Importance of physiological integration of dwarf bamboo to persistence in forest understorey: a field experiment

Abstract

Summary1 Sasa spp., dwarf bamboo which dominate the undergrowth of temperate forests in Japan occur as clonal fragments in which ramets in light gaps to are connected to those in shaded understoreys by long rhizomes. We test whether persistence under shaded conditions is supported by translocation of assimilates from illuminated ramets. A dense population of Sasa palmata growing at an open site, was exposed to two light conditions (homogeneous: open-open and heterogeneous: open-shaded) and two rhizome connection treatments (intact and severed) in a full factorial design. 2 Ramet mass, and the mass of many parts of the clonal fragments, was much lower in the shade than in the open, but this effect was less marked when the rhizome connection was intact than when it was severed. Clone parts in shade may therefore be supported by translocation from connected clone parts in the open, with such physiological integration enhancing persistence where light supply is heterogeneous as in the gap -understorey continuum. 3 Above-ground biomass was reduced sooner than that below ground. Clonal fragments of S. palmata recover via dormant buds on rhizomes, whose longer persistence would therefore enhance performance of the clonal fragment. 4 Specific leaf area (SLA) was greater in shade than in the open, irrespective of rhizome connection, suggesting that individual leaves show morphological plasticity independently of only physiological integration.

Clonal identification by microsatellite loci in sporadic flowering of a dwarf bamboo species, Sasa cernua

“…Yamazaki and Nakagoshi (2005) reported a similar result for S. kurilensis, where the living culm height was lower than the dead culm height, indicating that taller mature culms had flowered and died. The mechanism that results in the difference between flowering and vegetative culms of the same clone of S. cernua can partly be attributed to the underground connections of the clumps (Saito et al 2000;Saitoh et al 2002Saitoh et al , 2006Saitoh and Seiwa 2007); this, however, is beyond the scope of our study.…”

Distribution, abundance, and effect on plant species diversity of Sasa borealis in Korean forests

“…Once established, the plants annually produce new ramets (culms) on their long, thin rhizomes (Makita 1998) and grow approximately 1 to 2 m tall. Because of the physiological integration between connected rhizomes, they can overcome resource deficiencies (Saitoh et al 2002). In addition, their very shade-tolerant nature means that they can occupy the forest floor and become dominant as their populations increase infinitely (Yuruki et al 1987;Park et al 2012).…”

Genets of dwarf bamboo do not die after one flowering event: evidence from genetic structure and flowering pattern

“…Sasa species are clonal plants, thus the physiological integration among intraclonal ramets enables a genet to integrate local heterogeneity with resource availability (Hartnett and Bazzaz 1983;Alpert and Mooney 1986;Evans 1992;Kelly 1995;Saitoh et al 2002Saitoh et al , 2006. Since production of seeds and flowers of Sasa requires huge resources at mass flowering, the source-sink balance at mass flowering will be different from that during the non-flowering period.…”