Abstract:

Plants have evolved defenses against herbivores to improve their survival and reproduction. In order to study the relationship between resistance and cone yield in two larch species, contents of free amino acid in needles of Larix gmelinii and L. olgensis with different cone yield were measured by using high performance liquid chromatography(HPLC) with pre-column derivatization. The results showed that 17 kinds of free amino acids were detected out, and among them phenylalanine was the highest in both species. It was interesting to find there were significant differences in the several free amino acids related to resistance between the two species. Moreover, the contents of Alanine, Arginine, Glutamic acid, Isoleucine, Lysine, Phenylalanine and Valine in L. gmelinii were significantly different, and the contents of Asparagine and Phenylalanine in L. olgensis were significantly different, with different cone yield. The content of Asparagine in L. gmelinii was significantly less than in L. olgensis. The total content of free amino acids in leaves with the lowest cone yield was significantly lower than that in other grades of cone yield, and the total content of free amino acids increased with the increasing cone yield. It was concluded that the cone yield directly affected resource allocation in the needles of larch and further changed palatability and resistance of the herbivores. Furthermore, the difference of species was also important for resistance to their herbivores.

Key words: cone yield, Larix gmelinii, Larix olgensis, free amino acid, HPLC(high performance liquid chromatography)