The International Conference on “Photosynthesis and Hydrogen Energy Research” was inaugurated in 2004 in Trois Rivières, Canada, as “Photosynthesis and Post-Genomics Era”. It was conceived by its founders, Suleyman I. Allakhverdiev (Russia), Vyacheslav (Slava) Klimov (Russia), Robert Carpentier (Canada), and Prasanna Mohanty (India) to be an alternating conference to the bigger International Congress on Photosynthesis, which was then held every three years. The name was changed to the International Conference on Photosynthesis (ICP) in 2011. In 2013, “Hydrogen Production” was added, and then finally the current name, “International Conference on Photosynthesis and Hydrogen Energy Research for Sustainability”, was used in 2015. The conferences over the last twenty years have been held in three continents – North America, Europe, and Asia – and have been very successful in attracting participants with the latest ideas in photosynthesis, hydrogen production, and energy sustainability. Here we describe all 12 conferences, with details of the major events of each conference.Major points of the conference were: (1) Recent advances in the understanding of the basic mechanisms of water splitting (photosystem II) and the reactions around photosystem I in photosynthetic organisms. (2) The role of hydrogen production in photosynthesis. (3) The role of innovations in photosynthesis and hydrogen production in the development of global sustainability.

Chlorophyll fluorescence (ChlF), a sensitive, real-time, and nondestructive indicator of photosynthesis, enables noninvasive elucidation of the complex physiological and biochemical processes of plants. It plays a unique and important role in plant research, ecological evaluation, and agriculture. To provide a holistic picture of research on ChlF applications over the past decade, a knowledge map was first conducted, which revealed six major areas of ChlF applications in plant stress evaluation and reduction, including drought stress, temperature stress, salt stress, water stress, toxicity stress, and nitrogen stress. This work then systematically summarized the literature in each of the six areas. Finally, we examined practical application bottlenecks and outlined key challenges and frontiers in future ChlF research.

Understanding stress responses of endangered plants is vital for their conservation under climate change. We examined the effects of iso-osmotic drought (PEG) and salinity (NaCl) on the growth and physiology of three populations of the critically endangered legume Onobrychis conferta subsp. conferta (OC1, OC2, OC3) endemic to North-Western Tunisia. Both stresses reduced photosynthesis, stomatal conductance, intercellular CO2, and carboxylation efficiency, while increasing intrinsic water-use efficiency. PSII photoinhibition (Fv/Fm decline) occurred after 6 d. Prolonged stress suppressed growth and water content, particularly under salinity, but enhanced root elongation and root-to-shoot ratios in OC1 and OC2. OC3, from dry grasslands, showed higher water retention, photosynthetic efficiency, and adaptive morphology than OC1 (Pinus forest) and OC2 (watercourse edge), highlighting ecotype-dependent tolerance. OC1 exhibited increased root allocation under salinity, exhibiting a salt-avoidance strategy. Identifying resilient ecotypes is crucial for conservation, restoration, and adaptation of O. conferta to increasing drought and salinity.

Crop productivity depends largely on photosynthetic efficiency, which is key to converting light energy into assimilates for biomass accumulation. The use of biostimulants such as melatonin (MEL) has emerged as a sustainable alternative to improve internal processes in plants and increase production. However, its effect on beans has not yet been clearly described. This study evaluated the foliar application of MEL on physiological and productive variables of Strike beans (Phaseolus vulgaris L.). The plants were grown in vermiculite/perlite substrate (2:1) for 60 d, applying MEL [0, 1, 10, and 100 μM] weekly from 15 d after sowing. All three doses increased biomass and yield; treatment with 100 μM increased biomass by 64.9%, and 1 μM increased yield by 223.7%. Photosynthetic rate and transpiration also improved, with 10 μM being the most effective dose. Finally, sucrose concentration increased by up to 81%. Therefore, the results show MEL as a potential biostimulant for Strike bean production.

Herein, we report on the 2025 Gordon Research Conference (27 July–1 August) and its preceding Gordon Research Seminar (26–27 July) on Photosynthesis, entitled “Mechanisms of the Process Driving the Biosphere Through the Lenses of Experiment and Computation”. Both were held at Sunday River Resort in Newry, Maine, USA. The seminar and conference brought together an international group of photosynthesis researchers to discuss the most cutting-edge work uncovering photosynthetic mechanisms via computation, genetic manipulation, systems biology, structural biology, and much more.

The effects of additional far-red light (FRL) on the growth parameters, photosynthetic activity, and pro- or antioxidant balance of Lactuca sativa L. plants grown for 30 d were studied. The plants were grown under white light-emitting diodes with equal PAR intensities at red/far-red light ratios of 0.29, 0.89, and 1.67 and without FRL. Compared to the absence of the FRL, growth at a 0.29 ratio caused an increase in plant biomass and leaf area, but a decrease in PSII activity, net photosynthetic rate (PN) per unit area, and stomatal conductance. High irradiance for 4 h at 1,000 μmol(photon) m–2 s–1 decreased PSII activity and PN, but to the least extent in the 0.89 option. The possible pathways of the FRL's impact on the photosynthetic apparatus were analysed.

Cultivated soybean is a globally important crop; understanding its responses to different light spectra within the canopy is essential, especially considering the limited agricultural area. Energy flux and spectral quality are key components of the light environment that determine photosynthesis and, consequently, plant growth. These factors influence the composition and structure of photosystem II, thereby affecting energy partitioning between photochemical and nonphotochemical processes. This study evaluated the photosynthetic performance of two soybean genotypes under four light environments with distinct spectral compositions but equal energy flux. Results showed that PSII efficiency improved by the wavelengths outside the PAR range, irrespective of genotype. However, quantum yield parameters revealed genotype-specific responses under blue and red light. Plants exposed exclusively to red light exhibited reduced photosynthetic efficiency and increased photodamage after prolonged exposure, consistent with red light syndrome.

In this study, we evaluated the physiological response of the photosynthetic apparatus [using chlorophyll a fluorescence (ChlaF) measurements], changes in leaf nutrient contents, and productivity of 16 Coffea canephora clones grown alone (NC, full sunlight) or intercropped with Hevea brasiliensis (IC, shaded). Shade from H. brasiliensis trees influenced the physiological performance of coffee plants. Some of these coffee clones achieved clear responses to shading by rubber trees, indicating that the responses of coffee plants to intercropping are genotype-specific. The PSII complex of the NC plants was more susceptible to photoinhibition, especially clones 02, 73, 143, and 109A, which had increased minimal fluorescence, specific energy fluxes per reaction centers, maximum photochemical quantum yield, quantum efficiency of electron transfer from QA– to the electron transport chain beyond QA–, and number of active PSII reaction centers per cross section, performance index for conservation of energy from captured excitons to reduction of intersystem electron acceptors, and lower maximum fluorescence. In contrast, the higher photosynthetic efficiency and productivity of the clones under shaded conditions indicated their potential for cultivation together with H. brasiliensis.