Nitrate inhibition of germination in Ericaceae relates to seed size and mycoheterotrophy

Nitrate is a well-known regulator of several processes in plants, including seed germination. It generally induces germination, but its effect is species-specific, and germination of some species is even inhibited. It is not clear what drives these differences. Nevertheless, it is striking that the germination of initially mycoheterotrophic orchids is generally inhibited by nitrate, indicating that this may be an adaptive trait allowing the seeds to detect sites with low nutrient availability, favourable for mycoheterotrophic plants. Whether this unusually negative response to nitrate is a general feature of mycoheterotrophic plant germination remains unknown. We focused on the family Ericaceae, which contains lineages that are either fully or initially mycoheterotrophic together with autotrophic ones, and we tested the germination response of selected species to nitrate. We found high variability in the germination responses even within members of this family. Fully and initially mycoh..., Seeds were cultivated axenically in vitro on media with various amount of nitrate or ammonium ion. We also measured dimensions of dry ripe seeds. , , # Nitrate inhibition of germination in Ericaceae relates to seed size and mycoheterotrophy

[https://doi.org/10.5061/dryad.gtht76hwv](https://doi.org/10.5061/dryad.gtht76hwv)

## Description of the data and file structure

The seeds were cultivated axenically in vitro on media with various concentration of nitrate or ammonium ion to count germination rate. We also measured dimensions of ripe seeds.

### Files and variables

#### File: klicivosti.txt

**Description:** 

##### Variables

* species: plant species tested
* ion: the ion tested - nitrate (NO3-) or ammonium (NH4+)
* concentration: the concentration of the tested ion in mg·l-1 of NO3- or NH4+ [mg·l-1].
* germination_rate: the proportion of germinated seeds counted after cultivation [%].

#### File: seed\_dimensions.txt

**Description:** 

##### Variables

* plant: plant species tested
* coat_length: total length of the seed [mm]
* coat_width: total width of the seed [mm]
* live_length: length of the living part (embryo plus en...