Abstract
It is found that the growth of Dendrobium huoshanense was dependent on Fe(3)O(4), while the bioavailability of plants to ordinary Fe(3)O(4) was low on the earth. In order to improve the growth, quality and yield of D. huoshanense, we used Fe(3)O(4) NPs (100 or 200 mg/L) that was easily absorbed by plants as nano-fertilizer to hydroponically treat seedlings of D. huoshanense for 3 weeks. Fe(3)O(4) NPs induced not only earlier flowering and increased sugar content and photosynthesis, but also stressed to plants, increased MDA content and related antioxidant enzymes activities. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) revealed that Fe(3)O(4) NPs caused a significant accumulation of Fe and some other nutrient elements (Mn, Co, B, Mo) in stems of D. huoshanense. Metabolomics revealed that the metabolites were reprogrammed in D. huoshanense when under Fe(3)O(4) NPs exposure. Fe(3)O(4) NPs inhibited antioxidant defense-related pathways, demonstrating that Fe(3)O(4) NPs have antioxidant capacity to protect D. huoshanense from damage. As the first study associating Fe(3)O(4) NPs with the quality of D. huoshanense, it provided vital insights into the molecular mechanisms of how D. huoshanense responds to Fe(3)O(4) NPs, ensuring the reasonable use of Fe(3)O(4) NPs as nano-fertilizer.