Characteristic of morphology, anatomy and histology of a seminal root of wild rice, Oryza glumaepatula

Abstract

Crop breeding in root traits to acclimate abiotic stress is required. It is necessary to propose genetic resources of roots that have resistance to environmental stress. Oryza glumaepatula, a wild rice species, grows in the Amazon basin, where the soil water contents fluctuate greatly. Thus, we hypothesized that O. glumaepatula has characteristics cultivated rice does not have. We examine seven traits of a seminal root in comparison with rice cv. Taichung 65 (T65): number of lateral roots, root hair length, cortex to stele ratio (cortex/stele), aerenchyma to cortex ratio (aerenchyma/cortex), formation of Casparian strips and suberin lamellae at the exodermis and deposition of lignin at the sclerenchyma. O. glumaepatula IRGC105668 had the same number of lateral roots as T65, but had longer root hairs. In the IRGC105668, the cortex/stele and the aerenchyma/cortex were lower than those of T65. IRGC105668 well-developed Casparian strips and suberin lamellae at the exodermis, whereas T65 hardly formed them. The level of lignification at the sclerenchyma of IRGC105668 was similar to that of T65. We found that five of the seven traits of IRGC105668 (root hair length, cortex/stele, aerenchyma/cortex and formation of Casparian strips and suberin lamellae at the exodermis) were significantly higher than those of T65. In particular, three traits (root hair length and formation of Casparian strips and suberin lamellae at the exodermis) were significantly different from those of T65, and it is expected to be useful as genetic resources for breeding.