Effect of Nitrogen Fertilizer on the Accumulation and Distribution of Dry Matter in Broomcorn Millet

[Objective] To understand the effect of nitrogen application on dry matter accumulation and allocation dynamics in broomcorn millet. [Method] The accumulation and distribution of dry matter were studied using cultivars Jin Shu 7 and Huang Mizi at different levels of nitrogen fertilizer at the jointing stage. [Result] The results showed that increasing N application led to the increase of green leaf area and the delay of leaf senescence, which was beneficial to the accumulation of dry matter.Appropriate nitrogen application(90 kg/hm2) could coordinate the translocation rate of dry matter among different plant parts, thereby enhancing the yield of broomcorn millet; among different organs, the contribution rate of stem to kernel was greater than that of leaf to kernel; there was obvious correlation between dry matter and yield. For Jin Shu 7, leaf area and dry weight of spike showed significant negative correlation with yield. [Conclusion] The formation of grain yield of broomcorn millet involved the accumulation and allocation of dry matter, the appropriate amount of nitrogen application(90 kg/hm2) could improve the rates of translocation and contribution of dry matter, thereby promoting the yield of broomcorn millet.

Profound changes of mitochondria during postmortem condition used as freshness indicator in grass carp(Ctenopharyngodon idella)muscle

Flesh quality changes during postmortem condition are involved with apoptosis initiation.Therefore,flesh quality evaluation based on the alteration of apoptosis process is quite important.Mitochondria,the regulation place of apoptosis,undergo profound changes in fish muscle during postmortem.Thus,this study aimed to investigate whether mitochondrial related parameters during apoptosis process constitutes a putative early fish freshness marker.Mitochondrial profound impairments during postmortem at 4◦C for 5 days demonstrated that the structural changes[double layer membranes and cristae,volume,swelling,membrane potential(ΔΨm),MPTP opening and membrane fluidity]and dysfunctional changes[energy deficiency and disharmony of Ca2+homeostasis]were occurred during postmortem alteration for energy deficiency and the oxidation by ROS accumulation.Study also investigated energy metabolism related products,TVB-N,lipid and protein oxidation.Compared with the insignificantly increased traditional freshness indicators(except K value)at the initial stage(day 1),the most sensitive parameters based on mitochondrial impairment were[mitochondrial swelling,depolarization ofΔΨm,and membrane fluidity].Therefore,these above parameters might be considered as suitable and early indicators for freshness evaluation.