Date of Award
Master of Science
Jorge L. Gardea-Torresdey
The response of plants to copper oxide nanoparticles (nCuO) in presence of the phytohormones such as IAA, is unknown. In this study, green pea (Pisum sativum) plants were cultivated to full maturity in soil amended with nCuO, CuO bulk (bCuO), and CuCl2 at 50 and 100 mg/kg and indole-3-acetic acid (IAA) at 10 and 100 µM. Several analytical techniques were used to evaluate the effects of treatments in the agronomical, physiological, and biochemical effects of treatments. Results showed that only CuCl2 reduced root length and number of leaves. Root copper (Cu) increased in plants exposed to nCuO without IAA; however, the three Cu compounds, at the highest concentration, increased it when combined with 100 µM IAA. There was a variety of responses in essential nutrient accumulation in plant systems. Except for the combination of nCuO and IAA, both at the highest concentration, nCuO did not affect Ca accumulation in tissues. Different responses were found with the other treatments. Manganese (Mn) decreased by 19% in stems of nCuO and CuCl2 treated plants, in the presence of IAA at 10 µM. The highest concentration of nCuO and IAA reduced Mg in stems by 35%. On the other hand, in the absence of IAA, CuCl2 at 50 and 100 mg/kg increased Sulfur (S) in leaves by 217% and 264% and by 93% and 118% in stems, respectively ( p ≤ 0.05). Both the number of seeds and seed weight were reduced in treatments that included IAA at 10 µM. However, the protein content (%) was enhanced in plants treated with 10 µM of IAA. Chlorophyll was affected by CuCl2 at both IAA concentrations, but mainly in treatments involving 10 µM of IAA. Catalase (CAT) activity in roots was reduced in plants exposed to nCuO and 10 and 100 µM of IAA, but increased in treatments with no IAA. Overall, results have shown that the combination of nCuO and IAA caused different effects in pea plants. Unexpectedly, exposure of IAA at 10 µM, and nCuO at 50, resulted in an increase in seed protein compared with the absolute control, which suggests a possible benefit for human nutrition.
Received from ProQuest
Ochoa, Loren, "Evaluating The Effects Of The Phytohormone Indole-3-Acetic Acid In The Response Of Green Pea (Pisum Sativum L.) To Nanoscale CuO Exposure In Soil" (2016). Open Access Theses & Dissertations. 712.