Seasonality of PSII thermostability and water use e ffi ciency of in situ mountainous Norway spruce(Picea abies)

The stability of monocultural,even-aged spruce forests at lower altitudes in Central Europe is seriously threatened by the prospects of global climate change.The thermostability and water use efficiency of their photo synthetic apparatus might play a vital role in their successful acclimation.In this study,photo systemⅡ(PSⅡ)performance(OJIP transient,rapid light curves)and thermostability were analyzed in Norway spruce(Picea abies(L.)Karst.)throughout the growing season of the exceptionally warm year 2018(May-September)in the Western Carpathians,Slovakia.These measurements were accompanied by analysis of pigment concentrations in the needles.In addition,gas-exchange temperature curves were produced weekly from June until September to obtain intrinsic water use efficiencies.At the beginning of the growing season,needles exposed to heat stress showed significantly higher basal fluorescence and lower quantum yield,performance index,critical temperature thresholds of PSII inactivation and nonphotochemical yield in comparison to other months.The overall thermostability(heat-resistance)of PSII peaked in July and August,reflected in the lowest basal fluorescence and the highest quantum yield of PSII,critical temperature thresholds and yield of non-photochemical quenching under heat stress.Additionally,the ratio between chlorophyll and carotenoids was the highest in August and had a positive impact on PSII thermostability.Moreover,the high-temperature intrinsic water use efficiency was significantly higher during July and August than in June.Results show that15-year-old trees of Picea abies at 840 m a.s.l.exhibited acclimative seasonal responses of PSII thermostability and intrinsic water use efficiency during an exceptionally warm year.Our results suggest that mountainous P.abies at lower altitudes can acclimate their photosynthetic apparatus to higher temperatures during summer.

DNA Barcoding and the International Barcode of Life Project in China

1.Scientific and Social Benefits of DNA Barcoding Along with the accelerated global trade and climate change,the needs for sustainable development and for understanding biodiversity are increasing.Rapid and accurate species identification and sustainable utility of biodiversity resources have become a great need for the world.

Some Phenomena of the Interaction Between Vegetation and a Atmosphere on Multiple Scales

This article studies the response of the distribution pattern and the physiological characteristics of the ecosystem to the spontaneous precipitation and the interaction between vegetation and the atmosphere on multiple scales in arid and semi-arid zones, based on measured data of the ecological physiological parameters in the Ordas Plateau of northern China. The results show that the vegetation biomass and the energy use efficiency of photosynthesis are especially sensitive to the annual precipitation; strong and complex interactions exist between the vegetation and the atmosphere on multiple scales leading to supernormal thermal heterogeneity of the underlying surface, the strong vortex movement and turbulence. This study can facilitate understanding of the land surface processes and the influences of global climate change as well as human activities on the human environment in the arid and semi-arid zones. It also aids in improving the parameterization schemes of turbulent fluxes of a heterogeneous underlying surface for land surface processes in climate models.

Productivity and the Survival Rate after Winter Management of Seven Tropical Forage Accessions in Subtropical Region of China

Forage production and quality of five tropical grass accessions (Guimu-1 hybrid elephant grass (PG1), Mulato II (M II), Ubon paspalum (PU), hybrid elephant grass (PH) and Reyan 11 paspalum (PR11)) and two tropical legume accessions (Reyan 5 stylo (SR5) and Ubon stylo (SU)) were evaluated in a field experiment in a subtropical area with hot summers and cold winters in Guangxi, China. Three forage stubble cover managements: no cover (CK), dry mass cover (MC) and plastic cover (PC) were applied at the end of the summer period to evaluate cold tolerance and accession survival over the winter. Photosynthesis measurements were taken from the forages in mid-summer. The results showed that PG1 accession produced significantly higher dry matter yields (67.0 t·ha-1) than the other grass and legume accessions. Legume accessions SU and SR5 produced much less dry matter (6.4 - 7.2 t·ha-1) compared to the grasses. M II, PU and PR11 contained the largest proportion of leaf. PG1 and PH showed good cold tolerance (survival rate >85%) under -1°C conditions without any cover management. PR11 had better cold tolerance than PU. M II exhibited very poor winter survival under no cover and with massive cover, and only survived well under plastic cover. The two stylo accessions died completely under all winter cover management treatments. In the growing season, under a given photosynthesis photon flux density (PPFD) = 1500 μmol m-2 s-1, the net photosynthesis rate Pn of all the seven accessions was above 28 μmol m-2 s-1, of which hybrid elephant grass and M II were above 42 μmol m-2 s-1. Though these 7 tropical accessions yielded high production in the grow season, stylo and M II are sensitive to cold in subtropical region of Guangxi. The result suggests that PG1 and PU are good accessions and can be used as productive perennial pasture, while stylo and M II are simply considered as annual one. Additionally, if paspalum was trained in cool region before being introduced to subtropical region, it may present both productivity and enhancive cold tolerance.

