Response of Contrasting Rice Genotypes to Zinc Sources under Saline Condition

Abiotic stresses are among the major limiting factors for plant growth and crop productivity.Among these,salinity is one of the major risk factors for plant growth and development in arid to semi-arid regions.Cultivation of salt tolerant crop genotypes is one of the imperative approaches to meet the food demand for increasing population.The current experiment was carried out to access the performance of different rice genotypes under salinity stress and Zinc(Zn)sources.Four rice genotypes were grown in a pot experiment and were exposed to salinity stress(7 dS m^(−1)),and Zn(15 mg kg^(-1)soil)was applied from two sources,ZnSO4 and Zn-EDTA.A control of both salinity and Zn was kept for comparison.Results showed that based on the biomass accumulation and K^(+)/Na^(+)ratio,KSK-133 and BAS-198 emerged as salt tolerant and salt sensitive,respectively.Similarly,based on the Zn concentration,BAS-2000 was reported as Zn-in-efficient while IR-6 was a Zn-efficient genotype.Our results also revealed that plant growth,relative water content(RWC),physiological attributes including chlorophyll contents,ionic concentrations in straw and grains of all rice genotypes were decreased under salinity stress.However,salt tolerant and Zn-in-efficient rice genotypes showed significantly higher shoot K^(+)and Zn concentrations under saline conditions.Zinc application significantly alleviates the harmful effects of salinity by improving morpho-physiological attributes and enhancing antioxidant enzyme activities,and the uptake of K and Zn.The beneficial effect of Zn was more pronounced in salt-tolerant and Zn in-efficient rice genotypes as compared with salt-sensitive and Zn-efficient genotypes.In sum,our results confirmed that Zn application increased overall plant’s performance under saline conditions,particularly in Zn in-efficient and tolerant genotypes as compared with salt-sensitive and Zn efficient rice genotypes.

Microhardness,Microstructure and Electrochemical Efficiency of an Al(Zn/xMg) Alloy after Thermal Treatment

The influence of Mg on the microhardness,microstructure and electrochemical efficiency of Al（Zn/xMg） alloys have been investigated.Al（Zn/xMg） alloys were prepared by metal mould casting method to diminish the process cost and to generate an alloy with homogenous microstructure and less casting porosity.Vickers hardness,X-ray diffraction,scanning electron microscopy and transmission electron microscopy were performed to determine the Mg influence on the AlZn alloy.Electrochemical efficiency was used to relate the influence of Mg with the thermal treatment on the corrosion behavior of the Al（Zn/xMg） alloy.The results reveals the presence of Al 32（MgZn） 49 phase for two events;the first is when the Mg content is above 5.49% in as-cast condition,and the second after the thermal treatment is carried out at 450℃ for 5 h.The results also show that the microhardness and electrochemical efficiency have been influenced by the presence of Al 32（MgZn） 49 phase.The addition of Mg modifies the microstructure,increases the content of Al 32（MgZn） 49 phase and improves the electrochemical efficiency.

Zinc Requirements of Tropical Legume Cover Crops

Tropical soils are deficient in essential plant nutrients, including zinc (Zn). Using cover crops in cropping systems is an important option to improve soil fertility for sustainable crop production. However, success of cover crops in highly weathered tropical infertile acid soils is greatly influenced by adequate levels of available soil micronutrients. A greenhouse experiment was conducted to evaluate the Zn requirements of ten major tropical legume cover crops. The Zn levels used were 0, 10, 20 and 40 mg·kg-1 soil. Overall, shoot and root dry weight and maximum root length increased significantly in a quadratic fashion with increasing Zn rates in the range of 0 to 40 mg·kg-1. The Zn × cover crops interactions for shoot and root dry weight, maximum root length, Zn concentration (content per unit dry weight), Zn uptake (concentration × dry weight) and Zn use efficiency (dry weight per unit Zn uptake) were significant, indicating variation in these traits with the change in soil Zn levels. Collectively, maximum shoot dry weight was achieved with the application of 22 mg Zn·kg-1 of soil. Similarly, maximum root dry weight and root length were obtained with the addition of 22 and 17 mg Zn·kg-1 soil, respectively. Overall, Zn concentration and Zn uptake were significantly increased in a quadratic manner with the increase in the soil Zn levels in the range of 0 to 40 mg·kg-1. However, Zn use efficiency (dry weight per unit Zn uptake) decreased in a quadratic fashion with the increasing soil Zn levels from 0 to 40 mg·kg-1. Jack bean, black velvet bean, pueraria, and gray velvet bean with high Zn use efficiency appear to be suitable cover crops for low Zn soils.

Study of a position-sensitive scintillator neutron detector

The investigation of a novel thermal neutron detector is developed to fulfill the requirements of the high intensity power diffractometer （HIPD） at the Chinese Spallation Neutron Source （CSNS）. It consists of two layers of 6LiF/ZnS（Ag） scintillators, two layers of crossed WLSF arrays, several multi-anode photo multiplier tubes （MA-PMT）, and the matching readout electronics. The neutron detection efficiency of the scintilltors, the light transportation ability of the WLSF, and the spatial linearity of the readout electronics are measured and discussed in this paper. It shows that the sandwich structure and the compact readout electronics could fulfill the needs of the HIPD. A prototype with a 10 cm×10 cm sensitive area has been constructed to further study the characteristics of the neutron scintillator detector.