【作者】 胡学运；

【导师】 任正隆；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2010， 硕士

【摘要】 土壤盐化、高温及遮荫等逆境是限制全球小麦生产力的主要非生物因子,而利用小麦-黑麦1BL/1RS易位染色体培育的“持绿”小麦新品种的产量得到大幅度的提高。为探讨其耐盐性,本研究对含有1BL/1RS易位染色体的三个“持绿”小麦新品种：川农12(CN12),川农17(CN17)和川农18(CN18),以及用作对照且同样含有1BL/1RS易位染色体的洛夫林10(LV10)和非易位系小麦基因型绵阳11(MY11)和中国春(CS)采用不同浓度的NaCl处理,测定了0 mM和100 mM NaCl条件下的胚芽鞘长度、相对伸长速率(RER)、鲜重、干重、渗透势,以及脯氨酸、可溶性糖、Na+、K+的含量等形态及生理学参数。另外,为阐明高温及暗胁迫对活体旗叶衰老过程的影响,本实验选取具有明显“持绿”特性的小麦品种CN17和正常衰老型小麦品种MY11进行对比研究。我们分别研究了长期的高温和暗胁迫对开花后旗叶的叶绿素含量、光合特性和叶绿素荧光参数的影响。从而为小麦的超高产栽培及育种提供理论支持。主要得到以下研究结果：1.相对胚芽鞘长度(盐胁迫条件下胚芽鞘长度与对照条件下的比值)比绝对胚芽鞘长度作为小麦耐盐性鉴定的更可靠指标。2.本研究中100 mM浓度的NaCl溶液能够很好地区分不同小麦材料对盐的耐性强弱。结合100mMNaCl胁迫下多个生理及形态指标的变化程度,本实验供试的六个小麦品种的耐盐性由强到弱依次是：LV10>CN17>CN18>CN12>CS> MY11。3.在100 mM NaCl胁迫条件下CN12、CN17和CN18的胚芽鞘相对长度显著比MY11大,且这三个姊妹系品种之间的耐盐性也存在着一定的差异。综合所有的证据,可以认为在MY11的遗传背景下,1RS对小麦的耐盐性有一定的贡献。4.在盐胁迫条件下,CN18的胚芽鞘具有高的选择吸收K+的能力,从而能够更加有效地排除Na+。通过隔离Na+于液泡中,降低了细胞质中的Na+,从而使CN12具有更强的忍受高Na+浓度条件的能力。良好的渗透调节能力则是小麦品种CN17的主要耐盐机制。5.CN18 Na+含量的变化与CN12和CN17明显不同,表明易位染色体的断裂点的不同影响其对盐的耐性能力,并从一定程度上改变了其盐耐性机制。LV10的耐盐水平比CN12、CN17和CN18高的原因在于其不同的系谱来源和培育环境。6.与大田中自然生长的植株衰老表现不同,对照条件下,“持绿”型小麦品种CN17表现出叶片边缘先于茎杆及叶脉区衰老的现象。主要原因在于本实验中对照条件的光照强度远比大田条件下弱,致使CN17的源和库之间的不平衡关系发生变化,由库受限变为源不足。7.在对照条件下,光合作用速率的首次降低,是光合器官的活性及气孔因素对突然变化的环境作出反应所致,之后气孔因素成为主要原因,而在MY11旗叶衰老的最后阶段,光化学器官受到严重破坏。而在整个胁迫处理时间内,CN17的光合器官仅受到一定程度的破坏。8.热胁迫条件下,MY11和CN17的旗叶均比对照条件下加速了衰老进程。但CN17的光化学器官比MY11更耐热胁迫。9.高温所引起光合参数的下降主要源于光合器官受到破坏。而CN17通过降低热耗散率来应对光能捕获率的下降,从而暂时在一定程度上维持了PSⅡ反应中心的捕光潜力和电子传递能力。10.与对照条件下植株的旗叶相比,将整株成年小麦放入连续的暗环境中,小麦旗叶的衰老被诱导发生。11.在暗胁迫条件下,CN17的光合器官反而比MY11先受到损害。CN17失去了比MY11“持绿”的优势。CN17和MY11具有不同的源库关系是该现象出现的主要原因。更多还原

