Adaptive strategies based on shrub leaf-stem anatomy and their environmental interpretations in the eastern Qaidam Basin.

BACKGROUND: Water stress seriously affects the survival of plants in natural ecosystems. Plant resistance to water stress relies on adaptive strategies, which are mainly based on plant anatomy with following relevant functions: (1) increase in water uptake and storage; (2) reduction of water loss; and (3) mechanical reinforcement of tissues. We measured 15 leaf-stem anatomical traits of five dominant shrub species from 12 community plots in the eastern Qaidam Basin to explore adaptive strategies based on plant leaf-stem anatomy at species and community levels. and their relationship with environmental stresses were tested. RESULTS: Results showed that the combination of leaf-stem anatomical traits formed three types of adaptive strategies with the drought tolerance of leaf and stem taken as two coordinate axes. Three types of water stress were caused by environmental factors in the eastern Qaidam Basin, and the established adaptive strategy triangle could be well explained by these environmental stresses. The interpretation of the strategic triangle was as follows: (1) exploitative plant strategy, in which leaf and stem adopt the hydraulic efficiency strategy and safety strategy, respectively. This strategy is mostly applied to plants in sandy desert (i.e., Nitraria tangutorum, and Artemisia sphaerocephala) which is mainly influenced by drought stress; (2) stable plant strategy, in which both leaf/assimilation branches and stem adopt hydraulic safety strategy. This strategy is mostly applied to plants in salty desert (i.e., Kalidium foliatum and Haloxylon ammodendron) which aridity has little effect on them; and (3) opportunistic plant strategy, in which leaf and stem adopt hydraulic safety strategy and water transport efficiency strategy. This strategy is mostly applied to plants in multiple habitats (i.e., Sympegma regelii) which is mainly affected by coldness stress. CONCLUSION: The proposed adaptive strategy system could provide a basis for elucidating the ecological adaptation mechanism of desert woody plants and the scientific management of natural vegetation in the Qinghai-Tibet Plateau.

Sitagliptin Extends Lifespan of Caenorhabditis elegans by Inhibiting Insulin/Insulin-Like Signaling and Activating Dietary Restriction-Like Signaling Pathways.

INTRODUCTION: The discovery of longevity molecules that delay aging and prolong lifespan has always been a dream of humanity. Sitagliptin phosphate (SIT), an oral dipeptidyl peptidase-4 (DPP-4) inhibitor, is an oral drug commonly used in the treatment of type 2 diabetes (T2D). In addition to being antidiabetic, previous studies have reported that SIT has shown potential to improve health. However, whether SIT plays a role in the amelioration of aging and the underlying molecular mechanism remain undetermined. METHODS: Caenorhabditis elegans (C. elegans) was used as a model of aging. Lifespan assays were performed with adult-stage worms on nematode growth medium plates containing FUdR with or without the specific concentration of SIT. The period of fast body movement, body bending rates, and pharyngeal pumping rates were recorded to assess the healthspan of C. elegans. Gene expression was confirmed by GFP fluorescence signal of transgenic worms and qPCR. In addition, the intracellular reactive oxygen species levels were measured using a free radical sensor H2DCF-DA. RESULTS: We found that SIT significantly extended lifespan and healthspan of C. elegans. Mechanistically, we found that several age-related pathways and genes were involved in SIT-induced lifespan extension. The transcription factors DAF-16/FOXO, SKN-1/NRF2, and HSF-1 played important roles in SIT-induced longevity. Moreover, our findings illustrated that SIT-induced survival benefits by inhibiting the insulin/insulin-like signaling pathway and activating the dietary restriction-related and mitochondrial function-related signaling pathways. CONCLUSION: Our work may provide a theoretical basis for the development of anti-T2D drugs as antiaging drugs, especially for the treatment of age-related disease in diabetic patients.

Vessel diameter is related to amount and spatial arrangement of axial parenchyma in woody angiosperms.

Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.

A global analysis of parenchyma tissue fractions in secondary xylem of seed plants.

