Impact of high temperatures on the marketable tuber yield and related traits of potato

Kim, Y.U.,Seo, B.S.,Choi, D.H.,Ban, H.Y.,Lee, B.W. Gauthier-Villars ; Elsevier Science Ltd 2017 European journal of agronomy Vol.89 No.-

<P>A rapid warming of 2.8-5.3 degrees C by the end of this century is expected in South Korea. Considering the current temperature during the spring potato growing season (emergence to harvest; ca. 18 degrees C), which is near the upper limit of the optimum temperature for potato yield, the anticipated warming will adversely affect potato production in South Korea. The present study assessed the impact of high temperature on the marketable tuber yield and related traits of cv. Superior (which makes up 71% of the annual potato production in South Korea) in four temperature-controlled plastic houses and an outdoor field (37.27 N, 126.99 degrees E) during 2015-2016. The target temperatures of the four plastic houses were set to ambient (AT), AT+1.5 degrees C, AT + 3.0 degrees C, and AT + 5.0 degrees C. The marketable tuber yield was significantly reduced by 11% per 1 degrees C increase over a temperature range of 19.1-27.7 degrees C. The negative impact of high temperature was associated not only with the yield loss of total tubers, which was mostly explained by the slower tuber bulking rate, but also the reduced marketable tuber ratio under temperatures above 23 degrees C, which was mainly attributed to the reduced number of marketable tubers (r = 0.79***). Under moderate temperatures below 23 degrees C, the source limited the number of marketable tubers without reducing the marketable tuber ratio. In contrast, the number of marketable tubers was, limited by the marketable tuber set at the early growth stage rather than the source under the higher temperatures, which resulted in the reduction in the marketable tuber ratio below 56%. These results suggest that the objectives of breeding and agronomic management for adapting to the rapid warming in South Korea should include maintaining the ability to form tubers at the early growth stage under high temperatures, as well as the photosynthetic capacity and sink strength of the tubers.</P>

Climatology of GPS signal loss observed by Swarm satellites

Gauthier-Villars 2018 Annales geophysicae Vol.36 No.2

Meteor echo height ceiling effect and mesospheric temperature estimation from meteor radar observations

Gauthier-Villars 2018 Annales geophysicae Vol.36 No.5

Effects of transgenic poplars expressing increased levels of cellular cytokinin on rhizosphere microbial communities

Nam, K.J.,Kim, D.Y.,Nam, K.H.,Pack, I.S.,Park, J.H.,Jeong, S.C.,Choi, Y.I.,Noh, E.W.,Kim, C.G. Gauthier-Villars ; Elsevier Science Ltd 2014 European journal of soil biology Vol.63 No.-

Considerable effort has been made in biotechnology to increase plant biomass. Altering cellular levels of plant hormones, including cytokinin, by genetic modification, has been one way to achieve the goal as it is involved in a variety of processes related to plant growth and development. However, the alteration inevitably may change physiological and biochemical characteristics of plants, and thus could affect the relationship between plants and other organisms interacting with the plants such as microorganisms inhabiting in the rhizosphere. To determine if these indirect effects on rhizosphere microorganisms, mediated by hormonal changes in plants, do occur, we investigated the microbial biomass and community structure associated with transgenic Populus trees with altered cellular cytokinin levels, using phospholipid fatty acid (PLFA) analysis. Three transgenic lines expressing increased levels of cellular cytokinin (T1403, T1410, and T1413) and their non-transgenic isoline (BH) were planted at three locations (Suwon, Cheongwon, and Jinju) in 2011. Soil samples were collected near the base of each tree monthly, from May to September. Indicator PLFAs were utilized to calculate the microbial (bacterial and fungal) biomass, and PLFA profiles were developed to characterize the structure of those communities. Over the growing season, soils from Cheongwon and Jinju had similar microbial biomasses (PLFAs indicating functional groups) whereas, at Suwon, the biomass associated with the rhizosphere of Line T1413 was significantly different from that of the other transgenics and the control. At Cheongwon and Jinju, the structure of the rhizosphere microbial communities differed significantly between Lines T1403 or T1410 and BH, but only in May and June. By contrast, those structures were similar in all sampling months for each line at Suwon. Our results indicate that the influence resulting from genetic modification of the poplar trees on the rhizosphere microbial community is only temporary and inconsistent depending upon location and genetic line.

Survival of Azospirillum brasilense flocculated cells in alginate and its inoculation effect on growth and yield of maize under water deficit conditions

Joe, M.M.,Karthikeyan, B.,Chauhan, P.S.,Shagol, C.,Islam, Md.R.,Deiveekasundaram, M.,Sa, T. Gauthier-Villars ; Elsevier Science Ltd 2012 European journal of soil biology Vol.50 No.-

The objective of this study was to compare the efficiency of Azospirillum brasilense MTCC125 flocculated cells with standard grown cells under in vitro conditions and in association with maize (Zea mays L.) under field conditions. The results revealed that A. brasilense flocculated cells had higher survivability in alginate bead (37 x 10<SUP>6</SUP> CFU g<SUP>-1</SUP> dry wt.) and disinfected soil (11 x 10<SUP>6</SUP> CFU g<SUP>-1</SUP> dry wt.) after 12 months of storage in room temperature. A. brasilense flocculated cells offered a higher degree of resistance to dehydration in terms of reduction in water availability (a<SUB>w</SUB>) and their survivability was 12% higher in soil and 27% higher in alginate compared to standard grown cells. The adhesion efficiency of A. brasilense flocculated cells was 54% higher to hydrophobic polystyrene and 101% higher to maize roots when compared to standard grown A. brasilense cells. Furthermore, flocculated cells had better spermoplane survivability (48%) and spermosphere colonization (73%) along with a concomitant enhancement on the germination percentage (11%) and vigor index (23%) of maize. Field studies with A. brasilense flocculated cells conducted under normal irrigated conditions and by withholding irrigation at 25, 50, and 75% available water-holding capacity (AWHC) showed a significant increase in plant height (19%), plant dry weight (16%), grain yield (31%), stover yield (17%) and nitrogen uptake (18%) compared with standard grown cell treatment.

