| In order to verify the mechanism that nitrogen use efficiency (HNUE) variety rape (No.27)could use nitrogen efficiently meanwhile coordinated the contradiction of seed protein and oil.With HNUE variety rape and low nitrogen use efficiency (LNUE) variety rape (No.6) as the materies, soil culture test and sand culture test were used under two nitrogen conditions(that is normal nitrogen condition and nitrogen stress condition) to explore:(1) difference of activities of SPS and PEPC in lesf, silique(early Silique stage), husk and grain(silique mid-term stage) of different nitrogen use efficiency rape and their influence on seed-oil; (2) the transportation amount and rate of nitrogen and carbon and loss amount and rate of nitrogen of the two rape varieties; (3) difference of accumulation of nitrients, dry mater and oil-accumulation of the two rape varieties, test results are as follows:1. Activities of SPS and PEPC of HNUE(No.27) variety in leaf from vegetative period to flowering period were higher than that of LNUE(No.6) variety under two nitrogen conditions, the same tendency was found in silique at early Silique stage as well as in grain and silique husk at silique mid-term stage. While the SPS/PEPC of the two variety rape were changed at different growth periods, SPS/PEPC of HNUE(No.27) variety in leaf at vegetative stage was higher than that of LNUE(No.6) variety, SPS/PEPC of the two varieties rape was similar in leaf at flowering stage, instead SPS/PEPC in main reproduction organs at silique stage of HNUE(No.27) variety were lower than that of LNUE(No.6) variety, which revealed that amount of delivery of carbon skeleton to C metabolism and N assimilation of HNUE(No.27) variety was more than that of LNUE(No.6) variety during the whole growth period and the response of C metabolism to N assimilation of HNUE(No.27) variety was stronger than that of LNUE(No.6) variety at early growth of the stage,while at late growth stage the response of HNUE(No.27) variety was lower compared to LNUE(No.6) variety.2.Nitrogen transportation rate and amount of HNUE(No.27) variety were larger than that of LNUE(No.6) variety as well as nitrogen harvest index, but N loss was lower, meanwhile Carbon transportation amount and rate of HNUE(No.27) variety were larger than that of LNUE(No.6) variety,which illustrated that HNUE(No.27) variety had stronger nitrogen and carbon transportation and reuse ability3.Seed yield of HNUE(No.27) was significantly greater than that of LNUE(No.6) under the two nitrogen conditions as well as seed oil content and oil yield and harvesting index.4.K accumulation of the two rape varies were similar under normal nitrogen condition and HNUE variety was higher under nitrogen stress condition, K accumulation of HNUE(No.27) were lower than that of LNUE(No.6) there showed opposite rule under nitrogen stress condition at bolting stage; P accumulation the two rape varies were similar at flowering stage and P accumulation of HNUE(No.27) was higher than that of LNUE(No.6),K accumulation of HNUE(No.27) was higher than that of LNUE(No.6) at silique stage; P accumulation of HNUE(No.27) was higher than that of LNUE(No.6) at harvest stage and K accumulation showed the opposite rule.5.Influence of nitrogen levels on indicators above were as below, grain yield, PEPC activity, amount of carbon transport and transport rates, K were higher under normal nitrogen condition than under nitrogen stress, and oil content, SPS activity, SPS/PEPC, K and P accumulation amount under normal nitrogen condition were lower than under nitrogen stress condition,but above indicators of differences among varieties were not changed. Reproductive stage rapeseed the accumulation of dry matter in vegetative organs greatly weakened, organic carbon accumulation and canola oil are closely related. Two varieties both showed that P accumulation under normal nitrogen condition was higher than under nitrogen stress, K accumulation showed the same trendency from bolting stage to silique stage, while at harvest stage K accumulation under normal nitrogen was lower.In total, Compared to LNUE(No.6) variety, more carbon skeleton was transported into C and N metabolism pathway in HNUE(No.27) variety during the whole growth period. This was the important premise for HNUE variety to coordinate the contradiction between C-N metabolisms. Response of C metabolism to N assimilation was higher during earlier growth stage than what observed during later growth stage. Meanwhile, higher proportion of C in vegetative organs was transported into seed during later growth stage, which meet the demands of carbon skeleton in C and N metabolism and coordinated the contradiction between seed oil and protein contents during later growth stage. |
