Many photosynthetic organisms globally, including crops, forests and algae, must grow in environments where the availability of light energy fluctuates dramatically. How photosynthesis maintains high efficiency despite such fluctuations in its energy source remains poorly understood. Here we show that Arabidopsis thaliana K+ efflux antiporter (KEA3) is critical for high photosynthetic efficiency under fluctuating light. On a shift from dark to low light, or high to low light, kea3 mutants show prolonged dissipation of absorbed light energy as heat. KEA3 localizes to the thylakoid membrane, and allows proton efflux from the thylakoid lumen by proton/potassium antiport. KEA3’s activity accelerates the downregulation of pH-dependent energy dissipation after transitions to low light, leading to faster recovery of high photosystem II quantum efficiency and increased CO2 assimilation. Our results reveal a mechanism that increases the efficiency of photosynthesis under fluctuating light.

The effect of high temperatures on harvest index (HI) and morphological components that contribute to HI was investigated in two lines (Bd21 and Bd21-3) of Brachypodium distachyon, a C3 grass recognized as a tractable plant, to address critical issues associated with enhancing cereal crop yields in the presence of global climate change. The results demonstrated that temperatures ≥32 °C eliminated HI. Reductions in yield at 32 °C were due primarily to declines in pollen viability, retention of pollen in anthers, and pollen germination, while abortion of microspores by the uninucleate stage that was correlated with abnormal tapetal development resulted in yield failure at 36 °C. Increasing temperatures from 24 to 32 °C resulted in reductions in tiller numbers but had no impact on axillary branch numbers per tiller. Grain developed at 24 and 28 °C primarily in tiller spikes, although spikes on axillary branches also formed grain. Grain quantity decreased in tiller spikes but increased in axillary branch spikes as temperatures rose from 24 to 28 °C. Differential patterns of axillary branching and floret development within spikelets between Bd21 and Bd21-3 resulted in higher grain yield in axillary branches of Bd21-3 at 28 °C. The response of male reproductive development and tiller branching patterns in B. distachyon to increasing temperatures mirrors that in other cereal crops, providing support for the use of this C3 grass in assessing the molecular control of HI in the presence of global warming.

According to climate projection models, the global temperature is expected to rise by at least 1.5°C by the end of this century. According to some studies the expected rise in Serbia is even higher. Global warming may result in creating new areas for forest growth. Although creating new forests would be a positive outcome in some areas, global warming can cause negative impacts in other areas, and this can lead to forest loss and the shift of geographical ranges, or even extinction, of plant species. The European beech is the dominant forest tree species in Serbia, featuring high ecological importance and economic value. In mixed or pure stands, beech forests cover approximately 660,400 ha, accounting for 29.3% of the total Serbian forest area. In the present study, the effects of climate change on the distribution of the European beech stands in Serbia, with an emphasis on their elevation shifts, were examined using species distribution models (SDMs). Data for the present tree cover in Serbia, climate projections, and environmental data were used for model building. The models were first tested against present inventory data. In these tests, the models were found to provide accurate projections, as shown by their true skills statistics (TSS) values ranging from 0.652 to 0.736 and area under the curve (AUC) values ranging from 0.868 to 0.937. The potential distribution patterns predicted by the models indicate that the European beech elevational distribution in Serbia would decrease, exhibiting a significant upward shift in elevation during the first part of this century. Current beech stand locations could be changed, and other areas at higher elevations may be more suitable for beech growth. After 2071, European beech stands at elevations below 500 m would be even smaller. This change is caused by temperature rise and occurrence of climate extremes. However, on the highest elevations, further upward shift of the species is not expected.

Extreme weather conditions, namely droughts, heat waves, heavy rains, floods, and landslides are becoming more frequent globally and in Serbia as a result of climate change. Generally, various parts of human society are affected by changing climate conditions. Forest ecosystems are one of the most sensitive systems to weather and climate. In that sense, small changes may lead to large disturbances including forest decline, outbreaks of insect pests and diseases and eventually mortality. In Serbia, the average temperature in forest ecosystems of the most important and abundant forest tree species has risen for more than 1°C in the last thirty years (1990-2019) in comparison to the previous period (1961-1990). During the last thirty years, the northern and western parts of Serbia experienced an increase in precipitation as opposed to the southern and eastern parts of the country. If one takes a closer look at the climate within a particular forest stands, it would seem that the effect of precipitation decrease is stronger in less humid parts of a tree species range. In this paper, we discuss various aspects of climate change impacts on forests and forestry, including forest ecology, genetics, physiology, pests and diseases, ground vegetation, monitoring, reporting and verification system, climate change litigation and perspectives of forests in the 21st century in Serbia.

Summary: This study tested the hypothesis that a third dimension of urban gardening, in the form of green terraces