Plant, Soil and Environment - In Press
The temperature sensitivity of stable organic carbon storage rises with increasing soil salinityOriginal Paper
Chao Li, Yanling Tian, Wei He, Yanhong Lou, Hong Pan, Quangang Yang, Guoqing Hu, Yuping Zhuge, Hui Wang
Soil salinization is a key determinant in soil fertility decline, exerting a direct negative impact on soil organic carbon. In the context of global warming, investigating the response mechanisms of soil organic carbon pools with varying salinity levels to climate change is essential for accurately assessing the carbon cycle and emission potential of degraded soils. Based on soil samples (S1–S6) collected along a coastal salinity gradient, indoor incubation experiments were conducted at 15 °C and 25 °C to characterize soil respiration and its temperature sensitivity (Q₁₀). Double-exponential models were used to simulate soil organic carbon (SOC) mineralization, characterizing active and stable organic carbon pools. The results demonstrated that the Q₁₀ value of the stable organic carbon pool (7%-8% of SOC mineralization) was 103% higher than that of the active organic carbon pool (the initial 1% of SOC mineralization). The Q₁₀ value of the stable organic carbon pool was 32.6% higher at the high-salinity sites (S1, S2) than at the low-salinity sites (S4, S5). Soil organic carbon, total nitrogen (TN), and total salt (TS) were key regulators of Q₁₀. The Q₁₀ of the active organic carbon pool correlated positively with SOC and TN but negatively with TS, whereas the stable pool showed the opposite trends. The stable organic carbon pool exhibits a salinity-amplified Q₁₀, implying that predictive models must account for this mechanism to avoid substantially underestimating carbon losses from degraded saline soils.
Decoupling of stomatal and mesophyll recovery drives photosynthetic resilience to water deficit in sugar beet: evidence from multiscale structural and functional traitsOriginal Paper
Yangyang Li, Zengyuan Tian, Jixia Su, Kaiyong Wang, Pengpeng Zhang, Hua Fan
Water deficit severely constrains sugar beet productivity by impairing photosynthetic capacity. However, the underlying structure-function mechanisms conferring photosynthetic resilience remain poorly characterized. This study investigates the temporal dynamics of photosynthetic limitations and structural adaptations in sugar beet during water deficit and subsequent rehydration. We found that water deficit significantly reduced the maximum net CO2 assimilation rate (ANmax) and carboxylation rate of Rubisco (Vcmax) by impairing CO2 diffusion and biochemical processes. The reduction in photosynthetic capacity is primarily and stably attributed to mesophyll limitation, while contributions from stomatal and biochemical limitations flexibly change with deficit degree and rehydration. Severe water deficit caused irreversible structural damage that hinders recovery even after rehydration, while moderate water deficit allows partial restoration of leaf and chloroplast function. Partial least squares structural equation modeling (PLS-SEM) demonstrated that CO2 diffusion was governed by the volume fraction of intercellular air space (fias, β = 0.28) and surface areas of the chloroplasts exposed to leaf intercellular air spaces (Sc/S, β = 0.35), with Sc/S indirectly influencing mesophyll conductance (gm) through fias mediation (β = 0.53). Severe water deficit caused irreversible fias reduction and chloroplast interface damage (59% cell volume loss). These findings establish that resilience to water deficit in sugar beet depends on mesophyll structural integrity, with fias and Sc/S as key modulators of gm recovery. The study advances understanding of stress recovery mechanisms in sugar beet and provides a framework for multiscale crop improvement in the context of climate change.
