【作者】 吕长文；

【导师】 王三根； 王季春；

【作者基本信息】 西南大学 ， 作物学， 2011， 博士

【摘要】 甘薯以其广适性与多样化的用途,在我国的粮食安全与食品工业发展中发挥了重要作用。本文据前期的实验,在48份育种资源材料中选择出6个不同类型甘薯品种,立足于重庆区域生态条件,重点就不同品种及类型甘薯块根形成与膨大期间的光合特性、内源激素、氮钾分配、淀粉代谢谢等生理性状以及高效栽培的理化调控模式等作了深入研究,系统比较了块根各生长发育阶段不同品种间以及不同类型间的差异与动态变化,并结合进一步的相关分析,明确了甘薯各性状指标间的相关性,为不同类型甘薯品种定向高效选育和高产栽培提供了理论基础和依据,具有一定的指导与应用价值。主要研究结果如下：1.不同类型甘薯光合特性比较比较6个甘薯品种的光合色素表明,绵粉1号叶绿素相对含量较高,而其他品种的叶绿素含量无显著差异,叶绿素与甘薯淀粉或干物质相关不显著。光合一光强回归曲线表明,各品种净光合速率随光合有效辐射的增强呈抛物线变化,高淀粉类型品种光补偿点的理论值相对低于低淀粉类型品种,净光合速率的最大值与光饱和点的理论最大值均以渝薯2号最高、豫薯10号最低。在甘薯块根膨大盛期,不同品种的净光合速率、蒸腾速率、气孔导度、水分利用率等日变化趋势各不相同,但胞间CO2浓度与气孔限制值的变化趋势基本一致。甘薯一天内光合速率的下降受到气孔限制和非气孔限制因素的双重影响。从不同类型品种间的光合变化来看,环境温度对低淀粉类型的光合速率和蒸腾速率的影响较大,高淀粉类型品种的光合特性受不同气温的影响较小,表现更为稳定。对所有品种的相关分析表明,蒸腾速率与生物产量之间为显著负相关,气孔导度与净光合速率呈显著正相关、与蒸腾速率呈极显著正相关;就高淀粉类型品种而言,净光合速率与蒸腾速率及胞间CO2浓度均表现为显著正相关；就低淀粉类型品种来说,净光合速率与鲜薯产量呈显著正相关,蒸腾速率与淀粉产量呈显著负相关关系。2.不同类型甘薯块根膨大期N、K分配差异从不同品种藤蔓与块根干物质的氮、钾含量变化看,甘薯藤蔓的含氮量自块根形成后逐渐下降,其干物质含氮量仅为2%左右,而块根含氮量在整个块根膨大期间变化较小,且前后期含量基本一致。藤蔓和块根含钾量在块根膨大期间也相对稳定。从氮、钾在藤蔓与块根干物质中的分配比例看,藤蔓含氮量极显著高于块根含氮量;藤蔓与块根中的含钾量则刚好相反。对不同类型甘薯的研究表明,高淀粉类型品种块根干物质含氮量在0.68%～0.86%之间,藤蔓含氮量在1.98%～3.32%之间,低淀粉类型品种块根与藤蔓含氮量分别在0.69%～0.86%和2.00%～3.17%之间,但无论是藤蔓还是块根,氮素含量在不同类型品种间无显著差异：高淀粉类型品种的块根含钾量为5.83%～6.66%,藤蔓含钾量为3.19%～3.70%,而低淀粉品种的块根与藤蔓含钾量分别为6.12%～6.36%与3.48%～3.90%。此外高淀粉类型品种块根含钾量变率大于低淀粉类型,藤蔓含钾量则以低淀粉类型品种相对较高。相关分析结果表明,对所有品种来说,块根的含钾量与其含氮量之间呈显著正相关,藤蔓的含钾量与根冠含钾量之比也达到了显著负相关；就高淀粉类品种而言,藤蔓含氮量与干率之间、根冠含钾量之比与商品薯率之间均为极显著正相关,块根含钾量与生物产量呈显著负相关；低淀粉含量类型品种的藤蔓含氮量与生物产量呈显著正相关关系,藤蔓含钾量与生物产量、与淀粉产量分别呈极显著正相关和显著负相关关系。3.不同类型甘薯淀粉代谢差异ADPG-焦磷酸化酶在淀粉合成与积累过程中至关重要,其活性在甘薯块根膨大期间随外界环境温度的下降呈下降趋势,且在不同类型品种间活性大小显著差异,但该酶对甘薯淀粉含量并不起决定作用。在此期间,蔗糖合成酶(SS)和磷酸蔗糖合成酶(SPS)活性均以高淀粉类型品种的相对较高。就糖类物质变化来看,所有品种块根膨_大的初期和后期还原糖含量较高而中期相对较低,可溶性糖含量在整个块根膨大期间波动较小；同时低淀粉含量类型品种的还原糖与可溶性糖含量均较高,而高淀粉含量类型品种的淀粉积累量较高。此外,不同品种的淀粉粒大小的比例存在差异,但粒形多为圆球形,且几乎全是单粒淀粉。相关分析表明,块根的还原糖含量与鲜薯产量、与干物质含量分别为极显著的正相关和负相关关系,与生物产量呈显著的正相关；可溶性糖含量与鲜薯产量之间为极显著正相关,与干物质含量以及淀粉产量均表现为显著负相关。高淀粉类型品种的SPS与商品薯率呈显著正相关,可溶性糖含量与淀粉产量及SS/SPS均为显著正相关；低淀粉类型品种的SPS活性与淀粉产量之间、可溶性糖含量与鲜薯产量之间均为显著正相关,SS/SPS与生物产量也为显著正相关,但与淀粉产量呈极显著负相关。4.不同类型甘薯内源激素动态比较研究结果表明,在块根形成初期,各品种叶片中(ZR)、生长素(IAA)和脱落酸(ABA)的含量均呈上升趋势,到后期又呈现出不同程度的下降,在移栽后110天时的ABA含量以绵粉1号、渝薯2号与S1-5较高；而ZR、IAA、赤霉素(GA3)以及三者之和与ABA含量的比值在块根膨大中期较低,但在膨大后期南薯88、北京2号以及豫薯10号的相应比值又显著上升。不同类型品种的激素含量变化表明,移栽后80天之前,以高淀粉含量类型品种的ZR与IAA含量较高,之后则以低淀粉类型品种的较高；GA3含量在两类品种间差异较小,但在块根膨大末期低淀粉类型品种的GA3含量相对较高。此外,各种激素比值在两类品种块根膨大期间的变化趋势基本一致,且在95天左右的生育阶段内,以高淀粉类型高于低淀粉类型,随着膨大期的进一步延长,比值大小在两类品种间变化趋势相反。对所有品种进行相关分析表明,仅有甘薯商品薯率与ZR为极显著的负相关,而其他激素与产量性状的相关不显著；就不同类型品种而言,高淀粉类型甘薯ABA与鲜薯产量呈极显著负相关,而IAA/ABA与商品薯率呈显著负相关；低淀粉类型品种的GA3与淀粉产量呈显著正相关。可见,ZR含量升高不利于大薯的形成,ABA对于高淀粉类品种的鲜薯产量不利,GA3则有利于低淀粉类甘薯淀粉产量的提高。5.不同类型甘薯高产栽培理化调控模式采用正交回归试验设计,分别对渝薯2号、南薯88和豫薯10号三个不同类型品种进行以氮肥、钾肥和去分枝三因素的栽培模式调控。研究表明,渝薯2号关于经济产量和淀粉产量的回归方程达到显著水平,但该品种的生物产量及商品薯率的理论方程的总回归均不显著,而对于中低淀粉类型品种南薯88和豫薯10号,所有产量指标的回归方程均不显著。可见在设定产量性状的调控模式下,不同类型品种对三因素的敏感度是有差别的。通过各调节因子的调控效应研究发现,去分枝因素对各品种都有不利影响,降低产量。低氮施用量有利于提高高淀粉类型品种渝薯2号的经济产量和淀粉产量；对于兼用型品种南薯88,施氮有助于提高生物产量,同时施高氮、高钾肥且不去分枝可获得的经济产量也较高,钾肥还可提高其商品薯率,此外去分枝对其淀粉产量形成不利；而饲用型品种豫薯10号对钾素的需求尤为明显,钾肥对各产量性状都有显著的影响,同时钾肥与去分枝还存在明显的互作效应。可见在甘薯生产中“打藤”或“刈蔓”的做法是不可取的,而应根据不同品种,采用因品种制宜、因生产目的制宜的理化调控措施,才能实现科学种薯,高产高效。更多还原

