【作者】 代惠萍；

【导师】 冯佰利；

【作者基本信息】 西北农林科技大学 ， 作物栽培学与耕作学， 2008， 硕士

【摘要】 糜子是我国北方旱区主要粮食作物和经济作物,具有抗旱、耐瘠、生育期短等特点,在种植业结构调整和优质、高效农业发展中具有重要作用。随着人们膳食结构的调整和保健意识的增强,作为医食兼用的重要食品资源,糜子在现代功能型食品开发中的地位迅速上升。然而,由于糜子科研起步较晚,基础性研究比较薄弱,尤其是对产量和品质形成起决定作用的拔节后植株代谢生理特性缺乏系统研究,大田生产缺乏适栽品种,加之栽培管理粗放,单产水平普遍较低。因此,加强糜子品种选育,探索糜子植株生长发育特性,提高籽粒产量和品质成为糜子生产亟待解决的问题。本研究以近年来选育的糜子品种为材料,采用田间试验与室内分析相结合,较为系统研究了糜子产量形成的关键时期—籽粒灌浆期植株代谢的相关生理参数—叶绿素、可溶性蛋白质、可溶性糖、丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性以及根系活力等指标;并对糜子幼苗抗旱性、根系与旗叶衰老的生理生化机制等进行了初步探索,得出以下主要结论:1.糜子幼苗PEG胁迫试验结果表明,参试品种糜子幼苗的耐旱能力表现为:榆糜3号>榆糜1号>榆糜2号>冀承黍1号。在PEG胁迫条件下,榆糜3号幼苗叶绿素和可溶性蛋白含量明显高于榆糜1号、榆糜2号、冀承黍1号;叶片保护性酶(SOD、CAT和POD)活性高于榆糜1号、榆糜2号、冀承黍1号,脂膜过氧化程度低;MDA含量积累速度较慢且含量低,叶片衰老速度缓慢,代谢强度降低缓慢,从而表现出较强的耐旱性。2.拔节期以后,不同叶位叶绿素含量、可溶性蛋白质含量均呈下降趋势;在同一生育时期表现为旗叶>倒二叶>倒三叶>倒四叶>倒五叶。拔节34 d左右,糜子不同叶位叶片SOD、CAT和POD保护酶活性呈下降趋势,旗叶平均衰减速率分别为7.14、6.67和36.36 U·g-1·d-1;倒二叶平均衰减速率分别为8.6、4、9和36.31 U·g-1·d-1;倒三叶平均衰减速率分别为8.29、5.6和41.37 U·g-1·d-1;倒四叶平均衰减速率分别为8.5、5.64和45.49 U·g-1·d-1;倒五叶平均衰减速率分别为10.52、25.33和41.66 U·g-1·d-1;旗叶能维持相对较高的SOD、CAT和POD活性,有效延缓了叶片衰老进程。3.拔节34 d左右,糜子根系与旗叶(SOD、CAT和POD)活性与可溶性蛋白含量呈下降趋势,根系酶活性平均衰减速率分别为2.82、4.54和36.36 U·g-1·d-1;旗叶酶活性平均衰减速率分别为7.14、6.67和34.21 U·g-1·d-1;膜脂过氧化产物丙二醛(MDA)含量呈上升趋势,根系活力下降0.59 mgTTC·g-1·h-1FW,衰老程度根系显著大于叶片。根系和叶片衰老密切相关,从丙二醛含量的变化看,根系衰老早于叶片,根系衰老引发和加剧了叶片衰老。因此,改善根际营养,提高生育前期根系活力有助于延缓地上叶衰老。4.拔节期到成熟,糜子地上部干物质积累呈近“S”型的增长趋势;干物质积累过程表明,拔节34-48 d是糜子生物产量和籽粒“库”形成的关键时期。糜子的根、叶片、茎、鞘干物质积累均呈单峰曲线变化,均是向籽粒提供同化物的“源”,其中主茎开花节位叶片是籽粒充实的主要源器官。不同时期糜子植株干物质积累和转运存在着显著差异。高产品种各器官在灌浆期干物质积累和转运能力强,尤其是根系与叶片干物质积累多,具有较大的“源”,后期向籽粒运转量高。具有较大的库容,最终获得了较高的收获指数和籽粒产量。更多还原