Parenchyma is an important tissue in secondary xylem of seed plants, with functions ranging from storage to defence and with effects on the physical and mechanical properties of wood. Currently, we lack a large-scale quantitative analysis of ray parenchyma (RP) and axial parenchyma (AP) tissue fractions. Here, we use data from the literature on AP and RP fractions to investigate the potential relationships of climate and growth form with total ray and axial parenchyma fractions (RAP). We found a 29-fold variation in RAP fraction, which was more strongly related to temperature than with precipitation. Stem succulents had the highest RAP values (mean ± SD: 70.2 ± 22.0%), followed by lianas (50.1 ± 16.3%), angiosperm trees and shrubs (26.3 ± 12.4%), and conifers (7.6 ± 2.6%). Differences in RAP fraction between temperate and tropical angiosperm trees (21.1 ± 7.9% vs 36.2 ± 13.4%, respectively) are due to differences in the AP fraction, which is typically three times higher in tropical than in temperate trees, but not in RP fraction. Our results illustrate that both temperature and growth form are important drivers of RAP fractions. These findings should help pave the way to better understand the various functions of RAP in plants.

Ultrathin (∼30 µm) flexible monolithic perovskite/silicon tandem solar cell.

The efficiency of rigid perovskite/silicon tandem solar cells has reached 33.9%. However, there has been no report on flexible perovskite/silicon tandem solar cells due to the challenge of overcoming the poor light absorption of ultrathin silicon bottom cells while maintaining their mechanical flexibility. Herein, we report the first demonstration of the perovskite/silicon tandem solar cell based on flexible ultrathin silicon. We show that reducing the wafer thicknesses and feature sizes of the light-trapping textures can significantly improve the flexibility of silicon without sacrificing light utilization. In addition, the capping of the perovskite top cells can further improve the device's mechanical durability by shifting the neutral plane toward the silicon surface that is prone to fracture. Finally, the resulting ultrathin (∼30 µm) flexible perovskite/silicon tandem solar cell achieves a certified stabilized efficiency of 22.8% with an extremely high power-to-weight ratio of 3.12 W g-1. Moreover, the flexible tandems exhibit remarkable bending durability, maintaining 98.2% of their initial performance after 3000 bending cycles at a radius of only 1 cm.

Olanzapine for the prevention of postoperative nausea and vomiting after gynecologic laparoscopic surgery: a randomized controlled trial.

Purpose: This study was designed to investigate the prophylactic effect of oral olanzapine in postoperative nausea and vomiting after gynecologic laparoscopic surgery. Methods: ASA I-II, aged 18-75 years, planned to undergo gynecologic laparoscopic surgery with general anesthesia in adult female patients. Using the randomized numbers table, the patients were placed in two groups. Oral olanzapine 5 mg or placebo was given 1 h before anesthesia. All patients received standard antiemetic prophylaxis with dexamethasone and granisetron. The primary outcome was nausea and/or vomiting in the 24 h after the postoperative. Results: A total of 250 patients were randomized, and 241 were analyzed. The primary outcome occurred in 10 of 120 patients (8.3%) in the olanzapine group and 23 of 121 patients (19.2%) in the placebo group (p = 0.014). According to Kaplan-Meier analysis, the probabilities of nausea and/or vomiting in the 24 h after the postoperative in the olanzapine group were lower than in the placebo group (log-rank p = 0.014). In a multivariate Cox analysis, the variables of use of olanzapine [hazard ratio (HR): 0.35, 95% confidence interval (CI): 0.16-0.79; p = 0.012] and use of vasoactive drugs (HR: 2.48, 95% CI: 1.07-5.75; p = 0.034) were independently associated with nausea and/or vomiting in the 24 h after the postoperative. Conclusion: Our data suggest that olanzapine relative to placebo decreased the risk of nausea and/or vomiting in the 24 h after gynecologic laparoscopic surgery. Trial registration: The trial was registered prior to patient enrollment at The Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=166900, link to registry page, Principal investigator: Nanjin Chen, Date of registration: 25 April 2022).

