Abstract: Seagrass is a kind of marine submersed higher plants, and belongs to typical rhizomatousclonal plants. Rhizome diameter and ramet weight are the first and the second useful descriptors of seagrass size, respectively, while body size is a key identification feature for seegrasses. In this paper, a comprehensive analysis was made on the 6 module indices and 18 growth indices of seagrass. The results indicated that fruit size, leaf size, and shoot weight were speciesspecific. Shoot plastochrone, branching rate of horizontal rhizome, leaf production per year, shoot longevity, and branching rate of vertical rhizome were the most speciesspecific dynamic properties, suggesting that the difference in seagrasses growth dynamics was mainly reflected in the clonal growth capacity and ramet life cycle length. Large seagrasses displayed a phalanx clonal architecture, while small seagrasses except Cymodocea nodosa displayed a guerrilla growth strategy. The horizontal spreading rate of large seagrasses genets was slower than that of small ones. There existed allometric relationships between segrasses size and their architectural properties and dynamic properties. With increasing seagrass size, the plastochrone interval and longevity of leaf, ramet, and node extended in modular growth level, and the horizontal internodal length and elongation rate of horizontal rhizome, ramet production rate, branching rate, and branching angle decreased while spacer increased in clonal growth level. The physiological integration among clonal fragments enhanced with the increasing size. For the seagrass populations, the biomass increased while the density decreased when the seagrass size increased. Therefore, seagrass size strongly affected the architecture module, growth type, clonal architecture, population density, and productivity of seagrasses. The differences in form, growth dynamics, and module component showed the differences of seagrasses in their life strategy and ecological functions, which could be the useful information in exploring the restoration theory of seagrass bed.

Key words: Collichthy lucidus, the Yangtze Estuary, diet composition, feeding habit, seasonal variation.