Twenty days following planting, a second application of Urea was made at the same rate. Containers were irrigated to container capacity each day to maintain even soil moisture.Plants were grown in a temperature-controlled greenhouse at California Polytechnic University in Pomona, CA, USA. Containers were arranged in a randomized complete block design with five replications. Temperature was maintained at 27˚C and 13˚C . Radishes and mustard were grown until bulb formation at 37d. Entire plants were harvested including bulb and leaves. Plants from each experimental unit were independently washed five times in municipal water to remove any soil particles, dust or media. Plants were placed in individual paper bags and dried at 105˚C for 48 h. Dried plant matter was ground and shipped to UCANR lab for lead analysis. Samples were prepared to utilize nitric acid/hydrogen peroxide microwave digestion and lead tissue concentration was determined by ICP-AES as described above. Treatment differences of tissue lead content and other variables were analyzed using Minitab 16 software and GLM and ANOVA with Tukey’s Honestly Significant Difference Test. Salinas Clay Loam soil was collected from an unfertilized agricultural field in Santa Paula, CA, USA . Cieneba Sandy Loam was collected from a non-agricultural site in Norco, CA, USA . Soil was added to fill 10 cm round plastic containers: 580 g Salinas clay loam and 620 g Cieneba sandy loam were weighed into containers . Lead nitrate and lead sulfate were added to soils to produce soils with 600 ppm of lead. Calcium nitrate was added to lead sulfate treated soils at an equivalent nitrate loading rate to account for potential nitrate fertility effects in the lead nitrate treatments. This allows that all plants were exposed to equal amounts of nitrate while experiencing lead from different salts. Previous germination studies indicated the extra salinity from Calcium nitrate would not interfere with germination or growth. Radish cultivars “Cherry Belle”, “Rudolf” and “French Breakfast” were seeded and irrigated as described above. In this experiment, plants grown under similar greenhouse conditions, were harvested after 60d, washed and processed as above. The experiment was a factorial design arranged in complete randomized blocks.
The main factors were: Radish variety ; lead source and soil type . Each treatment combination was replicated five times for a total of 60 experimental units. The data were analyzed using GLM and ANOVA with Tukey’s HSD by Minitab 16 software. Main effects and significant interactions are summarized in separate tables low round pots. A final experiment was designed to examine radish lead nitrate uptake in clay and sand soil textures at different lead loading rates to each soil. All five radish cultivars were used and sourced as previously described. Greenhouse temperatures ranged from 38˚C to 26˚C . The same sand and clay soils were weighed and measured into containers as in methods 2.2. A concentration range of lead nitrate was added to bring the soil to 0, 150, 300, 600 and 1200 ppm Pb. Lead nitrate was evenly distributed into each weighed soil and mixed before adding to containers. Seeds of the five radish cultivars were added as before. Plants were grown for 60d and then harvested and washed as previously described. Treatments were arrangedon a single greenhouse bench in a randomized complete block design with a factorial arrangement of treatments using five replications. Dry matter and tissue lead concentration were obtained as previously described and the data analyzed with Minitab 16 software using the GLM and Tukey’s HSD procedures. Soil from the Claremont, CA site was measured at the UCANR lab to contain 158ppm lead. While Red Giant Mustard accumulated more lead that radish cultivars, it did not “hyper-accumulate” than concentrations above the level measured in the Claremont soil. Radish and mustard accumulated more lead in their tissues from contaminated site soil than from soilless media. Radish cultivars were not significantly different from each other in tissue lead content or accumulated lead All radish cultivars absorbed less lead than Giant Red Mustard.Radish cultivars grown in Cieneba Sandy Loam accumulated significantly more lead in their tissues and had a higher total mass of lead than plants grown in the Salinas Clay loam. Source of lead did not affect tissue lead concentration or tissue lead mass. Cultivars were not significantly different from each other in lead uptake, however, cultivar “Rudolf” grew significantly less biomatter. Interactions between main effects were not significant.Increasing concentrations of lead nitrate in soil resulted in increased tissue lead and total lead mass accumulation.
Radish tissue dry matter was not affected by increasing lead nitrate concentration in either soil. Maximum lead accumulation was seen in the 600 – 1200 ppm treatments. Lead accumulation in radish tissues followed a clear linear increase consistent with concentration increases in either soil type up to 600 ppm lead nitrate. Radish cultivars were not significantly different in their tissue lead concentrations but the tissue lead mass was greatest for cultivars “French Breakfast” and “White Beauty”. Cultivar “Rudolf” accumulated the least lead , but also grew less vigorously than the other cultivars . The effect of soil texture on radish lead uptake was significant ; radishes growing in clay soil absorbed and concentrated less lead in tissues than radishes growing in sandy loam soil. Increasing lead concentration in either soil resulted in increased tissue lead concentrations and tissue lead mass across varieties.While food insecurity in the United States declined from 2008 to 2012, it is still significant—affecting > 15% of the population. Localized food production can reduce food insecurity among vulnerable populations. Much of localized food production in urban agriculture settings takes place in community gardens that have been renovated from other uses or were vacant land. In our study, radishes were grown and harvested from soil obtained from a lead-contaminated site. The site in Claremont contained soil Pb levels higher than allowed by the United States Environmental Protection Agency. The site was a potential community garden and still poses risk to any who would grow and consume food crops from there, especially vegetables such as radish that will accumulate lead in its tissues. While radish cultivars did not vary significantly in their uptake of lead from the Claremont, Ca soil, the hyper-accumulator Reg Giant Mustard accumulated significantly more Pb than radish. Specific data on uptake of toxic metals by plants, especially cultivars within a taxon is lacking in the literature. Our study verifies the potential for one of the most commonly planted vegetables by urban gardeners to absorb lead from soil. Radish is a non-mycorrhizal member of the Brassicaceae and because of its lack of affiliation with fungal soil partners, it is able to take up metals that would otherwise be sequestered by mycosymbionts. Although radish cultivars did not have lead uptake differences in our first experiment using Claremont, Ca soil, we did find significant varietal differences especially in total lead accumulation in experiment 3.3 with higher lead loading rates.
