Study On Adaptability Of Salinity And Waterlogging Of Sugar Beet Varieties

1. Screening waterlogging tolerant sugar beet cultivars (lines): Tianyan309, ST21015(indicatedas ST), KWS3418(indicated as KWS), HK-3, Y-77-6-3(indicated as Y-77), Y-80-4-3(indicatedas Y-80) and Y-86(indicated as Y-86) were used for screening waterlogging tolerant sugar beetcultivars. The results showed that the degree of tolerance to waterlogging in shoot dry weight ofseven sugar beet cultivars was Y-77＞ST＞Tianyan309＞Y-80＞KWS＞HK-3＞Y-86, in rootdry weight was HK-3＞Y-77＞ST＞Y-80＞Tianyan309＞KWS＞Y-86, and in chlorophyllcontent was Y-77＞HK-3＞ST＞Y-86＞Tianyan309＞Y-80＞KWS. Based on these results,Y-86was screened out as waterlogging tolerant and Y-77as waterlogging sensitive cultivar.Therefore, Y-86and Y-77were used in the present experiment to investigate the combined effectof salinity and waterlogging on sugar beet.2. Effects of salinity and waterlogging on seedling emergence and young seedling growth in twosugar beet cultivars (lines) Y-86and Y-77: the results indicated that,120mmol/L NaCl had nosignificant effect on the seedling emergence of Y-86, while it decreased the value of emergenceof Y-77. Waterlogging had no significant effect on the seedling emergence of Y-86at1and120mmol/L NaCl, but waterlogging markedly decreased seedling emergence of Y-77under120mmol/L NaCl. Salinity reduced shoot and root dry weight, chlorophyll content of two cultivarsY-86and Y-77, especially for Y-77. Salinity significantly increased Na+content and reduced K+content in leaves of two cultivars Y-86and Y-77, especially in Y-77. Waterlogging markedlydecreased shoot and root dry weight of Y-86and Y-77at120mmol/L NaCl, especially in Y-77.Waterlogging had no significant effect on content of chlorophyll in Y-86, but it markedlydecreased the content of chlorophyll in Y-77. Waterlogging had no significant effect on the leafNa+content of Y-86. Waterlogging had no significant effect on the leaf Na+content of Y-77at1mmol/L NaCl, but waterlogging increased leaf Na+content of Y-77at120mmol/L NaCl.Waterlogging reduced leaves K+content of Y-86and Y-77. Therefore, Y-86was more tolerant tosalinity and waterlogging stress compared to Y-77.3. Effects of salinity and waterlogging on seedling growth and physiological index in Y-86and Y-77: salinity and waterlogging reduced the shoot and root dry weight, especially in the root dryweight of Y-77. Salinity and waterlogging increased leaf Na+content. For example, waterloggingmarkedly increased leaf Na+at120mmol/L NaCl. Waterlogging significantly reduced leaf K+content regardless of NaCl concentration in Y-86and Y-77. Waterlogging decreased leaf K+moreseverely in Y-77than Y-86at120mmol/L NaCl. Salinity and waterlogging increased Na+content in the roots, but decreased K+content, especially when Y-77were treated withwaterlogging at120mmol/L NaCl. Waterlogging significantly increased leaf MDA content inY-86and Y-77at1and120mmol/LNaCl.Salinity tends to decrease leaf SOD activity in Y-86and Y-77regardless of waterloggingtreatment. Waterlogging had no significant effect on leaf SOD activity in Y-77, but increased thevalue in Y-86at1and120mmol/L NaCl. Salinity increased the activity of leaf APX and CAT inY-86, but the opposite trend was shown in Y-77regardless of waterlogging treatment;waterlogging increased leaf APX and CAT activity in Y-86at120mmol/L NaCl, butwaterlogging had no significant effect on those values in Y-86at1mmol/L NaCl, and Y-77at1and120mmol/L NaCl.Salinity tends to decrease root porosity of Y-86and Y-77, especially in Y-77. Waterloggingincreased root porosity of Y-86and Y-77regardless of NaCl concentration.4. Effects of salinity and waterlogging on photosynthetic performance of Y-86and Y-77: ingenerally, salinity and waterlogging decreased chlorophyll a, b and a+b in Y-86and Y-77.Salinity decreased net photosynthetic rate (Pn), intercellular CO2concentration (Ci), stomatalconductance (Gs), transpiration rate (Tr), the maximum photochemical efficiency (Fv/Fm),photochemical quenching (Qp) and actual photochemical efficiency (ΦPSII). Waterlogging had1ess adverse effect on those values compared to salinity. However, waterlogging decreasedcertain values more severely in Y-77than Y-86at120mmol/L NaCl.