Preventing nausea and vomiting after laparoscopic gynecological surgery: the benefits of using olanzapine Why was this study done? Despite the use of antiemetics, postoperative nausea and vomiting remain prevalent. Furthermore, patients who undergo gynecological laparoscopic surgery are at an increased risk. Therefore, this study investigated whether oral Olanzapine could reduce the incidence of nausea and vomiting after gynaecological Laparoscopy? What did the researchers do? The research team examined patients who underwent gynecological laparoscopic surgery under general anesthesia. They observed the occurrence of nausea and vomiting within 24 hours after surgery in patients who either received or did not receive Olanzapine treatment. The goal was to assess the effectiveness of Olanzapine in reducing postoperative nausea and vomiting. What did the researchers find? The addition of Olanzapine, when combined with granisetron and dexamethasone, resulted in a decreased risk of nausea and/or vomiting within the 24 hours following gynecologic laparoscopic surgery, as compared to the placebo. Administering oral Olanzapine at a dosage of 5 mg reduced the incidence of nausea and vomiting after gynecological laparoscopy from 19.2% to 8.3%. What do the findings mean? This study has identified a safe and effective medication for preventing postoperative nausea and vomiting. Implementing Olanzapine as a preventive measure can significantly reduce the incidence of nausea and vomiting following surgery, thereby enhancing the overall medical experience for patients.

Wood anatomical correlates with theoretical conductivity and wood density across China: evolutionary evidence of the functional differentiation of axial and radial parenchyma.

BACKGROUND AND AIMS: In recent years considerable effort has focused on linking wood anatomy and key ecological traits. Studies analysing large databases have described how these ecological traits vary as a function of wood anatomical traits related to conduction and support, but have not considered how these functions interact with cells involved in storage of water and carbohydrates (i.e. parenchyma cells). METHODS: We analyzed, in a phylogenetic context, the functional relationship between cell types performing each of the three xylem functions (conduction, support and storage) and wood density and theoretical conductivity using a sample of approx. 800 tree species from China. KEY RESULTS: Axial parenchyma and rays had distinct evolutionary correlation patterns. An evolutionary link was found between high conduction capacity and larger amounts of axial parenchyma that is probably related to water storage capacity and embolism repair, while larger amounts of ray tissue have evolved with increased mechanical support and reduced hydraulic capacity. In a phylogenetic principal component analysis this association of axial parenchyma with increased conduction capacity and rays with wood density represented orthogonal axes of variation. In multivariate space, however, the proportion of rays might be positively associated with conductance and negatively with wood density, indicating flexibility in these axes in species with wide rays. CONCLUSIONS: The findings suggest that parenchyma types may differ in function. The functional axes represented by different cell types were conserved across lineages, suggesting a significant role in the ecological strategies of the angiosperms.

Lycium barbarum glycopetide prolong lifespan and alleviate Parkinson's disease in Caenorhabditis elegans.

Introduction: Lycium barbarum glycopeptide (LbGp) is the main bioactive compound extracted from the traditional Chinese medicine. L. barbarum berries and has been proven to have numerous health benefits, including antioxidative, anti-inflammatory, anticancer, and cytoprotective activities. However, the antiaging effect of LbGp remains unknown. Methods: The lifespan and body movement of C. elegans were used to evaluate the effect of LbGp on lifespan and health span. The thrashing assay was used to determine the role of LbGp in Parkinson's disease. To investigate the mechanisms of LbGp-induced antiaging effects, we analyzed changes in lifespan, movement, and the expression of longevity-related genes in a series of worm mutants after LbGp treatment. Results: We found that LbGp treatment prolonged the lifespan and health span of C. elegans. Mechanistically, we found that LbGp could activate the transcription factors DAF-16/FOXO, SKN-1/Nrf2, and HSF-1, as well as the nuclear receptor DAF-12, thereby upregulating longevity-related genes to achieve lifespan extension. In addition, we found that the lifespan extension induced by LbGp partially depends on mitochondrial function. Intriguingly, LbGp also ameliorated neurodegenerative diseases such as Parkinson's disease in a DAF-16-, SKN-1-, and HSF-1-dependent manner. Conclusion: Our work suggests that LbGp might be a viable candidate for the treatment and prevention of aging and age-related diseases.

Surface Reconstruction for Efficient and Stable Monolithic Perovskite/Silicon Tandem Solar Cells with Greatly Suppressed Residual Strain.

