Arbuscular mycorrhizal fungi display desired potential to boost crop productivity and drought acclimation. Yet, whether nanoparticles can be incorporated into arbuscular mycorrhizal fungi for better improvement and its relevant morphologic and anatomical evidences are little documented. Pot culture experiment on wheat (Triticum aestivum L.) was conducted under drought stress (30% FWC) as well as well watered conditions (80% FWC) that involved priming of wheat seeds with iron nanoparticles at different concentrations (5mg L⁻¹, 10 mg L⁻¹ and 15 mg L⁻¹) with and without the inoculation of Glomus intraradices. The effects of treatments were observed on morphological and physiological parameters across jointing, anthesis and maturity stage. Root colonization and nanoparticle uptake trend by seeds and roots was also recorded. We observed strikingly high enhancement in biomass up to 109% under drought and 71% under well-watered conditions, and grain yield increased to 163% under drought and 60% under well-watered conditions. Iron nanoparticles at 10 mg L⁻¹ when combined with Glomus intraradices resulted in maximum wheat growth and yield, which mechanically resulted from higher rhizosphere colonization level, water use efficiency and photosynthetic rate under drought stress (P < 0.01). Across growth stages, optical micrograph observations affirmed higher root infection rate when combined with nanoparticles. Transmission electron microscopy indicated the penetration of nanoparticles into the seeds and translocation across roots whereas energy dispersive X-ray analyses further confirmed the presence of Fe in these organs. Iron nanoparticles significantly enhanced the growth-promoting and drought-tolerant effects of Glomus intraradices on wheat.

Phthalate ester (PAE) accumulation in crops poses great risks to human health and has aroused great concern. Here, we investigated variations in di-n-butylphthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) accumulation by various Chinese flowering cabbage cultivars and revealed their variation mechanism. There were significant differences (p < 0.05) in shoot PAE concentrations of 28 cultivars. Moreover, significant positive correlations between DBP and DEHP concentrations in shoots of all cultivars indicated that they could be taken up simultaneously by various cultivars. Due to the lower translocation factor of low-PAE accumulator, its shoot PAEs concentrations were much lower than root compared to high-PAE accumulator. Further, subcellular distribution showed that PAE concentrations of root cell walls and organelles were much higher than those of shoots in low-PAE accumulator. Therefore, lower translocation from root to shoot and more PAEs accumulating in cell walls and organelles of root might act as main formation mechanism of low-PAE accumulator.

Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic.

Biochar has the potential to remediate heavy metals in agricultural soil and mitigate nitrous oxide (N₂O) emissions; however, the effects of biochar on heavy metal remediation, the soil microbial community and N₂O emissions are not completely understood. In this study, we conducted a pot experiment in which Glycine max L. (soybean) was cultivated in two cadmium (Cd)-contaminated soils (low, 3.14 mg kg⁻¹; high, 10.80 mg kg⁻¹) to investigate the effects of biochar on the bioremediation of Cd, N₂O emissions and the rhizosphere microbial community structure. The bioaccumulation of Cd in the plant shoots and roots increased with all biochar addition rates (0%, 1%, 5% and 10%); unexpectedly, the translocation capacity of Cd to the edible parts of the plant significantly decreased to 0.58 mg kg⁻¹, which was close to the edible threshold (0.4 mg kg⁻¹). The abundance and activities of functional marker genes of microbial nitrification (amoA) and denitrification (nirK, nirS and nosZ) were quantified with quantitative PCR, and we found that biochar addition reduced the precursor production of rhizoshpere N₂O by inhibiting the transcription of the nirK gene. In addition, the nitrogenase activity during anthesis (S) was significantly (P < 0.05) increased with 1% (v/v) biochar addition. Noticeably, biochar addition only changed the microbial community structure in the very first stage before eventually stabilize. This study highlighted that biochar has the potential ability to maintain the quality of agricultural crops, remediate Cd-contaminated soils and may help reduce N₂O emissions without disturbing the microbial community.

Salinisation of soil is associated with urban pollution, industrial development and rising sea level. Understanding how high salinity is managed at the plant cellular level is vital to increase sustainable farming output. Previous studies focus on plant stress responses under salinity tolerance. Yet, there is limited knowledge about the mechanisms involved from stress state until the recovery state; our research aims to close this gap. By using the most tolerance genotype (SS1-14) and the most susceptible genotype (SS2-18), comparative physiological, metabolome and post-harvest assessments were performed to identify the underlying mechanisms for salinity stress recovery in plant cells. The up-regulation of glutamine, asparagine and malonic acid were found in recovered-tolerant genotype, suggesting a role in the regulation of panicle branching and spikelet formation for survival. Rice could survive up to 150 mM NaCl (∼15 ds/m) with declined of production rate 5–20% ranged from tolerance to susceptible genotype. This show that rice farming may still be viable on the high saline affected area with the right selection of salt-tolerant species, including glycophytes. The salt recovery biomarkers identified in this study and the adaption underlined could be empowered to address salinity problem in rice field.

