Title: Effects of Salinity on Photosynthetic Physiology and Chlorophyll Fluorescence Characteristics of Mulberry(Morus alba) Seedlings
Abstract: The pot experiments on effects of salt stress on photosynthetic physiology and chlorophyll fluorescence characteristics of 1-year-old mulberry(Morus alba) seedlings were conducted with a common stock of mulberryShishengsang which adapted to the Yellow River valley and northwestern areas.The seedlings were treated with NaCl concentrations of 1,3,5 and 7 g·kg-1,and with fresh water as the control.By using LI-COR 6400 portable photosynthesis system and PAM-2100 portable pulse-modulated chlorophyll fluorescence system,the net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentrations(Ci),transpiration rate(Tr)and other indexes were measured on the 1st,2nd,3rd,7th and 21th day after salt stress treatments.The results showed that the salinity in NaCl concentration of 1 g·kg-1 had no significant impact on Pn of mulberry seedlings,but it significantly inhibited Pn under treatment with NaCl concentration of 3,5 and 7 g·kg-1,especially,the effects of salt in NaCl concentration of 5 and 7 g·kg-1 on it were greater.Moreover,Pn gradually decreased as NaCl concentration increased.In addition,the salt had no significant effects on Gs,Ci,Tr and WUE under treatments with NaCl concentration of 1 and 3 g·kg-1,however Gs,Tr and WUE significantly decreased but Ci significantly increased when the mulberry seedlings were treated with NaCl concentration of 5 and 7 g·kg-1.Moreover,the salinity had impact on the kinetic parameters of chlorophyll fluorescence of mulberry seedling leaves.During the experiments,the original fluorescence(Fo) showed a declining trend,but non-photochemical quenching of fluorescence(NPQ) were at first increased and then decreased with the increment of NaCl concentration,however,the differences of Fo and NPQ under various salt stress treatments were not significant.However,salinity didn't significantly affect the maximal fluorescence(Fm),original light energy transforming efficiency(Fv / Fm),PSⅡlatent activity(Fv / Fo) and quantum yield of PSⅡelectron transport(ΦPSⅡ) of mulberry seedling leaves under treatments with NaCl concentrations of 1 and 3 g·kg-1,but Fm, Fv / Fm,Fv / Fo and ΦPSⅡ evidently declined when treated with NaCl concentrations of 5 and 7 g·kg-1.It denoted that NaCl critical concentration of mulberry seedlings of 1 year old was between 3 and 5 g·kg-1.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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Cited By Count: 1
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