The varieties “French Breakfast” and “White Beauty” absorbed the most lead and are both lacking in anthocyanin production–they form white tubers. Since anthocyanins can act as metal chelating agents, those radish cultivars lacking anthocyanins may accumulate more lead from contaminated soils. We found that tissue lead concentration was not significantly different between cultivars in any our experiments. Radishes in experiment 3.2 absorbed and accumulated greater amounts of lead than those in experiment 3.3 despite higher soil lead concentrations in the later experiment. This may be because the experiment was conducted in summer with higher daytime and night temperatures. The effect of off-season cultivation and increased temperatures on Brassicaceae lead uptake is not known. Since lead mass accumulation is the product of tissue lead concentration x biomass, significance of the cultivar response to lead mass accumulation in experiment 3.3 could be due to the reduced biomatter accumulation in cultivar “Rudolf” which grew consistently less biomatter in all experiments than most other cultivars. Soils are complex ion exchanging environments. All soils carry a negative charge and thus will adsorb Pb cations. While Pb is considered persistent in soil, this does not preclude its uptake by plants. Clay soils have higher cation exchange capacity and thus adsorb cations onto cation exchange sites. Lead is considered largely immobile in soils, but in sandy soil, particularly when low in organic matter, with neutral to acid soil reaction, Pb may enter soil solutions and thus be taken up by plant roots. In our study, we found greater radish Pb uptake in sandy versus clay soil, consistent with others’ findings. Contaminated sandy soils appear to pose more risk to consumers of vegetables growing in those sites rather than loam, clay, or highly organic matter enriched systems that will better adsorb the Pb cations. Slightly alkaline high CEC soils strongly adsorb lead, and it is less available for immediate plant uptake. Since soil texture affects lead uptake, not all soils pose the same risk to food supplies. Reliance only on soil testing may give inaccurate estimates of what may be absorbed by plants because so many urban soils are modified by adding organic matter, plastic pots 30 liters or importing other soil textural classes that are not mapped. We have shown that radish is a reliable bio-assay plant to detect lead in soil. While analyzing soil directly will give data on possible lead loading rates, it may not accurately predict the amount of lead that will be taken up by crop plants; making plant growth bioassays an important assessment tool. Edaphic conditions such as cation exchange capacity, species of lead present, and presence of sulfur all have effects on absorption of lead from soil. In our study, either species tested, whether highly soluble , or less soluble , were both absorbed by radish resulting in similar lead tissue concentrations. Elemental sulfur may be oxidized in soil reducing soil reaction making metals more available. This would not occur with lead sulfate since the sulfur is already fully oxidized. Metal absorption by radish is more likely affected by soil pH and organic matter percentage and type.
Our findings suggest radish cultivars can vary in lead uptake depending on soil lead concentration, soil type, and their overall growth which is an important factor in the calculation of lead mass accumulated by a given crop. Radish cultivars are not known to be hyper-accumulators but can absorb biologically significant levels of lead from contaminated soil. Hyper-accumulators tend to be rapid and productive growers in the Brassicaceae family and their use in phytoremediation of contaminated sites is well documented.Radish, as well as all farm products, should still be consumed with caution when produced in urban farms with soil lead contamination. This is especially true since the Food and Agriculture Organization and the World Health Organization determined that “There is no known lead exposure minimum that does not cause IQ impairment”.Non-human primates are similar to humans in terms of genetic evolution, immunesystem, physiology and metabolism as well as other features.In addition, similarities in cancer genetics between humans and NHPs have been reported, particularly in great apes. Therefore, NHP species are considered as good models for human cancer research. However, due to the low incidence of cancer in non-human primates and the reduced sample size compared to human studies, more data and reports need to be documented, particularly regarding spontaneous tumours. Most studies of cancer in NHPs involved monkeys and great apes. Despite the relevant phylogenetic position of prosimians, few reports of neoplastic diseases have been described in these species. Neoplasia in lemurs has been scarcely reported apart from some primary liver tumors and pulmonary tumors. However, improving our knowledge on prosimian cancer would be useful to trace the evolution of this disease in humans. The current study focuses on a case of T-cell intestinal lymphoma in a female ring-tailed lemur hosted in Parco Natura Viva, an Italian zoological garden. Prior to 2005 the 5-year old female ring-tailed lemur did not show any clinical sign of illness. In March 2005 a 5-yr-old female ring-tailed lemur, belonging to a collection of 30 lemurs, was evaluated for apathy, in appetence and few episodes of regurgitation. She was thin and showed abdominal pain during palpation. Hematologic tests did not reveal abnormalities; thus a medical treatment with carprofen and Joscina N-Butilbromuro was performed.