Effects of Soil-Delivered Manufactured Nanomaterials on Soybean Plants

Transcription

1 DBI , Effects of Soil-Delivered Manufactured Nanomaterials on Soybean Plants 2 nd Sustainable Nanotechnology Organization Conference November 3, 2013 John H. Priester, Jorge L. Gardea-Torresdey, Patricia A. Holden

2 Why Soybean? Provides more edible oil and protein than any other crop (for both human and livestock consumption). In the U.S.: 77.5 million acres (40% of world production). $30 billion agricultural economy. ( (

3 Terrestrial Ecosystems in Nanotox (from Holden, Nisbet, Lenihan, Miller, Cherr, Schimel, Gardea-Torresdey ACR)

4 ZnO and CeO 2 nanoparticles Commonly used in household items (ZnO; cosmetics and sunscreen) and catalysis applications (CeO 2 ; diesel engines). Can enter soil through biosolids or direct deposition. Previously studied in hydroponic experiments.

5 Experiment Overview: Greenhouse. Organic Farm Soil. Treatments: Control (no added Zn/Ce) Low, Medium, High nano-zno (0.05, 0.1, 0.5 g/kg) Low, Medium, High nano-ceo 2 (0.1, 0.5, 1.0 g/kg) 4 Planted, 4 Un-Planted pots/treatment 48 Days of Growth.

6 Plant Growth and Biomass CeO 2 ZnO = Control = Low = Medium = High = Control = Low = Medium = High 7 d 48 d Stem Length reduced with nano-ceo 2 Soybean Plant Part Dry Biomass and Total Dry Biomass (g / plant), According to Treatment * Trmt Stem Leaf Pod Root Nodule Total ** Control 0.90 ± 0.09 a,b 2.27 ± 0.16 a 1.82 ± 0.18 b,c 0.83 ± 0.09 a 0.19 ± 0.00 a 6.01 ± 0.32 a,b Low nano-ceo ± 0.21 a 1.59 ± 0.39 a 1.44 ± 0.28 a,c 0.69 ± 0.08 a 0.14 ± 0.04 a 4.40 ± 0.96 a Med nano-ceo ± 0.16 a,b 2.21 ± 0.32 a 1.52 ± 0.14 a,b 0.95 ± 0.11 a,b 0.24 ± 0.05 a,b 5.72 ± 0.67 a,b High nano-ceo ± 0.13 a,b 2.43 ± 0.22 a 1.41 ± 0.09 a 0.91 ± 0.14 a,b 0.19 ± 0.03 a,b 5.90 ± 0.58 a,b Pod Mass/plant reduced at high CeO 2 Low nano-zno 0.87 ± 0.10 a,b 2.06 ± 0.28 a 1.85 ± 0.17 b,c 1.23 ± 0.38 a,b 0.18 ± 0.06 a,b 6.20 ± 0.76 a,b Med nano-zno 0.90 ± 0.21 a,b 2.33 ± 0.44 a 1.71 ± 0.10 b,c 1.01 ± 0.14 a,b 0.26 ± 0.07 a,b 6.22 ± 0.82 a,b High nano-zno 1.03 ± 0.06 b 2.40 ± 0.08 a 1.95 ± 0.17 c 1.11 ± 0.05 b 0.25 ± 0.02 b 6.74 ± 0.20 b Increased Mass with ZnO (from Priester et al PNAS.)

7 Metal Accumulation Concentration of Ce in various plant parts at harvest (mg/kg dry tissue) * Treatment Root Nodule Stem Leaf, x1,000 Pod Control ± ± ± ± ± 0.03 Low nano-ceo ± ± ± ± ± 0.02 Med nano-ceo ± ± ± ± ± 0.07 High nano-ceo ± ± ± ± ± 0.03 Ce accumulated most in below ground tissue Concentration of Zn in various plant parts at harvest (mg/kg dry tissue) * Treatment Root Nodule Stem Leaf Pod Control ± ± ± ± ± 2.83 Low nano-zno ± ± ± ± ± 3.13 Med nano-zno ± ± ± ± ± 5.75 High nano-zno ± ± ± ± ± 3.19 High CeO 2 Control Zn accumulated in all tissue, including edible portions (pods/leaves) Ce in Nodules: High ZnO Control Empty nodules with CeO 2 Zn in Seeds: Zn in Leaves: High ZnO Control (from Priester et al PNAS.)

