treatment, AN, g s, and g m had decreased notably. At this stage SL increased markedly and MCL even more so, while BL remained relatively constant. After re-watering, the recovery of AN, g s, and g m was rapid, although remaining below the levels of the control plants, while Vcmax fully regained control levels after 3 days of re-watering. MCL remained the main limitation factor irrespective of the degree of photosynthetic recovery. In conclusion, in our experiment MCL was the main photosynthetic limitation factor of R. delavayi under water stress and during the recovery phase, with the regulation of g m probably being the result of interactions between the environment and leaf anatomical features.