# Photophysiology data from smooth cordgrass (Sporobolus alterniflorus) measured in a North American saltmarsh using pulse amplitude modulated (PAM) fluorescence

## TL;DR

This paper provides photophysiology data from smooth cordgrass measured in a saltmarsh using PAM fluorescence, offering insights into its photosynthesis under varying environmental conditions.

## Contribution

The study presents in situ PAM fluorescence measurements and derived photophysiological parameters for Sporobolus alterniflorus in a tidal saltmarsh.

## Key findings

- Quantum yield of photosystem II and electron transport rates were calculated from PAM fluorescence measurements.
- Rapid light curves were fitted to estimate the relationship between electron transport rates and photosynthetic photon flux density.
- Data were collected from plants at different shore positions and times of day, capturing environmental variability.

## Abstract

Coastal saltmarshes play an important role as an interface between terrestrial and marine environments. Sporobolus alterniflorus (smooth cordgrass) occurs naturally along the east coast of North America, from Texas to Quebec, where it often forms extensive monospecific stands. Sporobolus alterniflorus is highly productive and is often the dominant plant in terms of biomass. This data set presents variable chlorophyll fluorescence measurements made in situ from the leaves of Sporobolus alterniflorus growing in a tidal saltmarsh ecosystem (North Inlet, South Carolina, United states). Measurements were made using pulse amplitude modulated (PAM) fluorescence. The data include raw measurements of variable fluorescence (Ft) and maximum fluorescence (F’m) made at 12 different actinic photosynthetic photon flux densities (PPFD). These data were used to calculate the quantum yield of photosystem II (ΦPSII) and estimate electron transport rates (ETRs). Rapid light curves (RLCs) were fitted to the ETRs to parametrize the relationship between ETR and PPFD in S. alterniflorus under different environmental conditions. Measurements were made from S. alterniflorus culms growing at different positions on the shore and at different times of the day. These data provide a resource for researchers interested in the photophysiology and photosynthesis of Sporobolus alterniflorus, and saltmarsh ecology and management.