Effects of Short-term High Temperature Stress on the Photosynthesis of Potato in Different Growth Stages

[Objective] The aim was to study the effects of short-term high temperature stress on the photosynthesis of potato in different growth stages. [Method] Choosing powder potato named Longshu No.3 widely cultivated in Ningxia as test material,the changes of stomata conductance （Gs）,transpiration rate （Tr） and CO2 concentration difference between internal and external leaf chamber,net photosynthetic rate （Pn） and photosynthetic water use efficiency （WUE） in different growth stages under short-term high temperature were analyzed. [Result] During seedling stage,the hysteretic nature of net photosynthetic rate and CO2 concentration difference between internal and external leaf chamber of potato could be found under high temperature stress,while the change trends of stomata conductance and transpiration rate under high temperature stress were consistent to that at normal temperature,but stomata conductance and transpiration rate were higher than those at normal temperature,and CO2 concentration difference between internal and external leaf chamber affected net photosynthetic rate most obviously. During branching stage,the change trends of net photosynthetic rate,CO2 concentration difference between internal and external leaf chamber,stomata conductance and transpiration rate under high temperature stress and normal temperature were similar,but they changed abruptly and reached peak value at noon under high temperature stress,while there existed consistent variation of water use efficiency under high temperature stress and at normal temperature,and CO2 concentration difference between internal and external leaf chamber also affected net photosynthetic rate most greatly,next came transpiration rate. [Conclusion] High temperature stress affected the photosynthesis of potato in different growth stages,and it was more obvious during branching stage than seedling stage,while CO2 concentration difference between internal and external leaf chamber had the most important influence on net photosynthetic rate.

Fractal Nature of Crack Growth under Different Temperature

We have studied numerically a simple crack growth model in a two-dimensional triangular lattice of bonds and nodes which incorporates the surface of a growing crack bond-breaking probability P-i similar to exp{(-V-i+E(i))phi(T)}, where E(i) is elastic energy stored in the i-th bond. Different energy temperature factors phi(T) are employed during crack formation and propagation process with a uniform dilation strain case and a shear case and with periodic boundary condition in the horizontal direction. Our results show that the patterns of the cracks generated are fractal structure and the effective fractal dimensionalities decrease with the increase of the temperature factor phi(T)(the absolute temperature T decreasing). In the paper we also discuss the relation between the effective fractal dimension D-eff (the radius R(g) of gyration) and the fractal dimensions D (the radius R of circular), and also give their modification values Omega about two kinds of methods in the lattice model.

Temperature Dependence of Raman Scattering in 4H-SiC Films under Different Growth Conditions

The microRaman scattering of 4H-SiC films, fabricated by low pressure chemical vapor deposition under different growth conditions, is investigated at temperatures ranging from 80 K to 550K. The effects of growth conditions on E2 （TO）, E1 （TO） and A1 （LO） phonon mode frequencies are negligible. The temperature dependences of phonon linewidth and lifetime of E2 （TO） modes are analyzed in terms of an anharmonic damping effect induced by thermal and growth conditions. The results show that the lifetime of E2 （TO） mode increases when the quality of the sample improves. Unlike other phone modes, Raman shift of A1 （longitudinal optical plasma coupling （LOPC）） mode does not decrease monotonously when the temperature increases, but tends to blueshift at low temperatures and to redshift at relatively high temperatures. Theoretical analyses are given for the abnormal phenomena of A1 （LOPC） mode in 4H-SiC.

DNA Methylation of pacap Gene Is Involved in Growth Superiority of Female Half Smooth Tongue Sole(Cynoglossus semilaevis)in Different Salinities

Pituitary adenylate cyclase activating polypeptide(PACAP)and growth hormone-releasing hormone(GHRH)play important roles in the GH/IGF growth axis in fishes.To determine whether epigenetic change is involved in the regulation of pacap and ghrh responses to low salinity stress in Cynoglossus semilaevis,the correlation between growth traits,DNA methylation status and gene expression level in low salinity(15,S15)and optimal salinity(30,S30)at day 7(D7)and day 60(D60)were analyzed.Results showed that exposure to low salinity for 60 days attenuated C.semilaevis growth rate.Under low salinity,DNA methylation level of pacap promoter increased in females and decreased in males at day 7,but inverted at day 60.Additionally,pacap expression was up-regulated in both males and females.The pacap promoter methylation level was higher and expression level was lower in female than in male.The results suggest that pacap promoter methylation level is negatively correlated to mRNA level and positively correlated to body weight,while gene expression level is negatively related with body weight.With the decrease of salinity,DNA methylation level of ghrh promoter and exon1,as well as its gene expression displayed minor changes.Overall,pacap gene seems to play an important role in fish growth,contributing to female growth superiority,while ghrh gene seems not pertinent under salinity stress.The results indicate that low salinity potentially affects fish growth through regulating DNA methylation in pacap promoter.This study expands the understanding of the molecular mechanism of how salinity modulates fish growth from the epigenetic perspective.

