【作者】 王俊忠；

【导师】 黄高宝；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2010， 博士

【摘要】 玉米是我国重要的粮食和饲料作物,研究玉米高产理论对于确保我国粮食安全具有重大意义。本文设置施氮方式和施氮量两组试验,研究了氮肥使用对高产夏玉米源库代谢特征的调节作用。施氮方式试验共设5个处理:①不施肥（CK）;②种沟施肥（T1）:随播种开沟施入磷酸二铵300 kg/hm²、KCl300 kg/hm²和尿素750 kg/hm²;③种沟施肥+小口期追氮（T2）:随播种开沟施入磷酸二铵300 kg/hm²、KCl 300 kg/hm²,小喇叭口期追施尿素750 kg/hm²;④种沟施肥+拔节期追氮+大喇叭口期追氮（T3）:随播种开沟施入磷酸二铵300 kg/hm²、KCl300 kg/hm²,拔节期追施尿素300 kg/hm²,大喇叭口期追施尿素450 kg/hm²;⑤控释肥（T4）:随播种开沟施入1333 kg/hm²控释肥（N: P₂O₅:K₂O=22:9:9）,尿素232 kg/hm²,KCL 100.05 kg/hm²。施氮量试验共设4个处理:①不施氮肥（N0）;②施氮量300 kg/hm²:基施尿素323 kg/hm²+大口期追施尿素323 kg/hm²（N1）③施氮量375kg/hm²:基施尿素323 kg/hm²+大口期追施尿素485kg/hm²（N2）④施氮量375kg/hm²:基施尿素323 kg/hm²+大口期追施尿素323kg/hm²+吐丝期追施尿素162kg/hm²（N3）。通过测定叶片的光合特性、蔗糖磷酸合成酶（SPS）、硝酸还原酶（NR）、蔗糖含量等指标,研究氮肥对源端活力的调节效应;通过测定籽粒蔗糖合成酶（SS）、酸性转化酶（AI）、淀粉积累等指标,研究氮肥对库活性的调节作用;通过测定活性氧清除酶系统和膜脂过氧化作用,研究氮肥对叶片衰老的调节作用;并利用¹⁵N示踪技术,探讨了不同氮肥运筹对玉米氮素分配与利用的影响。主要结果如下:1、施用氮肥对夏玉米群体的生长发育的影响不同施氮量处理使玉米的叶面积指数、地上部干重、株高、穗位高、茎粗均有不同程度地提高;不同施肥方式比较,以T3处理（种沟施肥+拔节期追氮+大喇叭口期追氮）的调节效果最显著,其次是T4处理（控释肥）。2、施用氮肥对夏玉米源端同化物供应能力的调节作用叶片的叶绿素含量大小为:T3>T4>T2>T1>CK,光系统II（PSII）最大光化学量子产量、光系统I（IPSII）实际光化学量子产量（ΦPSII）、光化学猝灭（qP）)、光合速率和气孔导度也表现出了一致的变化规律。说明,T3处理（种沟施肥+拔节期追氮+大喇叭口期追氮）较其他处理更有利于延缓玉米叶片衰老,提高叶片叶绿素含量和光系统II（PSII）潜在活性及光系统II（PSII）光化学的最大效率,从而降低光能热耗散,使叶片所吸收的光能较充分地用于光合作用,增加光系统II（PSII）天线色素对光能的捕获量及其效率,积累更多的同化物。蔗糖磷酸合成酶（SPS）活性的大小依次为:T3>T4>T2>T1>CK ,说明T3处理（种沟施肥+拔节期追氮+大喇叭口期追氮）的施肥方式更有利于叶片中蔗糖的积累,增大了源的同化物供应能力。因此,同一生育时期各施肥方式相比,T3处理的蔗糖含量较高。高产条件下,在施氮量150kg.hm^-2～300 kg.hm^-2范围内,增加氮肥用量穗位叶硝酸还原酶（NR）活性呈增高的趋势,到400 kg.hm^-2则有所下降。上述试验结果表明,使用氮肥,尤其是采用T3（种沟施肥+拔节期追氮+大喇叭口期追氮）施肥方式,不仅可以提高叶片的叶绿素含量,增强PSII的光化学活性,增加CO₂同化能力,而且可以提高叶片的硝酸还原酶（NR）、蔗糖磷酸合成酶（SPS）活性和可溶性糖含量,从而提高源端的物质供应能力,为实现高产奠定基础。3、施用氮肥对夏玉米库活性的调节效应施用氮肥可以显著提高夏玉米籽粒蔗糖合成酶（SS）和酸性转化酶（AI）活性,在籽粒发育阶段,除授粉后45d外,各施氮处理的蔗糖合成酶（SS）、酸性转化酶（AI）活性均与其对照达到了显著差异水平。不同的施肥方式相比,以T3处理（种沟施肥+拔节期追氮+大喇叭口期追氮）的酶活性较高,其次是T4处理（控释肥）。在授粉后5d～45d籽粒可溶性糖含量和淀粉含量呈增加趋势,且5d～15d淀粉含量增加迅速,蔗糖含量和蛋白质含量呈下降趋势,且5d～15d蔗糖含量下降迅速,说明蔗糖含量的下降与淀粉的大量合成有关。各个施氮处理均可促进籽粒灌浆,减少败育,增加穗粒数,提高产量,尤其是“种沟施肥+拔节期追氮+大喇叭口期追氮”的效果最显著。4、不同施肥方式对夏玉米的氮素分配与利用的影响研究比较了不同产量水平下（高产田与中产田）施氮处理对玉米氮素分配、利用的影响。结果表明,各施氮处理均以籽粒中氮素吸收量、分配率和利用率最高,其后是叶、茎、根。从全株和籽粒的氮素吸收量来看,高产田随着氮肥用量的增加呈先增后减的趋势,以HM（高产田、中等施氮量）处理最高,而中产田则随施氮量的增加而增加,以MH（中产田、高施氮量）处理最高。茎叶的氮素吸收量随氮肥用量的增加而增加。但不同地力水平下,玉米的氮肥利用率均随施氮量的增加而降低。根据本文试验结果,并综合考虑产量、氮肥利用率、养分转运及环境污染等因素,高产田夏玉米的施氮量应控制在300kg.hm^-2以内,中产田施氮量应控制在300～400 kg.hm^-2之间。5、提出了使用氮肥对夏玉米源库代谢调控及高产机理模式选用具有高产潜力的玉米品种,通过合理氮肥运筹,调节源、库活性,增强源供应能力和库储存能力,实现玉米高产高效。更多还原

【Abstract】 Maize （Zea mays L.） is one of the important grain crops and high-quality feedsin China. It play an significant role in ensuring food safety to research the mazie high-yielding theory. In order to research the regulation of Nitrogen application on source-sink metabolism on high-yield maize.In order to research the regulation of Nitrogen application on source-sink metabolism on high-yield maize.Five treatments were included in nitrogen fertilizer application patterns experiment, i. e. no nitrogen fertilizer, basal application in seed channel （diammonium phosphate, 300 kg/hm², KCl, 300 kg/hm², and urea, 750 kg/hm²）, basal application in seed channel （diammonium