Ebb-and-Flow Subirrigation Improves Seedling Growth and Root Morphology of Tomato by Influencing Root-Softening Enzymes and Transcript Profiling of Related Genes

Abstract

Ebb-and-flow subirrigation is a promising strategy to increase water use efficiency, avoid waterlogging or drought conditions, and promote the overall growth of vegetable crops. The aim of this study was to evaluate the seedling growth, root morphology, activities of root-softening enzymes, and transcript profiling of those enzyme-related genes in tomato under top sprinkle irrigation and ebb-and-flow subirrigation. The results showed that ebb-and-flow subirrigation could significantly improve stem diameter, root fresh weight, root dry weight, root volume, and root diameter of tomato by 9.42%, 45.92%, 44.82%, 15.61%, and 9.41%, as compared with top sprinkle irrigation, respectively. The ebb-and-flow subirrigation also maintained the root activity and photosynthetic rate of tomato seedlings. The activities of superoxidase dismutase, peroxidase, catalase, glutathione reductase, and ascorbate peroxidase of tomato roots under ebb-and-flow subirrigation were remarkably increased, while the malondialdehyde content was decreased compared with the plants grown under top sprinkle irrigation. Correlation analysis among activities of root-softening enzymes and transcriptomic profiling of their biosynthesis-related genes revealed that 10 genes might be responsible for regulation of studied enzymes. Overall, ebb-and-flow subirrigation could significantly promote the growth of tomato seedlings, so as to maintain high activity and promote the cultivation of high-quality and strong seedlings.