【作者】 张文君；

【导师】 鲁剑巍；

【作者基本信息】 华中农业大学 ， 植物营养学， 2012， 博士

【摘要】 矮牵牛(Petunia hybrida Vilm)属于茄科矮牵牛属,其具有生长周期短,易于栽培管理等特点,是国际上重要的盆花、花坛装饰植物并用于商业贸易的草本花卉。矮牵牛还是研究植物开花和花色素合成的重要模式植物之一。近年来,矮牵牛的种植面积仍在进一步扩大,在花卉产业链中具有重要的生产力价值,并在新品种的培育、组织培养、转基因改良和花期调控等领域取得一系列成果,但是随着新品种的不断培育更新,有关矿质营养以及养分管理方面的研究报道鲜见报道。由于肥料是影响花卉生长的重要因子之一,合理施肥不仅能提高花卉品质,而且对改善环境也起着至关重要的作用。因此本试验以矮牵牛为研究对象,采用土培和水培试验,系统研究了不同品种矮牵牛养分吸收特性及不同器官中的养分分配差异；分析了矿质养分对矮牵牛生长、开花及活性氧和花青素代谢的影响；并结合武汉绿地土壤养分状况分析,初步建立了矮牵牛最佳施肥用量。主要结论如下：(1)通过对三种主要矮牵牛栽培品种(重瓣豪放,单瓣迷你,单瓣豪放)养分吸收特性研究,结果表明矮牵牛植株中N、P、Ca、Mg、Fe、Mn、Cu和Zn养分含量均随生育期推进总体呈先上升后降低变化趋势,而K和Mn含量呈波动形变化趋势。不同矮牵牛品种对养分最大吸收量变化幅度为370.09-442.63mg N,46.13-65.73mg P,198.46-220.05mg K,282.21-307.12mg Ca,49.58-62.88mg Mg,5.98-7.21mg Fe,2.88-2.95mg Mn,0.35-0.52mg Cu和108-1.34mg Zn,累积量大小顺序为N>Ca>K>P>Mg>Fe>Mn>Zn>Cu.矮牵牛不同器官对元素吸收量及最大吸收时期均不相同,苗期到初花期阶段,茎,叶中各种元素含量最高,开花以后随着蒴果的逐渐形成,养分逐渐向生殖器官转移。养分累积率主要在蕾期和盛花期达到最大值,其中蕾期K,Mg和Mn最大累积率分别是42.74%,53.91%和30.80%；盛花期N,P,Cu和Zn最大累积率分别是29.49%,54.36%,37.79%和36.57%；Ca和Fe在衰败期达到最大值为26.95%和43.41%,以上说明蕾期和盛花期是矮牵牛生长及养分调控管理的关键时期。(2)武汉城市绿地土壤pH高于自然土壤,呈现中性偏碱趋势；土壤有机质含量比较低,土壤氮素含量缺乏,土壤有效磷和有效钾含量处于中等偏上水平；土壤中量元素有效Ca、Mg和S含量丰富；微量元素有效Fe、Mn、Cu、Zn及B含量较丰富。通过选取四种绿地土壤进行“3414”肥料配比试验,得出在供试的四种土壤上,氮肥的施用范围为0.28-0.54g/kg；磷肥施用范围为0.17-0.20g/kg；钾肥施用范围为0.19-0.23g/kg。氮磷钾综合比较,氮的需求量最大,为矮牵牛生长最主要限制因子,磷钾次之。(3)氮肥施用可提高矮牵牛叶片叶绿素含量,分枝数、植株干重等生长指标；存花数及总花朵数也随着氮肥施用的增加而增加。氮肥施用影响花瓣及叶片的活性氧代谢酶变化,并诱发了细胞膜脂过氧程度的高低。低氮胁迫条件下,叶片中O2·-产生速率显著增加,过氧化氢(H202)含量显著升高,最终导致膜脂过氧化产物丙二醛(MDA)含量升高；花瓣在氮胁迫下,并没有引起MDA含量的上升,说明缺氮胁迫对花瓣膜脂过氧化影响不明显。低氮胁迫花瓣中氮及蛋白质含量大幅降低,初生代谢和次生代谢对氮源的竞争可导致花青素次生代谢途径中酶活性的升高,从而促进了花青素含量增加,而花青素作为一种多酚物质,能高效清除植物体内产生的自由基,减轻植物氧化损伤。(4)磷肥施用可促进分枝数及干物质累积量的增加,增加存花数及总花朵数。低磷胁迫下,叶片和花瓣中抗氧化物酶活性显著升高,最终叶片中MDA含量显著升高,而花瓣中MDA含量却降低。低磷胁迫下,可溶性糖和黄酮含量均增加,说明低磷胁迫条件下花青素代谢的加强可能与糖在植物体内的运输受阻及黄酮类物质的大量分泌有关。(5)低钾胁迫条件下,减少植株分枝数,叶绿素含量,并且当日存花数及总花朵数也显著降低。钾还影响了叶片及花瓣中活性氧代谢的强弱。在低钾条件下,花瓣和叶片中MDA含量均有增加的趋势,说明钾缺乏引起花瓣及叶片中活性氧伤害。低钾胁迫下可溶性糖和苯丙氨酸含量增加,可为花青素合成提供良好的物质基础,并且钾与细胞含水量密切相关,钾的缺乏导致细胞中水分的丧失,而细胞含水量的降低造成的浓缩效应也可间接导致花青素含量的升高。(6)低铁条件下,矮牵牛生长及开花受到严重影响,其中新叶中叶绿素含量和总花朵数等指标显著降低。低铁胁迫下,叶片和花瓣细胞中抗氧化物酶的活性均显著降低,并最终造成花瓣和叶片中膜脂过氧化产物MDA的累积,导致植株过氧化损伤。低铁胁迫还可改变花瓣的结构,导致花瓣纵向直径及横向厚度的缩短,说明缺铁不利于花瓣生长。铁作为共因子直接参与花青素代谢,铁的缺乏直接导致花青素合成酶活性的降低,从而减少花青素的合成量。(7)利用高效液相-电喷雾-质谱联用(HPLC-ESI-MS)技术对花青素成分分析表明,氮磷钾及铁缺乏条件下,总离子流在530nm均检测出3个花青素特征峰,可能的化学结构为P1：矢车菊素-3-槐糖苷；P2：矢车菊素-3-葡萄糖苷(半乳糖苷)；P3：芍药素-3-葡萄糖苷(半乳糖苷)。对花青素组分比例进行分析,氮磷钾缺乏胁迫下,(矢车菊素)Cy及(芍药素)Pn型色素组成比例较为稳定；而在缺铁胁迫下,花青素组分有从Cy向Pn型转化的趋势。更多还原

【Abstract】 Petunia (Petunia hybrida Vilm.) belongs to the Solanaceae family and is a popular annual bedding ornamental plant using in the home gardens and commercial landscaping trade. The petunia plant has a short lifecycle and can be easily propagated asexually from cuttings, callus or protoplasts, it has been used as a model plant for studying genome sequencing and flavonoid synthesis. Currently, petunia is widely cultivation in highways, parks and residential quarters around the