【作者】 李成龙；

【导师】 吕金印；

【作者基本信息】 西北农林科技大学 ， 植物学， 2007， 硕士

【摘要】 水分是我国北方小麦生长的限制因子。小麦在不同生育期经常受到水分胁迫的影响,从而导致粮食减产。本研究选用不同小麦品种,采用盆栽试验,通过水分胁迫处理以及剪叶、包穗、包茎处理,研究了水分亏缺下不同器官光合产物对籽粒产量的贡献以及穗轴显微结构的变化,测定了水分亏缺下小麦不同生育期叶片保护酶活性、蔗糖磷酸合成酶(SPS)的活性以及光合特性等生理指标。获得以下主要研究结果:1.剪叶、包穗、包茎等处理研究结果表明,不同器官光合产物对穗粒重的贡献率差异显著。尤其水分亏缺下叶、穗对粒重的贡献率有所增加,而茎鞘和茎鞘贮存物的贡献率则大幅下降。2.不同水分处理下西农1043、陕253、长武134和郑引1号小麦旗叶SPS活性在开花期与灌浆期变化不同。开花期中度水分亏缺SPS活性升高,而重度水分亏缺则明显降低。灌浆期四种小麦旗叶SPS活性随着水分胁迫程度的增加而降低。在抽穗、开花和灌浆期小麦旗叶的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)随着水分亏缺程度的增加而降低。灌浆期郑引1号、陕253小麦旗叶SPS活性与Pn呈显著正相关。3.水分亏缺对抽穗期小麦穗轴维管束系统产生一定的影响,穗轴中大、小维管束数目、横截面积、导管直径和韧皮部面积沿穗轴自下而上依次减小,但下降幅度因维管束种类、穗轴部位而异。同正常供水处理相比,中度水分亏缺下穗轴中大、小维管束数目、面积、导管直径和韧皮部面积有所减小。重度水分亏缺则使穗轴中大、小维管束数目、面积、导管直径和韧皮部面积明显减小。表明水分亏缺显著改变了小麦穗轴维管束系统的显微解剖结构。4.水分亏缺对四种抗旱性不同的小麦叶片保护酶系统活性的影响表明,抽穗与开花期中度水分亏缺下旗叶保护酶活性高于对照,重度水分亏缺下保护酶活性降低;灌浆期超氧化物歧化酶(SOD)活性存在种间差异,过氧化物酶(POD)活性随着水分亏缺程度的增加而升高,过氧化氢酶(CAT)活性变化则同前两个时期一致。其中,SOD活性在抽穗期最高,POD活性在灌浆期最高,CAT活性则明显低于其它时期。表明在不同生育期保护酶系统活性的变化在水分亏缺条件下有明显差异。更多还原

【Abstract】 Water is the limited factor of the growth of wheat in the north of China. Effect of drought on wheat in different growth stages was obvious,which reduced the yield of wheat seriously. In this studay, pot experiments were carried out to learn the contribution of different organs to grain weight through the treatments of defoliate, darken ear and darken stem and the microstructure of rachis in different genotype wheat under water stress. We also determinated the activity of the protective enzymes and sucrose phosphate synthase(SPS) and the photosynthesis characteristics. Main results in this study are listed as follows:1. There were significant differences among different organs in the contribution to the per ear grain weight. Compared with normal water treatment,the contribution of leaf and ear to the per ear grain weight were increased under water deficit, but decreased in the stem sheath and its reserved substance.2. Changes of SPS of flag leaf in anthesis stage were different from that in filling stage which under different water treatments. The SPS increased under the moderate water deficit,while it decreased under the severe water dificit in anthesis stage. With the level of the water stress increasing,the SPS of flag leaf decreased in the filling stage. In the heading stage , anthesis stage and in the filling stage, the Pn、Gs and Tr decreased with the level of the water stress increasing. The SPS of flag leaf in filling stage was positively correlated with the Pn.3. The number and the area of macro-vascular bundle and small-vascular bundle of rachis and the diameter of vessel and the area of phloem decreased from base to top, but the decreased rate differed with the change of the kind of vascular bundle and position of rachis. Compared with normal water treatment, the number and the area of macro-vascular bundle and small-vascular bundle of rachis and the diameter of vessel and the area of phloem decreased under moderate water deficit, while it decreased obviously under the severe water deficit. It showed that the vascular bundle system of rachis in wheat changed apparently under water deficit.4. The activities of protective enzymes of flag leaf are higher under the moderate water deficit than that of control in heading and anthesis stages while decreased under the severe water dificit; In filling stage, superoxide dismutase (SOD)activity changed apparently from different species, peroxidase (POD)activity increased under water deficit while catalase (CAT)activity changed as that in the two former stages does. Superoxide dismutase (SOD)activity in heading stage is higher than that in the other two stages, Peroxidase (POD)activity is higher than that in the other two stages, and however, catalase (CAT)activity is lower than that in the other two stages. It showed that the activities of protective enzymes changed apparently in different growth stages under water deficit.更多还原