【作者】 张永平；

【导师】 王志敏；

【作者基本信息】 中国农业大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 本研究以挖掘小麦全株光合潜力、同步提高产量和水分利用效率为目标，在水肥限制条件下，研究群体、个体、器官光合源的时空变化特征及其生理机制，突出非叶器官光合作用，揭示不同基因型不同光合器官光合性能的差异。并通过设置不同密度、灌水处理试验，探索建立大群体、小叶形、高光效、低耗水群体结构的节水高产、超高产栽培技术原理。主要结论如下： 1 节水省肥高产群体中，非叶器官占有较大的绿色面积，对产量具有突出贡献。开花期单茎非叶面积占单茎总绿色面积的60％以上，群体绿色面积中非叶绿色面积也大于叶面积，且随着灌水量减少或密度的增大，非叶器官面积所占比例增加。统计分析表明，开花后群体总绿色面积以及非叶器官面积均与产量呈显著正相关。根据试验结果得出，实现7500～8250kg．hm^-2产量目标开花后适宜的LAI为4.81，其中上三叶高效LAI为3.11，非叶面积指数为6.86；单茎叶面积小尤其是上部叶片小、比叶重高、旗叶与茎秆夹角小，叶层透光好，群体光合速率和WUE均较高，这是节水高产群体的基本结构特征。采用器官遮光处理发现，穗光合对籽粒重的相对贡献率远大于旗叶叶片，穗下节间和旗叶鞘光合对粒重的贡献率也与旗叶相当。在旗叶节以上器官对粒重的总贡献率中，非叶器官的贡献率所占比例达70～80％，随灌水减少、密度增大而增加。 2 小麦植株中叶与非叶器官气孔与叶绿体结构存在明显差异，节水小麦后期非叶器官叶绿体结构具有较高的稳定性。电镜观察发现，非叶器官表面气孔密度、单个器官气孔总数均低于旗叶叶片。各器官气孔密度随灌水减少呈增大趋势，而单个器官气孔总数水分处理间差异不明显，非叶器官气孔数目受水分变化的影响较小。从气孔大小来看，穗部器官（护颖、外稃、内稃和芒）的气孔略小于其它器官；就气孔分布特征而言，穗部器官的气孔较多分布在器官内侧（腹面或近轴面），有利于穗光合对籽粒呼吸释放CO₂的重新固定。随着灌水次数减少，各器官气孔器及气孔口径均表现出长度增加、宽度减小的趋势。对叶绿体超微结构观察发现，在正常供水条件下，非叶器官的叶绿体数目少于叶片，其中护颖和外稃叶绿体含有较多的淀粉粒。灌浆后期干旱胁迫对旗叶叶片和外稃叶绿体结构破坏最为严重，与叶片相比，穗下节间、旗叶鞘和护颖叶绿体结构相对稳定。 3 节水栽培明显提高非叶器官的PEP羧化酶活性，增加PEPC／RUBPC比值，增强后期的光合耐逆机能。与旗叶叶片相比，穗、穗下节间和叶鞘的叶绿素相对含量（SPAD值）、PSⅡ活性（F_v/F_m）、净光合速率等相对较低，但光合功能期较长，在灌浆后期能保持较高的光合活性。同时，非叶器官气孔导度和蒸腾速率也低于叶片。开花后不同器官碳同化途径酶活性与其光合速率基本呈同步变化趋势。器官间比较，以穗部器官（护颖和外稃）PEPC活性最高，其次为穗下节间和旗叶鞘，而旗叶叶片的PEPC活性最低，水分胁迫下非叶器官PEPC活性呈上升趋势；RUBPC活性以旗叶和外稃较高，穗下节间、旗叶鞘和护颖相对较低，且随着灌水减少（或水分胁迫下），各器官RUBPC活性均有下降趋势。灌浆期非叶器官PEPC／RUBPC比值显著大于旗叶叶片，且随灌水次数减少（或水分胁迫下）表现出明显的增加趋势。同时发现，各器官RUBPC活性品种间差异不明显，某些器官（穗下节间和旗叶鞘）的PEPC活性存在基因型差异。 4 籽粒灌浆前期茎鞘和穗颖中积累大量果聚糖，并于灌浆后期迅速降解、转运，节水与高密度中国农业大学博士学位论文摘要............................栽培促进营养体果聚箱降解和向籽粒运转。试验表明，不同器官贮藏物质转运量及对籽粒贡献率均表现为茎鞘>叶片>穗颖，且随密度增大、灌水减少而增加。开花后营养器官WSC及其主要成分果聚糖迅速积累，并于花后6d一12d达积累高峰，之后迅速降解向籽粒转运。非叶器官总的水溶性碳水化合物（WSC）转移率和对籽粒贡献率均随灌水的减少或密度增大而增加.就时间特征而言，减少灌水或增大密度，器官花前WSC贡献增加，而花后WSC的贡献率相应减少;就空间特征而言，上部茎鞘总的WSC贡献率大于下部茎鞘。 5群体移l叶比（单位面积秘数与上三叶叶面积之比）是衡盘小麦节水栽培库源关系是否协调的适宜指标。结果表明，高穗叶比群体中非叶面积指数（以I）大于叶面积指数（LAI），冠层内光照状况明显改善，群体光合效率较高;在适宜叶面积基础上，增大穗叶比，非叶器官贮藏物质转移率和经济系数均提高，经济产量明显增加，而耗水量显著减少，从而使水分利用效率得到提高。节水省肥高产栽培适宜的枷叶比值为250一290穗加2. 综合以上研究认为，在适宜叶面积指数基础上，扩大群体中非叶绿色面积增加穗/叶比，是节水省肥条件下提高产量的重要机制。通过适当增加基本苗增加穗数，从而扩大群体库容并扩大群体中非叶光合面积;通过拔节前控水控制单茎叶面积，增加穗/叶比值，从而改普群体结构并提高叶片质量，在高密度下实现源库协调和群体高光效、高转运、低耗水的统一，这是冬小麦节水省肥高产栽培的基本技术原理。更多还原

