Figure 1. The location of study site in Zhangjiang Estuary,
Yunxiao, Fujian, China. Salinity in oligohaline upstream
site
ranged from 0‰ to 6‰, salinity in mesohaline midstream site ranged from
13‰ to 18‰ and salinity in euhaline downstream site ranged from 29‰ to
32‰.
The field transplant experiment was carried out in the estuary of the
Zhangjiang River in Yunxiao Country, Fujian Province, China
(23°53’-23°57’ N, 117°23’-117°30’ E) (Figure 1). In this area, the mean
annual air temperature is 21.5 °C and annual mean tidal variation is
2.32 m. According to the previous study, three study sites with
different salinities along the estuary of the Zhangjiang River were
chosen for field transplant experiment (Zhang et al. , 2012). The
salinity in oligohaline upstream site ranged from 0‰ to 6‰, in
mesohaline midstream site ranged from 13‰ to 18‰ and in euhaline
downstream site ranged from 29‰ to 32‰, respectively. All of these sites
experienced a semidiurnal tide.
To evaluate the effect of salinity on tillering, one-month old seedlings
of S. alterniflora were collected and held in greenhouse in April
2014. After 1 recover period of one week, 90 healthy seedlings were
selected and planted into 1× 1 m plots in the unvegetated mudflat at
each of the three sites (n = 6 seedlings × 5 plots × 3 sites). Each site
has 5 plots at 5 m intervals as biological replicates. All 15 plots were
located within 35 cm vertical elevation of each other and had similar
durations of tidal flooding (within 30-35 min per tidal period). The
number of tillers and the plant height of each seedling was counted
every month for 4 months after transplantation.