Dynamic changes of genomic methylation profiles at different growth stages in Chinese Tan sheep

Background:Tan sheep,an important local sheep breed in China,is famous for their fur quality.One-month-old Tan sheep have white,curly hair with beautiful flower spikes,commonly known as“nine bends”,which has high economic value.However,the“nine bends”characteristic gradually disappears with age;consequently,the economic value of the Tan sheep decreases.Age-related changes in DNA methylation have been reported and may be responsible for age-induced changes in gene expression.Until now,no genome-wide surveys have been conducted to identify potential DNA methylation sites involved in different sheep growth stages.In this study we investigated the dynamic changes of genome-wide DNA methylation profiles in Tan sheep using DNA from skin and deep whole-genome bisulfite sequencing,and compared the DNA methylation levels at three different growth stages:1,24,and 48 months old(mon1,mon24,and mon48,respectively).Results:In this study,11 skin samples from three growth stages(four for mon1,four for mon24,and three for mon48)were used for DNA methylation analysis and gene expression profiling.There were 52,288 and 236 differentially methylated genes(DMGs)identified between mon1 and mon24,mon1 and mon48,and mon24 and mon48,respectively.Of the differentially methylated regions,1.11%,7.61%,and 7.65% were in the promoter in mon1 vs.mon24,mon24 vs.mon48,and mon1 vs.mon48,respectively.DMGs were enriched in the MAPK and WNT signaling pathways,which are related to age growth and hair follicle morphogenesis processes.There were 51 DMGs associated with age growth and curly fleece formation.Four DMGs between mon1 and mon48(KRT71,CD44,ROR2 and ZDHHC13)were further validated by bisulfite sequencing.Conclusions:This study revealed dynamic changes in the genomic methylation profiles of mon1,mon24,and mon48 sheep,and the percentages of methylated cytosines were 3.38%,2.85% and 4.17%,respectively.Of the DMGs,KRT71 and CD44 were highly methylated in mon1,and ROR2 and ZDHHC13 were highly methylated in mon48.These findings provide foundational information that may be used to develop strategies for potentially retaining the lamb fur and thus improving the economic value of Tan sheep.

Resistance of Different Tomato Varieties against Tomato Powdery Mildew during Different Growth Stages

The pathogen of tomato powdery mildew （Oidium neolycopersici Kiss） was simultaneously inoculated into four varieties during seedling, flowering and fruiting stages under the same environmental conditions by inducing inoculation method, so as to study the resistance during different growth stages. Different varieties of plants and the plants during different growth stages were investigated after inoculation for 12 d, and disease epidemic curves were drawn according to survey data. The results showed that different varieties performed different resistance against powdery mildew and the same variety also showed different resistance during different growth stages. The susceptible extent of Lujia was the heaviest during seedling and flowering sages, while it showed the strongest resistance during fruiting stage; improved 96 -8 showed the highest resistance during seedling stage, but performed the lowest resistance during fruiting stage.

Study on the chemical composition of Nauclea officinalis in different months of the same year and different growth years

Objective:Based on the quality analysis of Nauclea officinalis in different growth years and different months in the same year,the most suitable harvest year and the specific month in the same year were determined according to the evaluation of the active components in the stem of medicinal parts of Nauclea officinalis.Methods:LC-MS/MS method was used to investigate the quality of Nauclea officinalis from different growth years and different months in the same year,mainly including the content determination of the active ingredients in the medicine.Results:With the prolongation of production life,the content of active ingredients in stem of Nauclea officinalis increased continuously.After reaching a certain number of years,the content of active ingredients increased little;In the middle of the same year,from mid-October to mid-June of the next year,the content of iso-vincin lactam was relatively high,especially between the end of March and the end of May.The content was high and stable,and the highest point was the stem sample collected in May.Conclusion:The content of each component in the stem of Nauclea officinalis with a growth life of more than 5 years has reached a relatively high and stable level.Nauclea officinalis with a growth life of more than 5 years should be collected as raw materials for medicinal materials.The month with high and stable content of isocyanoside lactam,namely May of each year,was taken as the best harvest time of gallbladder in one year.The best harvest time was from mid-October to mid-June of the next year,or from March to May of each year.