Despite the swift rise in power conversion efficiency (PCE) to more than 32%, the instability of perovskite/silicon tandem solar cells is still one of the key obstacles to practical application and is closely related to the residual strain of perovskite films. Herein, a simple surface reconstruction strategy is developed to achieve a global incorporation of butylammonium cations at both surface and bulk grain boundaries by post-treating perovskite films with a mixture of N,N-dimethylformamide and n-butylammonium iodide in isopropanol solvent, enabling strain-free perovskite films with simultaneously reduced defect density, suppressed ion migration, and improved energy level alignment. As a result, the corresponding single-junction perovskite solar cells yield a champion PCE of 21.8%, while maintaining 100% and 81% of their initial PCEs without encapsulation after storage for over 2500 h in N2 and 1800 h in air, respectively. Remarkably, a certified stabilized PCE of 29.0% for the monolithic perovskite/silicon tandems based on tunnel oxide passivated contacts is further demonstrated. The unencapsulated tandem device retains 86.6% of its initial performance after 306 h at maximum power point (MPP) tracking under continuous xenon-lamp illumination without filtering ultraviolet light (in air, 20-35 °C, 25-75%RH, most often ≈60%RH).

Long-chain anionic surfactants enabling stable perovskite/silicon tandems with greatly suppressed stress corrosion.

Despite the remarkable rise in the efficiency of perovskite-based solar cells, the stress-induced intrinsic instability of perovskite active layers is widely identified as a critical hurdle for upcoming commercialization. Herein, a long-alkyl-chain anionic surfactant additive is introduced to chemically ameliorate the perovskite crystallization kinetics via surface segregation and micellization, and physically construct a glue-like scaffold to eliminate the residual stresses. As a result, benefiting from the reduced defects, suppressed ion migration and improved energy level alignment, the corresponding unencapsulated perovskite single-junction and perovskite/silicon tandem devices exhibit impressive operational stability with 85.7% and 93.6% of their performance after 3000 h and 450 h at maximum power point tracking under continuous light illumination, providing one of the best stabilities to date under similar test conditions, respectively.

Variation in Tracheid Dimensions of Conifer Xylem Reveals Evidence of Adaptation to Environmental Conditions.

Globally distributed extant conifer species must adapt to various environmental conditions, which would be reflected in their xylem structure, especially in the tracheid characteristics of earlywood and latewood. With an anatomical trait dataset of 78 conifer species growing throughout China, an interspecific study within a phylogenetic context was conducted to quantify variance of tracheid dimensions and their response to climatic and soil conditions. There was a significant difference in tracheid diameter between earlywood and latewood while no significant difference was detected in tracheid wall thickness through a phylogenetically paired t-test. Through a phylogenetic principle component analysis, Pinaceae species were found to be strongly divergent in their tracheid structure in contrast to a conservative tracheid structure in species of Cupressaceae, Taxaceae, and Podocarpaceae. Tracheid wall thickness decreased from high to low latitudes in both earlywood and latewood, with tracheid diameter decreasing for latewood only. According to the most parsimonious phylogenetic general least square models, environment and phylogeny together could explain about 21∼56% of tracheid structure variance. Our results provide insights into the effects of climate and soil on the xylem structure of conifer species thus furthering our understanding of the trees' response to global change.

Pioglitazone Hydrochloride Extends the Lifespan of Caenorhabditis elegans by Activating DAF-16/FOXO- and SKN-1/NRF2-Related Signaling Pathways.

Pioglitazone hydrochloride (PGZ), a nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, is a universally adopted oral agent for the treatment of type 2 diabetes (T2D). Previous studies reported that PGZ could ameliorate the symptoms of aging-related diseases and Alzheimer's disease. However, whether PGZ participates in aging regulation and the underlying mechanism remain undetermined. Here, we found that PGZ significantly prolonged the lifespan and healthspan of Caenorhabditis elegans (C. elegans). We found that a variety of age-related pathways and age-related genes are required for PGZ-induced lifespan extension. The transcription factors DAF-16/FOXO, HSF-1, and SKN-1/NRF2, as well as the nuclear receptors DAF-12 and NHR-49, all functioned in the survival advantage conferred by PGZ. Moreover, our results demonstrated that PGZ induced lifespan extension through the inhibition of insulin/insulin-like signaling (IIS) and reproductive signaling pathways, as well as the activation of dietary restriction- (DR-) related pathways. Additionally, our results also indicated that beneficial longevity mediated by PGZ is linked to its antioxidative activity. Our research may provide a basis for further research on PGZ, as an anti-T2D drug, to interfere with aging and reduce the incidence of age-related diseases in diabetic patients.

