| Jerusalem artichoke (Helianthus tuberosus) is a kind of perennial and herbaceous plant belongs to the sunflower plants group in Asteraceae. Generally, Jerusalem artichoke is considered to be an important industrial crop for the multiple applications in economic and ecological interests. Tuber is well used as raw material in the fructose industry production for its high inulin concentration. The extraction and secretion of Jerusalem artichoke leaves and tubers are also confirmed to be antibacterial, antifungal, and anticancer activities. In addition, Jerusalem artichoke has various stresses, which suggesting that the important ecological values in soil improvement, desert control, and soil and water conservation. In this research, lines of suspension cell Jerusalem artichoke are generated by using tissue culture approach in vitro. Six elicitors, methyl jasmonate, salicylic acid, chitosan, yeast extract, Trichoderma viride, and AgNO3, are used to evaluate their different induced effect on inulin and phenolics. The concentration, production, and degree of polymerization of inulin, as well as concentration and composition of phenolics are analyzed after each elicitor treatment.(1) Three explants, leaf, internode and tuber, in combination with three hormones, NAA, 6-BA, and KT, which are used for optimization of callus inducible conditions. Through the investigations regarding induction rate, morphology, and dry weight, the internode is selected to be the best explant and its corresponding inducible condition is MS medium containing additional 1.0 mg/L NAA and 1.0mg/L 6-BA. Furthermore, considering factors that affect the suspension cells growth, a fourth factors experiment including inoculation amount, subculture liquid retention amount, sucrose concentration, and nitrogen source addition, is conducted to find its best culture conditions. The results shows that the best culture conditions for suspension cells growth are:MS medium containing additional 1.0 mg/L NAA, 1.0mg/L 6-BA, 0.5mg/L proline, 1.0mg/L glutamine, and 30g/L sucrose; 4g/100mL liquid culture medium inoculation; and 20mL remaining subculture solution. The corresponding cells growth curve is: lag period (0-4d), logarithmic growth phase (6-18d), and the subsequent stable period.(2) The elicited effect of six elicitors to the suspensioncells of Jerusalem artichoke is as follow:methyl jasmonate (250μmol/L)>AgNO3 (10 μmol/L)> salicylic acid (75 μmol/L)> chitosan (40 mg/L)>Trichoderma viride(90 mg/L)> yeast extract (0.25 mg/L), and the corresponding content of inulin is increased by 2.43,2.05,1.93,1.76,1.44,1.18 times respectively while the corresponding yield of inulin is increased by 3.09,4.60,2.26,2.76,2.06, 1.09 times.The lower degree of polymerization (Dp2-20) inulin content is also increased by treatment with the six elicitors in suspension cells of Jerusalem artichoke. The methyl jasmonate has a significant inducted effect on the Dp2-8 oligofructose, especially for the Dp6 oligofructose, under the treatment of methyl jasmonate, the Dp6 oligofructose content is increased from 2.17% to 29.15%. Under the treatment of salicylic acid, the Dp2-17 inulin content is significantly increased, especially for the Dp2-4 oligofructose, the content is increased from 8.16%、6.79%、7.17% to 20.86%、14.79%、18.53% respectively. The chitosan has a significant inductive effect on the Dp4 oligofructose content, under the treatment of chitosan, the Dp4 oligofructose content is increased from 0.52% to 56.42%. Under the treatment of yeast extract and Trichoderma viride, the Dp3 and Dp4 oligofructose are dramatically increased from 28.04%,22.77% to 50.78%,38.12% and 1.78%,32.57% to 50.78%,51.22% respectively. Under the treatment of AgNO3, the Dp3-12 inulin content is growingly increased, especially for the Dp7 oligofructose, the Dp7 oligofructose content is hereby increased from 0.01% to 11.15%.Based on the inulin content together with the lower degree of polymerization inulin content in the suspension cells of Jerusalem artichoke,the optimum concentration and processing time of six elicitors goes as follow:methyl jasmonate (250 μmol/L) for 6 days, salicylic acid (75 μmol/L) for 3 days, chitosan (40 mg/L) for 6 days, yeast extract (0.25 mg/L) for 12 days, Trichoderma viride(90 mg/L) for 3 days, AgNO3 (10 μmol/L) for 9 days.(3) The inducible effect of six elicitors on total phenol content in the suspension cells of inulin goes as:yeast extract (1.0 mg/L)> AgNO3 (5 μmol/L)>Trichoderma viride(90 mg/L)> salicylic acid (100 μmol/L)> methyl jasmonate (300 μmol/L)> chitosan (80 mg/L), and the total phenol content was increased 2.14、1.91、1.85、1.63、1.56、1.17 times respectively. The optimum processing time is methyl jasmonate for 12 days (1.34 times), salicylic acid for 6 days (1.92 times) and yeast extract for 3 days (1.19 times), and with the increased processing time, the increased total phenol content is lower than the control under the treatment of the other three elicitors.The 14 phenolics contents are obviously affected in the suspension cells of Jerusalem artichoke under the treatment of six elicitors. Under the treatment of methyl jasmonate, five phenolics contents are increased more than tenfold, the 4-hydroxicoumarin is increased to the most under the treatment of methyl jasmonate relative to other elicitors. With respect to other elicitors, seven phenolics contents (ferulic acid, salicylic acid,3-hydroxycinnamic acid, catechin, gallic acid, scopoletin and protocatechuic acid) are increased 159.22、106.47、 45.14、15.20、7.80、7.06、5.89 times respectively under the treatment of salicylic acid. Under the treatment of chitosan, six phenolics contents increase more than tenfold, especially for caffeic acid and sinapic acid, the contents are increased 98.88 and 79.50 times respectively. Under the treatment of yeast extract, the epicatechin and chlorogenic acid content are increased growingly 45.04 and 37.45 times respectively, and the 4-hydroxybenzoic acid and quercetin contents are also increased. The 14 phenolics contents are also increased in the suspension cells of Jerusalem artichoke under the treatment of Trichoderma viride and AgNO3, and the inducible effect is lower than the other four elicitors. |
PDF Full Text Request