A 173-point genetic linkage map of cucumber (Cucumis sativus L.), consisting of 116 SRAPs, 33 RAPDs, 11 SSRs, 9 SCARs, 3 ISSRs, and 1 STS, was constructed using 130 F 2 progeny derived from a narrow cross between line S94 (Northern China open-field type) and line S06 (greenhouse European type). The seven linkage groups spanned 1016 cM with a mean marker interval of 5.9 cM. Using the F 2 population and its F 3 derived families, a total of 38 QTLs were detected on five linkage groups with an LOD threshold of 3.0 for nine fruit-related traits: fruit weight, length, and diameter, fruit flesh thickness, seed-cavity diameter, fruit-stalk length, fruit pedicel length, length/diameter and length/stalk ratio. Of the identified QTLs, fsl4.3 for fruit-stalk length explained the largest portion of phenotypic variation (r 2 ¼ 30%). Several QTLs were detected in the same linkage region in different generations and different seasons. Additionally, several QTLs for various fruit traits were mapped to the same or neighbouring marker intervals, suggesting they are possible character associations for controlling cucumber fruit development.

Summary Green synthesis of ammonia by electrochemical nitrogen reduction reaction (NRR) shows great potential as an alternative to the Haber-Bosch process but is hampered by sluggish production rate and low Faradaic efficiency. Recently, lithium-mediated electrochemical NRR has received renewed attention due to its reproducibility. However, further improvement of the system is restricted by limited recognition of its mechanism. Herein, we demonstrate that lithium-mediated NRR began with electrochemical deposition of lithium, followed by two chemical processes of dinitrogen splitting and protonation to ammonia. Furthermore, we quantified the extent to which the freshly deposited active lithium lost its activity toward NRR due to a parasitic reaction between lithium and electrolyte. A high ammonia yield of 0.410 ± 0.038 μg s −1 cm −2 geo and Faradaic efficiency of 39.5 ± 1.7% were achieved at 20 mA cm −2 geo and 10 mA cm −2 geo, respectively, which can be attributed to fresher lithium obtained at high current density.

A maize genetic linkage map derived from 115 simple sequence repeat (SSR) markers was constructed from an F 2 population. The F 2 was generated from a cross between a stay-green inbred line (Q319) and a normal inbred line (Mo17). The map resolved 10 linkage groups and spanned 1431.0 cM in length with an average genetic distance of 12.44 cM between two neighbouring loci. A total of 14 quantitative trait loci (QTL) were detected for stay-green traits at different postflowering time intervals and identified by composite interval mapping. The respective QTL contribution to phenotypic variance ranged from 5.40% to 11.49%, with trait synergistic action from Q319. Moreover, maize stay-green traits were closely correlated to grain yield. Additional QTL analyses indicated that multiple intervals of stay-green QTL overlapped with yield QTL.

Waxy maize (Zea mays L. var. certaina Kulesh), with many excellent characters in terms of starch composition and economic value, has grown in China for a long history and its production has increased dramatically in recent decades. However, the evolution and origin of waxy maize still remains unclear. We studied the genetic diversity of Chinese waxy maize including typical landraces and inbred lines by SSR analysis and the results showed a wide genetic diversity in the Chinese waxy maize germplasm. We analyzed the origin and evolution of waxy maize by sequencing 108 samples, and downloading 52 sequences from GenBank for the waxy locus in a number of accessions from genus Zea. A sharp reduction of nucleotide diversity and significant neutrality tests (Tajima’s D and Fu and Li’s F*) were observed at the waxy locus in Chinese waxy maize but not in nonglutinous maize. Phylogenetic analysis indicated that Chinese waxy maize originated from the cultivated flint maize and most of the modern waxy maize inbred lines showed a distinct independent origin and evolution process compared with the germplasm from Southwest China. The results indicated that an agronomic trait can be quickly improved to meet production demand by selection.

Trichlorophenol (TCP) and its derivatives are introduced into the environment through numerous sources, including wood preservatives and biocides. Environmental contamination by TCPs is associated with human health risks, necessitating the development of cost-effective remediation techniques. Efficient phytoremediation of TCP is potentially feasible because it contains a hydroxyl group and is suitable for direct phase II metabolism. In this study, we present a system for TCP phytoremediation based on sugar conjugation by overexpressing a Populus putative UDP-glc-dependent glycosyltransferase (UGT). The enzyme PtUGT72B1 displayed the highest TCP-conjugating activity among all reported UGTs. Transgenic Arabidopsis demonstrated significantly enhanced tolerances to 2,4,5-TCP and 2,4,6-TCP. Transgenic plants also exhibited a strikingly higher capacity to remove TCP from their media. This work indicates that Populus UGT overexpression in Arabidopsis may be an efficient method for phytoremoval and degradation of TCP. Our findings have the potential to provide a suitable remediation strategy for sites contaminated by TCP.

The activity degradation mechanism of Pt/C and PtCo/C electrocatalysts in proton-exchange membrane fuel cells during the accelerated degradation test (ADT) was directly investigated by the in situ X-ray absorption fine structure (XAFS). Compared to Pt/C, the PtCo/C electrocatalyst possesses higher Pt 5d-orbital vacancy, low level of oxygen species chemisorption on the surface Pt atoms and shorter Pt−Pt bond length (R), and consequently an enhanced oxygen reduction reaction (ORR) activity. During the ADT process, a drastic drop in ORR activity after 30 000 ADT cycles can be observed in both the electrocatalysts in spite of their different activity degradation mechanisms. For Pt/C, XAFS results revealed that the oxidation of Pt during the ADT process induced the structure transformation from the partial-coverage surface PtO layer to the full-coverage surface and partial-coverage subsurface PtO layer, resulting in the loss of the Pt active site and consequently the decrease in the ORR activity. For PtCo/C, the oxidation of the Co atom induced the attenuation of strain and ligand effects, and the dissolution and segregation of CoO caused the increase in Pt outer layer thickness during the ADT process, mainly determined the decrease in ORR activity.

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