Hydraulic traits are coupled with plant anatomical traits under drought-rewatering cycles in Ginkgo biloba L.

Investigating the responses of plant anatomical traits of trees to drought-rewatering cycles helps us to understand their responses to climate change; however, such work has not been adequately reported. In this study, Ginkgo biloba L. saplings were subjected to moderate, severe, extreme and lethal drought conditions by withholding water according to the percentage loss of hydraulic conductivity (PLC) and rewatering on a regular basis. Samples of phloem, cambium and xylem were collected to quantify their cellular properties including cambium and phloem cell vitality, xylem growth ring width, pit aspiration rates and pit membrane thickness using light microscopy and transmission microscopy. The results showed that the mortality rate of G. biloba saplings reached 90% at approximately P88 (xylem water potential inducing 88% loss of hydraulic conductivity). The onset of cambium and phloem cell mortality might be in accordance with that of xylem embolism. Close negative correlations between xylem water potential and PLC and between xylem water potential and cambium and phloem mortality suggested that xylem hydraulic traits are coupled with anatomical traits under declining xylem water potential. Cambium and phloem cell vitality as well as xylem growth ring width decreased significantly with increasing drought conditions. However, xylem pit membrane thickness, cambial zone width and cambial cell geometry were not affected by the drought-rewatering cycles. The tracheid radial diameter, intertracheid cell wall thickness and tracheid density decreased significantly during both drought conditions and rewatering conditions. In addition to hydraulic traits, cambium and phloem cell vitality can be used as anatomical traits to evaluate the mortality of G. biloba under drought. Future work is proposed to observe the dynamics of pit aspiration rates under drought-rewatering cycles in situ to deepen our understanding of the essential role of bordered pits in the 'air-seeding' mechanism.

Continuous Light Does Not Compromise Growth and Yield in Mini-Cucumber Greenhouse Production with Supplemental LED Light.

Continuous lighting (CL, 24 h) can reduce the light intensity/light capital costs used to achieve the desired amount of light for year-round greenhouse vegetable production in comparison to short photoperiods of lighting. However, growth under CL has led to leaf injury characterized by chlorosis unless a thermoperiod or alternating light spectrum during CL is used. To date, there is no literature relating to how cucumbers (Cucumissativus) respond to CL with LEDs in a full production cycle. Here, we evaluated a mini-cucumber cv. "Bonwell" grown under 4 supplemental lighting strategies: Treatment 1 (T1, the control) was 16 h of combined red light and blue light followed by 8 h of darkness. Treatment 2 (T2) had continuous (24 h) red light and blue light. Treatment 3 (T3) was 16 h of red light followed by 8 h of blue light. Treatment 4 (T4) was 12 h of red light followed by 12 h of blue light. All treatments had a supplemental daily light integral (DLI) of ~10 mol m-2 d-1. Plants from all treatments showed similar growth characteristics throughout the production cycle. However, plants grown under all three CL treatments had higher chlorophyll concentrations from leaves at the top of the canopy when compared to T1. The overall photosynthetic capacity, light use efficiency, and photosynthetic parameters related to light response curves (i.e., dark respiration, light compensation point, quantum yield, and photosynthetic maximum), as well as the quantum yield of photosystem II (PSII; Fv/Fm) were similar among the treatments. Plants grown under all CL treatments produced a similar yield compared to the control treatment (T1). These results indicate that mini-cucumber cv. "Bonwell" is tolerant to CL, and CL is a viable and economical lighting strategy for mini-cucumber production.

Light Spectra and Root Stocks Affect Response of Greenhouse Tomatoes to Long Photoperiod of Supplemental Lighting.

