Biology subjects

Manafzadeh, S.

Publications and source records attributed to Manafzadeh, S..

3 recordsLinked to original sources

bioRxiv2019

Modularity and evolution of flower shape: the role of efficiency, development, and spandrels in Erica

O_LIThree hypotheses can explain floral modularity: the attraction-reproduction, the efficiency, and the developmental hypotheses.\nC_LIO_LIIn order to test these hypotheses and understand if pollination specialisation and pollination syndrome influence floral modularity, we focussed on the genus Erica: we gathered 3D data from flowers of species with diverse pollination syndromes via Computed Tomography, and analysed their shape via geometric morphometrics. In order to provide an evolutionary framework for our results we tested the evolutionary mode of floral shape, size, and integration under pollination syndrome regimes, and - for the first time-reconstructed the high-dimensional floral shape of their most recent common ancestor.\nC_LIO_LIWe demonstrate, for the first time, that the modularity of generalist flowers depends on development and that of specialists is linked to efficiency: in bird syndrome flower, efficiency modules were associated with pollen deposition and receipt, whereas in long-proboscid fly syndrome, they were associated with restricting the access to the floral reward. Only shape PC1 showed selection towards multiple optima, suggesting that PC1 was co-opted by evolution to adapt flowers to novel pollinators. Whole floral shape followed an OU model of evolution, and demonstrated relatively late differentiation.\nC_LIO_LIFlower shape modularity thus crucially depends on pollinator specialisation and class.\nC_LI

evolutionary biology↗

bioRxiv2017

Novel Computed Tomography-based tools reliably quantify plant reproductive investment

The flower is a bisexual reproductive unit where both genders compete for resources. Counting pollen and ovules in flowers is essential to understand how much is invested in each gender. Classical methods to count very numerous pollen grains and ovules are inefficient when pollen grains are tightly aggregated, and when fertilization rates of ovules are unknown. We thus established novel, Computed-Tomography-based counting techniques. In order to display the potential of our methods in very difficult cases, we counted pollen and ovules across inflorescences of deceptive and rewarding species of European orchids, which possess both very large numbers of pollen grains (tightly aggregated) and ovules. Pollen counts did not significantly vary across inflorescences and pollination strategies, whereas deceptive flowers had significantly more ovules than rewarding flowers. The within inflorescence variance of pollen to ovule ratios in rewarding flowers was four times higher than in deceptive flowers, possibly demonstrating differences in the constraints acting on both pollination strategies. We demonstrate the inaccuracies and limitations of previously established methods, and the broad applicability of our new techniques: they allow measurement of reproductive investment without restriction on object number or aggregation, and without specimen destruction.

plant biology↗

bioRxiv2017

Response of oriental xerophytes to the occidental industrial revolution

Since the Industrial Revolution, human activities have contributed substantially to climate change, by adding CO2 to the atmosphere, especially since the mid-20th century (the \"Great Acceleration\"). Climatic change does not have the same impact on different regions of the Earth, neither in the recorded past, nor in models of the future. Therefore, to anticipate on these changes, we need to understand and be able to predict the possible responses of the different regional vegetations of the world to these changes, and most significantly to increased drought conditions. The aim of this study is to understand the response of the xerophytes of the immense oriental Irano-Turanian bioregion to post-industrial global warming and to compare it with the response of the xerophytes of the neighbouring occidental Mediterranean bioregion. We measured stomata index and stomata density from 83 herbarium sheets (coll. 1821-2014) from species of the non-succulent xerophyte, Haplophyllum. We tested for differences before and after the \"Great Acceleration\" in both bioregions. SI decreased in the occidental species (significant only for abaxial leaf side), whereas SI significantly increased in the oriental species (both sides). We suggest that changes in both occidental and oriental species are linked to atmospheric CO2 due to the different constraints that act on their growth. In light-limited occidental species, atmospheric CO2 caused the stomata index decrease, whereas in the predominantly water-limited oriental species, increased drought stress and temperature (climatic change) caused stomata index increase. In conclusion, we propose that whereas atmospheric CO2 directly caused a decrease in stomata index in occidental xerophytes, it indirectly caused an increase in stomata index in oriental xerophytes via climate change (increase in aridity, drought stress, and temperature). This study highlights the considerable potential of research based on historical herbarium collections to answer ecological questions, especially regarding climatic change.

plant biology↗