Are alpine Gentianaceae plants mixotrophic?

V. G. Onipchenko^a, *, N. G. Lavrenov^a, A. V. Tiunov^b, M. I. Makarov^ba, M. J. A. Werger^c, A. A. Akhmetzhanova^a, T. G. Elumeeva^a, V. E. Smirnov^d,e,, Wang Qian^f, Wu Yan^f

^aLomonosov Moscow State University, Department of Geobotany
Leninskie Gory, 1/12, Moscow, 119234 Russia
^bSevertsov Institute of Ecology and Evolution, RAS
Leninsky prosp., 33, Moscow, 119071 Russia
^cPlant Ecology & Biodiversity, Utrecht University
Utrecht, 3508 ТВ, The Netherlands
^dCenter for Forest Ecology and Productivity, RAS
Profsoyuznaya, 84/32, Moscow, 117997 Russia
^eInstitute of Mathematical Problems of Biology, RAS
Vitkevich, 1, Pushchino, 142290 Russia
^fChengdu Institute of Biology, Chinese Academy of Sciences
Renminnanlu, 9, Chengdu, 610041 China
*e-mail: vonipchenko@mail.ru

Partially mycoheterotrophic (mixotrophic) plants are considered to be more common among phylogenetic lineages that include fully mycoheterotrophic plants. Gentianaceae is one such group. Mixotrophy is not well known for alpine plants in contrast to species of tropical and temporal forests. We tested the hypothesis that green alpine species from the Gentianaceae family can be partially mycoheterotrophic. Leaves of nine pairs of species (alpine plants from the Gentianaceae + reference neighboring AM plants from other families) were collected in Tibetan (Sichuan, China) and Caucasian (Karachai-Cherkessian Republic, Russia) mountains. Stable isotope (¹³C, ¹⁵N) natural abundances were determined in fully developed leaves. In each case leaves of Gentianaceae plants were enriched in ¹⁵N more than the leaves of other plants served as comparisons. Except for two species from the section Pneumonanthe (Gentiana asclepiadea and G. septemfida) the studied Gentianaceae plants did not show significant ¹³C enrichment. We suggest that relative ¹⁵N enrichment of leaves may be considered as an indication of partial mycoheterotrophy in alpine Gentianaceae.