Non-host plants:Are they mycorrhizal networks players?

Common mycorrhizal networks(CMNs)that connect individual plants of the same or different species together play important roles in nutrient and signal transportation,and plant community organization.However,about 10%of land plants are non-mycorrhizal species with roots that do not form any wellrecognized types of mycorrhizas;and each mycorrhizal fungus can only colonize a limited number of plant species,resulting in numerous non-host plants that could not establish typical mycorrhizal symbiosis with a specific mycorrhizal fungus.If and how non-mycorrhizal or non-host plants are able to involve in CMNs remains unclear.Here we summarize studies focusing on mycorrhizal-mediated host and non-host plant interaction.Evidence has showed that some host-supported both arbuscular mycorrhizal(AM)and ectomycorrhizal(EM)hyphae can access to non-host plant roots without forming typical mycorrhizal structures,while such non-typical mycorrhizal colonization often inhibits the growth but enhances the induced system resistance of non-host plants.Meanwhile,the host growth is also differentially affected,depending on plant and fungi species.Molecular analyses suggested that the AMF colonization to non-hosts is different from pathogenic and endophytic fungi colonization,and the hyphae in non-host roots may be alive and have some unknown functions.Thus we propose that non-host plants are also important CMNs players.Using non-mycorrhizal model species Arabidopsis,tripartite culture system and new technologies such as nanoscale secondary ion mass spectrometry and multiomics,to study nutrient and signal transportation between host and non-host plants via CMNs may provide new insights into the mechanisms underlying benefits of intercropping and agro-forestry systems,as well as plant community establishment and stability.

Differential aluminum tolerance and absorption characteristics in Pinus massoniana seedlings colonized with ectomycorrhizal fungi of Lactarius deliciosus and Pisolithus tinctorius

Plant tolerance to aluminum(Al)toxicity can be enhanced by an ectomycorrhizal(ECM)fungus through biological filtering or physical blockage.To understand the roles of ECM colonization in Al absorption with regard to Al tolerance,Pinus massoniana seedlings were inoculated with either Lactarius deliciosus(L.:Fr.)Gray isolate 2 or Pisolithus tinctorius(Pers.)Coker et Couch isolate 715 and cultivated in an acid yellow soil with or without 1.0 mM Al^(3+)irrigation for 10 weeks.Biomass production,Al bioaccumulation and transport in seedlings colonized by the two ECM fungi were compared,and the three absorption kinetics(pseudo-first order,pseudo-second order and intraparticle diffusion)models used to evaluate variances in root Al^(3+)absorption capacity.Results show that both fungi increased aboveground biomass and Al tolerance of P.massoniana seedlings,but L.deliciosus 2 was more effective than P.tinctorius 715.Lower Al absorption capacity,fewer available active sites and decreased affinity and boundary layer thickness for Al^(3+),and higher Al accumulation and translocation contributed to the increased Al tolerance in the ECM-inoculated seedlings.These results advance our understanding of the mechanisms and strategies in plant Alto lerance conferred by ECM fungi and show that inoculation with L.deliciosus will better enhance Al tolerance in P.massoniana seedlings used for forest plantation and ecosystem restoration in acidic soils,particularly in Southwest China and similar soils worldwide.

实时目标跟踪研究

针对图像序列中运动目标检测、跟踪的难点问题,提出了一种实时运动目标检测与跟踪算法。该算法基于自适应背景建模,获取运动目标背景模型和前景图像,从而实现运动目标检测;通过建立运动目标的位置、大小、形状以及颜色分布模型,构造运动目标全局匹配函数,结合目标活力特征,实现多运动目标连续匹配和跟踪。实验结果表明,相对于传统的运动目标跟踪方法,本文方法明显减少了运算时间,增强了环境适应性,实现了复杂场景下运动目标的准确检测和稳定跟踪,对非刚性目标的形变、旋转具有较强的鲁棒性。

High Efficiency of Propagation for Sagittaria sagittifolia Using a Temporary Immersion Bioreactor System