【Abstract】 Broomcorn millet(Panicum. miliaceum L.) is the main crops food and economic crops at drought-stricken areas in north China, have a drought resistant barren, reproductive characteristics of the short duration of the crop structure adjustment and high-quality, high-efficiency agriculture plays an important role in development. As people’s diets restructuring and strengthening of health awareness, as a fresh medical use of the important food resources, the status of broomcorn millet in the modern functional food development is rising rapidly. However, due to a latest start broomcorn millet research, basic research is relatively less, especially on the yield and quality of a decisive role in forming the metabolism of plants after jointing physiological characteristics lack of a systematic study and the lack of suitable field production plant varieties, and the extensive cultivation and management, yield levels are generally low. Therefore, the strengthening of broomcorn millet breeding, and exploring the growth and development of plants broomcorn millet, increasing grain yield and quality are the problems of broomcorn millet to be solved.In this study, in the broomcorn millet of breeding materials used in field and laboratory analysis of the combined system is more broomcorn millet yield on the crucial period - grain filling period related to the metabolism of plant physiological parameters - chlorophyll, soluble protein, soluble sugar , malondialdehyde (MDA) and superoxide dismutase (SOD), catalase (CAT), (POD) activity and root vigor, and other indicators of drought and broomcorn millet seedling, root and flag leaf senescence of physiological and biochemical mechanisms of a preliminary exploration, the following major conclusions are as follows:1. Broomcorn millet seedlings PEG stress test results show that the tested varieties of drought-resistant seedlings broomcorn millet capacity are as follows: Yu-Mi 3> Yu-Mi 1> Yu-Mi 2> Jicheng proso 1. In PEG stress conditions, Yu-Mi 3rd seedlings chlorophyll and soluble protein content was higher than that of Yu Mi 1, Yu Mi 2, Jicheng proso 1; leaves protective enzymes (SOD, CAT and POD) activity than-yu Mi 1, Yu Mi 2, Jicheng proso 1, membrane lipid peroxidation low level; slow accumulation of MDA content and low content of the slow pace of leaf senescence, and reduce the intensity of the slow metabolism, thereby demonstrating a strong drought tolerance.2. After jointing stage, the different leaf chlorophyll content, soluble protein content showed a downward trend in the same period of performance for the birth flag leaf> second leaf> third leaf > fourth leaf> fifth leaves. Jointing about 34 d, broomcorn millet different leaf blades of SOD, CAT and POD protection activity of a declining trend, the average flag leaf attenuation rate and 36.36, respectively 7.14,6.67 U ? g-1 ? d-1; second leaf of the average decay rate and 36.31 respectively 8.6,4.9 U ? g-1 ? d-1; third leaf average attenuation rate and 41.37, respectively 8.29,5.6 U ? g-1 ? d-1; fourth leaf of the attenuation rate for the average 8.5,5.64 and 45.49 U ? g-1 ? d-1; fifth leaves of the average rate of decay were 10.52,25.33 and 41.66 U ? g-1 ? d-1; flag leaf to maintain relatively high SOD, CAT and POD, effectively delayed the process of leaf senescence.3. At jointing about 34 d, broomcorn millet flag leaf and root (SOD, CAT and POD) activity and soluble protein content on a downward trend, the average activity of root decay rate and 36.36, respectively 2.82,4.54 U ? g-1 ? d-1 ; flag leaf activity of the average rate of decay and 34.21, respectively 7.14,6.67 U ? g-1 ? d-1; membrane lipid peroxidation product malondialdehyde (MDA) showed upward trend, root activity dropped 0.59 mgTTC? g-1? h-1 FW aging root level was significantly higher than leaves. Root and leaf senescence closely related to MDA from the changes, as early as the leaf senescence root, root and exacerbated the trigger senescence leaf senescence. Therefore, improving the rhizosphere nutrition, improving reproductive early root activity is helpful to delay the ground leaf senescence.4. From jointing stage to mature and broomcorn millet shoot dry matter accumulation was nearly“S”trend in the growth of dry matter accumulation process that jointing 34-48 d is the broomcorn millet of grain yield and the“library”of the crucial period. Broomcorn millet roots, leaves, stems, sheath dry matter accumulation curve showed a single peak, the seeds are provided to the assimilation of the“source”, which leaves the main stem of flowering grain-filling is the main source of organs. Different period’s broomcorn millet plant dry matter accumulation and transfer are significantly different. High-yielding varieties of grain filling stage organ in the dry matter accumulation and transfer ability, and especially the roots and leaves of dry matter accumulation, a larger“source”to the latter part of high grain operation. With greater capacity, we can get a higher grain yield and harvest index.更多还原