Molecular characterization of BZR transcription factor family and abiotic stress induced expression profiling in Brassica rapa

Saha, G.,Park, J.I.,Jung, H.J.,Ahmed, N.U.,Kayum, Md.A.,Kang, J.G.,Nou, I.S. Gauthier-Villars ; Elsevier Science Ltd 2015 Vol. No.

BRASSINAZOLE-RESISTANT (BZR) transcription factors (TFs) are primarily well known as positive regulators of Brassinosteroid (BR) signal transduction in different plants. BR is a plant specific steroid hormone, which has multiple stress resistance functions besides various growth regulatory roles. Being an important regulator of the BR synthesis, BZR TFs might have stress resistance related activities. However, no stress resistance related functional study of BZR TFs has been reported in any crop plants so far. Therefore, this study identified 15 BZR TFs of Brassica rapa (BrBZR) from a genome-wide survey and characterized them through sequence analysis and expression profiling against several abiotic stresses. Various systematic in silico analysis of these TFs validated the fundamental properties of BZRs, where a high degree of similarity also observed with recognized BZRs of other plant species from the comparison studies. In the organ specific expression analyses, 6 BrBZR TFs constitutively expressed in flower developmental stages indicating their flower specific functions. Subsequently, from the stress resistance related expression profiles differential transcript abundance levels were observed by 6 and 11 BrBZRs against salt and drought stresses, respectively. All BrBZRs showed several folds up-regulation against exogenous ABA treatment. All BrBZRs also showed differential expression against low temperature stress treatments and these TFs were proposed as transcriptional activators of CBF cold response pathway of B. rapa. Notably, three BrBZRs gave co-responsive expression against all the stresses tested here, suggesting their multiple stress resistance related functions. Thus, the findings would be helpful in resolving the complex regulatory mechanism of BZRs in stress resistance and further functional genomics study of these potential TFs in different Brassica crops.

Relating field-aligned beams to inverted-V structures and visible auroras

Gauthier-Villars 2015 Annales geophysicae Vol.33 No.10

Transgenic alfalfa plants expressing AtNDPK2 exhibit increased growth and tolerance to abiotic stresses

Wang, Z.,Li, H.,Ke, Q.,Jeong, J.C.,Lee, H.S.,Xu, B.,Deng, X.P.,Lim, Y.P.,Kwak, S.S. Gauthier-Villars ; Elsevier Science Ltd 2014 Vol. No.

In this study, we generated and evaluated transgenic alfalfa plants (Medicago sativa L. cv. Xinjiang Daye) expressing the Arabidopsis nucleoside diphosphate kinase 2 (AtNDPK2) gene under the control of the oxidative stress-inducible SWPA2 promoter (referred to as SN plants) to develop plants with enhanced tolerance to various abiotic stresses. We selected two SN plants (SN4 and SN7) according to the expression levels of AtNDPK2 and the enzyme activity of NDPK in response to methyl viologen (MV)-mediated oxidative stress treatment using leaf discs for further characterization. SN plants showed enhanced tolerance to high temperature, NaCl, and drought stress on the whole-plant level. When the plants were subjected to high temperature treatment (42 <SUP>o</SUP>C for 24 h), the non-transgenic (NT) plants were severely wilted, whereas the SN plants were not affected because they maintained high relative water and chlorophyll contents. The SN plants also showed significantly higher tolerance to 250 mM NaCl and water stress treatment than the NT plants. In addition, the SN plants exhibited better plant growth through increased expression of auxin-related indole acetic acid (IAA) genes (MsIAA3, MsIAA5, MsIAA6, MsIAA7, and MsIAA16) under normal growth conditions compared to NT plants. The results suggest that induced overexpression of AtNDPK2 in alfalfa will be useful for increasing biomass production under various abiotic stress conditions.

Outflow of low-energy O⁺ ion beams observed during periods without substorms

Gauthier-Villars 2015 Annales geophysicae Vol.33 No.3

<P>Numerous observations have shown that ions flow out of the ionosphere during substorms with more fluxes leaving as the substorm intensity increases (Wilson et al., 2004). In this article we show observations of low-energy (few tens of electron volts) ionospheric ions flowing out periods without substorms, determined using the Wideband Imaging Camera (WIC) and Auroral Electrojet (AE) indices. We use Cluster ion composition data and show the outflowing ions are field-aligned H+, He+ and O+ beams accelerated to energies of similar to 40-80 eV, after correcting for spacecraft potential. The estimated fluxes of the low-energy O+ ions measured at similar to 20 000 km altitude are > 10(3)-10(5) cm(-2) s. Assuming the auroral oval is the source of the escaping ions, the measured fluxes correspond to a flow rate of similar to 10(19)-10(21) ions s(-1) leaving the ionosphere. However, periods without substorms can persist for hours suggesting the low-energy ions flowing out during these times could be a major source of the heavy ion population in the plasma sheet and lobe.</P>

High-speed solar wind streams and polar mesosphere winter echoes at Troll, Antarctica

Gauthier-Villars 2015 Annales geophysicae Vol.33 No.6