A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions – pollen originating from plants raised in charcoal-Purafil® filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O3. The O3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O3 × CFA and CFA × O3 crossed plants. This suggests O3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol−1 O3 (10 h d−1) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit – a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O3, and potentially other gaseous pollutants, on reproductive biology during ‘risk assessment’ exercises.

Although elevated ground-level O3 has a species–specific impact on plant growth, the differences in soil biota responses to O3 pollution among rice cultivars are rarely reported. Using O3 Free-Air Concentration Enrichment, the responses of the rhizospheric bacterial communities in the O3-tolerant (YD6) and the O3-sensitive (IIY084) rice cultivars to O3 pollution and their differences were assessed by pyrosequencing at rice tillering and anthesis stages. Elevated ground-level O3 negatively influenced the bacterial community in cultivar YD6 at both rice growth stages by decreasing the bacterial phylogenetic diversities and response ratios. In contrast, in cultivar IIY084, the bacterial community responded positively at the rice tillering stage under O3 pollution. However, several keystone bacterial guilds were consistently negatively affected by O3 pollution in two rice cultivars. These findings indicate that continuously O3 pollution would negatively influence rice agroecosystem and the crop cultivar is important in determining the soil biota responses to elevated O3.

Mesocosms representing the BAP Priority habitat ‘Calcareous Grassland’ were exposed to eight ozone profiles for twelve-weeks in two consecutive years. Half of the mesocosms received a reduced watering regime during the exposure periods. Numbers and timing of flowering in the second exposure period were related to ozone concentration and phytotoxic ozone dose (accumulated stomatal flux). For Lotus corniculatus, ozone accelerated the timing of the maximum number of flowers. An increase in mean ozone concentration from 30ppb to 70ppb corresponded with an advance in the timing of maximum flowering by six days. A significant reduction in flower numbers with increasing ozone was found for Campanula rotundifolia and Scabiosa columbaria and the relationship with ozone was stronger for those that were well-watered than for those with reduced watering. These changes in flowering timing and numbers could have large ecological impacts, affecting plant pollination and the food supply of nectar feeding insects.

One emerging problem that recently has become a vastly acknowledged topic of concern is the environmental contamination by pharmaceuticals. Diclofenac (DCF) is one of the most common pharmaceuticals found, due to its high utilization and low removal rate in wastewater treatment processes. In this work, Solanum lycopersicum L. was used as a model to unravel how DCF contamination can affect crops, focusing on the internal mechanisms triggered by this exposure. For this purpose, plants were exposed to two different DCF concentrations (0.5 mg L⁻¹ and 5 mg L⁻¹). Results obtained here point towards a loss of shoot performance when plants were exposed to very high concentrations of DCF, but no delay or loss of yield in the flowering and fruit stages were ascribed to DCF contamination. Our data shows that a state of oxidative stress due to high reactive oxygen species accumulation was associated with this contamination, with very high DCF levels leading to a rise of lipid peroxidation, possibly accentuated by the inhibition of ROS-scavenging enzymes and unable to be counteracted by the visible upregulation of proline and the thiol-based redox network. Overall, these results allow to infer that in the current environmental context, no noticeable negative effects should be associated with the presence of DCF in soils where this crop is cultivated. However, the oxidative stress and lower biomass associated with the highest concentration are alarming, since DCF levels in the environment are continuously increasing and further measures are necessary to assess this problematic.

To better understand the Sb phytoavailability in rice, we studied Sb accumulation in rice (Zhongjiazao-17, widely cultivated in Hunan province) at different growth stages based on adding SbIII and SbV to waterlogged soils in 10, 50 and 100 mg kg−1 treatment levels. Proportional exogenous SbIII and SbV remained in the soil solution after equilibration. In SbIII treatments, the iron plaque (IP) amounts and Sb in rice roots sharply increased from tillering to jointing stages and then reduced at the following stages. However, in SbV treatments, they increased continuously from tillering to maturing stages. The accumulation trends of Sb in straws, ears and grains were consistent in SbIII and SbV treatments, rising from tillering to jointing stages followed with reducing from jointing to flowering stages slightly, and rising again significantly from flowering to maturing stages. The Tfsoil-grain values in all the Sb treatments were low (0.77 × 10−3-5.1 × 10−3), However, when Sb in waterlogged soils were higher than 50 mg kg−1, it could pose human health risk for residents.