Clonal Integration and Root Morphological Plasticity Influence the Response of Indocalamus latifolius to Nitrogen Heterogeneity in the Soil

Clonal plants generally possess greater growth adaptability under heterogeneous resource environments. Indocalamus latifolius (Keng) McClure has rarely been investigated regarding its clonal integration mechanisms and morphological plasticity under heterogeneous nitrogen (N) conditions. In this study, I. latifolius were exposed to different N distribution regimes with either connected or severed ramets. Biomass, root morphological, non-structural carbohydrate, and N were determined to investigate how clonal integration and root morphological plasticity enable I. latifolius to respond to heterogeneous N availability. Results revealed that compared with uniform N addition, the two localized N treatments promoted biomass accumulation of ramets in high-N patches, and localized N addition to daughter ramets was more beneficial to biomass accumulation of the clonal system. Clonal integration achieved through rhizome connection promoted growth and N accumulation in daughter ramets, increased root length and root soluble sugar content of ramets in low-N patches and reduced average root diameter. Overall, resource allocation was prioritized to daughter ramets and high-N patches; clonal integration drove compensatory root proliferation and morphological adjustment for ramets in low-N patches. This study advances the understanding of adaptive strategies adopted by clonal plants in heterogeneous habitats and lays a theoretical foundation for precision nutrient management of I. latifolius.