| Salix matsudana,an arbor species belonging to genus Salix?Salicaceae?,is also an excellent pulpwood and biomass energy tree species,a good choice for forestation on saline-alkali soil.Because of great adaptation,extensive distribution with natural pollination and natural regeneration in a long term,S.matsudana has abundant heritable variation in species.However,it is scarce for its research on genetic diversity,resistance,and utilizing property both in China and abroad so far.In this paper,222 clones of S.matsudana germplasms collected inland as test material,based on observation results of phenotypic traits and AFLP molecular markers,intraspecific genetic diversity was analyzed.On this basis,salt tolerance,pulping properties and caloric value were further studied,in order to lay a foundation for the selection of salt-tolerance species,afforestation species in the saline alkali soil,excellent clones of pulping and biomass energy.The results are as follows:1.Rich variation in qualitative traits of S.matsudana:?1?clones established by S.matsudana germplasms,which had no tomentum or little up and below leaves,a few clones had white or nearly transparent tomentum;?2?leaf margin were serrulate,shape wide lanceolate or lanceolate,growth pattern alternation;?3?among clones,many differences of colors and forms existed in both stem and branchlets,color of stem green and gray green,branchletsfrom yellow-green to reddish brown;?4?stem form is erect or slightly curved,some clones strong twisted;?5?most branchlets bent on,rarely pendulous or straight form.2.S.matsudana had abundant variation in phenotypic character:?1?leaf length 9.25cm-18.64cm?CV2.44%-17.28%?,leaf width 0.95cm-4.08cm?CV3.02%-20.12%?,leaf area 6.354cm2-42.03cm2?CV4.36%-33.15%?,with significant differences among clones?P<0.0001?;?2?tree height 1.18m-5.8m?CV2.41%-31.20%?,ground diameter 0.9cm-4.2cm?CV7.43%-42.16%?,with significant differences among clones?P<0.0001?;?3?relative range ofS.matsudana leaf length,leaf area,leaf width,tree height and diameter were 56.62%,32.01%,42.51%,57.41%,23.25%,indicating that 43.38%,67.99%,57.49%,42.59%,and 76.75% of variation were from that among clones;?4?.The differentiation coefficient analysis showed that the differences of traits were most from that among clones;leaf length,leaf width,leaf area,height and ground diameter of phenotypic differentiation coefficient were 89.28%,96.32%,93.44%,95.12%,89.76%,which showed that the difference among clones was the main source of the characters of differentiation.3.According to the principle of geographical distribution on uniformity,90 clones were selected and marked by AFLP from 222 germplasms;results showed that:?1?7 pairs of primers detected 896 loci,890 were polymorphic;percentage of polymorphism was 99.3%,that of primers were 98.11%-100%.Results showed that S.matsudana DNA has high polymorphism,with easy variation in molecular level;?2?Nei's genetic diversity?H?was 0.2322 and Shannon information index?I?was 0.3746;clustering was analyzed by UPGMA,and tested by Decenter with good results?r=0.84856?.4.Based on phenotypic and genetic observation data,core collection of S.matsudana germplsms were tried to be founded.Under 4 sizes of 20%,15%,10%,5%,ratio of phenotypic retained respectively were 96.92%,95.38%,93.85%,92.31%.Range conformity respectively were 93.33%,93.33%,87.52%,76.47%,with average conformity 98.86,98.37,95.32,85.31.And variance of phenotypic frequency were respectively 88.63%,89.44%,87.87%,90.67%.All the results indicated that it was feasible to built core collection of S.matsudana germplsms and size of 15% was recommended.5.By comprehensive evaluation on 90 samples of S.matsudana clones,18 clones of 41,48,52,55,59,65,70,97,103,104,106,111,127,142,147,174,196 were selected to be salt stressed.Ground diameter was from 0.85 cm to 1.9cm,and growth conditions from high to low ranked 55>70>142>111>54>65>106>48>41>59>147>127>196>97>174>103>52>104;9 clones of great growth were further analyzed for content change of protective enzyme activity and cell membrane permeability;after 30 d,SOD content1.23-4.63U·mg-1,POD0.04-0.25U·mg-1,with significant difference among clones?P<0.05?.CAT,MDA and cell relative electrolyte conductivity had no significant difference.The comprehensive evaluation showed that ability of salt tolerance among 9 clones 111>55>48>65>106> 70>41>54>142.6.Further analysis of fiber morphology,pulping characteristics and calorific value of these 9 clones showed that:?1?holocellulose content 73.3%-76.14%,nitric acid ethanol cellulose content 40.77%-47.45%,acid accumulator insoluble lignin content 18.455%-20.69%,pentosan content 20.925%-24.55%,cold water extractives4.875%-6.825%,hot water extractives 7.72%-9.15%,1%NaOH extractives 25.72%-27.275%,benzene alcohol extractives 2.23%-4.22%,fiber length 0.553mm-0.797 mm,fiber width 25?m-31.07?m,and ratio of fiber length to width 20.2-25.7,curl index 0.031-0.039,kink index 0.198-0.364,kink number per mm 0.102-0.198,kink angle 3.59-5.41 with average 4.32,fines percent 12.78%-22.338%,comprehensive evaluation showed that all the tested clones are better than p172,and clones ranked 111>106>55>65>70>48>p172;?2?caloric value 26.96kJ·g-1-31.716kJ·g-1,ash content 0.38%-0.7%,AFCV 14kJ·g-1-31.92kJ·g-1,and calorific value comparison ranking 106>55>p172>70>48>65> 111. |
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