Flowering and quality of seeds and pollen in endangered populations of Betula humilis

Abstract Key message Lowered pollen and seed quality of B. humilis compared to its widespread tree relatives may threaten populations at the southwestern edge species range. Inability produce vital propagules is main threat persistence rare plants edges distribution. In present investigation, factors responsible for low germinability shrub birch ( Betula ) seeds in peripheral were analysed. As are found phosphorus (P)-limited peatlands with high groundwater levels, impact PO 4 3− ion contents table flowering was also studied. Qualities those congeners silver pendula downy pubescens ), which usually represent a reproductive performance. We revealed that poor germination ability caused by proportions empty (44.8%) partially developed embryos (47.3%). The insufficient numbers viable be consequence low-quality pollen, as only 1.6% grains sprouted. significantly lower than pollen; thus, there risk pollination female flowers birches. Positive relationships between P concentrations birches, but not humilis. availability ions did affect flowering, male inflorescences more numerous stands higher levels. Consequently, maintenance crucial efficient sexual reproduction