【Abstract】 Because of its strong adaptability and versatile purposes, nowadays sweet potato has been playing great roles in food security and processing industry in China. Based on the previous experiment that six different types of cultivars in sweet potato had been choosed from 48 varieties or lines of breeding germplasm, and established in the ecological condition of Chongqing, this thesis mainly researched physiological traits such as photosynthetic characteristics, endogenous hormones, distribution of nitrogen and potassium, starch metabolism, and highly efficient planting mode controlled by physical and chemical measures, systematically contrast the difference and dynamic changes of different sweet potato varieties and types during tuberous root thickening. Through correlation analysis, the relationship among every trait of sweet potato was been obtained, which would provide theoretical foundation and base for high-efficiency breeding and high-yield cultivation of different types of sweet potato. The main experimental results were as follows.1. Contrast on photosynthetic characteristics of different types of sweet potatoThe research that contrasted photosynthetic pigment from six varieties of sweet potato suggested that the relative content of chlorophyll in Mianfen-1 leaves was higher. There was no significant difference between others, and no remarkable relationship between chlorophyll content and content of starch or dry matter. The regression curves, concerned with photosynthesis and photo intensity, indicated that Pn of every variety had changed parabolically with PAR increasing. The theoretical LCP of high-starch type of sweet potato was lower than that of low-starch type. Both the maximum of Pn and theoretical LSP from Yushu-2 were higher, while both of them from Yushu-10 were lower. During thickening, the changing trends of Pn, Tr, Gs, WUE every cultivar were different absolutely. However the changing curves about Ci and Ls were same basically. The photosynthetic rate was influenced by both stomatal limitation and non-stoma limitation. For different types, Pn and Tr of low-starch type were more apt to be affected by environmental temperature, and Pn of high-starch type was more stable. For all cultivars, the correlativity analysis suggested that the related coefficient between Tr and biomass was remarkably negative, there were significantly positive correlativity between Gs and Pn, and large significantly positive correlativity between Gs and Tr. For high-starch type, there was markedly positive correlation between Pn and Tr, Pn and Ci. For low-starch type, there were markedly positive correlation between Pn and tuberous roots yield, negative correlation between Tr and starch yield.2. Nitrogen and potassium distribution of different types of sweet potato during thickeningIn dry matter of vines or tuberous roots, the nitrogen content that decreased gradually after tuberous root formation accounted for 2% in vines, and it in tuberous root changed a little during thickening. The potassium content both in vines and in tuberous root was relatively stable. For distribution of N and K, N content in vines was far more than it in tuberous root, while K content was on the contrary. For high-starch type, N content of tuberous root ranged from 0.68% to 0.86%, and that of vine did from 1.98% to 3.32%; for low-starch type, N content of tuberous root and vine ranged from 0.69% to 0.86% and from 2.00% to 3.17% respectively. Correspondingly. for