Stresses

Megaplatypus mutatus, a major poplar pest in South America, tunnels into the xylem, weakening trunks and reducing wood quality. Volatile organic compounds (VOCs) are key mediators of plant–insect interactions and may reflect genotype-specific defence strategies. This study analysed VOC profiles of young and adult Populus deltoides cv. Harvard and P. × canadensis cv. Conti 12 under natural M. mutatus infestation. Gas chromatography–mass spectrometry putatively annotated 31 VOCs, including green leaf volatiles (GLVs), pentyl leaf volatiles (PLVs), terpenes, alcohols, aromatics and phenolics, 12 of which, to our knowledge, have not been previously reported in Populus VOC profiles. Harvard trees showed ~14.5-fold higher total VOC abundance than Conti trees. In Conti, constitutive VOC emissions remained stable regardless of infestation status or age. In contrast, under infestation, Harvard trees emitted10-fold higher constitutive VOCs than non-infested Harvard trees and ~52-fold higher than Conti, a pattern consistent with increased defensive activity. GLVs and PLVs relatively dominated both genotypes, although Harvard showed higher emissions. Terpenes were not detected in young Conti trees under our analytical conditions but were abundant and diverse in infested Harvard trees, which may indicate a stronger terpene-associated response in this clone. Several compounds were detected only under specific genotype–condition combinations in our dataset and therefore represent candidate volatiles for future behavioural and functional studies. These results are consistent with differences in VOC emission patterns between genotypes and age classes, improve our understanding of putative chemical cues in the interaction between Populus and M. mutatus, and provide a basis for future work towards sustainable pest management strategies.

Chilling has been recognized as a stress factor adversely impacting plant growth and productivity. Even a slight decrease in temperature may significantly reduce crop yield. Recently, biostimulants have emerged as a new tool for enhancing the chilling tolerance of cold-sensitive plants. The early stages of cucumber growth often occur under suboptimal temperatures, which motivated the aim of the current study to assess the effect of a protein hydrolysate (PH) on the physiological performance of young cucumber plants subjected to chilling stress. The results showed that low temperatures caused severe chilling stress by inducing changes in growth, photosynthesis, and nitrogen assimilation. These adverse effects were mitigated when the PH was supplied. The ameliorating effect could be due to a remedial influence on photosynthetic pigment content, facilitating light harvesting and energy utilization. The potential impact of the PH treatment on the redox balance was demonstrated by the activation of the G6PD gene. The possible effect of the biostimulant on nitrate assimilation was tested by measuring nitrate reductase activity, which improved after application of the biostimulant. Moreover, the activity of phenylalanine ammonia-lyase (PAL) in PH-supplied plants was also increased, further confirming the enhanced protective capacity of the plants. All obtained results indicate the beneficial effect of PH application on cucumber plants and their chilling resilience.

Accumulating evidence suggests that exposure to pollution from environmental cadmium (Cd) contributes to diabetic kidney disease as indicated by albuminuria and a progressive decrease in the estimated glomerular filtration rate (eGFR). This study examined the effects of Cd exposure on eGFR and the excretion rates of albumin (E_alb) and β₂-microglobulin (E_β2M) in 65 diabetics and 72 controls. Excretion of Cd (E_Cd) was a measure of exposure, while excretion of N-acetylglucosaminidase (E_NAG) reflected the extent of kidney tubular cell injury. In participants with an elevated excretion of E_β2M, the prevalence odds ratios (POR) for a reduced eGFR rose 6.4-fold, whereas the POR for albuminuria rose 4.3-fold, 4.1-fold, and 2.8-fold in those with a reduced eGFR, diabetes, and hypertension, respectively. Using covariance analysis, which adjusted for the interactions, 43% of the variation in E_alb among diabetics could be explained by female gender (η² = 0.176), E_NAG (η² = 0.162), hypertension (η² = 0.146), smoking (η² = 0.107), and body mass index (η² = 0.097), while the direct contribution of E_Cd to E_alb variability was minimal (η² = 0.005). Results from a mediating-effect analysis imply that Cd could contribute to albuminuria and a falling eGFR through inducing tubular cell injury, leading to reduced reabsorption of albumin and β₂M.