色季拉山蒲公英属总黄酮及糖分含量种间差异及随海拔和坡向的变化

Interspecific differences in total flavonoid and sugar content in Taraxacum in Shergyla Mountain and their variation with altitude and slope orientation

[目的]蒲公英属是西藏最常见的药食两用植物,研究其植株内主要药理活性成分黄酮类、多糖以及其他糖分含量在种间差异以及随着坡向和海拔梯度的变化特征,对其高效开发利用具有重要的指导意义。[方法]以6种蒲公英属植物毛柄蒲公英、大头蒲公英、锡金蒲公英、灰果蒲公英、反苞蒲公英和角苞蒲公英不同坡向和海拔样地的全草样本为研究材料,分别对植株中的总黄酮和几种糖分含量进行测定和分析。[结果](1)总黄酮含量在毛柄蒲公英西坡3900m样本中最高(80.96mg/g),而锡金蒲公英东坡2300m样本中含量最低(29.08mg/g),并显著低于其他样本(P<0.05)。(2)总糖含量在反苞蒲公英东坡2000m样本中达440.55mg/g,显著高于其他样本;而锡金蒲公英西坡4200m样本仅63mg/g,显著低于其他样本。(3)所有样本中还原性糖含量最高为61.1mg/g,最低为35.98mg/g,但不同种质和不同海拔高度之间的差距不如总糖含量明显。(4)多糖含量在反苞蒲公英东坡2000m和锡金蒲公英西坡3000m样本高达320mg/g以上,而锡金蒲公英西坡4200m和3900m以及毛柄蒲公英西坡3900m样本含量不足70mg/g,并与其他样本差异显著。[结论]西藏蒲公英属植物中黄酮和多糖含量较高,并在不同种之间差异明显;黄酮和多糖含量随海拔升高或坡向呈相反变化趋势,而多糖和总糖含量则有相似的变化规律;高海拔和西坡向可能有利于黄酮积累,低海拔和东坡向可能有利于多糖积累。

[Objective]Taraxacum is an important medicinal and edible herb distributed commonly in Xizang.We aim to determine the content of the major pharmacologically active ingredients,including total flavonoids,polysaccharides,and other sugars,in different dandelion species and analyze the effect of altitude and slope orientation to provide guidance for the exploitation and utilization of Taraxacum resources in Xizang.[Methods]Six Taraxacum species were used as materials,including T.eriopodum(D.Don)DC.,T.calanthodium Dahlst.,T.sikkimense Hand.-Mazz.,T.maurocarpum Dahlst.,T.grypodon Dahlst.,and T.stenoceras Dahlst.,which were growing at different altitudes and slopes in Shergyla Mountain of Xizang.The content of total flavonoids and several sugars was analyzed.[Results](1)The total flavonoid content of T.eriopodum on the west slope at 3900 m(80.9 mg/g)was higher than the others,and the total flavonoid content of T.sikkimense on the east slope at 2300 m(29.08 mg/g)was lower than the other samples(P<0.05).(2)The total sugar content of T.grypodon on the east slope at 2000 m was 440.55 mg/g,which was different from other samples,but T.sikkimense on the west slope at 4200 m was the lowest(63 mg/g).(3)The highest content of reducing sugar was 61.1 mg/g and the lowest was 35.98 mg/g in all samples,but the difference between different species and different altitudes was not as obvious as total sugar.(4)The polysaccharide content in T.grypodon on the east slope at 2000 m and T.sikkimense on the west slope at 3000 m was above 320 mg/g,while the content of T.sikkimense on the west slope at 4200 m and 3900 m and T.eriopodum on the west slope at 3900 m was below 70 mg/g,lower than the other samples.[Conclusion]The total flavonoids and polysaccharides of Taraxacum in Shergyla Mountain are high,which vary among different species.Total flavonoids and polysaccharides are altered oppositely with the changes in altitudes and slopes,while polysaccharides and total sugars show a similar pattern with the changes in altitudes and slope orientation.High altitude and west slope orientation may be conducive to the accumulation of flavonoids,while low altitude and east slope orientation may be conducive to the accumulation of polysaccharides.