A Golden2-like transcription factor, BnGLK1a, improves chloroplast development, photosynthesis, and seed weight in rapeseed

Enhancing photosynthetic efficiency is a major goal for improving crop yields under agricultural field conditions and is associated with chloroplast biosynthesis and development.In this study,we demonstrate that Golden2-like 1a(BnGLK1a)plays an important role in regulating chloroplast development and photosynthetic efficiency.Overexpressing BnGLK1a resulted in significant increases in chlorophyll content,the number of thylakoid membrane layers and photosynthetic efficiency in Brassica napus,while knocking down BnGLK1a transcript levels through RNA interference(RNAi)had the opposite effects.A yeast two-hybrid screen revealed that BnGLK1a interacts with the abscisic acid receptor PYRABACTIN RESISTANCE 1-LIKE 1-2(BnPYL1-2)and CONSTITUTIVE PHOTOMORPHOGENIC 9 SIGNALOSOME 5A subunit(BnCSN5A),which play essential roles in regulating chloroplast development and photosynthesis.Consistent with this,BnGLK1a-RNAi lines of B.napus display hypersensitivity to the abscisic acid(ABA)response.Importantly,overexpression of BnGLK1a resulted in a 10%increase in thousand-seed weight,whereas seeds from BnGLK1a-RNAi lines were 16%lighter than wild type.We propose that BnGLK1a could be a potential target in breeding for improving rapeseed productivity.Our results not only provide insights into the mechanisms of BnGLK1a function,but also offer a potential approach for improving the productivity of Brassica species.

GC-MS Analysis of Chemical Components of Volatile Oil in Different Parts of Fennel( Foenicuzu vulgare Mill. )

[Objectives] This study was conducted to analyze the composition of volatile oil in different parts of fennel(Foenicuzu vulgare Mill.) and to compare the differences in the composition of volatile oil in different parts of fennel.[Methods]The steam distillation method was applied to extract volatile oil from different parts of fennel,and the components of volatile oil from different parts of fennel were separated and identified by GC-MS.The relative content of each component was determined by the peak area normalization method.[Results]37,33,18,and 44 chemical components were separated from the volatile oil of fennel roots,stems,young leaves and fruit,respectively,accounting for 98.64%,99.34%,99.59% and 95.99% of the total volatile oil of corresponding parts.A total of 77 chemical components were identified in the four parts,of which 5 were common components.The main component of the volatile oil in the stems and young leaves was trans-anethole.The main components of the volatile oil in fruit were estragole and trans-anethole.And the main component of the volatile oil in the roots was dill apiol.The components in the volatile oil of fennel roots,stems,young leaves and fruit were different in type and content.[Conclusions]This study provides a theoretical reference for the further effective development and utilization of fennel resources.

HPLC Determination of Oleanolic Acid and Ursolic Acid in Chaenomeles cathayensis from Guizhou

[Objectives]This study was conducted to establish a method for determining the contents of Chaenomeles cathayensis(Hemsl.)Schneid.,and analyze the changes in effective components of C.cathayensis grown in Guizhou,so as to provide data support for the production and quality control of C.cathayensis.[Methods]The contents of ursolic acid and oleanolic acid in C.cathayensis in different areas of Guizhou were determined.The HPLC method was adopted under following conditions:chromatographic column waters C18 column(4.6 mm×150 mm,5.0μm);mobile phase:methanol-0.1 mol/L ammonium acetate(85∶15);column temperature:25℃;detection wavelength:257 nm;flow rate 1.0 ml/min.[Results]Through methodological investigations,HPLC could be used to detect the contents of the two terpenoids oleanolic acid and ursolic acid in C.cathayensis from Guizhou.The content of oleanolic acid ranged from 0.076%to 0.144%,and the content of ursolic acid ranged from 0.201%to 0.439%.[Conclusions]A method for determining the contents of C.cathayensis was established using the HPLC method with oleanolic acid and ursolic acid as the index components.The method is accurate,reliable,and simple and easy to implement,and can serve as a reference and support for quality evaluation and standard improvement of C.cathayensis.

Field-scale spatial variability of soil calcium in a semi-arid region:Implications for soil erosion and site-specific management

Excess calcium(Ca)in soils of semi-arid and arid regions has negative effects on soil structure and chemical properties,which limits the crop root growth as well as the availability of soil water and nutrients.Quantifying the spatial variability of soil Ca contents may reveal factors influencing soil erosion and provide a basis for site-specific soil and crop management in semi-arid regions.This study sought to assess the spatial variability of soil Ca in relation to topography,hydraulic attributes,and soil types for precision soil and crop management in a 194-ha production field in the Southern High Plains of Texas,USA.Soils at four depth increments(0-2,0-15,15-30,and 30-60 cm)were sampled at 232 points in the spring of 2017.The Ca content of each sample was determined with a DP-6000 Delta Premium portable X-ray fluorescence(PXRF)spectrometer.Elevation data was obtained using a real-time kinematic GPS receiver with centimeter-level accuracy.A digital elevation model(DEM)was derived from the elevation data,and topographic and hydraulic attributes were generated from this DEM.A generalized least-squares model was then developed to assess the relationship between soil Ca contents of the four layers and the topographic and hydraulic attributes.Results showed that topographic attributes,especially slope and elevation,had a significant effect on soil Ca content at different depths(P<0.01).In addition,hydraulic attributes,especially flow length and sediment transport index(STI),had a significant effect on the spatial distribution of soil Ca.Spatial variability of soil Ca and its relationships with topographic and hydraulic attributes and soil types indicated that surface soil loss may occur due to water or wind erosion,especially on susceptible soils with high slopes.Therefore,this study suggests that the application of PXRF in assessing soil Ca content can potentially facilitate a new method for soil erosion evaluation in semi-arid lands.The results of this study provide valuable information for site-specific soil conservation and crop management.