Abstract
Investigating the effects of drought stress and subsequent recovery on the structure and function of chloroplasts is essential to understanding how plants adapt to environmental stressors. We investigated Ctenanthe setosa (Roscoe) Eichler, an ornamental plant that can tolerate prolonged drought periods (40 and 49 days of water withdrawal). Conventional biochemical, biophysical, physiological and (ultra)structural methods combined for the first time in a higher plant with in vivo small-angle neutron scattering (SANS) were used to characterize the alterations induced by drought stress and subsequent recovery. Upon drought stress, no significant changes occurred in the chloroplast ultrastructure, chlorophyll content, 77K fluorescence emission spectra and maximal quantum efficiency of PSII (Qy dark), but the actual quantum efficiency of PSII (Qy light) decreased, the amounts of PSI-LHCII complexes and PSII monomers declined, and that of PSII supercomplexes increased. Thickness of the leaf and of the adaxial hypodermis, chloroplast length and granum repeat distance (RD) values decreased upon drought stress, as shown by light microscopy and SANS, respectively. Because of the very slight (nm-range) changes in RD values, the large biological variability (significant differences in RD values among the leaves and studied leaf regions) and the invasive sampling required for this method, transmission electron microscopy (TEM) hardly showed significant differences. On the other side, in situ SANS analyses provided a unique insight in vivo into the fast structural recovery of the granum structure of drought-stressed leaves, which happened already 18 h after re-watering, while functional and biochemical recovery took place on a longer time scale.
| Original language | English |
|---|---|
| Article number | e14621 |
| Journal | Physiologia Plantarum |
| Volume | 177 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2025 |
Funding
The authors are grateful to Győző Garab and Zsuzsanna Várkonyi (HUN-REN Biological Research Center, Szeged, Hungary) and to Nihal Kutlu and Asim Kadioglu (Karadeniz Technical University, Trabzon, Türkiye) for the idea to use C. setosa plant in our experiments. The authors would like to thank Tünde Szabó-Szöllősi and László Papp (Botanical Garden of ELTE, Budapest, Hungary) for providing the plant material for the experiments. We are grateful to Csilla Gergely (ELTE) for TEM and LM embedding and sectioning and Györgyi Balogh (ELTE) for her technical assistance with gel electrophoresis. We would like to thank Gusztáv Schay (Semmelweis University, Budapest, Hungary) for advice on statistical analyses. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to EQ-SANS on proposal numbers IPTS-26180.1 and 27426.1. G.N. is grateful to Mary-Ellen Donnelly (ORNL and Canadian Light Source Inc., Canada) for her help in the acclimation of the plants. We would like to thank the Paul Scherrer Institute (PSI), Villigen, Switzerland, for providing us beamtime for the SANS experiments on the SANS-II beam-line at the Swiss Spallation Neutron Source SINQ for preliminary measurements checking the signal of intact C. setosa plants. This work was financed by the OTKA FK 124748 research grant of the National Research, Development, and Innovation Office (NRDIO). The work of U.R. was also financed from the OTKA PD 138540 grant. K.S. would like to thank the support from the Bolyai János Research Scholarship of the Hungarian Academy of Sciences and from the ÚNKP-23-5 New National Excellence Program from the source of the National Research, Development, and Innovation Fund. R.H. is grateful to Tempus Public Foundation (Hungary) for the Stipendium Hungaricum Ph.D. Scholarship. The authors are grateful to Győző Garab and Zsuzsanna Várkonyi (HUN‐REN Biological Research Center, Szeged, Hungary) and to Nihal Kutlu and Asim Kadioglu (Karadeniz Technical University, Trabzon, Türkiye) for the idea to use plant in our experiments. The authors would like to thank Tünde Szabó‐Szöllősi and László Papp (Botanical Garden of ELTE, Budapest, Hungary) for providing the plant material for the experiments. We are grateful to Csilla Gergely (ELTE) for TEM and LM embedding and sectioning and Györgyi Balogh (ELTE) for her technical assistance with gel electrophoresis. We would like to thank Gusztáv Schay (Semmelweis University, Budapest, Hungary) for advice on statistical analyses. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to EQ‐SANS on proposal numbers IPTS‐26180.1 and 27426.1. G.N. is grateful to Mary‐Ellen Donnelly (ORNL and Canadian Light Source Inc., Canada) for her help in the acclimation of the plants. We would like to thank the Paul Scherrer Institute (PSI), Villigen, Switzerland, for providing us beamtime for the SANS experiments on the SANS‐II beam‐line at the Swiss Spallation Neutron Source SINQ for preliminary measurements checking the signal of intact plants. This work was financed by the OTKA FK 124748 research grant of the National Research, Development, and Innovation Office (NRDIO). The work of U.R. was also financed from the OTKA PD 138540 grant. K.S. would like to thank the support from the Bolyai János Research Scholarship of the Hungarian Academy of Sciences and from the ÚNKP‐23‐5 New National Excellence Program from the source of the National Research, Development, and Innovation Fund. R.H. is grateful to Tempus Public Foundation (Hungary) for the Stipendium Hungaricum Ph.D. Scholarship. C. setosa C. setosa