【Abstract】 Soil salinization, high temperature and dim light are major abiotic stresses influencing wheat productivity world widely, while wheat-rye 1BL/1RS translocated chromosome has been successfully used in wheat yield improvement for growing ’stay green’ wheat cultivars. To determine the salt-tolerance of them, three new ’stay green’ wheat cultivars with 1BL/1RS translocated chromosome Chuannong12 (CN12), Chuannong17 (CN17) and Chuannong18 (CN18) were treated with various NaCl concentration, and Lovrin10 (LV10) also with the1BL/IRS translocated chromosome, and wheat genotypes both Mianyangll (MY11) and Chinese Spring (CS) without the translocated chromosome were used as the controls. Several morphological and physiological parameters coleoptile length, relative elongation rate(RER), fresh weight, dry weight, osmotic potential, and contents of solutes such as proline, soluble sugars, Na+ and K+ were recorded under both 0 and 100mM NaCl conditions. On the other hand, in order to illuminate the effects of heat/darkness stress on the senescence process of intact flag leaves,’stay green’ wheat cultivar CN17 and normal senescence-type wheat cultivar MY11 were investigated. We studied the effects of long-time heat and darkness stress on chlorophyll content, photosynthetic characteristics and chlorophyll fluorescence of flag leaf during the senescence period for the purpose of providing theoretical evidence of super-high-yield cultivation and breeding of wheat. The main results are as follows:1. The compared percentage of coleoptile length (the coleoptile lengths of the treated to those of the control) is perhaps a more reliable index in screening salt-tolerance of wheat than coleoptile length.2. In this study,100 mM NaCl concentration showed strong ability to differentiate the salt-tolerance. Combining the different degrees of change in the physiological and morphological parameters under 100 mM NaCl condition suggested that the salt-tolerant ability from strong to weak was:LV10>CN17>CN18>CN12>CS>MY11.3. Statistical analysis showed that CN12, CN17 and CN18 had higher average compared percentages of coleoptile length than MY11 had, when under 100 mM NaCl concentration level, and the larger P value would result from the different salt-tolerant levels among the three sister lines were also obviously in this study. Together all the evidences, we can draw a conclusion IRS in certain wheat genetic background would have some contribution to salt-tolerance.4. Under salt stress conditions, the coleoptile of CN18 might have higher K+ versus Na+ selectivity that could exclude Na+ more effectively, while CN12 had stronger tolerance to high Na+ concentration conditions resulted from the reduction of cytosolic Na+ by sequestering Na+ in the vacuoles. However, the osmotic adjustment probably played an important role in the salt-tolerant mechanism of CN17.5. The different changes of Na+ contents between CN18 and both CN12 and CN17and also showed the breakpoint of the translocated chromosome influence salt-tolerance ability as well as modifying salt-tolerant response mechanisms. The different pedigree and original environment might be an important reason for salt-tolerant level of LV10 was much higher than that of CN12, CN17 and CN18.6. For ’stay-green’ wheat CN17, Under CK condition, the distal parts of flag leaves were senescence earlier than veins. This phenomenon was different from flag leaves of CN17 that came from field growing conditions. The main reason was that the illumination intensity of CK condition was much lower than those of field growing conditions. Under CK condition, the sourses of CN17 were insufficient.7. Under CK condition, Pn was influenced by both the stomatal factor and photosynthetic activity for the abrupt shift of surroundings. After this time, stomatal factor is the main aspect limiting photosynthesis. At the late senescence stage of MY11, activities of the photosynthetic apparatus were the main limiting factor. During the whole process of treatment, the photosynthetic apparatus of CN17 were destroyed only a little.8. Under heat treatment condition, the senescence processes were induced in both flag leaves of CN17 and MY11. While the photochemical apparatus in CN17 had higher heat tolerance than those in MY11.9. The main reason of decrease of Pn under heat stress condition is the destruction of photosynthetic apparatus. To reply the decreasing of the efficiency of excitation capture, CN17 decreased heat dissipation rate. So the maximum photochemical efficiency of PS II and the electron transport rate were protected to a certain extent.10. Compared with flag leaves of plants under CK condition, senescence could be induced in wheat flag leaf when put the whole adult plants into continuous darkness condition.11. Under darkness condition, photosynthetic apparatus of CN17 were injured earlier than those in MY11. CN17 had lost its ’stay green’ function compared with MY11. The different relationship between sources and sinks in CN17 and MY11 is the main reason for the phenomenon.更多还原