An Analysis on Leaf Traits of 22 Helianthus tuberosus Germplasm Resources Introduced from Abroad

Atomic absorption spectrophotometry, sulfuric acid and potassium dichromate oxidation method and ultraviolet spectrophotometry, were used to determine mineral elements, fiber, the content of chlorogenic acid and flavones in leaves of 24 Helianthus tuberosus Linn. resources, and the characteristics of the leaf introduced from abroad were evaluated. The results showed that the highest water content of 22 species was F12 (27.58%), and the lowest was F16 (19.02%). The difference in mean water content between the species from Denmark and France was small, but it was lower than that of Qingyu 3 and Qingyu 4. There were 3 orbicular leaves, 1 long oval-shaped leaf and 18 oval leaves. The highest K content in the leaves was F19 (30.62 mg/g), which was 2.5 times than Qingyu 3. The highest Mg content was D8 (14.17 mg/g). The Fe content had little difference, ranging from 0.09 mg•g−1 to 0.19 mg/g. The highest Ca content was D8 (26.87 mg/g). The highest level of chlorogenic acid and flavones was F7, 2.55% and 1.24 g/100 g respectively. The highest fiber content was F9 (16.7%), and the lowest was F19 (7.36%). Through the analysis of the main component and the clustering analysis, when the genetic distance was 0.65, the 24 resources can be divided into three major categories. The first category of leaves were mainly oval and orbicular; the second category of leaves were long oval-shaped; the third category of leaves were oval. There was a difference between the various indexes in the leaf of different kinds of Helianthus tuberosus Linn. resources. Finally, F19, D8, F9, F7, D14 and D11, 6 specific species (F19, D8, F9, F7, D14 and D11) were screened out for further studies in the future.