Vegetation Map and Vegetation Monographs of China

Vegetation Map of China As the most significant component of an ecosystem,vegetation plays the most important role in maintaining biodiversity and providing the necessary resources for human beings.A vegetation map shows the major vegetation types of a region and their geographic distribution patterns.

The Germplasm Bank of Wild Species, Southwest China

Green plants are the primary producers of ecosystems on Earth.However,plant diversity is currently being lost at an unprecedented rate,perhaps as much as 100-to1000-fold higher than during the recent geological past,resulting in an associated decrease in

The CAS Bio-specimen Centers in Sound Progress

Bio-specimen centers, including herbaria and zoological museums, are the most integrated places for the storage of specimens, which are real samples and the most important vouchers for taxonomic and biodiversity studies. The information carried by

Biodiversity Research in the Chinese Academy of Sciences

The year 2010 has been designated the International Year of Biodiversity by United Nations. The theme for this initiative is 'Biodiversity is life and biodiversity is our life.' A

Anatomical and chemical characteristics associated with lodging resistance in wheat

Anatomical and chemical characteristics of stems affect lodging in wheat(Triticum aestivum L.) cultivars. Traits associated with lodging resistance, such as plant height, stem strength, culm wall thickness, pith diameter, and stem diameter, were extensively investigated in earlier studies. However, the solid stem trait was rarely considered. In this study, we measured a range of anatomical and chemical characteristics on solid and hollow stemmed wheat cultivars. Significant correlations were detected between resistance to lodging and several anatomical features, including width of mechanical tissue, weight of low internodes, and width of stem walls. Morphological features that gave the best indication of improved lodging resistance were increased stem width, width of mechanical tissue layer, and stem density. Multiple linear regression analysis showed that 99% of the variation in lodging resistance could be explained by the width of the mechanical tissue layer, suggesting that solid stemmed wheat has several anatomical features for increasing resistance to lodging. In addition, microsatellite markers GWM247 and GWM340 were linked to a single solid stem QTL on chromosome 3BL in a population derived from the cross Xinongshixin(solid stem)/Line 3159(hollow stem). These markers should be valuable in breeding wheat for solid stem.

Monepaloside K, a New Triterpenoid Saponin from Morina nepalensis var. alba Hand. - Mazz.

One new triterpenoid saponin, monepaloside K (1) was isolated from the water-soluble part of the whole plant of a famous Tibetan medicinal herb, morina nepalensis var. alba Hand.-Mazz.. Its structure was determined to be 3-O-a-L-arabinopyranosyl-(13)-b-D- xylopyranosyl siaresinolic acid on the basis of spectroscopic evidences, especially 2D NMR techniques.

Using Morphology and Phylogeny to Characterize and Classify Fungi:Fungal Diversity Notes

Fungi play critical roles in all ecosystems,functioning as decomposers,epiphytes,endophytes,symbionts of plants,and animal and plant pathogens.Despite their importance,they are severely understudied organisms.That is about to change.A landmark new study resulting from a collaboration between the CAS Kunming Institute of Botany(KIB)and Yunnan Agricultural University aims to fill these gaps in knowledge by coupling fungal morphology with modern-day molecular data technologies.

Chinese Forest Biodiversity Monitoring and Research

A Review 1.Preliminary investigations in China's forest ecosystems and the establishment of institutions In the1950s,Chinese Academy of Sciences(CAS) and several relevant institutes organized a series of large-scale comprehensive surveys on the flora and

Spatial patterns and environmental factors influencing leaf carbon content in the forests and shrublands of China

Leaf carbon content(LCC)is widely used as an important parameter in estimating ecosystem carbon(C)storage,as well as for investigating the adaptation strategies of vegetation to their environment at a large scale.In this study,we used a dataset collected from forests(5119 plots)and shrublands(2564 plots)in China,2011-2015.The plots were sampled following a consistent protocol,and we used the data to explore the spatial patterns of LCC at three scales:plot scale,eco-region scale(n=24),and eco-region scale(n=8).The average LCC of forests and shrublands combined was 45.3%,with the LCC of forests(45.5%)being slightly higher than that of shrublands(44.9%).Forest LCC ranged from 40.2%to 51.2%throughout the 24 eco-regions,while that of shrublands ranged from 35%to 50.1%.Forest LCC decreased with increasing latitude and longitude,whereas shrubland LCC de-creased with increasing latitude,but increased with increasing longitude.The LCC increased,to some extent,with increasing temperature and precipitation.These results demonstrate the spatial patterns of LCC in the forests and shrublands at different scales based on field-measured data,providing a reference(or standard)for estimating carbon storage in vegetation at a regional scale.

