【作者】 柳洪鹃；

【导师】 史春余； 张立明；

【作者基本信息】 山东农业大学 ， 作物栽培学与耕作学， 2011， 硕士

【摘要】 为了探讨甘薯施用腐植酸和钾肥改善品质的生理基础,本试验选用北京553和济薯22两个食用型品种为试验材料,于山东农业大学农学实验站进行试验。主要研究结果如下:1腐植酸对甘薯产量和营养品质的影响1.1对块根产量的影响施用腐植酸可提高北京553的块根产量,HA17处理增幅达到显著水平;济薯22施用腐植酸后对产量的影响达不到显著水平。腐植酸影响产量的原因也因品种而异,北京553施用腐植酸后通过提高单薯重来增产,主要是促进中、小薯向大薯转化;而济薯22施用腐植酸是通过提高单株结薯数使产量略有升高,主要是提高了大薯的数量比例。1.2对甘薯块根营养品质的影响施用腐植酸后降低了块根中淀粉含量而显著提高了块根中可溶性糖的含量。施用腐植酸后主要降低了块根中直链淀粉含量,支链淀粉含量略有降低,同时降低了直、支比,改善了块根的适口性。同时可溶性糖含量的增幅大于淀粉含量的降幅,说明施用腐植酸能促进淀粉向可溶性糖转化,从而提高可溶性糖含量。施用腐植酸后功能叶中磷酸蔗糖合酶活性显著提高,功能叶中蔗糖含量也显著提高,结合茎蔓中蔗糖含量下降或相似,同时块根中不溶性酸性转化酶和碱性转化酶活性提高,说明施用腐植酸后增加了源端光合产物的供应,保证了光合产物运输通道的畅通,增强了库端光合产物的卸载能力,保证了蔗糖的供应。而蔗糖合酶活性的降低,则减少了淀粉的合成,增加蔗糖的积累;淀粉酶活性的提高也减少了淀粉的含量,增加了葡萄糖的含量;SST活性的提高则促进碳素向果聚糖库的转移,是果聚糖含量增加的生理原因之一;可溶性酸性转化酶活性的提高为果糖和葡萄糖含量的积累奠定基础。综上,腐植酸通过以下三种方式增加块根中可溶性糖含量:第一,提高块根中可溶性糖的供应量;第二,腐植酸抑制了块根中可溶性糖向淀粉的转化;第三,腐植酸促进了块根中淀粉向可溶性糖的转化。通过对主要生长时期块根中维生素C含量的测定,发现北京553块根中维生素C的主要积累时期为生长中后期,而济薯22的主要积累时期为生长前期和后期,施用腐植酸后显著提高了各时期块根中维生素C的含量。通过对主要生长时期块根中硝态氮含量的测定,发现济薯22中硝态氮主要积累时期为生长中后期,施用腐植酸后显著降低了各时期块根中硝态氮含量。对北京553的研究发现,施用腐植酸提高了主要生长时期块根中氨基酸含量而降低了硝态氮的含量,即腐植酸促进硝态氮向氨态氮转化,减少硝态氮的含量从而改善块根的品质。2钾肥对块根产量和营养品质的影响2.1对块根产量的影响增施钾肥可以显著提高块根产量,增产原因存在品种差异。北京553施用钾肥后既提高单薯重又提高单株结薯数,主要是提高了大薯的数量比例和质量比例;济薯22施用钾肥后显著提高了单株结薯数,对单薯重影响不大。2.2对块根营养品质的影响甘薯施用钾肥后能提高块根中可溶性糖含量,同时淀粉含量也升高。块根中可溶性糖各组分含量均显著提高,而淀粉含量的提高主要是施钾提高了直链淀粉含量。钾肥提高可溶性糖含量的生理原因与腐植酸有相同之处,即施用钾肥也能改善源端光合产物的供应,保证光合产物运输通道的畅通,增强库端光合产物的卸载能力,保证蔗糖的供应;通过提高可溶性酸性转化酶活性提高果糖和葡萄糖的含量;通过提高SST活性提高果聚糖含量。不同之处在于,钾肥能显著提高SS的活性促进淀粉的合成,而收获期块根中淀粉含量略有升高,主要是因为钾肥显著提高了块根淀粉酶活性,促进淀粉水解,减少淀粉含量而促进可溶性糖的积累。施用钾肥可以提高块根中维生素C的含量,而降低块根中硝态氮的含量,改善块根品质。更多还原