the part of high-starch type, K ranged from 5.83% to 6.66% and from 3.19% to 3.70%; for low-starch type, K ranged from 6.12% to 6.36% and from 3.48% to 3.90%. In addition for high-starch type, the changing range of K content was larger than that for low-starch. While K content of vine was relatively higher for low-type. Correlative analysis for all varieties suggested that K was related with N positively in root. And K in vine was closely related with the K content ratio of root to top negatively. For high-starch type, there were remarkably significant relationship between K content in vine and percentage of dry matter, and between K. content ratio of root to top and commercial percentage; and there was remarkably negative correlation between K content of root and biomass. For low-starch type, there were markedly positive correlation between N content in vine and biomass, large markedly positive correlation between K content in vine and biomass, and notably negative correlation between K content in vine and starch yield.3. The starch metabolic difference of different types of sweet potatoAGPP was essential for starch synthesis and accumulation. Its activity descended with environmental temperature declining and took on a marked difference between two types of sweet potato during thickening. Moreover it could not be the decisive factor of starch content in sweet potato. In this period, both SS and SPS activities were higher in high-starch type. For reducing sugar of all cultivars, its content was relatively high at initial thickening phase and at late stage, and it was relatively low at middle stage. However soluble sugar content fluctuated little during all the time. Except that, the content of two kinds of sugars was higher in low-starch type while the starch accumulation was higher in high-starch type. At the same time the percentage of different sizes of starch granules was not same for all cultivars, majority of granules appeared pellet-shape, and they almost were single-granule starch. The correlation analysis showed that the reducing sugar in root was very significantly and positively correlated with tuberous root yield, very significantly and negatively with dry matter content, significantly and positively with biomass. Moreover soluble sugar and tuberous root yield took a very significantly positive relationship, while the relationship was significant negative both between soluble sugar and dry matter content and between soluble sugar and starch yield. For high-starch type, there were all the significant positive relationship between SPS activity and commercial percentage, between soluble sugar and starch yield, and between soluble sugar and SS/SPS. For low-starch type, SPS activity was markedly and positively correlated with starch yield, and soluble did same with tuberous root yield. Also SS/SPS did same with biomass, but it did very significant and negative with starch yield.4. Dynamic comparison of endogenous hormones in different types of sweet potatoThe results showed that at initial thickening phase, the content of ZR,IAA and ABA in leaves increased, and it began to decline differently at last phase. At the time of 110 days after transplantation, the content of the three hormones was relatively high for