The desiccation tolerance of the intertidal seagrass Zostera japonica has been demonstrated in a number of studies; however, the factors limiting expansion of intertidal seagrass species into subtidal zones remain controversial. We transplanted Z. japonica shoots from the intermediate intertidal zone into the plots with and without Z. marina shoots in both the lower intertidal and shallow subtidal zones to investigate the factors controlling Z. japonica growth in these zones. Daily photon flux density at the Z. japonica canopy level was attenuated by both water depth and coexisting Z. marina shoots but more strongly by Z. marina shoots than water depth in the transplant plots. The shoot density and biomass of Z. japonica transplants were significantly lower in transplant plots in the subtidal zone than in the lower intertidal zone. Although the photon flux density was significantly lower in transplant plots containing Z. marina shoots, the growth of Z. japonica transplants did not differ significantly between plots with and those without Z. marina shoots. Z. japonica transplants exhibited photoacclimatory responses such as increased shoot height and chlorophyll content under the lower-light conditions, offsetting the reduced light availability so that no significant differences in transplant growth occurred between plots with and those without Z. marina shoots. As the growth of Z. japonica transplants decreased significantly in the subtidal zone, the interactive effects of environmental stresses associated with tidal inundation and reduced light availability may restrict penetration of the intertidal seagrass Z. japonica into the subtidal zone. The persistence of high photosynthetic performance after air exposure and a regular arrangement of the densely overlapped leaves atop wet sediments may be desiccation tolerance mechanisms for Z. japonica in the intertidal zone.

多项研究表明潮间带海草Zostera japonica的耐干燥性。但是，限制潮间带海草物种向潮间带扩展的因素仍然存在争议。我们将潮间带中部的日本粳稻苗移植到潮间带下部和浅潮下带有无滨海菜芽的地块中，以研究控制这些区域中粳稻生长的因素。Z. japonica冠层水平的日光子通量密度被水深和共存的Z. marina枝条减弱，但被Z. marina强烈减弱比移栽地块的水深要高。的拍摄密度和生物量结缕草移植是器官移植地块比在较低的潮间带显著降低在潮下带。尽管在含有Z. marina枝条的移植地中，光子通量密度显着降低，但在有Z. marina枝条的地块与没有Z. marina枝条的地块之间，Z。japonica移植的生长没有显着差异。粳稻移植物表现出光适应性反应，例如在低光照条件下增加了枝条高度和叶绿素含量，抵消了光利用率的降低，因此在有和没有滨海假单胞菌芽的地块之间，移植物的生长没有显着差异。随着潮带下日本粳稻移植物的生长显着下降，与潮汐淹没和光利用度降低相关的环境胁迫的相互作用可能会限制潮间带海草的穿透。进入潮下带。暴露于空气后高光合性能的持续存在以及湿沉积物上方密集重叠的叶子的规则排列可能是潮间带日本粳的干燥耐性机制。