Comparison of sand burial-dependent growth responses of two Tragopogon species from different habitats

Wind-driven sand movement leading to sand burial is an essential environmental factor in coastal sand dunes; therefore, plants native to sand dunes need to possess specific adaptations. The present study aimed to compare responses to variable sand burial intensity of Tragopogon heterospermus, rare plant species native to coastal dunes, and Tragopogon pratensis taxonomically related grassland species. Plants in culture were established from seeds collected in natural habitats, cultivated in an automated greenhouse, and individuals of different age were buried by sand in the different depths. Both plants had basic sand burial tolerance, seen as an elongation of adult plants’ leaf bases under moderate sand burial conditions. However, only dune-adapted T. heterospermus plants exhibited efficient resource allocation from roots to shoots with increased sand accretion intensity. T. heterospermus plants had pronounced age dependence of burial tolerance, with higher sensitivity to sand burial at an earlier stage due to small shoot height and, possibly, certain physiological factors.