Search

Start Over Coverage 30-41

2. Overaccumulation of glycine betaine enhances tolerance of the photosynthetic apparatus to drought and heat stress in wheat

Creator:
Wang, G. P., Li, F., Zhang, J., Zhao, M. R., Hui, Z., and Wang, W.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, chloroplast ultrastructure, fatty acids, Hill activity, lipids, nonradiative energy, disiipation, oxygen-evolving complex, and thylakoid membrane
Language:
Multiple languages
Description:
To investigate the role of glycine betaine in photosynthesis under stress, a transgenic wheat (Triticum aestivum L.) line T6 overaccumulating glycine betaine and its wild type Shi4185 were used. Seedlings were exposed to conditions of drought (30%, PEG-6000), heat (40°C) and their combination. The results revealed ultrastructural damage to the chloroplast and thylakoid lamellae with the withered phenotype by both drought and heat stress, and the damage was exacerbated by the combination of drought and heat. The appearance of a K step in the typical O-J-I-P curve and the decrease of Hill activity indicated a reduction of oxygen evolving complex function caused by stress. The greater damage was found in wild type than T6. Overaccumulation of glycine betaine in T6 could protect lipids in the thylakoid membrane from damage and stabilize the index of unsaturated fatty acids under stress. A lower ratio of monogalactosyl diacylglycerol/digalactosyl diacylglycerol and higher phosphatidylglycerol content in the thylakoid membrane of T6 were also observed under stress. These effects can promote stability of the thylakoid membrane. Otherwise, glycine betaine overaccumulation decreased photoinhibition of PSII under stress. The results also suggest that xanthophyll cycle-dependent non-radiative energy dissipation may be involved in the GB-mediated effects on PSII function under stress conditions. and G. P. Wang ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Spatial particle size distribution at intact sample surfaces of a Dystric Cambisol under forest use

Creator:
Beck-Broichsitter, Steffen, Gerriets, Marisa R., Neumann, Martin, Kubat, Jan-Frantisek, and Dusek, Jaromir
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
laser diffraction method, sieve and pipette method, and geoprocessin
Language:
Slovak
Description:
The idea of the present study is to describe the spatially varying particle size distribution (PSD) along intact aggregate surfaces with the laser diffraction method (LDM) of four silty-loamy and OC enriched horizons of a Dystric Cambisol from the Uhlířská catchment (Czech Republic) with the laser diffraction method (LDM). Besides, the comparability of the LDM with the sieve and pipette method (SPM), the reproducibility, and the effect of pretreatment on the particle size distribution derived by LDM were analysed. The laser diffraction method enables rapid and continuous particle size distribution measurements with required sample amounts of 0.1–0.2 g for each measurement compared to 5–20 g for SPM. The LDM-derived PSD’s can be directly compared with the standardised SPM-derived PSD’s by using regression analysis with coefficients of determination (r²) between 0.83 and 0.93. Sample pretreatment following standardised proceedings indicates a better comparability between the particle size distributions of both methods. Besides, the highest coefficients of variation of up to 78.6 and therefore the lowest reproducibility were found for the unpretreated PSD of the AE and Bs horizon. Thus, limited evaluability and reproducibility of soil material enriched in organic carbon (OC), used in the current study, needs further analysis. For spatial analysis of PSD’s along intact surfaces of soil aggregates and profiles, spatial data interpolation by inverse distance weighting (IDW), kriging, and triangulated irregular networks (TIN) can be used for detailed measuring, mapping, and spatial extension of the sand, silt, and clay fractions at unsampled locations using a set of samples of known locations. The information offers the possibility of comparing and verifying data obtained by non-invasive midinfrared spectroscopy and Vis–NIR spectroscopy by spatial extension for given soil aggregates and profiles.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public