world, which means that petunia offers the potential value for high economic income on flower industry. However, recent progress in nutrient management of petunia is less reports. In intensive horticulture, the management of mineral nutritients are a key factor on ornamental value and environment quality. In this study, we compared growth characteristics, biomass accumulation and NPK translocation among three cultivars of petunia at different developmental stages, analyzed the reactive oxygen and secondary metabolites under different nutrient deficiency stress, studied the optimal amount of Petunia by pot experiment and hydroponic experiment. The main results are summarized as following:(1) Three cultivars of potted petunia (the double florabunda, single milliflora and single florabunda) were compared accumulation and distribution characteristics for mineral nutrition. The resultes showed N, P, Ca, Mg, Fe, Mn, Cu and Zn accumulation were gradually decreased with developmetal stage; the dynamic changes of K and Mn accumulation showed undulate curve. In different cultivars, the maximum absorption amount were370.09-442.63mg N,46.13-65.73mg P,198.46-220.05mg K,282.21-307.12mg Ca,49.58-62.88mg Mg,5.98-7.21mg Fe,2.88-2.95mg Mn,0.35-0.52mg Cu and1.08-1.34mg Zn with the order N> Ca> K> P> Mg> Fe> Mn> Zn> Cu in these reserch. The mineral nutrients were main distribution in the leaves and stems during the seedling stage and early flowering stage, when the growth central changed from vegetative growth to reproductive growth, these mineral nutrients translated into bud, flower and capsules. The maximum uptake stage generally occurred at bud and full-bloom stage, K, Mg and Mn accumulation rate were42.74%,53.91%and30.80%at bud stage, respectively; N, P, Cu, and Zn accumulation rate were29.49%,54.36%,37.79%and36.57%at full-bloom stage, respectively; Ca and Fe maximum accumulation rate were26.95%and43.41%at senescence stage. The above study suggested that bud and full-bloom stage were important stage for nutrients management. (2) Urban Soils pH were weakly alkaline compared with nature soil, soil organic matter was at deficient or middle level, soil N was at deficiency level, available P and K were at optimum or abundance level, available Ca, Mg, S, Fe, Mn, Cu, Zn and B were at optimum level. In addition, based on the "3414" fertilizer experiment design, pot experiments in greenhouse were conducted to study the effects of NPK fertilizers and fertilizer recommendation amount on four tested soil, the results showed the range of N recommendation amount was0.28-0.54g/kg; P2O5was0.17-0.20g/kg; K2O was0.19-0.23g/kg.