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Zhang Z.-H.,Hunan Agricultural University | Zhang Z.-H.,Hunan University | Zhang Z.-H.,Hunan Provincial Key Laboratory of Farmland Pollution Control and Agricultural Resources Use | Zhang Z.-H.,National Engineering Laboratory of High Utilization Efficiency of Soil Fertilizer Resource | And 25 more authors.
Australian Journal of Crop Science | Year: 2012

Large amount of N03 --N are accumulated in vacuole, and cannot be timeously reducted, reutilized and transported into cytoplasm. It is the main reason for great N03--N accumulation in vacuole and nitrogen (N) use efficiency cannot be further improved. Transport mechanism of N03 --N across tonoplast is explained in this paper, there are two proton pumps (H+-ATPase and H+-PPase) on tonoplast with absolutely different biology functions and physical characteristic. Mg·ATP and Mg·PPi are the specific substrates of H+-ATPase and H+-PPase respectively, hydrolysis H+ is pumped into vacuole, and contribution to build electrochemical proton gradient between cytoplasm and vacuole. N03 --N transport from vacuole to cytoplasm greatly depends on electrochemical proton gradient, N03 --N transport from cytoplasm to vacuole is mainly achieved by vacuole H+/N03-antiport system, while symport system (vacuole N03 --N combined with anion) is of benefit for vacuole N03 --N transporting into cytoplasm. N03 --N transported by proton pump of tonoplast is influenced by NR activity in cytoplasm, N03 --N can be continuing assimilation and reduction by NR in cytoplasm, and accelerating vacuole N03 --N transported into cytoplasm. These results will supply references and research forecast for further study on efficiency and practicable methods of N utilization, and improving reuse efficiency of N03 --N in plant tissues.


Zhang Z.,Hunan Agricultural University | Zhang Z.,National Engineering Laboratory of High Utilization Efficiency of Soil Fertilizer Resource | Song H.,Hunan Agricultural University | Song H.,National Engineering Laboratory of High Utilization Efficiency of Soil Fertilizer Resource | And 12 more authors.
Plant Production Science | Year: 2012

The relationship between nitrogen efficiency (NE), defined as seed yield per unit nitrogen (N) application, and seed quality was examined in two oilseed rape (Brassica napus L.) varieties at 5 N application levels, 0.6, 3, 6, 12, 15 mmol L -1, N 1, N 2, N 3, N 4 and N 5, respectively. Seed yield, oil yield and protein content were increased with the increase in N application level, but NE and oil content were decreased, and the fatty acid composition in seed was hardly changed. Analysis of seven fatty acids revealed a slight decrease in the contents of erucic acid and arachidonic acid with the increase in N application level, but no obvious change in the contents of palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. Compared with the low NE variety H29, the seed yield and contents of erucic acid and arachidonic acid in the high NE variety bin270 were more markedly increased with the increase in N application level, and the oil content was hardly changed. The seed yield, oil content and oil yield were higher in the high NE variety than in the low NE variety at all 5 N application levels. There were no significant differences in protein, palmitic acid, stearic acid and oleic acid contents between the varieties at any of the 5 N application levels, but there were slight differences in the linoleic acid and linolenic acid contents between the two varieties. In brief, N application improved oil yield more greatly in the high NE variety than in the low NE variety, but hardly affected the fatty acid composition. Therefore, the seed quality and oil content of oilseed rape may not be decreased by breeding of a high NE variety with a high N absorption efficiency and high N use efficiency.


Huang H.-T.,Hunan Agricultural University | Zhang Z.-H.,Hunan Agricultural University | Zhang Z.-H.,National Engineering Laboratory of High Utilization Efficiency of Soil Fertilizer Resource | Song H.-X.,Hunan Agricultural University | And 7 more authors.
Chinese Journal of Ecology | Year: 2012

The fact that large amount of NO3 --N accumulated in vacuole cannot be timely transported into cytoplasm and then reduced and reutilized is the main reason for the great NO3 --N accumulation in vacuole and for the nitrogen use efficiency unable to be further improved. This paper reviewed the transportation mechanisms of NO 3 --N in vacuole membrane. Vacuole membrane has two proton pumps, H+-ATPase and H+-PPase, which have absolutely different biological functions and physical characteristics, with Mg · ATP and Mg · PPi as the specific substrates, respectively. The H + obtained through the hydrolysis of these substrates is pumped into vacuole, and contributes to the electrochemical proton gradient between cytoplasm and vacuole. The NO3 --N transportation from vacuole to cytoplasm is greatly depended on the electrochemical proton gradient. The NO3"-N transportation from cytoplasm to vacuole is mainly depended on the vacuole H+/NO3 - antiport system, while the symport consisted of vacuole NO3 --N and other anions benefits the transportation of NO3 --N from vacuole to cytoplasm. The transportation of NO3 --N based on the proton pump of vacuole membrane is also affected by the cytoplasm nitrate reductase (NR) activity. Cytoplasm NR can continuously assimilate and reduce NO3-N, making the NO3 --N accumulated in vacuole more transported into cytoplasm and utilized. This review could provide-reference for the further study on the efficient and practicable measures of plant nitrogen utilization, and for improving the NO 3 --N reutilization efficiency.

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