Microstructure evidence of rice lodging resistance based on quantitative X‐ray microtomography

Abstract

Even though lodging seriously affects the growth and development of rice (Oryza sativa L.) little is known about the stem and root microstructural characteristics of lodging resistant and non-lodging resistant rice. In this study, one lodging resistant rice variety lingliangyou238 (R1), and two non-lodging resistant rice varieties, luliangyou996 (S1) and zhuliangyou819 (S2), were used to conduct synchrotronbased X-ray micro-computed tomography. We found that the lodging resistant rice variety R1 had a third internode (N3) length that was reduced by 37.4% compared to S1. Meanwhile, the area of stem cross section, area of the medullary cavity, and the number of large and small vascular bundles in the N3 of R1 increased by 73.56, 73.10, 18.55, and 17.74%, respectively, compared to S2. In the 3D structure, there are many pore structures in the inner wall of the rice stalk. Quantitative analysis showed that the ratio of length/width of the pores of R1 was lower than S1 and S2. In the fourth internode, the volume and surface area of the large vascular bundle vessel of R1 was greater than S1 and S2. In the root system, we found that R1 had more cortical cells, and its length/width value was lower than S1 and S2. Our findings implied that besides the 2D level, more 3D information is needed to reveal the relationship between lodging and the spatial structure of the crop.