| The potato(Solanum tuberosum L.)tuber development process has an important effect on yield and quality of tuber.The formation and development of tubers is a continuous and complex process that is regulated by avariety of factors.Carbohydrate not only provide energy for the formation and development of potato tubers,but also act as a signal molecule to regulate the formation and development of tubersin vitro.To study the development process of potato tubers under different disaccharides,the regulation of four disaccharides on potato tuberization was revealed.In this study,the stolons form the seedlings of the potato tetraploid cultivar "Atlantic" were used as experimental materials by adding different concentrations of sucrose,trehalose,maltose and lactose.The effects of four disaccharides on the phenotype,carbohydrate and the related enzyme activities of sucrose metabolism were examinated.The physiological effects of disaccharide on the formation and development of potato tubers were analysied.The detailed results were as following:The morphogenesis of potato tuber was investigated under four disaccharides treatment in vitro.With the increase of the concentration of sucrose,maltose and lactose from 0.05 mol/L to 0.25 mol/L,the percentage of tuberization,fresh weight,dry weight and diameter of tubers was increased and significantly higher than the control.The maximum value was appeared under 0.25 mol/L treatment.The percentage of tuberization,fresh weight,dry weight and diameter of tubers was increased and significantly higher than the control.Compared with 0.25 mol/L treatment,the percentage of tuberization,fresh weight,dry weight and diameter of tubers were decreased with the increase of sugars concentration from 0.30 mol/L to 0.40 mol/L.With the increase of trehalose concentration from 0.05 mol/L to 0.20 mol/L,the percentage of tuberization,fresh weight,dry weight and diameter of tubers increased significantly compared with the control.With the increase of the concentration of trehalose from 0.05 mol/L to 0.20 mol/L,the percentage of tuberization,fresh weight,dry weight and diameter of tubers was increased and significantly higher than the control.The maximum value was appeared under 0.20 mol/L treatment.Compare with 0.20 mol/L treatment the percentage of tuberization,fresh weight,dry weight and diameter of tubers were decreased with the increase of the concentration of trehalose from 0.25 mol/L to 0.40 mol/L.Under 0.30 mol/L treatment,the tuberization was completely inhibited.The tuberization beginning time was delayed gradually with the trehalose concentration increasing.Compared to other disaccharides,sucrose regulates the morphology of tuber bestin vitro.The carbohydrates of potato tuber were investigated under four disaccharides in vitro.With the increaseof the concentration of sucrose,maltose and lactose from 0.05 mol/L to 0.25 mol/L,the content of sucrose and starch increased gradually.The content of sucrose and starch was the highest under 0.25 mol/L treatment.With the increase of concentration from 0.30mol/L to 0.40 mol/L,the content of sucrose and starch decreased compared with the concentration of 0.25 mol/L.The fructose content increased with the increase of the concentration of maltose and lactose.The content of glucose increased with the increase of the concentration maltose,and the glucose content reached the maximum under 0.25 mol/L lactose concentration treatment.The fructose and glucose content of tuber were significantly lower than the control,and the minimum value was appeared under 0.25 mol/L sucrose concentration treatment.The glucose,fructose,sucrose and starch content were the maximum,under 0.20 mol/L trehalose concentration treatment.The related enzyme activities of sucrose metabolism of potato tuber were investigated under four disaccharides treatment in vitro.With the increase of the concentration of sucrose,maltose and lactose from 0.05 mol/L to 0.25 mol/L,the sucrose phosphate synthase(SPS)activity increases gradually.The maximum value was appeared under 0.25 mol/L,the activity of SPS was 904.39,945.74 and 834.63 ?g/min/g FW,respectively.Compared with the concentration of 0.25 mol/L treatment,the activity of SPS was decreased with the increase of the concentration offrom 0.30mol/L to 0.40mol/L.The minimum value was appeared with the concentration of sucrose and maltose was 0.25 mol/L,soluble acid invertase(S-AI)activity was 3.19 and 17.13 ?g/min/g FW.The minimum value was appeared with the concentration of sucrose and maltose was 0.25 mol/L,sucrose synthase(SS-I)was 89.63 and 92.88 ?g/min/g FW.With the concentration of lactose was 0.25 mol/L,the minimum value was appeared,the activity of S-AI was 38.13 ?g/min/g FW,while the maximum value was appeared,the activity of SS-I was194.27 ?g/min/g FW.The maximum value was appeared with the trehalose concentration of 0.20 mol/L,the activity of SPS,S-AI andSS-I was 824.29,79.46 and 224.37?g/min/g FW,respectively.The trend of sucrose phosphate synthase activity is basically consistent with the trend of the content of sucrose in tuber.The four disaccharides catalyze the synthesis and decomposition of reducing sugar,sucrose and starch by regulating the related enzyme activities of sucrose metabolism,maintain the carbon balance,promote the formation and development and change the morphological of tubers in vitro. |
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