【Abstract】 In order to identify the photosynthetic potential of different plant parts in winter wheat, to improve yield and water use efficiency (WUE) simultaneously, the photosynthetic source change characteristics and ecological physiology mechanics were studied in population, individual and organ level at different development stage under water and fertilizer limited condition, especially non-leaf organs, i.e., ear, internodes, leaf sheath. And the genetic difference in photosynthetic capacity in different organs was also studied. In addition, by setting different plants density and irrigation treatments, some points were also focused on the culture technology principles of water saving and super high yield by establishing the population structure with higher density, smaller phylliform, higher photosynthetic capacity and lower water consumption.1. In the population of water-saving, fertilizer-reducing and high-yielding, green area of non-leaf organs was larger than leaf blade, which contributes much to yield. Non-leaf organs green area accounted for 60% of total green area per stem , and non-leaf area index (NAD was higher than leaf area index(LAI), the proportion of NAI in the total green area index( GAD increased gradually with reducing irrigation times or increasing plant density. Statistic analysis indicated that GAI and NAI post-anthesis were correlated positively with yield, and to obtain the yield with 7500~8250kg.hm-2 , the suitable LAI, highly active LAI and NAI of three uppermost leaves after anthesis was 4.81, 3.11, 6.86 respectively.; The water-saving and high-yield population in winter wheat had such primary structure characteristics as lower leaf area per stem especially smaller size upper leaf, higher specific leaf weight, smaller angular between flag leaf and stem, better light intensity in canopy, which could lead to higher canopy photosynthetic rate and WUE. By shading plant parts treatment, photosynthetic contribution of ear to grain yield was found higher greatly than that of flag leaf blade, and the total contribution of peduncle and sheath to grain yield was equal to leaf blade. Photosynthetic contribution of non-leaf organs above flag leaf node to grain yield accounted for 70%~ 80%,which increased with water supply decreasing or plant density increasing.2. There was obvious difference in stoma and chloroplast ultrastructure between leaf blade and non-leaf organ in winter wheat plant, chloroplast ultrastructure of non-leaf organs showed more stable compared with leaf blade in the late development stage under water-saving culture condition. Through electron microscopic, stomatal frequency and total stoma quantity of non-leaf organs was found lower than that of flag leaf. Stomata frequency of various organs increased with the decrease of water supply, but the total stoma number per organ did not increase. In stomata size, stoma of apparatus on the ear (glume, lemma,palea,awn) was a little smaller than that of other organs. With the decrease of water supply, stomatal aperture length of various organs increased, but the width of those decreased gradually. As to the stomatal distribution, stoma located mostly in the inner side(ventral or adaxial) of organs in ear, which could contribute to re-fixing CO2 released by grain respiration. The chloroplast ultrastructure was also observed, and the results showed that chloroplast number of non-leaforgans was lower than that of leaf blade, and many starch grains were found in the chloroplast of glume and lemma under normal water supply condition. The chloroplast structure of flag leaf blade and lemma was destroyed severely subjected to drought stress at the later stage of grain filling, while the peduncle, sheath and glume showed relatively stable.3. Under water-saving cultivation condition , PEPCcase activities and PEPC/RUBP ratio of non-leaf organs increased obviously, which increased the photosynthetic stress tolerance capability at the later grain-filling stage. There was significant difference in the photosynthet更多还原