(3) Nitrogen fertilization increased chlorophyll content, branches number, dry weight as well as flower number. Active oxygen metabolism and lipid peroxidation were variation under the different nitrogen concentration. With decreasing of N concentrations, O2·-production rate, H2O2and MDA content increased significantly in leaves, however flowers showed non-significantly increased of MDA content. Nitrogen content and protein content reduced in the flowers under N deficiency, which increased enzyme activity and anthocyanins accumulation through competing on nitrogen source between primary metabolism and secondary metabolism, anthocyanins as phenolic compounds may effectively scavenge free radical effective in plants.(4) Phosphorus fertilization increased branches number, dry weight as well as flower number. Antioxidant enzyme activity increased significantly in leaves and flowers under P deficiency stress, however MDA content increased significantly on leaves that had opposite effect on flowers. Soluble sugar and flavonoids content increased with decreasing P concentration, thus, anthocyanins accumulation would relate to flavonoids secretion and sugar transport.(5) Branches number, dry weight and flower number were decreased with reducing the potassium concentration. MDA content both in leaves and flower were increased under K deficiency stress, which caused lipid peroxidation of petunia. Phenylalanine and flavonoids content were increased under K deficiency stress. phenylalanine and flavonoids as synthesis precursor of anthocyanins metabolism, which may lead to anthocyanins accumulation on petals. In addition, potassium had positive correlationand on water content of cell, anthocyanins accumulation also may incease by concentration effect.(6) Iron deficiency significantly influenced growth and blooming of petunia. The chlorophyll content of young leaves significantly increased with increasing Fe concentration. Activity of antioxidant enzyme significantly decreased in leaves and flowers under Fe deficiency stress, which increased MDA content and peroxidation damage. Flowers were the majoy ornamental organ of Petunia, Fe application changed corolla anatomy, corolla diameter and length of cross-sections of Fe-deficiency treatment were much lesser than that of Fe-sufficient treatment. In addition, Fe as co-factor of anthocyanins synthase directly participated in anthocyanins synthesis, so anthocyanins content had positive correlation on Fe concentration.(7) The extract of the petal of Petunia was analyzed by HPLC-ESI-MS, identification and peak assignment of anthocyanins was based on comparison of their retention times and mass spectral data with those of standards and published data. Three peaks identified as cyanidin3-sophoroside, cyanindin-3-glucoside (galactose) and Peonidin-3-glucoside (galactose) both in nutrient deficiency and nutrient supply treatment. Ratio of anthocyanins content showed non-transformation on N, P, K deficiency treantment and changed from Cy to Pn under Fe-deficiency.更多还原