Plant apomixis is rare in Himalayan high-alpine flora

Viktorie Brožová,Jiří Doležal,Petr Koutecký

doi:10.1038/s41598-019-50907-5

Abstract

Gametophytic apomixis is a way of asexual plant reproduction by seeds. It should be advantageous under stressful high altitude or latitude environment where short growing seasons, low temperatures, low pollinator activity or unstable weather may hamper sexual reproduction. However, this hypothesis remains largely untested. Here, we assess the reproductive mode in 257 species belonging to 45 families from the world’s broadest alpine belt (2800–6150 m) in NW Himalayas using flow cytometric seed screen. We found only 12 apomictic species, including several members of Poaceae (Festuca, Poa and Stipa), Rosaceae (Potentilla) and Ranunculaceae (Halerpestes, Ranunculus), which are families typical for high apomict frequency. However, several apomictic species were newly discovered, including the first known apomictic species from the family Biebersteiniaceae (Biebersteinia odora), and first apomicts from the genera Stipa (Stipa splendens) and Halerpestes (Halerpestes lancifolia). Apomicts showed no preference for higher elevations, even in these extreme Himalayan alpine habitats. Additional trait-based analyses revealed that apomicts differed from sexuals in comprising more rhizomatous graminoids and forbs, higher soil moisture demands, sharing the syndrome of dominant species with broad geographical and elevation ranges typical for the late-successional habitats. Apomicts differ from non-apomicts in greater ability of clonal propagation and preference for wetter, more productive habitats.

Highlights

Gametophytic apomixis is a way of asexual plant reproduction by seeds
There is a general opinion that gametophytic apomixis, the mode of plant reproduction via seeds formed by asexual way from gametophytic tissue, is more frequent in cold environments of higher latitudes and altitudes[1,2,3,4]
Data obtained from seed samples collected in Ladakh revealed 12 species with gametophytic apomixis out of total 257 species collected

Summary

Introduction

Gametophytic apomixis is a way of asexual plant reproduction by seeds It should be advantageous under stressful high altitude or latitude environment where short growing seasons, low temperatures, low pollinator activity or unstable weather may hamper sexual reproduction. Hörandl et al.[8] tried to verify the theory of higher frequency of apomicts in the European Alps by analysing 14 subnival species, all dependent on insect pollinators, to find out whether there is some effect of pollinator limitation[8] From these species, only Potentilla crantzii (Crantz) Beck ex Fritsch, an apomictic plant described earlier by Smith[36] was apomictic while other species showed seeds originated by sexual way, indicating that apomixis might be rather rare in high elevations. Himalayas provide extensive alpine environment potentially less favourable for insect pollinators compared to European mountains and more favourable for formation of apomixis due to severe ecological constraints[37]

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Results

Conclusion