Increasing the germination percentage of a declining native orchid (Himantoglossum adriaticum) by pollen transfer and outbreeding between populations

Abstract

The declining native orchid Himantoglossum adriaticum H. Baumann is a European endemic of priority interest (92/43/ EEC, Annex II). Northern Italian populations of H. adriaticum are small and isolated, with depressed seed set. Given the important implications for plant population conservation, we tested the hypothesis that artificial pollen transfer (hand-pollination) and outbreeding between populations increases fruit set and seed germination percentage.• The background fruit set and in vitro germination rates were determined for ten reference populations. An artificial cross-pollination experiment included (a) pollen transfer from one large population to two small and isolated populations; (b) pollen transfer between two small but not isolated populations; (c) within-population pollen transfer (control). All seeds were sown on a modified Malmgren's medium and cultured in a controlled environment. Germination percentage was compared using a Kruskal-Wallis ANOVA.• The background fruit set (mean = 18%) and germination (<5%) rates were consistently low across populations. Fruit set after hand-pollination was consistently 100%. Pollen transfer from the largest population to smaller populations resulted in an increase in total germination ranging from 0.9% to 2.9%. The largest increase in germination occurred between small-sized and less isolated populations (from 1.7% to 5.1%).• The results of pollen transfer between the small populations are particularly encouraging, as the mean increase in germination was almost four times that of the control. Outbreeding can be considered a valuable tool to increase genetic flow and germination in natural populations, limit the accumulation of detrimental effects on fitness driven by repeated breeding with closely-related individuals, thereby increasing the possibility of conservation of rare or endangered species.Plant Biology 21 (2019) 935-941

Intraspecific variability of leaf traits and functional strategy of Himantoglossum adriaticum H. Baumann

“…At regional level (Buffa et al 2016) the species is classified as NT (Near Threatened), but its status worsens in lowland areas. In Northern Italy, it is mostly found in dry grasslands and nearby ecotonal meso-xeric scrubland/woodland patches (Slaviero et al 2016;Del Vecchio et al 2019).…”

Figure 2 from: Baltieri M, Fantinato E, Del Vecchio S, Buffa G (2020) Intraspecific variability of leaf traits and functional strategy of Himantoglossum adriaticum H. Baumann. Plant Sociology 57(2): 105-112. https://doi.org/10.3897/pls2020572/03

“…At regional level (Buffa et al 2016) the species is classified as NT (Near Threatened), but its status worsens in lowland areas. In Northern Italy, it is mostly found in dry grasslands and nearby ecotonal meso-xeric scrubland/woodland patches (Slaviero et al 2016;Del Vecchio et al 2019).…”