Shoot removal interacts with soil temperature to affect survival, growth and physiology of young ramets of a bamboo

Global climate change has great effects on ecosystems via changes in air and soil temperature. While the effects of temperature have been extensively studied, relatively few studies have truly separated the impact of soil temperature from that of air temperature. Furthermore, little is known about how removal of older ramets may affect the performance of their interconnected younger ramets of bamboos. By maintaining air temperature constantly (at 17 °C) in growth chambers and manipulating soil temperature (2, 7, 12, 17 and 22 °C) using thermostatic water bath systems, we tested the effects of soil temperature and removal of the older ramets on survival, growth and physiology of its interconnected young ramet of a bamboo Indocalamus decorus. Soil temperature significantly affected the survival of the young ramet of I. decorus and also the growth and photosynthetic rate of the surviving young ramet when the shoots of its connected older ramets were not removed. Removing shoots of the older ramets greatly enhanced the survival of the young ramet at the two highest soil temperatures (17 and 22 °C) and the growth of the surviving ramet at 7 and 12 °C. We conclude that shoot removal of older ramets can interact with soil temperature to affect survival and growth of young ramets of the bamboo, and that resource sharing (translocation of photosynthates) from older ramets to young ramets of the bamboo is rather limited. Instead, newly emerged, interconnected ramets of bamboos may compete fiercely for resources stored in rhizomes. These results suggest that bamboo forest management should consider the balance between resource sharing and competition for resources stored in rhizomes under ongoing global climate change.