Silicon enhances root water uptake in salt-stressed cucumber plants through up-regulating aquaporin gene expression. Osmotic adjustment is a genotype-dependent mechanism for silicon-enhanced water uptake in plants. Silicon can alleviate salt stress in plants. However, the mechanism is still not fully understood, and the possible role of silicon in alleviating salt-induced osmotic stress and the underlying mechanism still remain to be investigated. In this study, the effects of silicon (0.3 mM) on Na accumulation, water uptake, and transport were investigated in two cucumber (Cucumis sativus L.) cultivars ('JinYou 1' and 'JinChun 5') under salt stress (75 mM NaCl). Salt stress inhibited the plant growth and photosynthesis and decreased leaf transpiration and water content, while added silicon ameliorated these negative effects. Silicon addition only slightly decreased the shoot Na levels per dry weight in 'JinYou 1' but not in 'JinChun 5' after 10 days of stress. Silicon addition reduced stress-induced decreases in root hydraulic conductivity and/or leaf-specific conductivity. Expressions of main plasma membrane aquaporin genes in roots were increased by added silicon, and the involvement of aquaporins in water uptake was supported by application of aquaporin inhibitor and restorative. Besides, silicon application decreased the root xylem osmotic potential and increased root soluble sugar levels in 'JinYou 1.' Our results suggest that silicon can improve salt tolerance of cucumber plants through enhancing root water uptake, and silicon-mediated up-regulation of aquaporin gene expression may in part contribute to the increase in water uptake. In addition, osmotic adjustment may be a genotype-dependent mechanism for silicon-enhanced water uptake in plants.

Silicon can improve drought tolerance of plants, but the mechanism still remains unclear. Previous studies have mainly concentrated on silicon-accumulating plants, whereas less work has been conducted in silicon-excluding plants, such as tomato (Solanum lycopersicum L.). In this study, we investigated the effects of exogenous silicon (2.5 mmol L-1) on the chlorophyll fluorescence and expression of photosynthesis-related genes in tomato seedlings (Zhongza 9) under water stress induced by 10% (w/v) polyethylene glycol (PEG-6000). The results showed that under water stress, the growth of shoot and root was inhibited, and the chlorophyll and carotenoid concentrations were decreased, while silicon addition improved the plant growth and increased the concentrations of chlorophyll and carotenoid. Under water sterss, chlorophyll fluorescence parameters such as PSII maximum photochemical efficiency (F v /F m), effective quantum efficiency, actual photochemical quantum efficiency (Ф PSII), photosynthetic electron transport rate (ETR), and photochemical quenching coefficient (q P) were decreased; while these changes were reversed in the presence of added silicon. The expressions of some photosynthesis-related genes including PetE, PetF, PsbP, PsbQ, PsbW, and Psb28 were down-regulated under water stress, and exogenous Si could partially up-regulate their expressions. These results suggest that silicon plays a role in the alleviation of water stress by modulating some photosynthesis-related genes and regulating the photochemical process, and thus promoting photosynthesis.

Objectives The aim of this study is to determine whether new European Kidney Function Consortium (EKFC) equation is more applicable than Asian-modified CKD-EPI equation in clinical practice, having a higher accuracy in estimating GFR in our external CKD population. Methods We calculated estimated GFR EKFC and GFR CKD-EPI independently using the EKFC and Asian-modified CKD-EPI formulas, respectively. The clinical diagnostic performance of the two equations was assessed and compared by median bias, precision, accuracy ( P 30 ) and so on, using 99m Tc-DTPA dual plasma sample clearance method as a reference method for GFR measurement (mGFR). The equation that met the following targets was superior: (1) median bias within ± 3 mL/min/1.73 m 2 ; (2) P 30 > 75%; and (3) better precision and 95% limits of agreement in Bland–Altman analysis. Results Totally, 160 CKD patients were recruited in our external cohort. GFR EKFC was highly related to mGFR, with a regression equation of GFR EKFC =mGFR × 0.87 + 5.27. Compared with the Asian-modified CKD-EPI equation, EKFC equation demonstrated a wider median bias (–1.64 vs. 0.84 mL/min/1.73 m 2 , p < 0.01) that was within 3 mL/min/1.73 m 2 and not clinically meaningful. Furthermore, the precision (12.69 vs. 12.72 mL/min/1.73 m 2 , p = 0.42), 95% limits of agreement in Bland–Altman analysis (42.4 vs. 44.4 mL/min/1.73 m 2 ) and incorrect reclassification index of the two target equations were almost identical. Although, EKFC equation had a slightly better P 30 (80.0% vs. 74.4%, p = 0.01). Conclusions The overall performance of EKFC equation is acceptable. There is no clinically meaningful difference in the performance of the Asian-modified CKD-EPI and EKFC equations within the limits imposed by the small sample size.

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Rationale:Camurati–Engelmann disease (i.e., progressive diaphyseal dysplasia) is an extremely rare autosomal dominant bone disorder. The most common clinical manifestations were chronic skeletal pain, waddling gait, muscular weakness.Patient Concerns:We described that a 27-year-old male with a 1-year history of intermittent tetany was referred for bone scintigraphy. The whole body bone scan images showed abnormal increased uptake of the tracer in the long bones of the upper and lower extremities as well as in the skull.Diagnoses:Combined the family history, the findings of the images and the genetic study, the diagnosis of Camurati–Engelmann disease was confirmed.Interventions and outcomes:The patient responded well to the treatment of calcium gluconate.Lessons:Bone scintigraphy would be helpful in the diagnosis and assessing the severity of Camurati–Engelmann disease.