Abstract:
Coastal plants are important members of coastal ecosystem, however the knowledges of salt tolerance and their ecological adaptations have not been fully understood yet. In this paper, salt tolerance of four typical plants,
Ipomoea pescaprae,
Canavalia cathartica,
Ilex integr and
Pittosporum pentandrum, are studied for purpose of coastal vegetation restoration. The plants were exposed to different gradient of NaCl solutions used leaf surface spray and root system absorption and the plant status, equivalent water thickness and chlorophyll content were observed and measured. The main results included that the salinity of 10 turned the old leaves of
P. pentandrum,
I. integra and
C. catharticayellow or caused yellow-brown spots. The salinities of 20-30 caused plant leaves to wither extending from the petiole to the vein and fall. The salinity of 30 caused some leaves to wither from the tip of leaves. Moreover,
I. pescaprae,
C. cathartica,
I. integr and
P. pentandrum could tolerate salinities of 10, 20, 20 and 30 in short-term stress on the roots, respectively. For Liana, the salt tolerance of
I. pescaprae was higher than that of
C. cathartica. While for dungarunga, the salt tolerance of
P. pentandrum was higher than that of
I. integra. All leaves of 4 plants su- stained the salinity stress of 30, the salt-tolerant ability turns out to be
I. pescaprae>
I. integra>
P. pentandrum>
C. cathartica. The results showed that the indexes of plant status gave better indications of salt tolerance. All 4 plants of high tolerance under salt stress can be used for coastal vegetation restoration. In practice, factors of coast elevations, distance to the sea, water and wave effects should all be fully considered in choosing proper plants for the restoration.