Evidence of Duck Activity Induced Anatomical Structure Change and Lodging Resistance of Rice Plant

The system of rice cultivation associated with duck raising is known as an integrated rice-duck (RD) farming system and has a long history in China and Asia. However, the roles of duck activities on rice physiological characteristics are unknown. Field and laboratory experiments were conducted to investigate mechanical stimulations of duck activities on rice physiological characteristics, and hence on morphology and anatomy. Here, we found that there were substantial variations in anatomical structure of the rice culm internodes and in lodging resistance of rice plants with and without the duck activities. Anatomical analysis showed a distinct difference between the RD and rice-no-duck (RND) treatments in culm wall thickness of the rice internodes. For internode N4, the culm wall from the RD treatment was more than 35% thicker than that from the RND treatment. In general, the epidermal layer of the rice culm was significantly denser for the internodes and the thickness of the culm walls increased from N1 to N4 under the RD farming system. Additionally, the areas of vascular bundles were larger and were better organized and structured in the RD treatment. Our results further revealed that the breaking-resistant strength increased whereas the lodging index of the rice culm decreased with duck activities.