Variability of morphological parameters of Trapa natans (Trapaceae, Magnoliópsida) during reintroduction into water bodies of the Saratov region from those of the Voronezh region

Abstract

The fruits of Trapa natans L. s. l. (Trapaceae), which has disappeared from the territory of the Saratov region, collected in the floodplain lakes of the Khoper river in the Voronezh region (Novokhopersky district), were sown in the fall of 2019 and spring of 2020 into the Khoper and Volga rivers within the Saratov region. In the fall of 2020, 17 recipient populations were observed, and the number of water caltrop rosettes in most of them was less than that of nuts sown. The number of rosettes equal to or greater than that of the nuts sown was observed in three recipient populations only. According to the morphometric parameters of the vegetative sphere, five recipient populations (Nos 6, 7, 9, 15, and 21) from the Khoper river approach the donor ones, while only two recipient populations (Nos 7 and 9) from the Khoper river approach them by the potential and actual seed productivity. The reintroduction of T. natans populations seems more promising in the Khoper river, whilst it is difficult in the Volga river due to sudden changes in the water level during the season.