Plant biomass and yield are largely dictated by the total amount of light intercepted by the plant (daily light integral (DLI)-intensity × photoperiod). It is more economical to supply the desired DLI with a long photoperiod of low-intensity light because it uses fewer light fixtures, reducing capital costs. Furthermore, heat released by the light fixtures under a long photoperiod extended well into the night helps to meet the heating requirement during the night. However, extending the photoperiod beyond a critical length (>17 h) may be detrimental to production and lead to leaf chlorosis and a reduction in leaf growth and plant vigor in greenhouse tomato production. It is known that red light can increase leaf growth and plant vigor, as can certain rootstocks, which could compensate for the loss in plant vigor and leaf growth from long photoperiods. Therefore, this study investigated the response of tomatoes grafted onto different rootstocks to a long photoperiod of lighting under red and other light spectra. Tomato plants 'Trovanzo' grafted onto 'Emperator' or 'Kaiser' were subjected to two spectral compositions-100% red or a mix of red (75%), blue (20%), and green (5%) light for 17 h or 23 h. The four treatments supplied similar DLI. Leaf chlorosis appeared in all plants under 23 h lighting regardless of spectral compositions between 20 and 54 days into the treatment. The yield for 23 h mixed lighting treatment was lower than both 17 h lighting treatments. However, the 23 h red lighting treatment resulted in less leaf chlorosis and the plants grafted onto 'Emperator' produced a similar yield as both 17 h lighting treatments. Therefore, both spectral compositions and rootstocks affected the response of greenhouse tomatoes to long photoperiods of lighting. With red light and proper rootstock, the negative yield impact from long photoperiod lighting can be eliminated.

Phylogeny Best Explains Latitudinal Patterns of Xylem Tissue Fractions for Woody Angiosperm Species Across China.

Investigating space allocation patterns of plant secondary xylem along a latitudinal gradient is useful to evaluate structure-function tradeoffs in woody angiosperm xylem. An anatomical dataset including 700 woody angiosperm species across China was compiled together with latitudinal and climate data for each species. The relative tissue fractions of vessels, fibers, and parenchyma (including ray and axial parenchyma) in xylem were analyzed to determine the effect of latitudinal differences and phylogeny on anatomical variation. The analyses revealed a trade-off between vessel and non-vessel fraction across latitude, with tissue fraction trade-offs mainly occurring between vessels and fibers, and between fibers and total parenchyma. Among 13 climate variables, thermal indices generally had greater explanatory power than moisture indices in bi-variate models for all cell types, while mean annual temperature, mean temperature of the coldest month, and annual actual evapotranspiration were included in the top multi-variate models explaining variance of different tissue fractions. Phylogeny and climate together explained 57-73% of the total variation in xylem space occupancy, with phylogeny alone accounting for over 50% of the variation. These results contribute to our knowledge of wood structure-function and are relevant to better understand forest response to climate change.

Alternating Red and Blue Light-Emitting Diodes Allows for Injury-Free Tomato Production With Continuous Lighting.

Plant biomass is largely dictated by the total amount of light intercepted by the plant [daily light integral (DLI) - intensity × photoperiod]. Continuous light (CL, 24 h lighting) has been hypothesized to increase plant biomass and yield if CL does not cause any injury. However, lighting longer than 18 h causes leaf injury in tomato characterized by interveinal chlorosis and yield is no longer increased with further photoperiod extension in tomatoes. Our previous research indicated the response of cucumbers to long photoperiod of lighting varies with light spectrum. Therefore, we set out to examine greenhouse tomato production under supplemental CL using an alternating red (200 µmol m-2 s-1, 06:00-18:00) and blue (50 µmol m-2 s-1, 18:00-06:00) spectrum in comparison to a 12 h supplemental lighting treatment with a red/blue mixture (200 µmol m-2 s-1 red + 50 µmol m-2 s-1 blue, 06:00-18:00) at the same DLI. Our results indicate that tomato plants grown under supplemental CL using the red and blue alternating spectrum were injury-free. Furthermore, parameters related to photosynthetic performance (i.e., Pnmax, quantum yield, and Fv/Fm) were similar between CL and 12 h lighting treatments indicating no detrimental effect of growth under CL. Leaves under CL produced higher net carbon exchange rates (NCER) during the subjective night period (18:00-06:00) compared to plants grown under 12 h lighting. Notably, 53 days into the treatment, leaves grown under CL produced positive NCER values (photosynthesis) during the subjective night period, a period typically associated with respiration. At 53 days into the growth cycle, it is estimated that leaves under CL will accumulate approximately 800 mg C m-2 more than leaves under 12 h lighting over a 24 h period. Leaves grown under CL also displayed similar diurnal patterns in carbohydrates (glucose, fructose, sucrose, and starch) as leaves under 12 h lighting indicating no adverse effects on carbohydrate metabolism under CL. Taken together, this study provides evidence that red and blue spectral alternations during CL allow for injury-free tomato production. We suggest that an alternating spectrum during CL may alleviate the injury typically associated with CL production in tomato.