Distribution of plant species and species-soil relationship in the east central Gurbantunggut Desert, China

The distribution of plant species and relationships between species and soil factors in the east central part of Gurbantunggut Desert was studied to provide more insight into the flora and determine differences in vegetation across various parts of the desert. Two-way Cluster Analysis showed that the vegetation in the area could be divided into three groups, the first group was dominated by the shrub species, Ephedra przewalskii and the grass species, Carex physodes mainly in areas of flat grounds and gentle slopes; the second group was dominated by C. physodes, Artemisia songorica and A. xerophytica mainly on the slope of sand dunes and the third group was dominated by the shrub species, Haloxylon persicum mainly on the top of sand dunes. There was no difference in plant density between Groups 1 and 2 but there was a significant decrease in Group 3. Soil water under vegetation Group 3 was much lower than that in the other two groups at all soil depths. The EC, organic matter, total P and soluble Na, Ca and Mg varied very similarly with soil water. Canonical corre- spondence analysis （CCA） satisfactorily assessed the species-soil relations in the area. The distribution of plant species was strongly correlated with the soil factors of water content, organic matter, EC and nutrients. The variations in species occurrence explained by the three CCA axes were about 70%, indicating that some explanatory site variables may exist outside our studied parameters. Soil texture is suggested to be included in future studies to improve the explanation of CCA.

Long-term changes in the tree radial growth and intrinsic water-use efficiency of Chuanxi spruce(Picea likiangensis var.balfouriana) in southwestern China

Elevated CO_(2) level in the atmosphere is expected and intrinsic water-use efficiency(iWUE).Although current found the tree growth decline in water-limited area,it is st to improve the tree growth rates results inferring from tree rings unclear whether spruce trees in humid southwestern China benefit from the increasing 002.In this study,tree-ring width data were used to investigate the tree radial growth rate of Chuanxi spruce(Picea likiangensis var.balfouriana).Moreover,combining with the tree-ring carbon isotope date,we analyzed the physiological responses of Chuanxi spruce to rising CO_(2) concentrations in the atmosphere(C_(a))associated with climatic change in southwestern China.From 1851 to 2009,iWUE of Chuanxi spruce rose by approximately 30.4%,and the ratio of atmospheric CO_(2) to leaf in-tercellular CO_(2) concentration(C_(j)/C_(a))showed no significant trend in the study area.The result suggested that Chuanxi spruce used an active response strategy when C_(a) was significantly increased,iWUE showed a significant increasing trend in parallel with tree radial growth,indicating that the increasing iWUE resulted in an increase in radial growth.These results suggest that spruce forests in southwestern China have not shown declining trends under increasing Ca and climate change scenarios,in contrast to trees growing in water-limited areas.Therefore,spruce forests benefit from the increasing CO_(2) in the atmosphere in the humid areas of southwestern China.

Three-dimensional modelling of soil organic carbon density and carbon sequestration potential estimation in a dryland farming region of China

Soil organic carbon density(SOCD)and soil organic carbon sequestration potential(SOCP)play an important role in carbon cycle and mitigation of greenhouse gas emissions.However,the majority of studies focused on a two-dimensional scale,especially lacking of field measured data.We employed the interpolation method with gradient plane nodal function(GPNF)and Shepard(SPD)across a range of parameters to simulate SOCD with a 40 cm soil layer depth in a dryland farming region(DFR)of China.The SOCP was estimated using a carbon saturation model.Results demonstrated the GPNF method was proved to be more effective in simulating the spatial distribution of SOCD at the vertical magnification multiple and search point values of 3.0×106 and 25,respectively.The soil organic carbon storage(SOCS)of 40 cm and 20 cm soil layers were estimated as 22.28×10^(11)kg and 13.12×10^(11)kg simulated by GPNF method in DFR.The SOCP was estimated as 0.95×10^(11)kg considered as a carbon sink at the 20–40 cm soil layer.Furthermore,the SOCP was estimated as–2.49×10^(11)kg considered as a carbon source at the 0–20 cm soil layer.This research has important values for the scientific use of soil resources and the mitigation of greenhouse gas emissions.

