Figure 2. Tiller number and plant height of Spartina
alterniflora in three study sites. (a) The number of tillers per
seedlings and (b) plant height were recorded every month. The solid
square represents seedlings grew at oligohaline (0-6‰) site, the open
circle represents seedlings grew at mesohaline (13-18‰) site, the solid
triangle represents seedlings grew at euhaline (29-32‰) site.
The field survey showed that both of the transplanted seedlings in
mesohaline site (salinity: 13-18‰) produced more tiller than that in
oligohaline site (salinity: 0-6‰) and euhaline site (salinity: 29-32‰)
(Figure 2a). In addition, the number of tillers in oligohaline site was
the lowest. Besides, plant height of S. alterniflora was
decreased with the salinity increased (Figure 2b). To further confirm
the effect of salinity on tillering, S. alterniflora seedlings
subjected to different salinities (0‰, 15‰, 30‰) were grown in
greenhouse. Similarly, we also found the S. alternifloraseedlings under 15‰ salinity showed more tillers than the seedlings
under 0‰ and 30‰ salinity (Figure 3, Figure 4). It was noticeable that
the first axillary bud was early observed at the basal node of S.
alterniflora seedling under 15‰ salinity treatment around
30th days (Figure 3a). To quantify the effect of
salinity on tillering, the percentage of tillering, tiller number per
seedlings and plant height of S. alterniflora seedlings were
recorded (Figure 4). The results showed that the percentage of tillering
in 15‰ salinity treatment was sharply increased from 30 days to 90 days
(Figure 4a) and the tiller number per seedlings was gradually increased
from 90 days to 150 days (Figure 4b). The moderate increases of the
percentage of tillering and the number of tillers per seedling were
observed under 30‰ salinity treatment. For 0‰ salinity treatment, the
percentage of tiller was slightly increasing and the number of tillers
per seedling was almost no change. Similar with the field results, the
plant height of S. alterniflora grown in greenhouse were
decreased with the salinity increased (Figure 4c). These results
indicate that the moderate salinity could promote the tillering process
in S. alterniflora seedlings, while low salinity or high salinity
are likely to inhibit the tillering process.