Although several studies have reported on the propagation of the Sagittaria sagittifolia to date, none of these methods have efficiently achieved the mass production of these plants. The present study aimed to investigate the propagation and growth of S. sagittifolia using a temporary immersion bioreactor system （TIBS） compared with conventional semi-solid and liquid culture. The effect of different immersion frequencies and immersion times together with supplementation of various plant growth regulators to the Murashige and Skoog （MS） medium was evaluated on shoot proliferation and plant growth. The results showed that the higher immersion frequency （every 6 h） and shorter immersion time （3 min and 10 rain） in medium containing 4 mg/L BA and 0.1 mg/L NAA produced the highest multiplication rate （23）, which are significantly higher than conventional semi-solid （3.6） and liquid （4.5） method, and the best plant growth parameter. While, the lower immersion frequency and longer immersion time （30 rain every 12 h and 60 min every 24 h） induced vitrification and pollution rate in shoot tips 16.6% and 19%, 42% and 37%, respectively. There is distinct decrease in pollution rate （8.3%） in TIBS （10 min every 6 h） compared with the conventional semi-solid and liquid cultures. Medium containing 4 mg/L BA and 0.5 mg/L NAA using 10 min immersion every 6 h showed satisfaction at the rooting stage, with high shoot proliferation rate （21.6）, 100% rooting and 94% plant survival. Therefore, applying TIBS in S. sagittifolia is an efficient method for scaling up the production of plantlets with high quality seedlings.

Genetic Diversity of Jinsha Pomelo and Its Closely-related Germplasms Assessed by SSR Molecular Markers

SSR molecular markers were used to analyze the genetic diversity of 8 Jinsha pomelo germplasm and its closely-related varieties from main planting area in Jiangxi Province. A total of 92 alleles were detected from 26 pairs of selected primers with 53. 68% of polymorphism. The alleles detected per locus were ranged from 2 to 8. On average,3. 54 alleles were amplified from per pair of primers. The similarity coefficients of the 8 varieties were in the range of 0. 729-0. 924.According to the genetic similarities based on UPGMA method,all materials were divided into two groups of Jinlan pomelo and Shatian pomelo at the similarity coefficient of 0. 738.

Cadmium pollution enhanced ozone damage to winter wheat:biochemical and physiological evidences

Combined effects of ozone （O3） and cadmium （Cd） on growth and physiology of winter wheat （Triticum aestivum L. cv. JM22） were determined. Wheat plants were grown without or with Cd and exposed to charcoal-filtered air （〈 10 ppb O3） or elevated O3 （80 ＋ 5 ppb, 7 hr/day） for 20 days. Results showed that O3 considerably depressed light saturated net photosynthetic rate （-20%）, stomatal conductance （-33%）, chlorophyll content （-33%）, and total biomass （-29%） without Cd. The corresponding decreases were further enhanced by 45%, 56%, 60% and 59%, respectively with Cd, indicating a synergistic effect of O3 and Cd on wheat. Ozone significantly increased the activity of superoxide dismutase （46%）, catalase （48%） and peroxidase （56%）. However, great increases in malondialdehyde （MDA） content （2.55 folds） and intercellular CO2 concentration （1.13 folds） were noted in O3＋Cd treatment compared to control. Our findings demonstrated that the increased anti-oxidative activities in wheat plants exposed to O3＋Cd might not be enough to overcome the adverse effects of the combination of both pollutants as evidenced by further increase in MDA content, which is an important indicator of lipid peroxidation. Precise prediction model on O3 damages to crop should be conducted to ensure agricultural production security by considering environmental constraints in an agricultural system in peri-urban regions.

Use of ^(15)N stable isotope to quantify nitrogen transfer between mycorrhizal plants

Aims Mycorrhizas(fungal roots)play vital roles in plant nutrient acquisition,performance and productivity in terrestrial ecosystems.Arbuscular mycorrhizas(AM)and ectomycorrhizas(EM)are mostly important since soil nutrients,including NH+4,NO
3 and phosphorus,are translocated from mycorrhizal fungi to plants.Individual species,genera and even families of plants could be interconnected by mycorrhizal mycelia to form common mycorrhizal networks(CMNs).The function of CMNs is to provide pathways for movement or transfer of nutrients from one plant to another.In the past four decades,both ^(15)N external labeling or enrichment(usually expressed as atom%)and ^(15)N naturally occurring abundance(d^(15)N,&)techniques have been employed to trace the direction and magnitude of N transfer between plants,with their own advantages and limitations.Important Findings The heavier stable isotope ^(15)N is discriminated against 14N during biochemical,biogeochemical and physiological processes,due to a greater atomic mass.In general,non-N2-fixing plants had greater d^(15)N values than N2-fixing(;0&)ones.Foliar d^(15)N often varied by 5 to 10&in the order:non-mycorrhizas/AMs>EMs>ericoid mycorrhizas.Differences in d^(15)N(&)or ^(15)N(atom%)values could thus provide N transfer information between plants.A range of between 0 to 80%of one-way N transfer had been observed from N2-fixing mycorrhizal to non-N2-fixing mycorrhizal plants,but generally less than or around 10%in the reverse direction.Plant-to-plant N transfer may provide practical implications for plant performance in N-limited habitats.Considering that N translocation or cycling is crucial,and the potential benefits of N transfer are great in both agricultural and natural ecosystems,more research is warranted on either oneway or two-way N transfers mediated by CMNs with different species and under field conditions.