Impact of tree diversity and environmental conditions on the survival of shrub species in a forest biodiversity experiment in subtropical China

Aims Although shrubs are an important component of forests,their role has not yet been considered in forest biodiversity experiments.In the biodiversity-ecosystem functioning(BEF)experiment with subtropical tree species in south-east China(BEF-China),we factorially combined tree with shrub species-diversity treatments.Here,we tested the hypotheses that shrub survival differs between the 10 planted shrub species,with lower survival rates of late-than early-successional species and is affected by environmental conditions,such as topography and top soil characteristics,as well as by biotic factors,represented by tree,shrub and herb layer characteristics.Methods We analyzed the survival of 42000 shrub individuals in 105 plots varying in tree and shrub species richness of the BEF-China project four years after planting.Shrub survival was analyzed with generalized linear mixed effects models at the level of individuals and with variance partitioning at the plot level.Random intercept and random slope models of different explanatory variables were compared with respect to the Bayesian Information Criterion(BIC).Important Findings Survival rates differed largely between the 10 shrub species,ranging from 26%to 91%for Ardisia crenata and Distylium buxifolium,respectively.Irrespective of species identity,single abiotic factors explained up to 5%of species survival,with a negative effect of altitude and slope inclination and a positive effect of the topsoil carbon to nitrogen ratio,which pointed to drought as the major cause of shrub mortality.In contrast,neither tree nor shrub richness affected shrub survival at this early stage of the experiment.Among the biotic predictors,only herb layer species richness and cover of the dominant fern species(Dicranopteris pedata)affected shrub survival.Overall,our models that included all variables could explain about 65%in shrub survival,with environmental variables being most influential,followed by shrub species identity,while tree species diversity(species richness and identity)and herb layer characteristics contributed much less.Thus,in this early stage of the experiment the biotic interactions among shrubs and between shrubs and trees have not yet overruled the impact of abiotic environmental factors.

Unrelated to phenylalanine: Feeding studies provide new insight into salicylic acid biosynthesis

How plants produce the important defense hormone salicylic acid(SA)has been studied for almost 50 years.The current understanding is that in land plants,SA is biosynthesized from chorismate through the isochorismate(IC)pathway and the phenylalanine ammonia-lyase(PAL)pathway(Dempsey et al.,2011).

Land-use impact on soil carbon and nitrogen sequestration in typical steppe ecosystems, Inner Mongolia

To explore the optimal land-use for soil carbon （C） sequestration in Inner Mongolian grasslands, we investigated C and nitrogen （N） storage in soil and soil fractions in 8 floristi- cally and topographically similar sites which subjected to different lancl-use types （free-grazing, grazing exclusion, mowing, winter grazing, and reclamation）. Compared with free-grazing grasslands, C and N storage in the 0-50 cm layer increased by 18.3% （15.5 Mg C ha-1） and 9.3% （0.8 Mg N ha-1） after 10-yr of grazing exclusion, respectively, and 21.9% （18.5 Mg C ha-1） and 11.5% （0.9 Mg N ha-1） after 30-yr grazing exclusion, respectively. Similarly, soil C and N storage increased by 15.3% （12.9 Mg C ha-1） and 10.2% （0.8 Mg N ha-1） after 10-yr mowing, respectively, and 19.2% （16.2 Mg C ha-1） and 7.1% （0.6 Mg N ha-1） after 26-yr mowing, respectively. In contrast, soil C and N storage declined by 10.6% （9.0 Mg C ha-1） and 11.4% （0.9 Mg N ha-1） after 49-yr reclamation, respectively. Moreover, increases in C and N storage mainly occurred in sand and silt fractions in the 0-10 cm soil layer with grazing exclusion and mowing. Our findings provided evidence that Inner Mongolian grassslands have the capacity to sequester C and N in soil with improved management practices, which were in the order： grazing exclusion 〉 mowing 〉 winter grazing 〉 reclamation.

PIF1 and RVE1 form a transcriptional feedback loop to control light-mediated seed germination in Arabidopsis^FA

The phytochrome B (phyB) photoreceptor plays a major role that inputs light signals to regulate seed dormancy and germination. PHYTOCHROME-INTERACTING FACTOR1 (PIF1) is a key transcription factor repressing phyB-mediated seed germination, while REVEILLE1 (RVE1) factor functions as a curial regulator in controlling both seed dormancy and ger-mination. However, the relationship between the PIF1-and RVE1-modulated signaling pathways remains mostly unknown. Here, we find that PIF1 physically interacts with RVE1. Genetic analysis indicates that RVE1 inhibition on seed germination requires PIF1;re-ciprocally, the repressive effect of PIF1 is partially de-pendent on RVE1. Strikingly, PIF1 and RVE1 directly bind to the promoter and activate the expression of each other. Furthermore, PIF1 and RVE1 coordinately regulate the transcription of many downstream genes involved in abscisic acid and gibberellin pathways. Moreover, PIF1 enhances the DNA-binding ability and transcriptional repression activity of RVE1 in regulating GIBBERELLIN 3-OXIDASE2, and RVE1 promotes PIF1's DNA-binding ability in modulating ABSCISIC ACID-INSENSITIVE3 expression. Thus, this study demon-strates that PIF1 and RVE1 form a transcriptional feedback loop that coordinately inhibits seed germi-nation, providing a mechanistic understanding of how phyB-mediated light signal is transduced to the seeds.