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Capture and geological storage of carbon dioxide (CO(2)) has been suggested to be essential to reduce emissions to the atmosphere and aid mitigation of global climate change. However, leakage from transport pipelines or carbon capture and storage (CCS) reservoirs may pose risks to vegetation and contribute to rising atmospheric concentrations [CO(2)]. This study examined effects on seedling emergence and growth when field bean plants (Vicia faba cv. Wizard) grown under field conditions were subjected to elevated soil [CO(2)] for 39 days after planting. The strong negative correlation between soil [CO(2)] and [O(2)] during the injection period created a hypoxic soil environment under conditions of elevated soil [CO(2)]. The damaging impact of this treatment became apparent early in the experiment as no seeds exposed to soil [CO(2)] >50% emerged, even after injection was discontinued. Some seeds exposed to soil [CO(2)] <50% produced seedlings, but many did not survive. Seedling emergence and survival in the gassed plots was greatest at [CO(2)] of 5-20%, but root and shoot growth was reduced relative to control plants. Seedling emergence and growth were negatively related to soil [CO(2)] and positively related to [O(2)], although it is not known which was more important in inducing the observed effects. These findings suggest that leakage of CO(2) from transport pipelines or CCS sites may greatly reduce seedling emergence and crop establishment in the vicinity of such infrastructures.

Al-Jabal Al-Akhdar (the Green Mountain) of Cyrenaica, Libya is known to have the highest plant species diversity in the country, particularly in the depressions and the valleys of the mountain. Wadi Al-Kouf is the largest valley in the mountain, with a rich flora of aromatic and medicinal plants. The present investigation was conducted to record and list the medicinal plant species growing in the valley during the flowering season of 2019. Results revealed that Wadi Al-Kouf hosts 107 medicinal plant species belonging to 49 families and 93 genera. Dicotyledons were the most represented group of angiospermae with 38 families, 79 genera and 89 species, whereas Monocotyledons were represented by only 8 families, 10 genera and 13 species. Asteraceae, Lamiaceae, Fabaceae and Solanaceae were the families with the highest number of species; 11, 9, 6 and 6 species, respectively. The most dominant life forms found in the valley were Therophytes (25.2%), Phanerophytes (25.2%) and Chamaephytes (24.3%), followed by Hemicryptophytes (15.9%) and Geophytes (9.3%). Nine endemic species were detected and recorded.

Increasing levels of atmospheric CO2 may change C and N dynamics in pasture ecosystems. The present study was conducted to examine the impact of four years of CO2 enrichment on soil and root composition and soil N transformation in natural pastureland. Plots of open-top growth chambers were continuously injected with ambient CO2 (350 µL L–1) and elevated CO2 (625 µL L–1). Soil cores exposed to ambient and elevated CO2 treatment were incubated and collected each year. Net N-mineralization rates in soil (NH4 +-N plus NO3ˉ–-N), in addition to total C and N content (%) of soil and root tissues were measured. Results revealed that elevated CO2 caused a significant reduction in soil NO3 (P < 0.05), however, no significant CO2 effect was found on total soil C and N content (%). Roots of plants grown under elevated CO2 treatment had higher C/N ratios. Changes in root C/N ratios were driven by changes in root N concentrations as total root N content (%) was significantly reduced by 30% (P < 0.05). Overall, findings suggest that the effects of CO2 enrichment was more noticeable on N content (%) than C content (%) of soil and roots; elevated CO2 significantly affected soil N-mineralization and total N content (%) in roots, however, no substantial change was found in C inputs in CO2-enriched soil.