phosphate, 300 kg/hm² and KCl, 300 kg/hm²）+ topdressing at 9 full expansion leaves stage（urea, 750 kg/hm²）, basal application in seed channel （diammonium phosphate, 300 kg/hm² and KCl, 300 kg/hm²）+ topdressing at 6 full expansion leaves stage（urea, 300 kg/hm²） + topdressing at 12 full expansion leaves stage（urea, 450 kg/hm²）, and applying controlled release nitrogen fertilizer in seed channel （N: P₂O₅:K₂O=22:9:9, 1333 kg/hm², urea, 232 kg/hm², and KCl, 100.05 kg/hm²）. The treatments were expressed as T0, T1, T2, T3 and T4, respectively. Four treatments were included in nitrogen fertilizer application rates experiment, i. e. 0 kg/hm², 300 kg/hm²（urea, basal application, 323 kg/hm² + topdressing at 12 full expansion leaves stage, 323 kg/hm²）, 375 kg/hm²（urea, basal application, 323 kg/hm² + topdressing at 12 full expansion leaves stage, 485 kg/hm²）, and 375 kg/hm²（urea, basal application, 323 kg/hm² + topdressing at 12 full expansion leaves stage, 323 kg/hm²+topdressing at silking stage, 162 kg/hm²）. The treatments were expressed as N0, N1, N2, and N3, respectively. The photosynthesis characteristic, sucrose phosphate synthase （SPS）, nitrate reductase （NR）, and sucrose content in maize leaf were determined to study the regulative effects of nitrogen fertilizer on“source”ability. The sucrose synthase （SS）, acid invertase （AI）, and starch accumulative characteristic in grain were determined to study the regulative effects of nitrogen fertilizer on“sink”ability. The endogenous oxygen radicals scavenging enzymes systems and membrane lipid peroxidation were determined to study the regulative effects of nitrogen fertilizer on leaf senescence. And the effects of nitrogen fertilizer on nitrogen use and distribution were studied by using ¹⁵N tracer technique. The main results were as follows:1. Effects on summer maize population growth after nitrogen applicationThe LAI, above ground dry matter, plant and ear height, and stem diameter were increased by nitrogen fertilizer. By comparing the nitrogen fertilizer application patterns, T3 showed greatest regulative effects, followed by T4.2. Regulation of“source”assimilation applicating ability on summer maize after nitrogen applicationThe order of the chlorophyll content, Fv/Fm,ΦPSII, qP, photosynthetic rate, and stomatal conductance was T3>T4>T2>T1>CK, which showed T3, by compared with other nitrogen fertilizer application patterns, has the greatest positive effects on delaying leaf senescence, increasing chlorophyll content, and increasing potential activity and maximum photochemical efficiency of PSⅡ.The light thermal dissipation was decreased and the catch and efficiency of PSⅡwas increased by T3 treatment, which resulted more assimilate accumulated under T3.The greatest SPS activity was under T3, followed by T4, T2, T1, and CK, respectively, which suggested T3 was benefit to most sucrose accumulated in leaf and“source”ability to support assimilate. As a result, sucrose content under T3 was greatest, by compared with other nitrogen fertilizer application patterns at same stage. And