Silicon enhances drought tolerance in buckwheat by coordinating anatomical, morphological, and phenolic responsesOriginal Paper
Jiri Krucky, Vaclav Hejnak, Pavla Vachova, Jana Ceska, Jan Kubes, Milan Skalický
Drought is one of the major abiotic stressors limiting crop growth and productivity. This study evaluated the effects of foliar silicon (Si) application on the anatomical structure of the primary root, the morphological traits, and biochemical indicators in three buckwheat (Fagopyrum esculentum) cultivars—La Harpe, Panda, and Smuga. Plants were grown in pots under controlled environmental conditions and assigned to four treatments: Control, Drought, Control + Si, and Drought + Si. Silicon application promoted the development of secondary xylem and improved root anatomical integrity, particularly in the La Harpe cultivar. At the morphological level, Si partially alleviated the drought-induced reduction in shoot dry weight and supported a more balanced biomass allocation between below- and above-ground parts. In addition, Si stimulated phenolic synthesis, leading to higher total phenolic content (TPC) and phenolic acid content (PAC) in both leaves and roots, with the most potent synergistic effect observed under Drought + Si treatment. These results demonstrate that Si acts as an integrative factor, coordinating structural, morphological, and biochemical responses, thereby enhancing buckwheat's resilience to drought. The extent of beneficial effects was genotype-dependent, confirming that the genetic background of individual cultivars determines the efficiency of Si utilization and drought tolerance.
The changes in Growth and metabolic adaptation responses in java plum seedlings exposed to Cassia javanica extract under salinityOriginal Paper
Abeer Elhakem, Rasha S. El-Serafy
Developing and employing new, sustainable, and eco-friendly biostimulants that stimulate plant growth and alleviate the harmful effects of environmental challenges is the main interest of many researchers. Salt stress is a critical restructure for plant growth and a limiting factor in crop productivity, particularly in the early stages of plants in the nursery. Syzygium cumini (L.) Skeels (Java plum) is an important fruit tree and is cultivated widely in gardens as an ornamental tree. Developing Cassia javanica subsp. Nodosa leaf extract (CLE) as a new sustainable and eco-friendly biostimulant for triggering the metabolic adaptation to salt stress in Java plum seedlings in the nursery was the main target for this report. The CLE successfully mitigated the reduction in the growth, biomass yield, and secondary metabolites of cultivated seedlings as affected by salinity. A depression occurred due to salt stress in the morphological traits and biomass yield, but an increase in their values was noticed following CLE spray application. Moreover, CLE stimulated the FRAP, CAT, and SOD enzymes and phenolic content and reduced hydrogen peroxide (H₂O₂) and lipid peroxidation levels. Additionally, CLE spray increased the seedlings’ biomass and stimulated the antioxidant system, osmoprotectants, and the tolerance to salinity stress. These observations provide new insights into the CLE’s potential as an eco-friendly biostimulant to stimulate salt tolerance in Java plum seedlings.
Nutrient balance in soil depending on red clover utilization methodsOriginal Paper
Halyna Panakhyd, Nadiia Kozak, Yurii Olifir, Tetiana Partyka, Oleh Havryshko, Hryhorii Konyk, Oleh Stasiv
The research was conducted in a long-term stationary experiment established on light grey forest surface-gleyed soil in 1965. The experiment is registered in the NAAS long-term field experiments registry (certificate No. 29) and the Global Long-Term Agricultural Experiments Network (GLTEN). The study examined the effect of growing red clover in a four-field crop rotation under different doses and ratios of fertilizers and lime on nutrient balance. Red clover was used for feed and feed-green manure purposes. The aim of the research was to substantiate optimal methods of utilizing this valuable forage crop and optimize fertilization systems to ensure sustainable agricultural development. Growing the first cut of red clover for feed purposes and the second as green manure with fertilization (N105P101K101 + organic fertilizers + liming) ensures accumulation in soil of 402 kg/ha of nitrogen, 150 kg/ha of phosphorus, and 204 kg/ha of potassium. These data are almost twice higher than indicators under minimal fertilization doses. Despite the reduction in symbiotic nitrogen fixation from 217 kg/ha to 147 kg/ha when growing red clover in crop rotation with intensive fertilization, it remains an effective phytobiological ameliorant.