Seed mass of angiosperm woody plants better explained by life history traits than climate across China.

Seed mass is a basic trait in studies of functional ecology. Examining how seed mass is affected by biotic and abiotic factors could improve our understanding of ecological strategies in plants. Here we examined the relationships of seed mass with 13 climate variables and seven life history traits, and partitioned the relative effects of life history traits vs. climate, based on seed mass data for 1265 woody angiosperm species in China. Our results showed that seed mass decreased with latitude, and most climate variables were positively correlated with seed mass. Geographic seed mass pattern was affected by both energy and water availability in the growing season, but the effect of energy availability was more important. Seed mass was also significantly related to other traits such as growth form, fruit type, dispersal mode, breeding system, leaf habit, fruit development time, and minimum juvenile period, with growth form and dispersal mode being the most closely related traits. Our results showed that climate explained much less variation in seed mass than life history traits, and that phylogeny played an important role in shaping the large-scale patterns of seed mass.

[Research advances in the relationships between biodiversity and invasiveness within plant communities].

This paper reviewed the theoretical, observational, and experimental studies on the relationships between biodiversity and invasiveness within plant communities. The contradictory conclusions made from these studies were summarized and analyzed, and suggestions were put forward to improve future researches. In theoretical studies, models were highly simplified and depended on unrealistic assumptions, e. g., single mechanism of biodiversity formation, balance between communities status, and similar characters of alien and native species, which limited the credibility of research conclusions. Most of the observational studies were not directly exploring the relationships between biodiversity and invasiveness, but inferring from invasion patterns occurred in nature. Different research scales always resulted in contradictory conclusions. In small-scale research where some biotic factors dominated species interaction, the relationships between biodiversity and invasiveness might be negative, while in larger-scale research, other co-varying extrinsic factors might override those biotic factors in small-scale research, and the relationships between biodiversity and invasiveness might be positive. Although most experimental studies were conducted in small scale and extrinsic influences were ruled out, some mistakes might still happen when constructing biodiversity gradients in the experimental communities. Among these mistakes, sampling effect was the most common one, and the others included building communities with same species abundance but varying richness and density. Some suggestions were put forward on improving the study of the relationships between biodiversity and invasiveness in plant communities. In future researches, we should integrate observational study with experimental study, pay more attention to research scale, avoid sampling effect, and couple model with experimental design.

[Correlation between gap structure and tree diversity of mixed-broad-leaved Korean pine forests in northeast China].

This paper studied the regeneration of tree species in the gaps of broad-leaved Korean pine forest, with the tree diversity in gaps and under closed canopy compared, and the relationship between biodiversity and gap structure analyzed. The results indicated that there was a significant difference between tree species diversity in gaps and under canopy (P < 0.01). In regeneration layer, the biodiversity in terms of Shannon-Wiener, evenness, and abundance indices was higher in gap community than under forest canopy, while the dominance of certain species in terms of Simpson's dominance index was increased from gaps to closed canopy (P < 0.01) . The biodiversity of succession layer in gaps and under closed canopy had an opposite trend. Tree species diversity of different layers reacted differently to the change of gap size class, e.g., Shannon-Wiener and abundance indices were higher, but Simpson's dominance index was the lowest in the succession layer of medium-size gap(100-250 m2) in broadleaved Korean pine forest of Changbai Mountain. The Shannon-Wiener index and evenness index reached the highest in the size of > or =250 m2 and <100 m2, and reached the lowest in the size of 200-250 m2 in regeneration layer. Simpson's dominance index reached the highest in the size of 200-250 m2. On the whole, tree species of different layers reacted differently to the change of gap size class, and the gap size class with more seedlings was not corresponding to the size class containing more medium-size trees. With gaps aging, tree diversity indices in the two layers behaved reciprocally.