A ^(15)N-Labeling Study of the Capture of Deep Soil Nitrate from Different Plant Systems

The objective of this study was to determine the efficiency of different plant systems in capturing deep soil nitrate （NO3-） to reduce NO3- leaching in a field plot experiment using 15N labelling. The study was conducted on a calcareous alluvial soil on the North China Plains and the plant systems evaluated included alfalfa （Medicago sativa）, American black poplar （Populus nigra） and cocksfoot （Dactylis）. ^15N-labelled N fertilizer was injected to 90 cm depth to determine the recovery of ^15N by the plants. With conventional water and nutrient management, the total recovery of ^15N-labeled NO3--N was 23.4% by alfalfa after two consecutive growth years. The recovery was significantly higher than those by American black poplar （12.3%） and cocksfoot （11.4%）. The highest proportion of soil residual ~SN from the labeled fertilizer N （%Ndff） was detected around 90 cm soil depth at the time of the 1st year harvest and at 110-130 cm soil depth at time of the 2nd year harvest. Soil %Ndff in 0-80 cm depth was significantly higher in the alfalfa treatment than those in all the other treatments. The soil %Ndff below 100 cm depth was much lower in the alfalfa than those in all the other treatments. These results indicated that ^15N leaching losses in the alfalfa treatment were significantly lower than by those in the black poplar and cocksfoot treatments, due to the higher root density located in nitrate labeling zone of soil profile. In conclusion, alfalfa may be used as a plant to capture deep soil NO3- left from previous crops to reduce NO3- leaching in high intensity crop cultivation systems of North China Plain.

Application of CRISPR/Cas9 technology in forages

Genome editing is an advanced genetic modification tool that facilitates the removal,insertion,or substitution of nucleotides in the genome of an organism for mutation induction.CRISPR/Cas9(clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9)is the most widely used genome editing tool that can precisely modify the specific sequence of a genome.Significant progress has been made in the use of CRISPR/Cas9 for the genetic improvement of food crops.However,in forage crops,the use of CRISPR/Cas9 is still in the infant stage with limited understanding and application.This article reviews current advances in the establishment and application of the CRISPR/Cas9 system in alfalfa,summarizes the application of CRISPR/Cas9 in several other forage legume and grass species,and discusses the prospects of CRISPR/Cas9 in the genetic improvement of forage crops.

Bioaccumulation of metals in human blood in industrially contaminated area

Heavy metals were analyzed in different foods crops, milk, meat and blood samples collected from different age group subjects such as children （1–12 years）, adolescent （12–18 years）, adults （18–45 years） and old age （above 45 and 55 years for males and females, respectively） from polluted and relatively less polluted areas. The results revealed that the consumption of contaminated food crops, meat and milk have significantly increased the concentrations of selected metals in the human blood. Cu, Zn and Mn concentrations were significantly higher （p 0.05） in the blood samples collected from the polluted area as compared to control area. Old people had accumulated high concentrations of metals as compared to the younger ones within the same area. Males accumulated higher concentrations of metals as compared to females.