Mianfen-1, Yushu-2 and S1-5. Otherwise the ZR, IAA, GA3 and the ratio of the sum of them to ABA were lower at the middle phase of thickening, and the corresponding ratio of Nanshu-88, Beijing-2 and Yushu-10 went up remarkably. For different type, the ZR and IAA high-starch type were higher before 80 DAP, after that it became opposite. And the GA3 changed not obviously different in two types during thickening, however it in high-starch sweet potato was higher than low-starch before 95 DAP, with tuberous root thickening proceeding, the changing tendency of GA3 content became contrary for the two types. For all varieties, only the very significant and negative relationship existed between commercial percentage and ZR content, and no notable relationship between other yield traits and hormones. As far as high-starch type was concerned, its ABA was very significantly and negatively related with tuberous root yield. And IAA/ABA did remarkably negative with commercial percentage. On the contrary obviously positive correlation occurred between GA3 and starch yield for the low-starch type. In general, that the ZR content became going up was not beneficial to big tuberous root formation, the ABA was disadvantageous to tuberous root yield of high-starch cultivar, and GA3 could make for increasing starch yield of low-starch variety.5. Physical and chemical controlling mode for high-yielding cultivation in different types of sweet potatoThe experiment, with orthogonal regression design, research the planting mode for three different types of cultivars (Yushu-2, Nanshu-88 and Yushu-10), whose growth and development were controlled by N fertilizer, K fertilizer and cutting branches. The results indicated that the equation about economic yield and starch yield of Yushu-2 was of significant regression, but the equation about biomass and commercial percentage was not significant for the total regression. For the low-starch type, such as Nanshu-88 and Yushu-10, their regression equations were not remarkable about all yield characteristics. Therefore under the circumstances of experimental controlling, different types of cultivars had discriminatory sensitivity to three factors. Through researching on the controlling effect of the factors, the measure, that cutting branches were not helpful to the three cultivars, would influence yield negatively. For dual-purpose cultivar Nanshu-88, fertilizing a small quantity of N fertilizer could help to improve biomass, and the economic yield could be obtained through fertilizing generous N and K fertilizer and cutting no branches. In addition, K fertilizer was beneficial to its commercial percentage while cutting branches could result in the starch yield declining. For the feeding cultivar, it was obvious that Yushu-10 especially demanded K fertilizer, which affected every yield trait significantly. At the same time the interactive effect was evident in fertilizing K and cutting branches. Therefore it was not advisable to cut or mow vines of sweet potato in reality. And also in terms of different cultivar, scientific planting sweet potato, high yield and good benefit could be achieved through physical and chemical controlling that based on adjusting measures to local conditions and varieties.更多还原