under high-yield condition, with the nitrogen fertilizer application rate increasing, NR activity in ear leaf was increased when application rate between 150kg.hm^-2 and 300 kg.hm^-2, and then decreased when application rate beyond 400 kg.hm^-2.The results suggested applying nitrogen fertilizer, especially using T3 application pattern, not only increase chlorophyll content, photochemical efficiency of PSⅡ, and CO₂ assimilation capacity in leaf, but also increased NR activity, SPS activity, and soluble sugar content in leaf, and then increased“source”ability to support assimilate, which was beneficial to obtain maize high-yield.3. Regulatory effects on“sink”ability of summer maize after nitrogen applicationApplying nitrogen fertilizer can increase SS and AI activity in grain significantly. During grain developing period, except 45d after pollination, by comparing with CK, SS and AI activity in grain increased significant under every applying nitrogen treatment. Compared with other nitrogen application patterns, T3 treatment increased SS and AI activity in grain greatest, followed by T4.From 5d to 45d after pollination, the content of soluble sugar and starch increased while the content of sucrose and protein decreased. And during 5d¹5d after pollination, starch content increased sharply and sucrose content decrease sharply in grain, which suggested sucrose content decrease was relative to starch production. The grain filling rate, grains per ear, and yield were increased under all applying nitrogen fertilizer treatments, especially under T3 treatment.4. Effects on nitrogen distribution and utilization of summer mazie in different nitrogen application approachesThe effects of nitrogen fertilizer application rates on nitrogen usingand distribution in summer maize under high- and middle-yield conditions were determined. The results showed the order of nitrogen uptake, distribution ratio, and use efficiency was same: grain>leaf>stem>root. Under high-yield condition, with nitrogen fertilizer application rate increased, nitrogen uptake by plant and grain was increased first, and then decreased, and the peak occurred under HM treatment. But under middle- yield condition, they increased with nitrogen fertilizer application rate and the peak occurred under MH treatment. The nitrogen uptake by stem increased and nitrogen use efficiency decreased with nitrogen fertilizer application rate under two yield conditions. Based on the results, taken yield, nitrogen use efficiency, nutrition transport, and environmental pollution into account, the recommended nitrogen application rate was under 300kg.hm^-2 in high-yielding field and 300～400 kg.hm^-2 in general-yielding field.5. Indicated the pattens of high-yield summer maize source-sink metabolism and high-yield mecaniques after nitrogen application Select high-yield maize variety and apply nitrogen fertilizer scientific can regulate“source”and“sink”activity, and increase the“source”support ability and“sink”storage ability, which result the high-yield and efficiency maize production.更多还原