【Abstract】 In order to find out the physiology basis of quality improvement of edible sweetpotato caused by humic acid and potassium fertilizer, an experiment was carried out in agronomy experimental station of Shandong Agricultural University with Beijing 553 and Jishu 22. The main results were as follows:1 Effect of humic acid (HA) on yield and nutrient quality of storage root1.1 Effect on yield of storage rootFor Beijing 553 yield in treatments with HA application were increased, thereinto yield effects of treatment HA17 reached the significant level. For Jishu 22 yield in treatments with HA application were increased without significant difference. The yield of different varieties were increased by HA application in different ways. Yield of Beijng 553 was increased by means of increasing fresh weight per lump. In other words HA could facilitate the change from mid-tuber and small-tuber to big-tuber. The reason of increasing yield for Jishu 22 was to increase storage roots lumps per plant. That was caused mainly by increasing the amount ratio of big-tuber.1.2 Effect on nutritional quality of storage rootAmylose content was reduced significantly and amylopectin content was reduced lightly after HA application which resulted in lower starch content of storage root. The reduction of rate of amylopectin to amylose content was caused by HA application which was benefit to taste of storage root. Treatment with HA application got higher soluble sugar content of storage root than that of storage root in the control, in addition the amplification of soluble sugar content was bigger than the decline rate of starch content. These declared that one of the reasons for increase of soluble sugar was to improve conversion from starch to soluble sugar.After the application of humic acid sucrose phosphate synthase activity was significantly increased in functional leaves, sucrose content in functional leaves were also significantly increased, the sucrose content of vine was decreased or similar, in addition insoluble acid invertase and alkaline invertase activity in storage root were increased significantly, all of these showed that application of humic acid could increase the supply of photosynthetic products, keep clear of photosynthate transport corridors and improve the offloading capabilities of storage root to ensure the supply of sucrose. The activity of sucrose synthase was decreased which gave rise to the diminution of starch synthesis and the increase of sucrose accumulation by use of HA; amylase activity was increased also by use of HA which brought less starch content and higher glucose content compared with the control; treatment with HA also got higher fructosan content by means of increasing SST activity than that of the control. HA increased the accumulation of fructose and glucose by means of increasing soluble acid invertase activity as well. To sum up, humic acid could increase the soluble sugar content in storage root by three ways: first, to enhance the supply of soluble sugar to storage root; second, to inhibite the conversion from soluble sugar to starch of storage root; last, to promote the conversion from starch to soluble sugar in storage root.The result got by determining the content of vitamin C during the key stages of growth showed that the main periods of accumulation of vitamin C in storage root were middle-late stage of growth for Beijing 553, while that for Jishu 22 were intermediate and final growth phases. Vitamin C content was significantly increased by use of HA.The result got by determining the content of nitrate during the key stages of growth showed that the main periods of accumulation of nitrate in storage root were middle-late stage of growth for Jishu 22, meanwhile treatments with HA got lower nitrate content than that of the control. The result got from Beijing 553 showed the amino acid content in storage root was increased during the key stages of growth, that meant HA could improve quality of storage root by the way of improving the changes from nitrate to ammoniacal nitrogen.2 Effect of K on yield and nutrient quality of storage root2.1 Effect of K on yield of storage rootAdding potassium fertilizer might significantly increase yield of storage root, but the reasons for yield increase were different among varieties. Both cutting storage roots lumps per plant and fresh weight per lump were increased by potassium application in Beijing 553. The main reason was potassium application could increase amount ratio and mass ratio of big-tuber. Yield of Jishu 22 was increased after using potassium by means of increasing storage roots lumps per plant.2.2 Effect on nutritional quality of storage rootPotassium could improve soluble sugar content of storage root markedly, starch content in storage root was increased as well. The increase of soluble sugar was caused by increase of all components of soluble sugar, while the increase of starch was caused by increase of amylase content mainly.The physiological causes of increasing soluble sugar content by use of potassium were similar to humic acid: potassium could enhance the supply of photosynthetic products, and keep clear of photosynthate transport corridors, meanwhile improve the offloading capabilities of storage root to ensure the supply of sucrose; in addition potassium could improve the content of fructose and glucose by means of increasing the activity of soluble acid invertase as well; besides fructan content was increased by increasing SST activity after potassium application. The effect of potassium on the activity of SS was different from HA. Potassium could improve the synthesis of starch, while content of starch in storage root was increased lighly caused by increase of amylase activity with potassium application mainly which resulted in lower starch content and higher soluble sugar content.The quality of storage root was improved by use of potassium via increasing content of Vitamin C and decreasing content of nitrate.更多还原