Effects of salt stress on photosynthetic characteristics of beach plum and other Prunus species

摘要

The photosynthetic and gas exchange characteristics of seven Prunus species, including four genotypes of beach plum (Prunus maritima Marshall, BO from North Carolina, Bl, B5 from Massachusetts, B3 from Michigan), sun plum [P. salicina Lindl, SP), wildpeach {P. persica (L.) Batsch, WP) and purple-leaf plum (P. cerasifera Ehrh, PL), were evaluated under salt stress to assess their relative salt-tolerance. The one-year-old seedlings were treated with 100 mM NaCl solution for 30 d, while various physiological indexes of leaf were evaluated. The results showed that the net photosynthesis rate (P/V), stomatal conductance (gs) and transpiration rate [Tr) of seven Prunus plants all decreased under salt stress, but differences existed among these plants regarding the extent by which each were impacted. For example, the rate of PN reduction was ranked as Bl (27.84%)PL>SP). In addition, the water utilization efficiency (WUE) of four beach plum genotypes increased under salt stress while the others decreased. The increase rate was ordered as B0>B3>B5>B1, and the rate of declination was ordered as PLwild peach>sun plum>purple-leaf plum, and the four beach plum genotypes could be sorted as Bl>B5>B3>B0.This indicates that beach plum had better salt-tolerance than other 3 Prunus species, and Bl and B5 had better salt-tolerance among 4 beach plum genotypes.