Water is crucial to plant growth and development. Under heterogeneous environmental water deficiency, physiological integration of the rhizomatous clonal plant triggers a series of physiological cascades, which induces both signaling and physiological responses. It is known that the rhizome of Phyllostachys edulis, which connects associated clonal ramets, has important significance in this physiological integration. This significance is attributed to the sharing of water and nutrients in the vascular bundle of clonal ramets under heterogeneous water conditions. However, the physiological characteristics of physiological integration under heterogeneous water stress remain unclear. To investigate these physiological characteristics, particularly second messenger Ca²⁺ signaling characteristics, long-distance hormone signaling molecules, antioxidant enzyme activity, osmotic adjustment substance, and nitrogen metabolism, ramets with a connected (where integration was allowed to take place) and severed rhizome (with no integration) were compared in this study. The vascular bundle structure of the rhizome was also observed using laser confocal microscopy. Overall, the results suggest that interconnected rhizome of P. edulis can enhance its physiological function in response to drought-induced stress under heterogeneous water deficiency. These measured changes in physiological indices serve to improve the clonal ramets’ drought adaptivity through the interconnected rhizome.

Recently, the endangerment of wild rattan population draws attention on the conservation and sustainable utilization of rattan resources. Rattan growing usually faces the light and water stress. Therefore, we aim to explore the combined effects of shade and drought on seedling growth, thus providing a theoretical ground for the conservation and artificial cultivation of the rattan. The combined effects of shade and drought on physiological and biochemical traits were studied in two-years-old Calamus viminalis seedlings. Photosynthetic indices including Pn, Gs, Tr, and Ci and physiological indices including MDA, SOD, POD, CAT, and Pro were measured under four levels of water treatments and four levels of shade. Shade, drought and their interaction have a significant effect on C. viminalis seedlings growth. Generally, moderate shade could alleviate the impact induced by drought. However, mild drought usually enhances the effect caused by shading. The result showed that the shade decreased Pn, Gs, and Tr but increased Ci, MDA content and Pro content. Either with the shading or drought increasing, the activity of SOD, POD, and CAT firstly increase and then declined. Drought reduced Pn, Gs, Tr, and Ci but increased the content of MDA and Pro. Overall, the result suggests that 25-50% shading and 65% RSWC water treatment are most beneficial for the growth of C. viminalis seedlings.