Effect of Salinity on the Growth and Physiology of Endangered Mangrove Plant Acanthus ebracteatus Seedlings
In order to explore the suitable salinity for the growth of Acanthus ebracteatus seedlings,the artifi-cial tidal simulation system was used to study the seedlings of A.ebracteatus in greenhouse.In this study,eight salinity gradients(0,5,10,15,20,25,30,35)were applied to investigate the effects of salinity stress on the growth and physiological indexes of A.ebracteatus seedlings.The results showed that when the water sa-linity was 0-15,the survival rate of A.ebracteatus seedlings was 100％and the growth status was good,and the biomass,plant height increment and basal diameter increment were maintained at a high level.When the salinity was 20 and above,the leaves of the seedlings of A.ebracteatus fell off and partial death.With the in-crease of salinity,the survival rate decreased continuously.After one week of salinity 30 and 35 treatment,the seedlings of A.ebracteatus all died.With the increase of salinity,the peroxidase(POD)activity and proline content in the leaves of A.ebracteatus seedlings showed an upward trend,and the salinity 20 and 25 treatment groups were significantly higher than other treatment groups(P＜0.05).Superoxide dismutase(SOD)activ-ity,soluble sugar content,soluble protein content and Malondialdehyde(MDA)content increased first and then decreased,and the inflection point appeared in the salinity 20 treatment group.Chlorophyll a,chloro-phyll b,initial fluorescence(F0),maximum fluorescence(Fm),variable fluorescence(Fv)and relative Elec-tron Transport Rate(ETR)generally increased first and then decreased.There was no significant difference in the maximum photochemical efficiency(Fv/Fm)among all treatment groups(P＞0.05).Correlation anal-ysis showed that salinity was significantly negatively correlated with the growth indexes of A.ebracteatus seedlings(P＜0.05),and the increase of salinity had different degrees of inhibition on the growth of A.ebracteatus seedlings.Salinity was significantly positively correlated with the physiological indexes of A.ebracteatus seedlings(P＜0.05),and the enzyme activity and osmotic adjustment substances had a strong re-sponse mechanism to salinity.The comprehensive analysis showed that the seedlings of A.ebracteatus could grow in an environment with salinity below 20.Salinity greater than or equal to 20 inhibited the growth and physiology of the plants and led to the death of some plants.The suitable salinity for growth was 0-15.
mangrove plantAcanthus ebracteatussalt stressgrowth indexphysiological index
万方数据
维普
