Derived woodiness and annual habit evolved in African umbellifers as alternative solutions for coping with drought

BMC Plant Biology

Anthony R. Magee¹  Alexei A. Oskolski²  Paulina Trzeciak³  Kamil E. Frankiewicz⁴  Łukasz Banasiak⁴  Mohammad Alsarraf⁴  Krzysztof Spalik⁴ 

[1] Department of Botany and Plant Biotechnology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg, South Africa;Compton Herbarium, South African National Biodiversity Institute, Kirstenbosch Research Centre, Rhodes Drive, 7700, Cape Town, South Africa;Department of Botany and Plant Biotechnology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg, South Africa;Komarov Botanical Institute, Prof. Popov 2, 197376, St. Petersburg, Russia;Faculty of Biology and Veterinary Sciences, Nicolaus Copernicus University, Lwowska 1, 87-100, Toruń, Poland;Institute of Evolutionary Biology, Faculty of Biology, University of Warsaw, Biological and Chemical Research Centre, Żwirki i Wigury 101, 02-089, Warsaw, Poland;

关键词: Apioideae;    Derived woodiness;    Habitat;    Nanobubon;    Notobubon;    Secondary woodiness;    Wood anatomy;   

DOI  :  10.1186/s12870-021-03151-x

来源: Springer

【 摘 要 】

BackgroundOne of the major trends in angiosperm evolution was the shift from woody to herbaceous habit. However, reversals known as derived woodiness have also been reported in numerous, distantly related clades. Among theories evoked to explain the factors promoting the evolution of derived woodiness are moderate climate theory and cavitation theory. The first assumes that woody habit evolves in response to mild climate allowing for prolonged life span, which in turn leads to bigger and woodier bodies. The second sees woodiness as a result of natural selection for higher cavitation resistance in seasonally dry environments. Here, we compare climatic niches of woody and herbaceous, mostly southern African, umbellifers from the Lefebvrea clade to assess whether woody taxa in fact occur in markedly drier habitats. We also calibrate their phylogeny to estimate when derived woodiness evolved. Finally, we describe the wood anatomy of selected woody and herbaceous taxa to see if life forms are linked to any particular wood traits.ResultsThe evolution of derived woodiness in chamaephytes and phanerophytes as well as the shifts to short-lived annual therophytes in the Lefebvrea clade took place at roughly the same time: in the Late Miocene during a trend of global climate aridification. Climatic niches of woody and herbaceous genera from the Cape Floristic Region overlap. There are only two genera with distinctly different climatic preferences: they are herbaceous and occur outside of the Cape Floristic Region. Therefore, studied herbs have an overall climatic niche wider than their woody cousins. Woody and herbaceous species do not differ in qualitative wood anatomy, which is more affected by stem architecture and, probably, reproductive strategy than by habit.ConclusionsPalaeodrought was likely a stimulus for the evolution of derived woodiness in the Lefebvrea clade, supporting the cavitation theory. The concurrent evolution of short-lived annuals withering before summer exemplifies an alternative solution to the same problem of drought-induced cavitation. Changes of the life form were most likely neither spurred nor precluded by any qualitative wood traits, which in turn are more affected by internode length and probably also reproductive strategy.

【 授权许可】

CC BY