Study On The Photosynthetic Performance And Productivity Of Different Phenotypes In Puna Chicory And Karyotypic Analysis Of The Variety

Under low selective pressures, there existed four different phenotypes of Puna Cichorium intybus L. including BL, BJ, HL and HJ. Nutrient compositions, diurnal changes of net photosynthetic rate and effects of related factors in leaves of different phenotypes and karyotypic analysis of the variety were studied in order to provide some scientific evidence for cultivating new variety purposely. Diurnal changes of net photosynthetic rate and related factors in leaves of puna chicory were measured using CI-340 portable photosynthesis system, the relationship between net photosynthetic rate and related factors were analyzed by correlation analysis and path coefficient analysis. Contents of different nutrient compositions were determined using conventional nutrient examination. Karyotype of the variety was analyzed by using conventional tablet-making of the cell chromosome of germinal root tip as materials and using picture processing software photoshop. The results were as follows:1. At stooling stage, the curves of diurnal changes of Pn in different phenotypes had two peaks and appeared"photosynthetic depressed"in the noon, however, different phenotype had different peak time and peak value. The order of daily average value of Pn in different phenotypes were HL(11.25μmol CO₂·m^-2·s^-1) > BL(9.48μmol CO₂·m^-2·s^-1) > HJ(9.15μmol CO₂·m^-2·s^-1) >BJ(8.83μmol CO₂·m^-2·s^-1), and HL was obviously higher than the other three phenotypes(P<0.05). The order of daily average value of transpiration rates in different phenotypes were HL(4.31mmol H₂O·m^-2·s^-1)>BL(3.55 mmol H₂O·m^-2·s^-1)=HJ(3.55 mmol H₂O·m^-2·s^-1)>BJ(3.37 mmol H₂O·m^-2·s^-1), and HL was obviously higher than the other three phenotypes(P<0.05).2. The order of related factors effected Pn of HL were C> Ci > T > E. The order of decision coefficient of related factors effected Pn of BL were C > PAR > RH > T > E > Ci, E and Ci were limiting factors. The order of decision coefficient of related factors effected Pn of HJ were C > RH > T > PAR > E > Ci, PAR,E and Ci were limiting factors. The order of decision coefficient of related factors effected Pn of BJ were C > PAR > E > T > RH > Ci, RH,T and Ci were limiting factors.3. The content of dry matter in BL-type puna chicory was the highest (15.59%), and was obviously higher than the other three phenotypes(P<0.01). The content of crude protein, crude fat and calcium in HL-type puna chicory were the highest, were 16.66%,3.31%,1.56% respectively, and noticeably higher than the other three phenotypes(P<0.01). Crude fiber content in HL-type puna chicory was the lowest (8.00%), and notably lower than the other three phenotypes (P<0.01). General energy in BL-type puna chicory was the highest (840.27 Kcal/Kg), and remarkably higher than the other three phenotypes(P<0.01).4. The order of variable coefficient of different nutrient compositions in different phenotypes were CP> CF> EE> GE > Ash > P > NFE. The variable coefficient of CP was the highest, the variable of NFE was lowest. Hence, the effect of phenotype of CP was the most notable, the effect of phenotype of NFE was the least notable.5. The karyotype formula of puna chicory was 2n = 2x =18= 18m, the range of relative length was 7.33～16.05%, mean arm ratios was 1.43, the ratio of the longest chromosome to the shortest one was 2.19, and all the arm ratios was less than 2, so the karyotype belonged to Stebbins 2B type. A chromosome deletion type existed in puna chicory, the karyotype formula was 2n = 2x =16= 16m, the range of relative length was 8.57～17.69%, and mean arm ratios was 1.39.6. In summary, stomata conductance had the decisive effect on diurnal changes of Pn in puna chicory and was the main decision variance, internal CO2 concentration was the major constrain, hence, stomatal factor was the major factor affected net photosynthetic rate of puna chicory. HL-type was high photosynthetic ability, high transpiration type. The contents of crude protein, crude fat and calcium in HL-type puna chicory were remarkably higher then the other three types, and crude fiber was the lowest of the four types, so the nutrition value of HL-type was the highest.