Bioaccumulation of 137Cs and 60Co in freshwater plants

Contamination of the aquatic environment by the heavy metals and radionuclides has become a serious concern in the world. In our study, gamma-spectrometry of freshwater plants Bacopa monnieri and Egeria densa growing in cultivation media spiked with 137CsCl and 60CoCl2 was used for quantitative determination of bioaccumulation kinetic and distribution Cs+ and Co2+ ions in plant tissues. We found, that bioaccumulation of Cs and Co by fully immersed B. monnieri in Hoagland media (HM) was dependent on ion concentration in medium. Approx. 5-times lower Cs uptake 2.9 nmol/g (d.w.) was obtained in plants cultivated in 20% HM than from deionized water. The maximal Co uptake was 4-times higher than cesium uptake at the same conditions. Both Cs and Co were localized mainly in roots. The highest immobilization from roots to shoots was found in the case of Co uptake from deionized water with concentration ratio [Co]leaves : [Co]stem : [Co]root = 1.00 : 5.33 : 56.8. Cesium uptake by submerged plant E. densa was also strongly dependent on nutrients concentration in medium. However, in the case of cobalt uptake this dependence was less pronounced. Nutrients concentration also had a significant influence on distribution of Cs between stems and leaves of E. densa. Cesium was localized in leaves, however with increasing of nutrients concentration in cultivation media Cs was localized for account of stem. On the other hand, cobalt was immobilized mainly in leaves in whole range of nutrients concentration. Obtained data can serve as a models for understanding of phytoaccumulation of radionuclides from open water ponds and water channels in the vicinity of nuclear power plants and monovalent and bivalent metals from industrial sources of contamination.

Pengaruh Jenis Sumbu Dan Konsentrasi Nutrisi Terhadap Sawi Samhong (Brassica juncea L.) Dengan Hidroponik Sistem Sumbu

The wick system is a hydroponic by utilizing the principle of capillarity of nutrient solutions that are absorbed by plant roots through the wick. Flannelette is a material that has the best water absorption and can be used as a wick, another alternative is stove wick. The concentration of nutrients given to plants must also be in needs. Samhong mustard is a type of mustard in the same class as pakcoy. This study aims to determine the effect of the type of wick and nutrient concentration on plant height, number of leaves, and plant weight using hydroponic wick system. The research method was carried out using two independent variables, namely the type of wick consisting of flannelette (S1) and stove wick (S2), and the nutrients concentration consisting of N1 (1,000 ppm), N2 (1,200 ppm), and N3 (1,400 ppm). The measurements results were compared using the Anova two-factorial design test with a level of 5%, and if the results were significantly different, then continued with the BNJ test at a significant level of 5%. The results showed that there was an effect of using different types of wicks and nutrient concentrations on the measurement results of samhong mustard. Flannel wick (S1) has better effect than the stove wick (S2), and the concentration of N1 nutrients has better effect than the concentrations of N2 and N3, with average plant height is 27.9 cm, average number of leaves are 18.8 strands, and the average plant weight is 128.6 g.

Impact of Macronutrients and Micronutrients on Soil Health Nutrients Concentration and Uptake by Maize (Zea mays L)

At the SHUATS Department of Soil Science and Agricultural Chemistry Research Farm, an experiment was conducted with the goal of determining the impact of application of macro and micronutrients, on soil health nutrients concentration and uptake by maize (Zea mays L). The experiment was put up based on this over a two-year period, beginning with the 2017 and 2018 cropping periods. Crbd was used as the experimental technique and it was replicated thrice with the following treatments combinations, NPK @ 50 and 100kgha -1, while for the micronutrients (Boron, Zinc and Copper) three levels of combination were used 0.3, 6 and 9kgha-1. The research project's findings showed all the determinants of soil health like soil reaction organic matter among others are at levels suitable for nutrients actions and plant growth, while plant parameters like maize cob diameter, dry matter, and nutrients concentrations in maize tissues have greatly improved. NPK @100kgha-1, Copper, Zinc, and Boron @ 9kgha-1 were the best treatment combinations with the best results. The above combinations of treatments will be suitable for the soils of that location based on the results of these studies.

Spatial distribution of the summer subsurface chlorophyll maximum in the North South China Sea

Based on the biological, nutrients and hydrological data in August 2018, the vertical chlorophyll a (Chl-a) concentration profiles and the relationship among surface Chl-a (Chl-a(0)) concentration, maximum Chl-a (Chl-a(m)) concentration and depth-integrated Chl-a (Chl-a(int)) concentration were studied in the Northern South China Sea (NSCS). The results indicate that there are 4 different patterns in the vertical Chl-a profiles in the NSCS: (i) Chl-a increases with depth from the surface (e.g. station 1); (ii) there exists subsurface chlorophyll maximum (SCM), with low Chl-a on the surface and at the bottom layers respectively (e.g. station 5); (iii) there is no SCM, only with high Chl-a on the surface and in the bottom (e.g. station 14); (iv) the 4th pattern is similar to (ii), with the higher Chl-a(0) (e.g. station 28). The SCM is observed at 95% stations in the NSCS and is not detected only at a few stations near the Pearl River (PR) estuary. These patterns are mainly regulated by alternative limitation of nutrients and light from the surface to the bottom of euphotic layer. For the pattern 1 (e.g. station 1), light is not a limited factor, and Chl-a and nutrients increase with depth. The pattern 2 (e.g. station 5) exists with the limitation of surface nutrients in offshore region. The nutrients increases with depth and the nutrients limitation turns to light limitation gradually from surface to bottom. And the SCM appears in the layer which need of the light and nutrients is roughly equivalent. Compared with that the offshore SCM, the nutrients for the pattern 3 (e.g. station 14) are rich on the surface with nutrients concentration and light irradiance. Therefore, it is seawater intrusion from the bottom that brings the higher nutrients concentration. The reason for the high Chl-a(0) on the pattern 4 (e.g. station 28) is terrestrial matter from the nearshore. High correlation (R2 = 0.5206, p<0.01) between the depth of SCM (Depth(m)) and Chl-a(0) indicates that the SCM depth is regulated by light masking effect of surface phytoplankton, generally with shallow nutriclines and fast light attenuation for high Chl-a(0) and vice versa low Chl-a(0) brings deeper nutriclines and light attenuate slowly with less shading effect. Further research results shows that Chl-a(int) and Chl-a(m) have a good correlation(R2 = 0.6397, p<0.01). However, the correlation between Chl-a(int) and Chl-a(0) is relative weak (R2 = 0.3202, p<0.01). That could be attributed to the availability of nutrients playing an important role in growth of phytoplankton, with high nutrients at upper euphotic layers for the stations with high Chl-a(0).