8 CeO 2 Effects on N - Fixation N-Fixation Potential Rate 9E-09 8E-09 7E-09 6E-09 5E-09 4E-09 3E-09 2E-09 1E mg Ce/kg Dry Nodule Mass N fixation halted at high Ce concentrations (from Priester et al PNAS.)

9 Ce and Zn Speciation (µ - XRF and µ - XANES) Nodule: High CeO 2 Pod: High CeO 2 Zn existed in oxygen containing complexes; not as ZnO nanoparticles Ce remained as CeO 2 throughout the plant (from Hernandez-Viezcas et al ACS Nano.)

10 Leaf Damage = Control = Low = Medium = High = Control = Low = Medium = High A = Control, B = High nano-ceo 2 A = CeO 2, B = ZnO Visual Leaf Damage, especially w/ceo 2 Treatment Chlorophyll A (mg/l per Chlorophyll B (mg/l per Total Chlorophyll (mg/l mg dry mass) mg dry mass) per mg dry mass) Control 0.53 ± 0.03 a 0.19 ± 0.01 a 0.73 ± 0.03 a Low nano-ceo ± 0.01 b 0.14 ± 0.00 b 0.49 ± 0.01 b Med. nano-ceo ± 0.01 c 0.18 ± 0.01 a,d 0.62 ± 0.02 c High nano-ceo ± 0.02 d 0.17 ± 0.01 c,d 0.56 ± 0.03 c,d Low nano-zno 0.35 ± 0.06 b,c,d 0.15 ± 0.03 a,b,e 0.51 ± 0.09 a,b,c Med. nano-zno 0.32 ± 0.03 b 0.15 ± 0.02 a,b,e 0.47 ± 0.05 b,d High nano-zno 0.32 ± 0.01 b 0.13 ± 0.01 e 0.45 ± 0.02 b Reduced chlorophyll levels Genetic Damage (InDels): An insertion was detected for one of the high ZnO plants

11 Leaf Damage, Cont. ZnO CeO 2 Total ROS significantly increases with Ce concentration but not Zn. Total ROS is significantly correlated (p = 0.02) with soil Ce concentration, but not leaf Ce (p = 0.21). Treatment Control Low nano-ceo 2 Med. nano-ceo 2 High nano-ceo 2 Low nano-zno Med. nano-zno High nano-zno MDA (µm per mg dry mass) 0.56 ± 0.08 a,b 0.81 ± 0.08 c,d 0.83 ± 0.10 c,d 0.57 ± 0.06 a,b 0.55 ± 0.03 a 0.55 ± 0.13 a,d 0.65 ± 0.03 b,c Evidence of oxidative damage (lipid peroxidation) w/ceo 2 Leaf Oxidative Damage correlates with Leaf ROS (p = 0.02)

12 Leaf Damage, Cont. Is Lipid Peroxidation correlated with indicators of soybean plant health reported in the PNAS paper? All combinations tested; 4 had significant correlations. p = 0.04 p = 0.02 p = 0.00 p = 0.05

13 Summary With nano-zno, Zn was taken up by the plants and distributed throughout edible tissues. With nano-ceo 2, intact particles accumulated in the plants, growth/yield was reduced, and N-Fixation was halted. Leaf damage was evident, and correlated with oxidative stress. Leaf oxidative damage was more prevalent with nano-ceo 2, although there was evidence of genetic damage with nano-zno.

14 Acknowledgments Contributors: Yuan Ge, Randy Mielke, Allison Horst, Shelly Cole Moritz, Katherine Espinosa, Jeff Gelb, Sharon Walker, Roger Nisbet, Youn-Joo An, Josh Schimel, Reid Palmer, Jose Hernandez-Viezcas, Lijuan Zhao And many others in the UC CEIN including the leadership. UC CEIN Funding: This material is based upon work supported by the National Science Foundation and the Environmental Protection Agency under Cooperative Agreement Number DBI and DBI Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Environmental Protection Agency. This work has not been subjected to EPA review and no official endorsement should be inferred. Foundational Funding: NSF: BES & DBI DOE (DE-FG02-06ER64250) U.S. EPA STAR Program R R833323