The Efficiency Droop of InGaN-Based Green LEDs with Different Superlattice Growth Temperatures on Si Substrates via Temperature-Dependent Electroluminescence

InGaN-based green light-emitting diodes （LEDs） with different growth temperatures of superlattice grown on Si （111） substrates are investigated by temperature-dependent electroluminescence between 100 K and 350K. It is observed that with the decrease of the growth temperature of the superlattice from 895℃ to 855℃, the forward voltage decreases, especially at low temperature. We presume that this is due to the existence of the larger average size of V-shaped pits, which is determined by secondary ion mass spectrometer measurements. Meanwhile, the sample with higher growth temperature of superlattice shows a severer efficiency droop at cryogenic temperatures （about 100 K-150 K）. Electron overflow into p-GaN is considered to be the cause of such phenomena, which is relevant to the poorer hole injection into multiple quantum wells and the more reduced effective active volume in the active region.

Combining QTL mapping and expression profile analysis to identify candidate genes of cold tolerance from Dongxiang common wild rice(Oryza rufipogon Griff.)

Rice（Oryza sativa L.）, a tropical and subtropical crop, is susceptible to low temperature stress during seedling, booting, and flowering stages, which leads to lower grain quality levels and decreasing rice yields. Cold tolerance is affected by multiple genetic factors in rice, and the complex genetic mechanisms associated with chilling stress tolerance remain unclear. Here, we detected seven quantitative trait loci（QTLs） for cold tolerance at booting stage and identified one cold tolerant line, SIL157, in an introgression line population derived from a cross between the indica variety Guichao 2, as the recipient, and Dongxiang common wild rice, as the donor. When compared with Guichao 2, SIL157 showed a stronger cold tolerance during different growth stages. Through an integrated strategy that combined QTL-mapping with expression profile analysis, six candidate genes, which were up-regulated under chilling stress at the seedling and booting developmental stages, were studied. The results may help in understanding cold tolerance mechanisms and in using beneficial alleles from wild rice to improve the cold tolerance of rice cultivars through molecular marker-assisted selection.

Study of Shifted UV Emission Peak of ZnO Nanowire Arrays

We have obtained vertically aligned ZnO nanowire arrays synthesized by microwave-assisted heating method with different growth time.From the room-temperature PL measurement,the strong deep-level emission and weak near band edge(NBE)emission can be seen.The deep-level emissions became weaker and deep-level emissions became stronger when the samples were annealed at 300℃for 30 min,meanwhile,the NBE emission peaks get red-shifted with growth time,and the longer the growth time,the more the peak shifting.This phenomenon can be attributed that the diameter of ZnO nanowires increases with growth time.This PL emission phenomenon is important in research of optoelectronic application.

Limiting stand density and basal area projection models for even-aged Tecomella undulata plantations in a hot arid region of India

This paper presents equations for estimating limiting stand density for Z undulata plantations grown in hot desert areas of Raj asthan State in India. Five different stand level basal area projection models, belonging to the path invariant algebraic difference form of a non-linear growth function, were also tested and compared. These models can be used to predict future basal area as a function of stand variables like dominant height and stem number per hectare and are necessary for reviewing different silvicultural treatment options. Data from 22 sample plots were used for modelling. An all possible growth intervals data structure was used. Both, qualitative and quantitative criteria were used to compare alternative models. The Akaike＇s information criteria differ- ence statistic was used to analyze the predictive ability of the models. Results show that the model proposed by Hui and Gadow performed best and hence this model is recommended for use in predicting basal area development in 12 undulata plantations in the study area. The data used were not from thinned stands, and hence the models may be less accurate when used for predictions when natural mortality is very significant.

Comparison and Measurement of Economic Growth in Coastal Areas and Inland Provinces of China

This study aims to measure the regional difference in economic growth and the driving effect of export of coastal areas for inland provinces in China from the perspective of labor division.Embedded input and output data are adopted on the basis of the input-output theory for economic growth and trade accounting.Since China’s accession to WTO,vertical specialization across areas has been improved in general,but the areas differ widely in their participation in labor division in the global value chain(GVC)and national value chain(NVC).Different areas in China mainly rely on local production for economic growth,but engagement in GVC and NVC labor division is the major driver for the country’s rapid economic growth.Under the external impact,local economic growth has relied less on the outside,but more on local production since 2008.The driving effect of export of coastal areas for inland provinces is mainly reflected in agriculture,indicating that inland provinces and cities indirectly participate in international division of labor mainly by providing raw materials for production for eastern areas.This study,based on GVC and NVC integration and interaction,conducts in-depth research on the driving effect of export of coastal areas for the economic development of inland provinces,and offers a new perspective for studying the regional difference in economic growth in China.