Different responses of arbuscular mycorrhizal fungal community to day-time and night-time warming in a semiarid steppe

Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.

Understanding High Saving Rate in China

This paper presents a detailed analysis of the Chinese saving rate based on the flow offunds data. It finds that the most widely adopted view of precautionary saving, which is regarded as the top reason for maintaining a high saving rate in China, is misleading because this conclusion is drawn from the household survey data. In fact, the household saving rate has declined dramatically since the mid-1990s, as is observed from the flow of funds framework. The high national saving rate is attributed to the increasing shares of both government and corporation disposable incomes. Insufficient consumption demand is caused by the persistent decrease in percentage share of household to national disposable income. Governmentdirected income redistribution urgently needs to be improved to accelerate consumption, which in turn would make the Chinese economy less investment-led and help to reduce the current account surplus.

Noteworthy Discrepancies in China's GDP Accounting

Consistency is essential in statistical data processing. This paper reports some notable discrepancies in China＇s GDP accounting, which are unexpectedly found after testing the consistency of GDP accounting and its components. Although these discrepancies are mainly attributed to the revision methodology adopted afier the 2004 economic census, the intention to harmonize GDP accounting data, in terms of production and expenditure, also contributes to the discrepancies. Our ftnding highlights the need for careful checking of consistency and for testing before formal release of any official statistics.

Climate variability and crop yields synergies in Tanzania’s semiarid agroecological zone

smallholders in most of Sub-Saharan Africa.These impacts have been more enormous to crop production and other attached livelihoods.However,the comprehensive assessment of these impacts has suffered numerous challenges because crop productivity is also susceptible to other factors involved in the production process.This study aimed to understand how crop yields are affected by climate change in the semiarid zone of Tanzania.The findings would establish a thorough literature within smallholder adaptation in the area.Furthermore,they will intensify strategies to cope with reduced yields attributed by climate-change impacts.Outcomes:There has been a dramatic decrease in rainfall(R^(2)=0.21)and increase in temperature(R^(2)=0.30).In addition,we found that rainfall and temperature variability had positive(R^(2)~0.5)and negative(R^(2)~0.3)correlations with crop yields,respectively.Discussion:The decline in yields at both local and national levels elevated the magnitude of food shortage and poverty.The increasing climate impacts necessitate undertakings of various studies to plan,design,recommend,and implement various useful adaptation measures,especially in the vulnerable communities.Conclusion:To limit climate effects,we need to increase investments in adaptation and mitigation measures.

Accumulation ofSOCunderorganicandno-fertilizations,anditsinfluenceon crop yieldsinTanzania’s semiaridzone

Introduction:To estimate differential accumulation of soil organic carbon(SOC)and its ecological significance is very important to smallholder farmers in the Tanzania's semiarid areas.This study investigated the accumulation of SOC and other important soil nutrients under organic and no-ferti lizations,and correlated SOC with crop yields.Using data from long-term experimental study sites of semiarid in Tanzania,we estimated SOC accumulation in different soil treatments and depths where a total of 128 soil samples were collected at the depths of 0-20 cm and 20-40 cm from two villages(sites)with organic ferilization and no-ferilization treatments.Sites under organic fertilization were defined as those which have received manure fertilization for more than 5 years on continuum basis.Outcomes:The accumulation of SOC was significantly greater in soils under organic fertiliza-tions(1.15 and 0.80 MgC ha-'at soil depth and 20-40 cm)and decreased with increa sing soil depths.Similarly,TN and P decreased from 0.40 and 2.40 Mg(0-20 cm)to 0.16 and 2.10 Mg(20-40 cm),respectively.Other important soil nutrients such as calcium(Ca^(2+)),potassium(K^(+)),magnesium(Mg^(2+)),and sodium(Na^(+))had similar patterm.In addition,soil bulk density was less under organic fertilization(1.1 g/cm^(3))than under no fertilization(1.2 g/cm^(3))and it increased with soil depths.Correspondingly,the crop yields were significantly higher(1.6 tn ha^(-1))under organic friliations than(0.6 tn ha^(-1))under no-fertilizations indicating that crop yields were significantly affected by SOC.Discussion:Organic fertilization i.e.,especially cattle manure in the area has considerable fertility potential.To optimize soil fertility potential,we need to consider such kind of ferilization from household to national level.Conclusion:Our results demonstrated that manure application was the best ferilization method for improving soil fertility in most croplands of Tanzania's semiarid areas,especially in this era of climate change scenarios.