Effects of Different Vermicompost Rates on Growth, 2-Acetyl-l-Pyrroline, Photosynthesis and Antioxidant Responses of Fragrant Rice (Oryza sativa L.) Seedling

Vermicompost is an organic fertilizer contains multiple nutrient elements. However, the application of vermicompost in fragrant rice production is rarely reported. In order to study the effects of vermicompost application on fragrant rice (Oryza sativa L.) seedling performances, present study was conducted with two fragrant rice cultivars and four vermicompost rate treatments (0 (CK), 2.5 (Wo 1), 5.0 (Wo2) and 10.0 (Wo3) g kg(-1)). The results showed that vermicompost treatments significantly increased dry weight of fragrant rice seedling by 8.31-32.56% compared with CK. 21.10-59.13% higher net photosynthetic rates and 10.66-59.16% higher chlorophyll contents (chlorophyll a, chlorophyll b and total chlorophyll) were recorded in vermicompost treatments than CK. Application of vermicompost also significantly increased 2-acetyl-1-pyrroline (2-AP, the key compound of fragrant rice aroma) content and reduced the transcript level of gene BADH2 which related to 2-AP biosynthesis in fragrant rice seedling. Moreover, compared with CK, vermicompost treatments enhanced activities of superoxide dismutase, peroxidase, catalase by 24.42-28.66%, 24.98-25.73% and 22.45-23.57%, respectively. 11.54-40.53% lower malonaldehyde contents were recorded in vermicompost treatments in related to CK. In conclusion, vermicompost improved growth, increased 2-AP content and might enhance stress resistant of fragrant rice seedling.