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Liu, T.-N., Gu, L.-M., Xu, C.-L. and Dong, S.-T. 2014. Responses of group and individual leaf photosynthetic characteristics of two summer maize (Zea mays L.) to leaf removal under high plant density. Can. J. Plant Sci. 94: 1449–1459. The present experiment was conducted during the growing seasons of 2012 and 2013 using two summer maize (Zea mays L.) cultivars, Zhengdan958 (a compact cultivar) and Jinhai5 (a semi-compact cultivar) grown at a plant density of 105 000 plants ha−1, to evaluate the influence of leaf removal on canopy apparent photosynthesis (CAP), individual leaf photosynthetic characteristics and grain yield. Plants were subjected to the removal of two (S1), four (S2) or six leaves (S3) from the top of the plant 3 d after anthesis (DAA), with no leaf removal as control (S0). The results of 2 yr indicated that with increased intensity of leaf removal, the transmission of light to lower strata of the canopy increased. With the removal of two leaves (S1), CAP increased and longer durations of CAP and green leaf are index were maintained during grain filling, whereas CAP in S2 and S3 treatments was inhibited and drastically declined. Generally, leaf removal appeared to stimulate an increase in the net photosynthetic rate (PN), stomatal conductance (gs) and chlorophyll content of the remaining ear leaves in S2 and S3 treatments prior to 26 DAA. Nevertheless, thereafter, plants in the S1 treatment had an advantage in terms of individual photosynthetic capacity. These results indicate that excising two leaves made plants more tolerant of high plant density due to enhanced photosynthetic capacity in ear leaves as well as a more efficient canopy structure, resulting in a better coordination of groups and individuals, and finally achieved significantly higher grain yield. In addition, relative to Zhengdan958, the effects of leaf removal on Jinhai5 were more apparent.

Li, G., Zhang, Z.-S., Gao, H.-Y., Liu, P., Dong, S.-T., Zhang, J.-W. and Zhao, B. 2012. Effects of nitrogen on photosynthetic characteristics of leaves from two different stay-green corn ( Zea mays L.) varieties at the grain-filling stage. Can. J. Plant Sci. 92: 671–680. The effects of nitrogen on the photosynthetic characteristics of two different stay-green corn (Zea mays L.) at the grain-filling stage were studied. Using a stay-green inbred line (Q319) and a non-stay-green inbred line (HZ4) as materials, using fast chlorophyll fluorescence-induction kinetics and 820 nm light-absorption curves, we analyzed the influences of nitrogen supplementation on photosystem I (PS I) and photosystem II (PS II). The results show that nitrogen fertilization has significant effects on promoting the net photosynthetic rate (P n ) in leaves at the grain-filling stage and on single-plant grain yield at the harvest stage (P n and grain yield were still significantly lower than those of Q319.

This study aims to explore the optimum nitrogen (N) application method by analyzing effects of variable N application stages and ratios on the N absorption and translocation of high-yield summer maize (DH661). The study included field experiments and 15 N isotopic dilutions for pot experiments. Results showed that the yield was not increased in a one-off N application at the jointing stage. The uptake of fertilizer-derived N in the grain increased with the increasing of N applied t imes. Compared to a single or double application, total N uptake (N up ) and biomass increased significantly by supplying N at the six-leaf stage (V6), ten-leaf stage (V10) and 10 days after anthesis in ratios of 3:5:2 and 2:4:4. The fertilizer-derived recovery rates were 67.5% and 78.1%, respectively. The uptake and utilization of fertilizer-derived N was enhanced by increasing the recovery rate of N supplied after anthesis, and reducing the absorption of soil-derived N. Therefore, the 2:4:4 application ratios was the optimal N application method.

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 (Mol7). 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.

Cu/Ta/Si stacks were prepared and, subsequently, annealed at 650 °C with different electric field intensity (0–4.0 kV/cm). The effect of electric field intensity on atomic diffusion was determined from cross-sectional TEM micrographs of Cu/Ta/Si stacks. The atomic diffusion as well as the growth of amorphous layer at Ta/Si interface tended to enhance with the increased electric field intensity at 650 °C. The growth of amorphous layer obeyed a logarithmic law. The reduction in diffusion activation energy Q by increased electric field intensity will accelerate the atom diffusion, leading to significant barrier failure of Cu/Ta/Si stacks.

Thymectomy is often successful as treatment for the autoimmune disease myasthenia gravis. One complication of the operation on such patients is respiratory difficulty especially post-operatively, due to interference with the already disturbed transmission of signals along damaged nerve-endings. Acupuncture anesthesia offers a solution to that problem. In this series of 90 patients, the results of operation under conventional general anesthesia were compared with those under acupuncture anesthesia. It was found that patients in the latter group suffered fewer complications.